The convergence is occurring against a widening public-health backdrop. The review reports that an estimated 2.4 million people aged 12 or older in the United States reported past-year methamphetamine use in 2024, while self-reported concurrent methamphetamine and fentanyl use nearly doubled between 2011 and 2017. Fentanyl positivity among methamphetamine-positive urine samples rose from 0.9% to 7.9% between 2013 and 2018. Because methamphetamine is sometimes intentionally mixed with fentanyl, people who believe they are using only a stimulant may be exposed to a potent opioid without knowing it, increasing the danger of overdose and other adverse outcomes.

Methamphetamine and fentanyl act through distinct but overlapping systems. The stimulant is highly lipophilic, enters the brain rapidly and has a substantially longer half-life than cocaine—about 12 hours in the cited pharmacological literature. It acts at trace amine-associated receptor 1 and disrupts vesicular monoamine transporter 2, producing marked increases in extracellular dopamine, noradrenaline and serotonin. These changes in mesocorticolimbic circuitry support reinforcement, cue learning and incentive salience. Repeated exposure can also sensitize behavioral responses, meaning that a fixed dose produces progressively stronger locomotor effects, and can alter brain systems associated with reward seeking and anxiety-like states.

Fentanyl, meanwhile, is a highly lipid-soluble opioid that binds with high efficacy to μ-opioid receptors. These Gi/o-coupled receptors reduce neuronal excitability and neurotransmitter release when activated. In the ventral tegmental area, where dopamine neurons project toward the nucleus accumbens and other reward-related regions, μ-opioid receptor activation on inhibitory GABAergic neurons can disinhibit dopamine cells. Acute fentanyl exposure therefore increases dopaminergic activity in circuits that participate in reward. Its high potency, rapid onset and relatively long half-life—three to seven hours—help explain why it can support both powerful reinforcement and substantial dependence.

Rodent studies show that both drugs readily become highly reinforcing. Methamphetamine-taking animals escalate their intake over repeated sessions, develop persistent preference for drug-paired environments and reinstate drug seeking after exposure to drug cues, stressors or a priming injection. Chronic exposure also produces withdrawal-related reductions in motivation for natural rewards and increases in anxiety-like behavior. Fentanyl produces a similar broad addiction profile: rodents rapidly acquire conditioned preference for fentanyl-paired locations, self-administer escalating amounts and reinstate seeking after extinction. Withdrawal from either drug can include stress, agitation, anxiety-like symptoms, anhedonia and reduced motivation, potentially supporting continued use through negative reinforcement as well as positive reinforcement.

The direct evidence for combined exposure points to a behavioral interaction rather than merely the sum of two separate drug effects. In one conditioned place-preference experiment in adult male rats, doses of methamphetamine and fentanyl that were ineffective when given separately successfully produced preference and reinstatement when administered together. In concurrent-access studies, rats adjusted their responses according to the relative reinforcing value of methamphetamine and fentanyl, showing that the drugs could function as substitutes under some conditions. Another study found that rats did not reduce their inter-infusion interval as fentanyl doses increased during combined self-administration to the same degree seen with fentanyl alone, resulting in greater overall intake. These findings indicate changes in reinforcement, but their magnitude depends on dose and experimental schedule.

Combined exposure may also join the motivational pathways associated with the two drugs. Rats trained to self-administer methamphetamine and fentanyl through concurrent access later showed cross-reinstatement after extinction: fentanyl-associated cues or fentanyl priming injections restored methamphetamine seeking, while methamphetamine-associated cues or priming injections restored fentanyl seeking. The result suggests that repeated co-exposure can create overlapping associations, allowing one substance or its cues to trigger pursuit of the other. The experiment was conducted in rats, and the finding cannot by itself establish how the same processes operate in human relapse.

Neurochemical findings are similarly intriguing but not yet conclusive. Methamphetamine-fentanyl self-administration produced significant reductions in dopamine release and reuptake in the nucleus accumbens, with a more pronounced hypodopaminergic state in males exposed to the combination than in animals receiving methamphetamine alone. Measurements were made roughly 22 hours after the final self-administration session, outside the acute drug effects, suggesting compensatory adaptations after repeated exposure rather than the immediate neurochemical response to intoxication. The contrast with evidence that acute μ-opioid receptor activation increases dopamine is not necessarily contradictory: intoxication and withdrawal-like states may involve different phases of mesolimbic signaling. A state that feels highly rewarding during exposure may therefore be followed by diminished responsiveness to ordinary rewards.

μ-opioid receptors are the leading candidate mechanism because they sit at the intersection of the two drugs’ reward circuitry. Blocking these receptors with naltrexone attenuates methamphetamine-induced conditioned place preference, behavioral sensitization and cue-induced craving in animal studies, while genetic deletion reduces methamphetamine sensitization in mice. Human studies likewise found that naltrexone reduced cue-induced craving and subjective hedonic responses to methamphetamine. Opioid antagonism also reduces methamphetamine-related drug seeking in some rodent paradigms. However, these experiments did not directly test fentanyl-methamphetamine combinations. Studies with morphine or heroin offer additional support for stimulant-opioid interactions, but their pharmacology differs from fentanyl, and sequential exposure cannot establish the consequences of simultaneous use.

Human reports add another dimension but remain limited by variable doses, routes and timing. People who use psychostimulants with opioids often describe the combination as balancing two drugs: the stimulant may counter opioid-related sedation, while the opioid may reduce stimulant-associated anxiety or restlessness. Such accounts suggest that both enhanced pleasure and relief from aversive states can motivate co-use. Clinical studies also associate stimulant-opioid use with more anxiety, depression, impulsivity, anhedonia and psychotic symptoms than stimulant use alone, but those findings do not prove that withdrawal from the combination is more severe than withdrawal from either constituent drug. Direct evidence on withdrawal after repeated methamphetamine-fentanyl exposure is particularly sparse.

The review’s central conclusion is therefore both promising and restrained: existing evidence supports a synergistic addiction potential for concurrent methamphetamine and fentanyl use, but the specific mechanism and full behavioral consequences remain under-examined. The most important research gaps are systematic dose-response comparisons, experiments separating simultaneous from sequential exposure, direct characterization of spontaneous and precipitated withdrawal, and studies that manipulate μ-opioid signaling during combined exposure. Measuring neural activity alongside dopamine release would also help distinguish changes in ventral tegmental circuit function from downstream alterations in the nucleus accumbens. Until those studies fill the gaps, the evidence supports concern about the combination, not a complete causal map of how it alters the human brain or whether every dose and pattern of use produces the same effect.

