The investigators used the Hamburg Nightmare Questionnaire to assess the type, frequency and components of nightmares. Depression, anxiety and stress symptoms were evaluated with the Depression, Anxiety, and Stress Scale-21. The study aimed to compare nightmare characteristics with the presence of depression, anxiety and stress symptoms among nursing students.

According to the abstract, students who reported nightmares once per week had symptom levels of 21.6% for depression, 29.0% for anxiety and 23.9% for stress. These figures were higher than the corresponding levels reported by students experiencing nightmares at other frequencies. The abstract also states that emotional involvement, physiological components and replicability were higher in nursing students with depression, anxiety and stress symptoms.

The results support an association between replicative nightmares and anxiety symptoms in this group of nursing students. The available evidence describes an observational association rather than establishing that nightmares cause depression, anxiety or stress. The published abstract does not provide details about participant recruitment, the distribution of students across nightmare-frequency categories, statistical uncertainty, potential confounding factors or other measures needed to assess the study’s broader limitations. The authors’ conclusion also calls for mental health professionals and nursing student mentors to consider the presence, type and components of nightmares when addressing students’ mental health, including possible psychopathology and suicidal behavior.

Subject of Research: Associations between nightmares and mental health symptoms among nursing students in southern Mexico

Article Title: Replicative, frequency and emotional component nightmares are associated with depression, anxiety, and stress in nursing students from southern Mexico

Article References: González-Castro, T. B., Genis Mendoza, A. D., López-Narváez, M. L., Tovilla-Zárate, C. A., García-Alejandro, B., Fresán, A., Peregrino-Bolaina, A., de la Rosa Pérez, H., Nicolini, H., & Hernández-Díaz, Y. (2026). Replicative, frequency and emotional component nightmares are associated with depression, anxiety, and stress in nursing students from southern Mexico. BMC Nursing. https://doi.org/10.1186/s12912-026-05341-0

Image Credits: AI Generated

DOI: 10.1186/s12912-026-05341-0

Keywords: nightmares, nursing students, depression, anxiety, stress, mental health, cross-sectional association, BMC Nursing, Replicative, frequency, emotional, component

The physiological logic behind the NightWare system rests on a well-documented phenomenon: nightmares, particularly those associated with post-traumatic stress disorder, are accompanied by measurable surges in autonomic arousal. Heart rate accelerates, movement increases, and the body behaves as though the threat depicted in the dream is real. By continuously sampling heart rate, accelerometer, and gyroscope data from a wrist-worn device, the algorithm builds an individualized profile of each sleeper’s normal nocturnal physiology and then detects departures from that baseline. The intervention threshold is not fixed but adaptively recalculated from the previous 1,000 minutes of recorded sleep, which means the system gradually refines its understanding of what constitutes an abnormal arousal episode for that specific person. When the computed stress index crosses the threshold, the watch delivers escalating vibrotactile stimulation in three graded levels, beginning with brief, gentle tap patterns and intensifying only if the arousal persists. The stated goal is to interrupt the nightmare without fully waking the patient, allowing a return to less disturbed sleep rather than replacing a nightmare with a prolonged awakening.

The design of this pilot reflects its real-world origins. Rather than recruiting volunteers through advertisements and enrolling them under experimental conditions, the investigators followed patients who had already been prescribed the device in routine clinical care, then asked them to complete structured self-report assessments at baseline, day 30, and day 60. The co-primary endpoints were deliberately simple and clinically interpretable: the number of nights with nightmares per week, recorded on a zero-to-seven scale, and nightmare-related distress, rated on a five-point ordinal scale from zero to four. Both endpoints showed statistically robust improvement. Nightmare frequency fell from a mean of 5.2 nights per week to 3.6, a reduction of 1.6 nights with a 95 percent confidence interval spanning 2.7 down to 0.5, and a standardized effect size of 1.0, which in behavioral research is considered a large effect. Distress fell from 2.9 to 1.3, also a 1.6-point change but with a tighter confidence interval of 2.2 to 1.0 and an effect size of 1.9, an exceptionally large value that reflects how consistently participants moved in the same direction on this measure.

