A groundbreaking meta-analysis published in Communications Psychology in 2025 has unveiled compelling evidence that lower intelligence quotient (IQ) scores constitute a significant risk factor for the development of physical and mental illnesses. The study, titled “Multilevel multiverse meta-analysis indicates lower IQ as a risk factor for physical and mental illness,” authored by Fries, Oberleiter, Bodensteiner, and colleagues, employs advanced multilevel analytical techniques to systematically examine the intricate associations between cognitive ability and health outcomes. This innovative approach provides unprecedented statistical rigor and resolves inconsistencies observed in previous research, marking a pivotal advancement in the understanding of cognitive epidemiology.
The research leverages a multilevel multiverse meta-analytic framework, an emergent methodology designed to assess the robustness of results across vast analytical choices and variability among studies. This approach allows the incorporation of numerous datasets, diverse analytic strategies, and multiple outcome measures simultaneously, thereby saturating the evidence with a comprehensive sensitivity analysis to eliminate the influence of selective reporting and methodological bias. By applying this rigorous framework, the researchers have discerned patterns suggesting that lower IQ is not merely correlated with but may indeed be a causal risk factor for various health concerns spanning both physical diseases and psychiatric disorders.
At the core of this work is the recognition that cognitive ability, often quantified through IQ testing, reflects an individual’s capacity for learning, reasoning, and problem-solving. While traditionally associated with academic and occupational outcomes, cognitive ability’s role as a systemic determinant of health has gained increasing attention. The present study synthesizes existing literature across multiple domains of health, capturing data from epidemiological cohorts, clinical samples, and longitudinal studies, thereby calibrating a meta-analytic map that is striking in scope and depth. The findings highlight that individuals with lower cognitive abilities face elevated risks of conditions ranging from cardiovascular diseases and metabolic syndromes to mood disorders and schizophrenia-spectrum illnesses.
This expansive meta-analysis interrogates over a hundred independent cohorts comprising tens of thousands of individuals worldwide. By integrating data across diverse populations and analytical models, the results achieve remarkable generalizability. The multiverse approach investigates alternative operationalizations of IQ—for example, fluid versus crystallized intelligence measures—as well as different health endpoints, including incident disease rates, severity indices, and mortality risks. Importantly, this methodological rigor reveals that the IQ-health link is extraordinarily resilient to the choice of analytical parameters, underscoring the robustness of the association and dismissing concerns about potential confounding or mere statistical artifacts.
From a mechanistic perspective, the study explores plausible biological and psychosocial pathways linking cognitive ability to health trajectories. Lower IQ may impair an individual’s ability to navigate complex healthcare systems, adhere to prescribed treatment regimens, or comprehend health literacy information, culminating in suboptimal health behaviors. Neurobiological theories posit that cognitive deficits may originate from shared underlying pathophysiology, including neurodevelopmental insults or systemic inflammation, which also predispose individuals to chronic illness. Moreover, socioeconomic factors intertwined with cognitive ability compound these risks, although the multilevel modeling efforts control for socioeconomic status to isolate IQ’s unique contribution.
Among physical illnesses, cardiovascular disease emerges as a prominent outcome associated with lower IQ scores. The meta-analysis confirms that individuals with lower cognitive ability demonstrate higher incidence rates of hypertension, coronary artery disease, and stroke. The underlying explanations include poor lifestyle choices such as smoking, inactivity, and unhealthy diets, which are more prevalent among persons with lower IQ due to reduced health literacy and problem-solving skills necessary for preventive behaviors. Furthermore, the data implicate metabolic syndrome and type 2 diabetes as common comorbid conditions in this vulnerable group.
The mental health ramifications linked to lower IQ are equally profound. The amalgamated data from psychiatric epidemiology show a consistent pattern where diminished intelligence levels correspond with increased susceptibility to disorders such as depression, anxiety, bipolar disorder, and schizophrenia. This association transcends diagnostic boundaries, suggesting that cognitive ability underpins general resilience mechanisms against psychopathology. Moreover, longitudinal analyses reveal that cognitive deficits often precede the onset of psychiatric symptoms, implying a potential etiological role rather than a consequence of illness.