Subject of Research: Behavioral and neurobiological consequences of concurrent methamphetamine and fentanyl use

Article Title: Separate and concurrent use of methamphetamine and fentanyl: behavioral and neurobiological consequences

Article References: Madden, J. T., Clark, B. J., Hamilton, D. A., & Pentkowski, N. S. (2026). Separate and concurrent use of methamphetamine and fentanyl: behavioral and neurobiological consequences. Frontiers in Behavioral Neuroscience, 20, Article 1966221. https://doi.org/10.3389/fnbeh.2026.1966221

Image Credits: AI Generated

DOI: 10.3389/fnbeh.2026.1966221

Keywords: methamphetamine, fentanyl, polydrug use, addiction, dopamine signaling, μ-opioid receptors, conditioned reward, drug seeking, rodent studies, withdrawal, Separate, concurrent

The team, led by corresponding author Michael D. Hambuchen, had previously shown that dexmedetomidine, a non-scheduled alpha-2 adrenergic agonist sedative, could be safely co-administered with naloxone in rats co-intoxicated with methamphetamine and fentanyl. Dexmedetomidine reverses fentanyl-induced sedation with naloxone while potently attenuating the agitation that naloxone unmasks, and it does so without potentiating opioid-induced respiratory depression, a property that makes it uniquely suited to polysubstance cases. But dexmedetomidine has a pharmacological quirk: its sedation is uniquely arousable, more like natural sleep than anaesthesia, and patients can typically respond to simple commands. That arousability is clinically useful for milder cases, allowing clinicians to monitor patients without deep sedation and its associated prolonged hospital stays. For severely agitated patients, or when clinicians need to perform intricate procedures such as placing an intravenous line, however, arousable sedation may simply not be enough.

Aggressively increasing the dexmedetomidine dose to achieve deeper sedation carries its own dose-dependent risks. Through alpha-2a receptor-mediated sympatholytic effects, dexmedetomidine initially causes hypotension and bradycardia, and at higher concentrations it further suppresses heart rate while raising blood pressure through alpha-2b receptor-mediated vasoconstriction. It inhibits insulin secretion from pancreatic alpha-2 receptors, potentially causing hyperglycaemia, and it lowers the thermoregulatory thresholds for shivering and vasoconstriction, producing hypothermia in humans. The Marshall team hypothesised that adjunctive ketamine, a dissociative NMDA antagonist anaesthetic with partial mu-opioid receptor agonism, could deepen dexmedetomidine’s sedation without escalating the dose and its attendant adverse effects. Ketamine brings its own advantages to polysubstance cases: like dexmedetomidine, it causes minimal respiratory depression, and its sympathomimetic activation of the cardiovascular system could counteract dexmedetomidine’s bradycardic and hypotensive tendencies. The dexmedetomidine-ketamine combination is increasingly used in human sedation, from paediatric dental patients to opioid-free anaesthesia protocols, but no study had ever tested it against stimulant-induced agitation.

The experimental design was deliberately rigorous. Male Sprague Dawley rats received 1 mg/kg of methamphetamine subcutaneously, a dose chosen because it produces robust locomotor activation with minimal stereotypy, closely mimicking the effect of intravenous methamphetamine. Fifteen minutes later, once the stimulant effect was fully underway, the rats received one of four treatments: saline control, low-dose dexmedetomidine at 0.032 mg/kg, low-dose dexmedetomidine plus 56 mg/kg ketamine, or high-dose dexmedetomidine at 0.18 mg/kg. The fifteen-minute delay was clinically meaningful, simulating the scenario in which naloxone unmasks agitation in a fentanyl-methamphetamine co-intoxicated patient and treatment begins after the opioid reversal is underway. The researchers tracked horizontal locomotor activity as a validated rat model of agitation, quantified arousability with an adapted rat coma scale based on the Glasgow coma scale used in humans, and monitored a battery of alpha-2 agonist class side effects including peripheral oxygen saturation, heart rate, blood glucose, and rectal temperature over four hours.

The locomotor results were striking. Both high-dose dexmedetomidine and the dexmedetomidine-ketamine combination almost completely eliminated methamphetamine-induced locomotor activity during the targeted ninety-minute post-treatment window, which encompassed the most intense phase of the stimulant response. Low-dose dexmedetomidine alone significantly reduced activity but only partially attenuated and shortened the methamphetamine effect. Over the full four-hour trial, the combination produced a smaller overall reduction than high-dose dexmedetomidine because of a post-sedation elevation in locomotor activity, which the authors interpret as ketamine emergence agitation, a well-documented phenomenon upon recovery from ketamine sedation that includes euphoria, vivid dreams, hallucinations, and delirium. The emergence response appeared less severe when rats awakened in the smaller, enclosed diuresis cages used during the sedation trial compared to the large open-field chambers, consistent with clinical evidence that awakening from ketamine in a minimally stimulating environment reduces emergence reactions. The authors suggest this effect could likely be managed by additional low-dose dexmedetomidine administration before patients awaken.

The sedation depth results revealed the combination’s decisive advantage. Despite significantly reducing locomotor activity, low-dose dexmedetomidine alone produced sedation that was almost completely arousable, with rat coma scale scores barely differing from saline controls. Even high-dose dexmedetomidine, which nearly eliminated movement for the entire trial, produced only partially arousable sedation. The low-dose dexmedetomidine-ketamine combination, by contrast, rapidly produced significantly deeper and less arousable sedation than every other group at the twenty-minute time point, precisely when methamphetamine-induced locomotor activity peaked in the control animals. At sixty minutes, the combination-treated rats remained substantially more deeply sedated than those receiving low-dose dexmedetomidine alone, comparable to the deepest sedation produced by high-dose dexmedetomidine, before returning to baseline by two hours. In a secondary qualitative measure, all rats treated with either dose of dexmedetomidine monotherapy required physical restraint for blood glucose and temperature measurements at every time point, while all eight combination-treated rats could be handled without restraint at both the twenty- and sixty-minute marks.

The side effect profile told an equally compelling story. High-dose dexmedetomidine produced minor but significant reductions in peripheral oxygen saturation at three time points, while neither low-dose dexmedetomidine nor the combination produced any significant oxygenation changes, though a subset of combination-treated rats showed early transient dips consistent with those occasionally seen in humans receiving rapid intravenous ketamine. All treatments reduced heart rate, as expected from dexmedetomidine’s sympatholytic effects, but high-dose dexmedetomidine produced the most intense bradycardia, persisting throughout the entire four-hour trial. The combination actually improved cardiovascular safety compared to low-dose dexmedetomidine alone: heart rate was significantly higher in the combination group between twenty and one hundred twenty minutes, and it returned to baseline by two hours rather than three, an effect the authors attribute to ketamine’s sympathomimetic activation opposing dexmedetomidine’s cardiosuppression. Blood glucose rose substantially in all treatment groups, largely recovering in the low-dose groups but remaining highly elevated after high-dose dexmedetomidine. Temperature dropped in all groups, but fully recovered in the low-dose groups by the trial’s end while remaining significantly depressed after high-dose dexmedetomidine. Overnight weight loss of roughly five percent occurred only in the high-dose dexmedetomidine group, further evidence of the combination’s superior tolerability.