The repeated-measures analysis of variance confirmed that the decline was progressive across all three time points rather than a single before-and-after shift, with p values of 0.009 for frequency and 0.003 for distress. Perhaps more informative than the averages are the individual response patterns. Seven of the ten completers reduced how often they experienced nightmares, and nine of ten reported less distress. Critically, not a single participant worsened on either measure over the 60-day observation window. In a condition where patients often cycle through multiple failed treatments, the absence of any deterioration, even in a sample this small, is a noteworthy signal about tolerability and acceptability, though it cannot by itself establish efficacy.

Adherence data offer another window into how the device functioned outside a controlled trial. Participants wore the system a mean of 76 percent of nights, equivalent to 45.6 of the 60 survey nights, with individual usage ranging from 55 percent to a full 100 percent. For a prescription digital therapeutic that requires putting on a dedicated watch every night, this level of sustained engagement is meaningful, particularly given that the population studied works unpredictable shifts, experiences fragmented sleep, and may be skeptical of novel interventions. Self-reported sleep quality and treatment satisfaction also improved over the study period, suggesting that the benefits participants perceived extended beyond the nightmare endpoints themselves.

The choice of first responders as the study population deserves emphasis. These are individuals whose occupational exposure to potentially traumatic events is not incidental but structural, woven into the routine of their work. A systematic review and meta-regression has estimated the worldwide current prevalence of PTSD among rescue workers at approximately 10 percent, several-fold higher than in the general population. Cross-sectional data from 242 active-duty first responders across the United States found that more than half reported trauma-related nightmare distress within the past week, 23.2 percent reported clinically significant distress, more than a third screened positive for provisional insomnia, and 23.1 percent for provisional PTSD. Those same participants reported a mean of roughly 12 lifetime traumatic event types, dominated by death-threat traumas such as sudden violent death, a profile that mirrors the realities of public safety work.

One finding from that broader literature is particularly relevant to why nightmares matter as a treatment target rather than merely a symptom to monitor. Trauma-related nightmares and hyperarousal symptoms were independently associated with fear of sleep, a fear of being vulnerable while sleeping, even after adjusting for remaining PTSD symptoms, insomnia, sex, and years of service. This suggests nightmares are not simply a passive marker of overall distress but may actively drive maladaptive sleep-avoidance behaviors that perpetuate insomnia and compound occupational impairment. In other words, reducing nightmare frequency and intensity could interrupt a self-reinforcing cycle in which the anticipation of nightmares makes sleep itself threatening, which in turn worsens the sleep deprivation that exacerbates PTSD symptoms.

The stakes extend beyond sleep quality. Frequent nightmares have been identified as an independent predictor of suicide: in a large prospective general-population cohort, frequent nightmares were associated with roughly twice the risk of death by suicide, an association that persisted after adjustment for other factors. Among 1,027 current and retired firefighters, career prevalence of suicidal ideation reached 46.8 percent and suicide attempts 15.5 percent, far exceeding general-population lifetime rates. Screening studies suggest 17 to 22 percent of urban firefighters meet criteria for clinically significant posttraumatic stress symptoms, a figure that likely exceeds diagnosed prevalence because of a culture of stigma that delays help-seeking. It must be stated plainly that the present pilot did not assess suicidality and makes no claim that the intervention reduces suicide risk; this literature is cited only to explain why nightmare reduction is a clinically meaningful objective in this population.

Existing treatments for nightmare disorder leave substantial gaps that a wearable approach is positioned to address. Imagery rehearsal therapy, the first-line behavioral treatment recommended by the American Academy of Sleep Medicine, involves rehearsing rewritten versions of recurring nightmares while awake, but qualified providers are scarce and a substantial proportion of patients cannot or will not engage in the therapy. Prazosin, an alpha-adrenergic antagonist long used off-label for PTSD-related nightmares, failed to separate from placebo on sleep quality or distressing dreams in the largest and most rigorous multicenter trial conducted to date, tempering enthusiasm for its routine use. For first responders specifically, occupational and fitness-for-duty considerations can further limit the use of centrally acting medications, since sedating or cognitively impairing drugs may conflict with carrying a firearm, driving an emergency vehicle, or making split-second decisions on duty. A non-pharmacologic, peripherally acting intervention that works during sleep without producing morning grogginess therefore occupies a genuinely unmet niche.

The regulatory pathway matters as well. NightWare was authorized by the U.S. Food and Drug Administration through the De Novo pathway in 2020 for the reduction of sleep disturbance related to nightmares in adults with nightmare disorder or PTSD-associated nightmares. The system consists of a pre-provisioned Apple Watch and paired iPhone prescribed as a dedicated therapeutic kit, which means it arrives configured for clinical use rather than requiring patients to supply their own hardware or navigate consumer setup. This prescription-only model distinguishes it from consumer wellness wearables and places it within a growing category of digital therapeutics that undergo regulatory review, though the evidentiary standards for such devices remain an evolving area of debate in the field.

Several limitations temper the enthusiasm warranted by these results, and the authors themselves characterize the findings as hypothesis-generating. The sample of ten completers is small enough that individual variation could substantially influence the group means, and the open-label design, in which participants knew they were receiving an active intervention and knew the study’s purpose, leaves open the possibility of expectancy effects and placebo response, both of which are well documented in sleep and psychiatric research. The reliance on self-report rather than validated instruments or objective measures such as polysomnography further limits the strength of the conclusions, as does the absence of a control group. Natural fluctuation in nightmare frequency over time, regression to the mean in patients selected at a particularly symptomatic moment, and the structured attention of repeated assessments could each contribute to apparent improvement. The 91 percent completion rate, while encouraging, also reflects a self-selected group willing to continue using the device, raising the possibility that less satisfied users dropped out.

What the pilot does establish is feasibility and a signal worth pursuing. The effect sizes observed, particularly the 1.9 for distress, are large enough that they would be difficult to attribute entirely to measurement artifacts, and the consistency of improvement across participants, endpoints, and time points lends credibility to the pattern. The real-world recruitment model, drawing from routine clinical care rather than a research registry, also offers a preview of how the intervention performs under ordinary prescribing conditions, which is often where promising treatments encounter their greatest practical challenges. Controlled studies with validated instruments, larger samples, and longer follow-up periods are the logical next step, and the authors explicitly call for them. If those trials confirm what this pilot suggests, first responders, a population that has historically been under-represented in nightmare-treatment research despite carrying a disproportionate share of the trauma burden, would gain a treatment option that works with their physiology rather than against their occupational constraints.

Broader implications extend to how digital therapeutics may reshape the treatment landscape for trauma-related sleep disorders more generally. Continuous physiological monitoring during sleep, paired with adaptive algorithms that personalize intervention thresholds, represents a fundamentally different approach from once-daily medications or weekly therapy sessions. Whether this paradigm delivers durable benefit, how it performs across diverse populations beyond first responders, and how it integrates with existing evidence-based treatments such as imagery rehearsal therapy and trauma-focused psychotherapy remain open questions. The present study, limited as it is, contributes a data point from a population whose sleep disturbances have too often been studied only in military veterans, and it demonstrates that prescription wearables can achieve meaningful engagement in a group whose schedules, stress levels, and occupational culture pose real barriers to conventional care.

Subject of Research: A wearable haptic-feedback device for reducing nightmare frequency and distress in first responders with PTSD

Article Title: Real-world reduction in nightmare frequency and distress among San Francisco first responders treated with a prescription wearable device: a 60-day open-label pilot

Article References: Robertson, B. D., Wargo, E. F., & Fay, J. (2026). Real-world reduction in nightmare frequency and distress among San Francisco first responders treated with a prescription wearable device: a 60-day open-label pilot. Frontiers in Sleep, 5, Article 1941077. https://doi.org/10.3389/frsle.2026.1941077

Image Credits: AI Generated

DOI: 10.3389/frsle.2026.1941077

Keywords: nightmares, PTSD, first responders, wearable device, NightWare, sleep quality, digital therapeutic, haptic feedback, pilot study, nightmare disorder, vibrotactile stimulation, open-label trial

The treatment at the center of this effort is Cognitive Behavioral Therapy for Nightmares, abbreviated CBT-N. It is a recently standardized protocol that consolidates the key components of previously existing nightmare therapies, including exposure to nightmare content, nightmare rescripting, and imagery rehearsal. Historically, the behavioral nightmare treatment literature has been mired in confusion, with inconsistent use of treatment components across manuals that carried the same name. The impetus for formalizing these components under the CBT-N umbrella was, in part, to reduce that confusion and make it easier for clinicians to deliver nightmare therapy with fidelity. Because the manual is so new, however, important questions remain about how to bring the treatment to the patients who need it most, such as veterans, and how the protocol is received by providers working in different clinical settings.