The renal pharmacokinetic findings added an unexpected dimension. Dexmedetomidine dose-dependently increased urine production, a known effect mediated through reduced vasopressin release, and unexpectedly reduced urine pH. More acidic urine can ion-trap methamphetamine and related compounds in the renal tubule, enhancing elimination, and the researchers observed a moderate, significant positive correlation between urine volume and the percentage of unchanged methamphetamine excreted, along with a moderate, significant negative correlation between urine pH and methamphetamine excretion. While the trend toward enhanced renal methamphetamine elimination after high-dose dexmedetomidine did not reach statistical significance in the main study, partly due to polyuria-induced urine loss during transport between measurements, the authors suspect this pharmacokinetic bonus could prove clinically meaningful and plan dedicated pharmacokinetic studies with serum measurements to evaluate any potential beneficial effects on systemic methamphetamine exposure.

The Marshall team is careful to frame these findings as preclinical proof-of-concept rather than a clinical recommendation. Future studies will test the intervention in a methamphetamine-fentanyl polysubstance scenario with naloxone reversal, mirroring their earlier dexmedetomidine-naloxone work, and a rigorous preclinical comparison with the benzodiazepine standard of care is needed to demonstrate superiority. Sex comparisons are also critical, as female rats and female humans are more sensitive to methamphetamine’s stimulant effects and dexmedetomidine’s sedative effects than males, while the sex-dependent effects of ketamine remain less consistently established across species. The study’s design was facilitated by a research team spanning clinical and preclinical research, pharmacy, veterinary medicine, and clinical toxicology, reflecting a strategy of clinically guided preclinical work designed to inform future human trials. If the combination survives those tests, clinicians could initially exploit dexmedetomidine’s uniquely arousable sedation for milder agitation, then administer adjunctive ketamine to deepen sedation only when necessary, offering a pharmacologically tailored alternative to a one-size-fits-all benzodiazepine approach in an era when methamphetamine rarely travels alone.

Subject of Research: Ketamine enhancement of dexmedetomidine attenuation of methamphetamine-induced agitation in rats

Article Title: Ketamine enhancement of dexmedetomidine attenuation of methamphetamine-induced agitation in rats

Article References: Budamkayala, M., Yalakala, J., Skeen, M. B., Karuturi, S., McPhillen, C., Bailey, K., Davies, T. H., & Hambuchen, M. D. (2026). Ketamine enhancement of dexmedetomidine attenuation of methamphetamine-induced agitation in rats. Journal of Pharmacy & Pharmaceutical Sciences, 29, Article 16294. https://doi.org/10.3389/jpps.2026.16294

Image Credits: AI Generated

DOI: 10.3389/jpps.2026.16294

Keywords: methamphetamine, dexmedetomidine, ketamine, agitation, preclinical, sedation, polysubstance, rat study, enhancement, attenuation, methamphetamine-induced, rats

The research team designed their experiment around a carefully staged protocol. Male rats received methamphetamine at a dose of 5 milligrams per kilogram per day for 21 consecutive days, a regimen sufficient to produce dependence-like neurochemical changes. After this exposure phase, the animals entered a nine-week withdrawal period. During withdrawal, one group of methamphetamine-exposed rats remained sedentary, while another group undertook moderate-intensity continuous training, commonly abbreviated as MICT. Control animals received saline instead of the drug. The researchers deliberately separated their statistical comparisons into phases: first comparing saline-treated animals with methamphetamine-exposed animals to establish what the drug itself did, then comparing methamphetamine-exposed sedentary rats with methamphetamine-exposed rats that exercised, to isolate the effect of training during withdrawal. This phased analytical approach allowed the team to distinguish drug effects from exercise effects rather than conflating the two.

Behaviorally, the consequences of methamphetamine exposure were stark. Using the open field test, a classic behavioral assay in which an animal is placed in an arena and its movements are tracked, the researchers found that methamphetamine-exposed rats traveled significantly shorter total distances, moved at lower velocities, and reared up on their hind legs less often than saline-treated controls. Rearing is generally interpreted as a marker of exploratory motivation and vertical activity, so its reduction signaled blunted curiosity and diminished spontaneous locomotion. Intriguingly, the methamphetamine-exposed animals showed a significant increase in grooming behavior, a repetitive self-directed action that in this context is often read as a stress-related or stereotyped response. Together, the pattern described animals that were less mobile, less exploratory, and more prone to repetitive behavior, a constellation consistent with the frontal cortical dysfunction that chronic stimulant exposure is known to produce.

To understand what was happening inside the frontal cortex, the team turned to real-time polymerase chain reaction, a technique that quantifies how actively specific genes are being transcribed into messenger RNA. They focused on a panel of seven genes: C/EBPβ, DDIT4, TSC-2, mTOR, LC3-II, Nrg-1, and EphB1. Several of these sit at the heart of the autophagy machinery, the cellular recycling system that engulfs damaged proteins and organelles and delivers them to lysosomes for degradation. LC3-II is a widely used molecular marker of autophagosome formation, while mTOR, the mechanistic target of rapamycin, is the master negative regulator of autophagy initiation. Upstream of mTOR, TSC-2 acts as a brake on mTOR signaling, and DDIT4, also known as REDD1, is a stress-induced protein that suppresses mTOR activity. C/EBPβ is a transcription factor that can drive the expression of autophagy genes under stress. Nrg-1 and EphB1, by contrast, are involved in neural development, synaptic signaling, and neuronal resilience.

The molecular readout after methamphetamine exposure told a coherent story of dysregulated autophagy signaling. Compared with saline controls, the methamphetamine-exposed rats showed significantly increased expression of C/EBPβ, DDIT4, TSC-2, and LC3-II in the frontal cortex, alongside significantly decreased expression of mTOR, Nrg-1, and EphB1. In plain terms, the drug appeared to push the autophagy system toward overactivation: the mTOR pathway, which normally keeps autophagy in check, was suppressed, while the upstream activators and the autophagosome marker LC3-II were elevated. At the same time, the reduced expression of Nrg-1 and EphB1 pointed to compromised support for synaptic maintenance and neuronal signaling. Because the frontal cortex governs executive function, decision-making, and behavioral inhibition, this molecular shift offers a plausible mechanistic bridge to the impaired locomotor and exploratory behavior observed in the open field.