A study by Bolstad and colleagues, recently published in the same journal, has begun answering those questions by bringing CBT-N into the Primary Care Mental Health Integration clinic at the Veterans Health Administration. This setting is notable for at least two reasons. First, behavioral health providers in this setting are embedded within primary care clinics, which do not typically assess nightmares. That integration allows behavioral health providers to see a much larger scope of patients than providers in traditional mental health clinics, including patients who may be reluctant to seek psychotherapy. Implementing CBT-N in this environment therefore has the potential to expand access to nightmare treatment for veterans at scale, reaching people who would never walk through the doors of a specialty sleep or PTSD clinic.

Second, the primary care mental health model follows a brief format of care, with patients receiving an average of two to three behavioral health sessions lasting only twenty to thirty minutes each. This is a stark departure from traditional mental health clinics, which typically entail at least six sessions of fifty to sixty minutes. CBT-N, by contrast, involves six sessions of sixty to ninety minutes. Evaluating the implementation of CBT-N in the primary care setting is therefore ideal for revealing how the treatment should be adapted for such a fast-paced environment, and whether the full protocol can survive compression into shorter encounters.

The findings from the Bolstad study reveal a striking tension between perceived benefit and perceived feasibility. Clinicians in the primary care integration setting perceived greater benefits of CBT-N for veterans compared to clinicians in other Veterans Health Administration mental health settings, such as the PTSD Clinical Team. They detected greater change in how veterans related to their nightmares, for example feeling less afraid of them, and they also perceived greater improvement in veterans’ mental health more broadly, including trauma-related and depressive symptoms and quality of life. Despite these perceived benefits, primary care clinicians rated CBT-N as less appropriate and less feasible to deliver than their counterparts in other settings did, with fifty-seven percent of them citing time constraints as the barrier. In response, the researchers propose adapting CBT-N for primary care by using shorter, more frequent sessions.

An important caveat accompanies these results. It is possible that veterans in the primary care setting appeared to do better because they were less distressed than those seen in traditional mental health clinics. Perhaps primary care clinicians intervened early in the nightmare-disease course, reducing the risk of worsening mental health, whereas clinicians in specialty settings likely saw patients who had already reached clinically significant distress. This interpretation assumes that nightmares are sentinel symptoms, the early treatment of which produces downstream preventive effects. That assumption could not be tested in the Bolstad study itself, but it is precisely the proposition now being examined in new research with acutely traumatized patients.

Nightmares affect anywhere from forty-six to seventy-three percent of acute trauma patients and serve as a prodrome for both PTSD and suicidal ideation. A research team at Henry Ford Health in Detroit is piloting a randomized controlled trial of behavioral sleep interventions delivered in the immediate aftermath of trauma, with the goal of halting the progression to post-trauma pathology. The trial enrolls patients discharged from thirteen emergency departments across the health system within seventy-two hours of a traumatic event. Patients are randomized and triaged based on symptoms to cognitive behavioral therapy for insomnia, CBT-N, or a sleep education control condition with or without nightmare education. Thus far, thirty-four patients have been randomized, most commonly following physical assault, and the demand for nightmare treatment has been significant, with more than eighty-five percent of acute trauma patients expressing interest in nightmare therapy.

The delivery method may be as important as the treatment itself. The interventions are delivered via telehealth video to reduce barriers to care, and the early numbers are encouraging: seventy-six and a half percent of randomized patients initiated treatment, whereas roughly half of patients discharged from the emergency department typically attend an outpatient mental health visit. Moreover, every patient enrolled so far found it very easy to attend the video sessions after trauma, and more than seventy percent said it would have been difficult to attend sessions had they been in person. When asked about preferred formats for future services, the overwhelming majority preferred video over in-person sessions, and all patients preferred video sessions over a mobile app. Future analyses will evaluate the preventive effects of early CBT-N and insomnia therapy on subsequent PTSD relative to control.