The most striking results emerged when the researchers examined what happened after nine weeks of withdrawal, with or without exercise. In the sedentary methamphetamine-withdrawn group, many of the drug-induced alterations persisted. But in the group that performed moderate-intensity continuous training during withdrawal, the picture changed substantially. Exercise significantly increased total distance traveled and rearing behavior in the open field test, indicating restored locomotor activity and exploratory drive, and it significantly decreased grooming behavior, suggesting a reduction in the stress-linked repetitive responding that methamphetamine had amplified. These were not subtle statistical artifacts; the exercised animals behaved measurably more like healthy controls than their sedentary withdrawing counterparts did.

At the molecular level, the exercise intervention produced a pattern that was almost a mirror image of the drug’s effects. Moderate-intensity continuous training significantly reduced LC3-II expression, the marker of autophagosome formation that methamphetamine had driven upward, and it significantly increased the expression of mTOR, Nrg-1, and EphB1, the genes the drug had suppressed. In other words, exercise appeared to rebalance the autophagy signaling network, pulling it back from the overactivated state that chronic methamphetamine exposure had imposed, while simultaneously restoring the expression of genes that support synaptic integrity and neuronal communication. The authors interpret this as evidence that MICT attenuates the molecular impairments caused by methamphetamine in the frontal cortex, and that this molecular rebalancing accompanies, and may underpin, the behavioral recovery observed in the open field.

The significance of these findings lies partly in what they suggest about the biology of addiction recovery. Autophagy is a double-edged sword in the addicted brain: it is essential for clearing toxic protein aggregates and damaged mitochondria, but excessive or poorly regulated autophagic activity can contribute to neuronal dysfunction and cell death. Methamphetamine is known to generate oxidative stress, mitochondrial damage, and protein misfolding in dopaminergic and cortical neurons, and an overdriven autophagy response is one plausible downstream consequence. By restoring mTOR activity and reducing LC3-II, exercise may have recalibrated this system toward a healthier set point. Meanwhile, the recovery of Nrg-1 and EphB1 expression hints that exercise supports the synaptic and neurotrophic machinery that stimulant drugs erode, potentially facilitating the repair of cortical circuits involved in craving, impulse control, and reward processing.

The study also carries practical implications, though the authors are careful to frame them within the limits of an animal model. Exercise-based interventions are inexpensive, widely scalable, and largely free of the side effects that complicate pharmacological treatments for stimulant use disorder, for which no approved medications currently exist. If the mechanisms observed in rats translate even partially to humans, structured moderate aerobic exercise during early recovery could serve as an adjunct therapy that eases the behavioral disturbances of withdrawal while promoting molecular repair in the prefrontal regions most damaged by methamphetamine. Rehabilitation programs for people recovering from stimulant addiction increasingly incorporate physical activity, and this study provides a mechanistic rationale for that practice, linking a specific exercise intensity to specific gene expression changes in a specific brain region.

Caveats remain, as they always do in translational neuroscience. Rats are not people, the dose and duration of methamphetamine exposure in the laboratory do not perfectly recapitulate human patterns of use, and the open field test captures only a slice of the behavioral repertoire affected by addiction. The researchers also note that their work was conducted in compliance with the ARRIVE 2.0 guidelines and approved by the ethics committee of Hakim Sabzevari University, and that the study received no external funding. Future work will need to determine whether the autophagy-related gene changes persist after exercise stops, whether they correlate directly with neuronal survival and synaptic density, and whether other exercise modalities, such as high-intensity interval training, produce similar or different molecular signatures. For now, however, the study stands as a compelling demonstration that the brain’s recovery from methamphetamine injury is not a passive process, and that moderate, sustained exercise can actively participate in it, one gene and one behavior at a time.

Subject of Research: Effects of moderate-intensity aerobic exercise on autophagy-related gene expression and behavior in the frontal cortex during methamphetamine withdrawal in rats

Article Title: Moderate-intensity continuous training modulates the expression of autophagy-related genes in the frontal cortex and improves behavioral responses in rats during methamphetamine withdrawal

Article References: Haghighi, A. H., Izadimanesh, F., Hosseini-Kakhak, S. A., Asadi-Shekaari, M., Marefati, H., Shahrabadi, H., Iellamo, F., Farsetti, P., Bei, R., & Perrone, M. A. (2026). Moderate-intensity continuous training modulates the expression of autophagy-related genes in the frontal cortex and improves behavioral responses in rats during methamphetamine withdrawal. BMC Pharmacology and Toxicology. https://doi.org/10.1186/s40360-026-01237-6

Image Credits: AI Generated

DOI: 10.1186/s40360-026-01237-6

Keywords: methamphetamine, withdrawal, autophagy, moderate-intensity continuous training, frontal cortex, mTOR, LC3-II, open field test, exercise, neurorehabilitation, gene expression, rats

The study, published in Archives of Sexual Behavior, was conducted by a team including Lucia Gallego-Deike, Marcos Bella-Fernández, and Hilario Blasco-Fontecilla, working with data from the Spanish Observatory on Drugs and Addictions. The EWSD is a multinational, web-based survey coordinated every three years by the European Union Drugs Agency across 30 European and neighboring countries. Spain has participated since 2021, and the 2024 edition collected data between May and June. To qualify, participants had to be 18 or older and report having used at least one of several substances in the previous year, including cannabis, cocaine, ecstasy/MDMA, amphetamine, methamphetamine, heroin, or any new psychoactive substance. The questionnaire spanned 225 questions and took roughly fifteen minutes to complete.

The technical detail in the new paper is considerable. Respondents were classified by both sex assigned at birth and gender identity, allowing the researchers to distinguish cisgender men, cisgender women, and transgender or non-binary participants. A respondent was counted as using a drug if they had consumed it within the previous 12 months, and they were categorized as engaging in chemsex if they identified a chemsex party as a context of use for at least one substance in that period. Statistical comparisons between subgroups used t-tests for quantitative variables and chi-square tests for qualitative ones, with all analyses performed in R version 4.3.2.

The most striking findings concern why people use drugs at all. Cannabis and heroin stand apart from the general recreational pattern. Nearly half of cannabis users, 49.73 percent, said they used it to relax or manage stress, as did 30.14 percent of heroin users. About a quarter of users of each substance reported taking them to improve sleep, and 26.35 percent reported using them to cope with anxiety or depression. This self-medication profile contrasts sharply with substances such as ecstasy/MDMA, where 73 percent of users reported purely recreational motives. The researchers note that comparable proportions of cannabis and heroin users reported consumption driven by dependence, despite the two substances carrying very different social perceptions of risk.