Together, these efforts point toward a broader rethinking of where mental health care happens. Providers working across different settings are encouraged to bring CBT-N into their own practices, including sleep medicine clinics, and can offer treatment to patients experiencing what researchers call DARC nightmares: dreams that cause Awakenings, are at least partially Remembered, and cause Clinically significant impairment. Remaining questions include whether and how CBT-N should be adapted for active-duty military personnel, first responders, and inpatients hospitalized after traumatic injury who may be physically unable to write about their nightmares as the protocol requires. Each population presents its own logistical and clinical constraints, and each represents a group in which nightmares are common but treatment access is scarce.

The overarching lesson from this line of research is sobering but actionable: not all who need mental health care are in the waiting rooms of behavioral health clinics. Nightmares are under-reported, under-detected, and therefore under-treated, and the patients most likely to benefit from nightmare therapy are often sitting in primary care offices or recovering at home after an emergency department visit rather than seeking specialty psychotherapy. As providers and researchers, the commentary’s authors argue, the field ought to be thoughtful about meeting patients where they are, and about adapting evidence-based treatments to fit those contexts, wherever they may be. If early intervention after trauma can genuinely interrupt the cascade toward PTSD and suicidal thinking, bringing nightmare therapy out of the specialty clinic and into primary and acute care could transform prevention for trauma survivors on a population scale.

Subject of Research: Implementation of cognitive behavioral therapy for nightmares in primary and acute care settings for trauma-exposed patients

Article Title: Bringing cognitive behavioral therapy for nightmares to patients with trauma: increasing access and feasibility via primary and acute care

Article References: Reffi, A. N., Peltzer-Jones, J., Moore, D. A., Johnson, J. L., & Drake, C. L. (2026). Bringing cognitive behavioral therapy for nightmares to patients with trauma: increasing access and feasibility via primary and acute care. Journal of Clinical Sleep Medicine, 22(1), Article 107. https://doi.org/10.1007/s44470-026-00108-5

Image Credits: AI Generated

DOI: 10.1007/s44470-026-00108-5

Keywords: nightmares, cognitive behavioral therapy, CBT-N, PTSD, trauma, veterans, primary care, emergency department, telehealth, sleep medicine, suicidal ideation, mental health access

The study team, led by E. M. S. K. Edirisinghe and colleagues, recruited 422 adults receiving maintenance dialysis at the national nephrology hospital, using consecutive non-probability sampling. Participants were interviewed with a structured questionnaire that combined several well-validated instruments: the Pittsburgh Sleep Quality Index, a widely used measure of sleep across seven components ranging from latency to daytime dysfunction; the Depression Anxiety Stress Scales-21, a shortened psychological screening tool; and six selected items from the Mannheim Dream Questionnaire, supplemented by four study-specific dream items. The interview-administered format matters in this setting, where literacy and fatigue can make self-completed questionnaires unreliable.

The headline numbers are stark. Seventy-two percent of participants—304 of the 422—qualified as poor sleepers on the Pittsburgh index, with a mean global score of 9.58 out of a possible 21, well above the conventional threshold of five that signals clinically relevant sleep disturbance. The mean total DASS-21 score was 20.71 with a standard deviation of 10.34, and when the researchers split the sample into tertiles, psychological symptom burden was spread widely across the cohort rather than concentrated in a small distressed minority. For a population already coping with a life-sustaining treatment regimen, the findings paint a picture of exhaustion layered on top of illness.

But the most striking results concern dreams. Of the ten dream characteristics assessed, six showed statistically significant correlations with psychological distress. The strongest was nightmare distress—the emotional impact of bad dreams—with a Spearman correlation coefficient of 0.50. Dream-related sleep disturbance followed at 0.47, and nightmare frequency at 0.46. In epidemiological terms, correlations of this magnitude are substantial, particularly for a phenomenon as rarely measured as dreaming. The suggestion that the emotional tone of sleep might mirror the emotional burden of waking life is not new in dream science, but demonstrating it in a dialysis cohort in rural Sri Lanka adds an unexpected and clinically useful data point.