Context matters as much as motive. Across the board, drugs were most often consumed at home, but music festivals and parties emerged as the most frequent public settings. This aligns with a well-established body of evidence: wastewater analyses in several countries have documented spikes in psychostimulant concentrations during festivals featuring rap, house, dance, pop, or rock music, and surveys of festival attendees have repeatedly identified MDMA and cannabis as the most common illicit drugs in those environments. Clubs and bars ranked slightly lower. Only cannabis and heroin appeared across an unusually wide range of environments, including schools, supervised drug use rooms, and natural settings.

The sexualized drug use findings carry the most public health weight. Sexualized drug use, or SDU, is an umbrella term for the intentional use of substances to enhance or facilitate sexual activity, practiced across genders and orientations but disproportionately represented among sexual-orientation and gender minorities. The paper emphasizes that no unified definition of SDU exists, and chemsex, its most specific subset, is likewise not recognized as a distinct diagnostic entity in the ICD-11. Chemsex conventionally involves stimulants, methamphetamine, GHB/GBL, and mephedrone, used before or during prolonged group sexual sessions, historically among men who have sex with men, often facilitated by geosocial networking apps and hosted in private residences or sex-on-premise venues.

The new data show that among the 874 respondents reporting drug use for sexual enhancement, 81.46 percent used only one substance, while 12.93 percent used two or more, and use of five or more drugs was rare. Male respondents reported sexual enhancement use at roughly twice the rate of female respondents. Cisgender men reported higher rates of sexualized use of cocaine (crack), heroin, and MDMA than cisgender women, while transgender or non-binary participants reported higher MDMA use for sexual purposes than cisgender women. Cannabis was the most frequently used substance for sexual enhancement across all gender groups, a finding consistent with its overall status as the most widely used illicit drug.

Chemsex itself remained a minority practice but displayed a distinctive signature. Of the 206 respondents who attended at least one chemsex session in the past year, the vast majority, 170 or 81.33 percent, were cisgender men, followed by 22 cisgender women (10.53 percent) and 14 transgender or non-binary individuals (6.70 percent). Methamphetamine and new psychoactive substances were primarily linked to chemsex parties, and the route of administration differed markedly from general drug users: injection and rectal insertion were far more prevalent among chemsex attendees, as was smoking in pipes. Injection within chemsex contexts, sometimes called slamsex, is a particularly high-risk variant associated with elevated likelihood of addiction, psychosis, neurological harm, overdose, and sexually transmitted infections.

The sociodemographic profile of sex-related drug users also diverged from the rest of the sample in statistically significant ways. Sex assigned at birth and gender identity both differed between groups, with p-values of 0.004 and below 0.001 respectively, and sex-related drug users were slightly younger, more often students, and included a modestly higher proportion of transgender or non-binary individuals, 3.66 percent versus 2.38 percent. Employment status also differed significantly. Notably, living situation, income, residency, and education showed no significant differences, echoing review literature that has found inconsistent sociodemographic correlates of SDU beyond gender and age.

Perhaps the most consequential implication of the study is its suggestion that chemsex epidemiology is shifting. Though the practice is traditionally associated with men who have sex with men, the presence of women among chemsex participants in this sample suggests the phenomenon may be expanding into heterosexual populations, a trend supported by emerging but still limited research on heterosexual men and women in party and club subcultures. Chemsex carries substantial risks, including unsafe sexual practices that raise HIV and hepatitis C transmission, drug-induced disinhibition that can lead to non-consensual encounters, and long-term mental health problems such as depression, anxiety, sleep disorders, psychotic symptoms, and cognitive decline. The authors argue that prevention campaigns, which have until now focused primarily on MSM communities, must adapt. They call for targeted strategies including health education, harm reduction, inclusive care services, and professional training, measures they say are essential to reduce harm and improve health outcomes as the landscape of sexualized drug use evolves.

Subject of Research: Sexualized drug use and chemsex patterns among illicit drug users in Spain

Article Title: Patterns of Drug Use Across Social and Sexual Contexts in Spain: Insights From the European Web Survey on Drugs 2024

Article References: Gallego-Deike, L., Bella-Fernández, M., López-Sánchez, L. M., Brime-Beteta, B., Ruiz-Medina, S., & Blasco-Fontecilla, H. (2026). Patterns of Drug Use Across Social and Sexual Contexts in Spain: Insights From the European Web Survey on Drugs 2024. Archives of Sexual Behavior. https://doi.org/10.1007/s10508-026-03525-y

Image Credits: AI Generated

DOI: 10.1007/s10508-026-03525-y

Keywords: chemsex, sexualized drug use, European Web Survey on Drugs, methamphetamine, cannabis, MDMA, public health, men who have sex with men, harm reduction, Spain, new psychoactive substances, drug use patterns

The researchers set out to answer a question that has shadowed addiction neuroscience for decades: what allows drugs to drive dopamine release at intensities that ordinary rewards never reach? Their hypothesis centered on energy. Dopamine terminals in the nucleus accumbens are extraordinarily metabolically demanding structures, packed with mitochondria positioned near active zones where vesicles of dopamine await release signals. When dopaminergic neurons fire at high frequency, the energy demands of packaging, mobilizing, and releasing vesicles can outstrip local ATP supplies. Previous work had established that presynaptic mitochondria buffer calcium and synthesize ATP on demand, but whether this mitochondrial machinery was specifically recruited during drug reward—rather than reward in general—remained unknown.

To watch mitochondrial calcium in real time, the team used a genetically encoded fluorescent indicator called 4mt-jGCaMP8s, targeted to the mitochondrial matrix, expressed selectively in dopaminergic neurons of mice. Using fiber photometry, they monitored calcium signals from dopaminergic terminals in the nucleus accumbens while animals received heroin, morphine, methamphetamine, or cocaine. The results were unambiguous: heroin and methamphetamine produced robust, rapid mitochondrial calcium transients in accumbal dopamine terminals, while cocaine did not. This selectivity held up under two-photon imaging with a head-mounted microscope in freely moving animals, and the signal was strongest in the core of the nucleus accumbens, a subregion closely tied to drug seeking. Critically, when animals consumed natural rewards such as sucrose, the same terminals showed no comparable mitochondrial calcium influx.

The gateway for this calcium was identified as the mitochondrial calcium uniporter, or MCU, a channel in the inner mitochondrial membrane that was molecularly identified more than a decade ago. MCU allows calcium to flow down its steep concentration gradient into the mitochondrial matrix, where it activates calcium-sensitive enzymes of the tricarboxylic acid cycle and stimulates oxidative phosphorylation. In essence, mitochondrial calcium influx is how a mitochondrion learns that its host cell is working hard and needs more fuel. The Beijing team confirmed that the drug-evoked signals depended on MCU: in dopaminergic neurons lacking the uniporter, or in neurons treated with the MCU inhibitors Ru360 and berberine, the drug-induced mitochondrial calcium rise was abolished, while cytoplasmic calcium responses to the drugs remained intact.

Why would drugs, but not natural rewards, engage this pathway? The answer emerged from optogenetic experiments in which the researchers artificially drove dopaminergic terminals at defined frequencies. At low stimulation frequencies of around 4 hertz, mimicking the modest firing rates associated with physiological rewards, mitochondrial calcium barely moved, and deleting MCU had no effect on evoked dopamine release. But at 20 and 40 hertz—intensities characteristic of drug-evoked activation—mitochondrial calcium influx became prominent, and its absence sharply reduced dopamine release measured with the GRAB_DA2m fluorescent sensor. The conclusion is elegant: MCU-mediated mitochondrial calcium is recruited only when dopaminergic neurons are pushed beyond their normal metabolic comfort zone, which is precisely the regime that addictive drugs occupy and that natural rewards do not.

The mechanism linking calcium to release proved to be energy. Using the genetically encoded ATP sensor ATeam1.03 targeted to mitochondria, the researchers showed that drug-like high-intensity stimulation drove a rapid rise in mitochondrial ATP production that required MCU. When they blocked ATP synthesis with oligomycin, or supplied exogenous ATP to neurons lacking MCU, the picture sharpened further: ATP replenishment rescued the vesicle release deficit in MCU-deficient neurons, while ATP depletion mimicked it. Probing the vesicle machinery directly with a pHluorin-tagged vesicular monoamine transporter, the team found that the readily releasable pool of dopamine vesicles was depleted in MCU knockout neurons, and that this deficit was restored by ATP supplementation. In other words, the mitochondrial calcium influx does not directly trigger release; it manufactures the ATP that keeps the release machinery stocked during metabolically punishing bursts of activity.

The behavioral consequences were decisive. Mice engineered to lack MCU specifically in dopaminergic neurons showed dramatically reduced locomotor responses to heroin and morphine, blunted conditioned place preference for opioids, and diminished cue-induced reinstatement of cocaine seeking after extinction—a laboratory model of relapse. Circuit-specific deletion confirmed the anatomy: removing MCU only from dopaminergic neurons projecting from the ventral tegmental area to the nucleus accumbens impaired heroin reward, whereas deletion in the projection to the prefrontal cortex did not. Pharmacological validation followed. Berberine, a natural compound recently characterized as an MCU inhibitor that disrupts the channel’s assembly with its regulatory partner EMRE, reduced mitochondrial calcium uptake in cultured dopaminergic neurons, attenuated heroin conditioned place preference when microinjected into the nucleus accumbens, and suppressed cue-induced reinstatement of cocaine seeking when given systemically.

Perhaps most striking is what did not happen. Mice lacking MCU in dopaminergic neurons performed indistinguishably from controls across a battery of tests probing dopamine-dependent physiology: spontaneous locomotion, working memory in the Y-maze, anxiety-like behavior, despair-related immobility, sucrose preference, motor coordination on the rotarod, and spatial learning in the Morris water maze. Food-conditioned place preference, a model of natural reward learning, was preserved. Whole-brain MCU knockout mice, generated with Nestin-Cre, developed normally with expected Mendelian ratios and showed no deficits in dopamine-related behaviors. The therapeutic window implied by these results is unusually wide: the bioenergetic pathway appears to be dispensable for everyday reward processing yet essential for the supraphysiological dopamine output that drugs commandeer.

The study reframes addiction as, in part, a metabolic disease of synapses. Drugs of abuse differ in their molecular targets—opioids bind receptors, methamphetamine reverses transporters, cocaine blocks reuptake—but they converge on a common output: high-intensity dopaminergic activation in the accumbens. This work shows that convergence extends to the mitochondria, which are forced into emergency ATP production to sustain the pathological signal. By targeting MCU, or the calcium-driven bioenergetics it enables, it may be possible to starve the addictive circuitry of its energy supply while leaving the mitochondria of ordinary reward signaling untouched. Considerable distance remains between mouse models and human therapy, and berberine’s properties as a drug candidate will need rigorous evaluation. But the identification of a drug-selective mitochondrial mechanism offers something addiction research has rarely possessed: a molecular distinction between the dopamine that fuels compulsion and the dopamine that fuels life.

Subject of Research: Mitochondrial calcium uniporter-mediated bioenergetics in dopaminergic terminals that selectively enable drug-induced dopamine release and addictive behavior

Article Title: Mitochondrial calcium influx-driven bioenergetics selectively enable drug addiction

Article References: Gao, J., Zhao, H., Han, X., Zeng, L., Pan, J., Liu, G., Wei, X., Liu, C., Wu, W., Chen, S., Chen, J., Li, T., Yin, J., Zhou, T., Zhang, X.-M., Li, A.-L., Li, T., & Pan, X. (2026). Mitochondrial calcium influx-driven bioenergetics selectively enable drug addiction. Nature Neuroscience. https://doi.org/10.1038/s41593-026-02421-x

Image Credits: AI Generated

DOI: 10.1038/s41593-026-02421-x

Keywords: addiction, mitochondria, mitochondrial calcium uniporter, dopamine, nucleus accumbens, reward, MCU, bioenergetics, opioids, methamphetamine, ATP, berberine

The scale of the transformation is captured in the official statistics. Before 2014, convictions for drug offences rose slowly, from just 8 cases in 2006 to 128 in 2013. After 2014, every indicator surged. The number of imprisoned accused individuals climbed more than fourteen-fold, from 171 in 2014 to a peak of 2,482 in 2023. Recorded drug consumers rose from 143 to a peak of 1,888 in 2022, while recorded traffickers increased from 28 to 1,070 over the same period, a nearly forty-fold rise that the author interprets as evidence of consolidated organized supply networks. Seizure data tell a parallel story: confiscated drug quantities reached 482,124 kilograms in 2023, and seized pharmaceutical pills exceeded 2.3 million tablets in the same year.

The timing is not coincidental. The study situates the drug surge within a cascade of overlapping shocks that began in 2014: the outbreak of the conflict with ISIS, the arrival of more than three million internally displaced persons and refugees, the suspension of the Kurdistan Region’s federal budget allocation, and a sharp collapse in global oil prices. Together these crises gutted public finances, drove up unemployment and poverty, and weakened the social institutions that normally restrain deviant behavior. The author argues that these structural pressures created conditions conducive both to expanded consumption and to the entrenchment of trafficking networks, transforming the region from a primarily consumer market into a strategic transit and distribution hub linking Iran, Syria and Türkiye.