To move beyond simple correlations, the team built a multiple linear regression model, adjusting for sleep quality and socio-demographic variables and applying a Benjamini–Hochberg correction to guard against false positives across multiple comparisons. Dream-related sleep disturbance emerged as the strongest independent predictor of distress, with a standardized beta of 0.34, followed by nightmare frequency at 0.27. Male sex, longer dialysis duration, higher global Pittsburgh Sleep Quality Index scores, and unemployment were all positively associated with distress, each with betas around 0.08 to 0.10. Being married was inversely associated, with a beta of minus 0.09, hinting at a protective effect of partnership. The model as a whole explained 43 percent of the variance in distress scores—adjusted R-squared of 0.43—which is respectable for psychological research in a medical population.

The direction of these associations invites careful interpretation, and the authors are appropriately cautious. Because the study is cross-sectional, it cannot establish whether distressing dreams drive psychological distress, whether distress breeds nightmares, or whether both flow from a common source such as chronic inflammation, uremia, or the sheer stress of dialysis dependence. Nor can the design determine whether dialysis patients dream more badly than the general population, since there was no comparison group. What the study does establish is that dream-related sleep disturbance carries information about distress that is not fully redundant with measured sleep quality or demographic risk factors—a non-trivial finding for anyone designing screening protocols.

The mechanistic plausibility is worth unpacking. Sleep in dialysis patients is already fragmented by physical discomfort, restless legs, pruritus, and the metabolic derangements of kidney failure. Rapid eye movement sleep, the stage in which vivid dreams and nightmares predominantly occur, is sensitive to stress hormones and to sleep fragmentation itself. A patient whose night is repeatedly interrupted may experience rebound REM periods punctuated by intense, emotionally charged dreams, which in turn heighten nocturnal arousal and further degrade sleep. This feedback loop—poor sleep breeding disturbing dreams breeding worse sleep—is a recognized model in insomnia research, and cognitive-behavioral therapy for insomnia is one established intervention that targets it. Whether such approaches work in dialysis populations remains to be tested.

The Sri Lankan setting gives the findings particular public health weight. Chronic kidney disease, including chronic kidney disease of undetermined aetiology, has reached epidemic proportions in agricultural regions of the country, and Polonnaruwa sits at the heart of the affected zone. In low- and middle-income countries, nephrology services are typically stretched to deliver life-sustaining dialysis, leaving psychological care and sleep medicine far down the priority list. The authors argue that sleep and psychological assessment should remain clinical priorities in dialysis units, and that a targeted question about recurrent distressing dreams—a query that costs nothing to ask—may help identify symptomatic patients who would otherwise go unnoticed.

The demographic predictors also deserve attention. The cohort was 67.1 percent male, with a mean age of 54.6 years, and male sex independently predicted higher distress even after adjustment. Longer time on dialysis and unemployment both added to the burden, consistent with the idea that the psychological toll of kidney disease accumulates with treatment duration and is compounded by lost livelihood. The inverse association with marriage echoes a long literature on social support and mental health, suggesting that household relationships may buffer some of the emotional cost of chronic illness in this cultural context.

For now, the study’s practical takeaway is modest but actionable: clinicians caring for dialysis patients should ask about sleep and about dreams, not as an afterthought but as part of routine assessment. A patient who reports nightmares that wake them and bleed into their daytime functioning may be flagging psychological distress that a standard medical review would miss. The authors are explicit that their findings warrant further evaluation rather than immediate causal claims, and that the absence of a comparison group means no one should conclude that dialysis patients are uniquely plagued by nightmares. Still, in a field where the inner experience of patients is so often reduced to lab values and clearance rates, a study that takes dreams seriously—and finds that they correlate with real, measurable suffering—represents a genuinely fresh angle on an old problem. The next step will be longitudinal work that can disentangle whether healing sleep, or healing dreams, helps heal the mind.