To capture a phenomenon that is clandestine, stigmatized and imperfectly recorded, the study employed a convergent mixed-methods design. Official records reveal decade-long trends but say little about the individuals behind them; the structured survey of 200 drug consumers and 100 people involved in trafficking documents socioeconomic profiles and behaviors; and 46 semi-structured interviews illuminate the lived mechanisms connecting poverty, addiction and illicit trade. Findings were treated as robust only where at least two independent data streams converged, a triangulation strategy the author says strengthens conclusions that no single source could support.

The survey results sketch a consistent demographic picture. Eighty-two percent of respondents were male, 38 percent were aged 25 to 34, and 56 percent were single. Nearly half were unemployed, 59 percent relied on some form of social assistance, half reported household incomes below 300,000 Iraqi dinars per month, and only 5 percent held a bachelor’s degree or higher. Polydrug use was the norm rather than the exception: 40 percent reported using two to three substances and 36 percent used four to five. Crystal methamphetamine was the most commonly used illicit drug at 69 percent, followed by hashish, marijuana and heroin, while tramadol led the pharmaceutical substances at 59 percent, ahead of diazepam, Trevin, Somadril, clonazepam and Captagon. Roughly 30 percent of respondents were involved in trafficking, and most reported that their drug involvement began with use rather than dealing.

The interviews add texture to these numbers and reveal a recurring trajectory from consumer to trafficker. Economic hardship was the most frequently cited condition, raised by most interviewees, with participants describing prolonged unemployment and the inability to meet family obligations as pressures that pushed them toward drugs as an escape or dealing as a source of rapid income. One 31-year-old man from Erbil explained that after losing his job years earlier, drugs became a way to escape the pressure of daily life. Peer influence emerged as a critical trigger for initiation, with many respondents describing how daily exposure to using friends normalized consumption. Family instability, absent parental supervision and weak emotional support featured prominently, and several traffickers described entering the trade explicitly to finance their own addiction after they could no longer afford it.

Participants were skeptical that policing alone could solve the problem. Some acknowledged that police operations temporarily reduced the visibility of drugs, but most believed enforcement failed to address the underlying social and economic pressures, and many users avoided treatment for fear of stigma and legal consequences. When asked about solutions, interviewees overwhelmingly called for comprehensive responses: job creation, economic support for vulnerable populations, accessible treatment and rehabilitation services, and community-based prevention. As one 32-year-old participant from Sulaimani put it, punishment alone cannot solve the problem; young people need jobs, rehabilitation services and hope for the future.

Theoretically, the study grounds its interpretation in Strain Theory and Social Disorganization Theory. Strain Theory holds that persistent economic stress and blocked legitimate opportunities generate pressure that increases the propensity for substance use and participation in illicit markets, while Social Disorganization Theory emphasizes how weakened institutions, population displacement and family disruption erode informal social control. The author argues that the Kurdistan Region since 2014 exhibits precisely the simultaneous escalation of individual-level economic strain and community-level institutional disorganization that both frameworks identify as conducive to drug problems, and that the frameworks, developed largely in Western urban settings, travel well to this Middle Eastern context of fiscal crisis and mass displacement.

The findings align closely with international evidence. The UN Office on Drugs and Crime independently identifies the Kurdistan Region as a crossroads of regional trafficking routes and documents sharp increases in methamphetamine and Captagon seizures since 2019, exactly the period in which the official series analyzed here accelerate. Iraqi public health authorities report that registered drug use disorders doubled between 2017 and 2021, and the predominance of crystal methamphetamine and misused pharmaceuticals among respondents mirrors the region-wide shift toward synthetic drugs, which are cheaper to produce, easier to conceal and harder to trace than traditional plant-based substances. Where the study diverges from much of the international literature is in its emphasis: rather than foregrounding supply routes and interdiction, it highlights the demand-side conditions of unemployment, income insecurity and family disruption that sustain local consumption and recruit consumers into trafficking.

Although several indicators declined in 2024, the author urges caution in interpretation. The drop may reflect genuine deterrence following intensified anti-narcotics enforcement and regional coordination in 2023 and 2024, or it may be an artifact of recording practices, a consequence of market adaptation toward compact synthetic substances that are harder to detect, or simply a base effect after the exceptional peaks of 2022 and 2023. All levels remain dramatically higher than before 2014. The study also acknowledges its limitations: the survey sample was purposive and composed entirely of drug-involved individuals, so it describes the affected population rather than estimating risk relative to the general population, and the cross-sectional design precludes causal inference.

The policy implications are concrete. The evidence supports targeted employment and vocational training for young men aged 18 to 34, linking cash assistance to reintegration and psychosocial services, expanding treatment capacity as a form of trafficking prevention by interrupting the financial pathway from use to dealing, creating clearer legal distinctions between users and traffickers with confidential treatment routes, and strengthening prescription monitoring for tramadol and benzodiazepines. Above all, the study concludes that enforcement alone is insufficient: sustainable progress requires integrated, multisectoral strategies combining economic empowerment, prevention, treatment, rehabilitation and social protection, tailored to a region still recovering from a decade of crisis.

Subject of Research: Socioeconomic correlates and trends of drug abuse and trafficking in the Kurdistan Region of Iraq from 2014 to 2024

Article Title: Recent trends and socioeconomic correlates of drug abuse and trafficking in the Kurdistan Region of Iraq from 2014 to 2024

Article References: Othman, A. T. (2026). Recent trends and socioeconomic correlates of drug abuse and trafficking in the Kurdistan Region of Iraq from 2014 to 2024. Discover Global Society, 4(1), Article 248. https://doi.org/10.1007/s44282-026-00612-2

Image Credits: AI Generated

DOI: 10.1007/s44282-026-00612-2

Keywords: drug abuse, drug trafficking, Kurdistan Region of Iraq, socioeconomic vulnerability, synthetic drugs, methamphetamine, Captagon, tramadol, unemployment, mixed methods, Strain Theory, social disorganization

The scale of the problem is staggering. According to the review, an estimated 4.3 million people in the United States meet diagnostic criteria for stimulant use disorder, nearly a quarter of them aged 25 or younger. National overdose deaths involving stimulants rose nearly 34-fold between 2002 and 2022, and 182,502 stimulant-related overdose deaths were reported between 2021 and 2024. More than 60,000 stimulant-related overdose deaths have been recorded annually in recent years, with 43.1 percent of stimulant-involved deaths between January 2021 and June 2024 also involving opioids. Black or African American and American Indian or Alaska Native communities have experienced disproportionately steep increases in stimulant-involved deaths, adding an urgent health equity dimension to the crisis.

Yet while medications exist for opioid, alcohol, and tobacco use disorders, stimulant use disorder remains one of the few major substance use disorders with no FDA-approved drug therapy, leaving clinicians dependent on behavioral interventions with limited long-term efficacy. It is against this backdrop that the LSU team examined the theoretical potential of Brixadi. Brixadi is an extended-release injectable buprenorphine that uses a fluid-crystal depot delivery system: after subcutaneous injection, the solution solidifies into a viscous crystalline gel that gradually releases the drug over one week or one month, producing stable plasma concentrations and sustained receptor occupancy. Peak plasma levels occur roughly 20 hours after injection, and steady state is reached by the fourth dose, with half-lives ranging from 3 to 5 days for weekly injections and 19 to 26 days for monthly ones.

Buprenorphine’s pharmacology is what makes the hypothesis plausible. The drug is a partial agonist at the mu-opioid receptor and an antagonist at the kappa-opioid receptor, binding with exceptionally high affinity—reported inhibition constants of approximately 0.2 nanomolar at the mu receptor and 0.07 nanomolar at the kappa receptor—and dissociating slowly. That ceiling effect on respiratory depression and euphoria underpins its favorable safety profile, while its high affinity allows it to displace full agonists such as fentanyl and heroin from receptors. But for stimulant addiction, the kappa receptor is the critical piece. Kappa-opioid receptors respond to dynorphins, endogenous peptides that suppress dopamine signaling in the mesolimbic reward pathway and generate dysphoria, stress responses, and drug craving. Chronic stimulant use upregulates prodynorphin transcription, elevating dynorphin levels and pushing the brain into a low-dopamine state that drives further drug seeking in a self-reinforcing loop.

Animal research supports this framework. Methamphetamine exposure increases dynorphin expression in the nucleus accumbens and preclinical cortex, and in mouse studies by Whitfield and colleagues, kappa receptor activation during abstinence appeared to create neuroadaptations that made methamphetamine more appealing, essentially fueling relapse through negative reinforcement. Conversely, pharmacologic blockade of the kappa receptor has, in some animal models, reduced drug-seeking behavior or methamphetamine self-administration, although the effects have not been uniform across species and paradigms. In rodents and rhesus monkeys, buprenorphine has also been shown to decrease cocaine self-administration and cocaine-seeking behavior, and rodent studies suggest buprenorphine reduces methamphetamine consumption and drug seeking partly through activation of the nociceptin/orphanin FQ peptide receptor.

Human evidence remains thin but intriguing. A double-blind randomized clinical trial by Ahmadi and Razeghian Jahromi found that buprenorphine reduced methamphetamine craving during withdrawal more effectively than methadone, though the 17-day trial could not determine whether the effect persisted or prevented relapse. Trials of concurrent opioid and cocaine dependence have reported reductions in cocaine use and craving with buprenorphine, and a combination of buprenorphine and naltrexone blocked compulsive cocaine intake in rodents without producing opioid dependence. Buprenorphine’s antidepressant-like effects in animal models—mediated through kappa receptors and stress modulation—further suggest it may blunt the hyperkatifeia, the intensified negative emotional state, that fuels relapse during stimulant withdrawal.

The strongest practical argument, however, may lie in polysubstance use. Toxicologic data show that 89.6 percent of individuals presenting for opioid use disorder treatment test positive for more than one substance, with a mean of 3.3 substances per person and up to 11 detected in some cases. Approximately one-third of individuals with opioid use disorder use stimulants concurrently, methamphetamine use in this population has risen by more than 80 percent, and over half of US overdose deaths from 2018 to 2024 involved concurrent opioid and stimulant use. Because opioid and stimulant use disorders converge on overlapping dopamine, reward, and stress circuitry—psychostimulants acting directly on dopaminergic transporters and opioids disinhibiting dopamine release indirectly—stabilizing the opioid component may disrupt the reinforcing environment sustaining stimulant use. Notably, when patients remained in buprenorphine treatment, one study found a 15 percent absolute reduction in methamphetamine use at six months, even though methamphetamine use predicted lower treatment retention overall.

Brixadi’s depot formulation may add distinct advantages in this population. Long-acting buprenorphine formulations have achieved treatment retention rates above 60 to 70 percent at six months, and maintenance on buprenorphine is associated with a greater than 50 percent reduction in all-cause mortality compared with no treatment. Monthly or weekly injections remove the daily adherence burden that trips up patients experiencing housing instability or limited transportation, minimize peak-to-trough fluctuations, and keep patients engaged in care long enough to benefit from behavioral therapies such as contingency management, the intervention with the best evidence for stimulant use disorder. The authors frame this as harm reduction: buprenorphine does not directly treat stimulant craving, but stabilizing opioid dependence may reduce chaotic polysubstance patterns, lower overdose risk, and create openings for broader therapeutic engagement.

The review is candid about its limitations. Brixadi is not approved for any stimulant use disorder, no clinical trial has demonstrated that buprenorphine reduces methamphetamine or cocaine use as a primary outcome, and much of the kappa-antagonism rationale rests on preclinical models and neurobiologic theory. Larger, well-controlled clinical trials are needed to determine whether the proposed mechanisms translate into meaningful reductions in stimulant use, craving, and relapse. Still, the convergence of an unmet clinical need, a well-characterized safety profile, plausible stress-and-craving pharmacology, and enormous polysubstance overlap makes the proposition difficult to ignore. With more than 60,000 stimulant-related deaths each year and no approved medication in sight, the authors argue that Brixadi’s extended-release profile and potential to counter withdrawal-related dysphoria and stress-induced drug seeking present a compelling case for accelerated clinical investigation.

Subject of Research: Evaluation of extended-release injectable buprenorphine (Brixadi) as a potential pharmacotherapy for stimulant use disorder

Article Title: Brixadi for Stimulant Use Disorder: Evolving Pharmacologic Considerations and Clinical Implications

Article References: Sawaya, M. F., McNulty, M. E., Germain, C. J. S., Hachem, I. A., Calix, M. S., Lormand, R. M., McComb, N. J. E., Shehab, A. A. A., Wrightson, J., Anwar, A. I., Fontenot, C. J., Kaye, A. D., & Murnane, K. S. (2026). Brixadi for Stimulant Use Disorder: Evolving Pharmacologic Considerations and Clinical Implications. Advances in Therapy. https://doi.org/10.1007/s12325-026-03772-4

Image Credits: AI Generated

DOI: 10.1007/s12325-026-03772-4

Keywords: Brixadi, buprenorphine, stimulant use disorder, methamphetamine, cocaine, kappa-opioid receptor, dynorphin, polysubstance use, opioid use disorder, harm reduction, pharmacotherapy, addiction