Subject of Research: Sleep quality, dream characteristics, and psychological distress in dialysis patients with chronic kidney disease

Article Title: Dreaming, sleep quality, and psychological distress among patients with chronic kidney disease at a national nephrology hospital in Sri Lanka: a descriptive cross-sectional study

Article References: Edirisinghe, E. M. S. K., Wimalasiri, A. J. W. A. N., Sirithunga, S. S., Ekanayake, A. G. W. K., Edirisinghe, D. A. S., Rathnakumari, K. N., & Perera, A. C. H. (2026). Dreaming, sleep quality, and psychological distress among patients with chronic kidney disease at a national nephrology hospital in Sri Lanka: a descriptive cross-sectional study. BMC Public Health. https://doi.org/10.1186/s12889-026-29765-0

Image Credits: AI Generated

DOI: 10.1186/s12889-026-29765-0

Keywords: chronic kidney disease, dialysis, sleep quality, nightmares, psychological distress, dreaming, Pittsburgh Sleep Quality Index, DASS-21, Sri Lanka, cross-sectional study, public health, sleep

The study drew on a large national cohort assembled from the Finnish Parkinson’s Association, an organization with roughly 7,500 members, of whom 5,373 were registered as Parkinson’s patients. From this registry, the researchers randomly selected 1,500 individuals and mailed a structured sleep questionnaire to 1,447 eligible participants between 2010 and 2011. Every included patient had a Parkinson’s diagnosis confirmed by a neurologist in accordance with national clinical guidelines consistent with the Gelb diagnostic criteria. The questionnaire incorporated validated sleep items from the Basic Nordic Sleep Questionnaire, a well-established instrument for quantifying subjective sleep complaints. A follow-up questionnaire was sent in 2014 to 2015, and after reminders and telephone contact, 183 participants provided complete data at both time points, forming the analytical cohort for the longitudinal comparison.

The researchers measured an unusually broad set of sleep domains at both time points. Daytime sleepiness was assessed with the Epworth Sleepiness Scale, restless legs syndrome with the international four-item diagnostic criteria, and REM sleep behavior disorder symptoms with the REM Sleep Behavior Disorder Screening Questionnaire, on which a score of six or higher suggests the disorder. Sleep apnea risk was screened with the STOP questionnaire, insomnia symptoms were captured through difficulty initiating sleep, nocturnal awakenings, early morning awakenings, and non-restorative sleep, and circadian timing was estimated from midsleep, the midpoint between sleep onset and wake time. The team also recorded medication use, converting self-reported drugs into levodopa equivalent doses, and screened depressive symptoms with Rimon’s Brief Depression Scale, an instrument deliberately designed to exclude insomnia items so that sleep complaints would not inflate depression scores.

Over the five-year interval, mean disease duration in the cohort rose from 5.5 to 9.7 years, mean levodopa equivalent dose increased from 607.8 to 732.6 milligrams, and the proportion of sedentary participants nearly doubled from 9.0 to 18.0 percent. Against this backdrop of advancing disease, the sleep data told a nuanced story. Total sleep time edged up only trivially, from 7.0 to 7.2 hours, a change that was not statistically significant. Individual insomnia symptoms, including trouble falling asleep, frequent night awakenings, early morning awakening, and unrefreshing sleep, showed no significant deterioration, and a composite measure capturing any insomnia symptom or regular use of sleep medication remained flat. Daytime fatigue and hallucinations were likewise stable, a finding that contrasts with several earlier reports describing insomnia as a progressively worsening complaint in Parkinson’s disease.

In sharp contrast, the symptoms tied to REM sleep pathology advanced markedly. The proportion of participants who talked in their sleep at least once a week nearly doubled, rising from 17.4 to 30.4 percent. Weekly nightmares increased from 14.8 to 24.6 percent. The mean REM Sleep Behavior Disorder Screening Questionnaire score climbed from 4.4 to 5.3 points, and the share of participants crossing the screening threshold of six or more rose from 28.9 to 39.9 percent. REM sleep behavior disorder, in which patients act out their dreams because the normal muscle paralysis of REM sleep fails, is recognized as a core prodromal feature of synucleinopathies, the family of neurodegenerative diseases that includes Parkinson’s, and it is strongly linked to later cognitive decline and a more aggressive disease course. The authors argue that the longitudinal rise in these symptoms reflects active progression of REM sleep pathology rather than an incidental annoyance.

Daytime sleepiness also worsened in clinically meaningful ways. The proportion of participants with an Epworth Sleepiness Scale score above 10, the conventional cutoff for excessive sleepiness, increased from 30.6 to 38.8 percent, while severe sleepiness, defined as a score above 15, rose from 8.9 to 14.8 percent. Daily napping grew from 21.4 to 31.7 percent of the cohort, likely mirroring the rising sleepiness. Prevalence of restless legs syndrome climbed from 21.0 to 31.2 percent, an increase the authors note is broadly consistent with cross-sectional studies showing elevated restless legs frequency in more advanced Parkinson’s disease. Because restless legs syndrome shares dopaminergic pathways with Parkinson’s itself, the rise alongside increasing levodopa doses could reflect inadequate treatment or, importantly, augmentation, a paradoxical worsening of symptoms caused by long-term dopaminergic therapy itself.

To understand what drove the worsening sleepiness, the researchers built multivariate logistic regression models with excessive daytime sleepiness as the outcome. Three factors emerged as independent predictors: higher depression scores, use of dopamine agonists, and high risk of sleep apnea on the STOP questionnaire. Dopamine agonist use carried an odds ratio of 3.92, meaning users faced nearly four times the odds of excessive sleepiness compared with non-users after adjustment. Notably, neither levodopa nor MAO inhibitor use was associated with sleepiness, and age, total sleep time, and REM behavior disorder screening score were not independently predictive. The authors emphasize that this pattern highlights the need to investigate secondary, potentially treatable causes, such as undiagnosed sleep apnea or depression, before attributing sleepiness solely to disease progression.

The study has important strengths and candidly acknowledged limitations. Its prospective design with a five-year interval and consistent use of a validated questionnaire at both time points allow genuine longitudinal inference across multiple sleep domains simultaneously, something most prior studies, which typically examined single symptoms in cross-sectional or short-term designs, could not provide. However, the follow-up sample of 183 is small relative to the baseline cohort of 611, and the analysis was restricted to participants with complete data at both points. Those who completed follow-up were younger, had shorter disease duration, higher body mass index, and better quality of life than those excluded, indicating a healthy-survivor effect that likely makes the reported changes conservative underestimates of true progression. The questionnaire-based approach also means that REM sleep behavior disorder and sleep apnea were identified through surrogate markers rather than video-polysomnography, the gold standard, and Parkinson’s diagnoses were self-reported as neurologist-confirmed without record re-verification.

Despite these caveats, the selective pattern of progression carries a clear clinical message. Sleep in Parkinson’s disease is not a single monolithic complaint that simply deepens over time; it is a collection of distinct disorders evolving on different trajectories, some driven by neurodegeneration, some by medication, and some by comorbid conditions. The stability of insomnia and total sleep time suggests that these features may reflect aging and individual vulnerability more than disease progression, whereas the rise in REM-related behaviors, sleep talking, and nightmares tracks the underlying neurodegenerative process and, as the team’s earlier work in this same cohort showed, is associated with increased mortality. The authors conclude that multi-domain sleep assessment should be routine in Parkinson’s care, and that sleep talking and REM behavior disorder screening scores deserve attention not merely as symptoms to soothe but as markers of disease progression with genuine prognostic weight. For patients and clinicians alike, the message is that worsening sleep deserves careful, domain-specific evaluation rather than a one-size-fits-all response.

Subject of Research: Longitudinal changes in sleep characteristics and sleep disorders over five years in Parkinson's disease

Article Title: Changes in sleep characteristics in Parkinson’s disease: a prospective 5-year follow-up study

Article References: Partinen, E., Ylikoski, A., Hublin, C., & Partinen, M. (2026). Changes in sleep characteristics in Parkinson’s disease: a prospective 5-year follow-up study. Journal of Clinical Sleep Medicine, 22(1), Article 166. https://doi.org/10.1007/s44470-026-00169-6

Image Credits: AI Generated

DOI: 10.1007/s44470-026-00169-6

Keywords: Parkinson's disease, sleep disorders, excessive daytime sleepiness, REM sleep behavior disorder, sleep talking, nightmares, restless legs syndrome, insomnia, dopamine agonists, sleep apnea, prospective cohort study, daytime napping