Interestingly, the meta-analysis provides insights into age-related cognitive decline and its convergence with physical and mental health outcomes. It suggests that the intersection between baseline IQ in early life and subsequent cognitive aging trajectories critically modulates later health risks. Individuals who commence adulthood with lower intelligence scores are more likely to experience accelerated cognitive deterioration, which further compounds their vulnerability to diseases, perpetuating a vicious cycle. This developmental perspective advocates for early-life interventions aimed at preserving and enhancing cognitive functions to promote long-term health.
Despite the strong associations found, the study meticulously addresses potential methodological limitations inherent in meta-analytic studies. The authors discuss sources of heterogeneity, publication bias, and reverse causation possibilities. Sensitivity analyses conducted through the multiverse framework bolster confidence that the reported findings are not artifacts of selective reporting or biased sample selection. Furthermore, the use of multilevel models allows differentiation between within-study and between-study variances, ensuring nuanced interpretations of effect sizes and heterogeneity.
The implications of this research extend far beyond academic discourse. Recognizing lower IQ as a bona fide risk factor calls for integrated public health strategies that incorporate cognitive assessments into routine medical screenings. Health practitioners are urged to consider cognitive ability when designing personalized prevention and intervention plans, ensuring information is accessible and actionable for individuals across the IQ spectrum. This paradigm shift could markedly enhance compliance with medical recommendations, reduce disease burden, and ultimately close disparities in health outcomes linked to cognitive disparities.
Moreover, the findings provide a compelling case for targeted educational and cognitive development programs commencing early in life. Such interventions may yield dual benefits by enhancing cognitive skills and fostering healthier lifestyle choices, thereby attenuating risk trajectories before the onset of clinical illness. Policymakers might leverage this evidence to allocate resources toward community-based cognitive enrichment initiatives as a component of comprehensive health promotion efforts.
In the scientific arena, the study sets a new standard for meta-analytic rigor. The adoption of multiverse methodologies to meta-analysis embodies a transformative approach, promoting transparency, reproducibility, and robustness in evidence synthesis. By showcasing how analytic flexibility influences conclusions and demonstrating methods to safeguard against interpretive bias, this work encourages future investigations to embrace similar frameworks, enhancing the credibility and impact of meta-research.
Furthermore, the integrative nature of the study underscores the importance of multidisciplinary collaborations bridging psychology, epidemiology, neuroscience, and public health. Such synergy enables a holistic understanding of complex biopsychosocial phenomena like the interplay between intelligence and health. The comprehensive dataset compiled and analyzed by Fries and colleagues serves as a valuable resource for researchers aiming to explore causal pathways and intervention potentials grounded in cognitive metrics.
Looking ahead, the research opens several promising avenues for exploration. Further work is warranted to dissect the causal mechanisms at molecular, neural, and behavioral levels, potentially employing longitudinal neuroimaging and genomics to elucidate pathways linking intelligence to health. The role of environmental moderators such as education quality, social support, and stress exposure also requires detailed examination. Ultimately, the insights garnered from this multilevel multiverse meta-analysis lay a solid foundation for precision medicine approaches that integrate cognitive and health data holistically.
In summary, Fries et al.’s seminal meta-analysis decisively demonstrates that lower IQ is a potent and independent risk factor for a wide array of physical and mental health disorders. By utilizing cutting-edge statistical methodologies, the study transcends prior analytical limitations, providing robust and generalizable evidence that cognitive ability profoundly influences health trajectories across the lifespan. These findings challenge clinicians, researchers, and policymakers alike to rethink traditional views of risk assessment and to harness cognitive metrics as vital tools in the quest for improved population health outcomes.
Subject of Research: The relationship between lower IQ and its role as a risk factor for physical and mental illnesses.
Article Title: Multilevel multiverse meta-analysis indicates lower IQ as a risk factor for physical and mental illness.
Article References:
Fries, J., Oberleiter, S., Bodensteiner, F.A. et al. Multilevel multiverse meta-analysis indicates lower IQ as a risk factor for physical and mental illness. Commun Psychol 3, 74 (2025). https://doi.org/10.1038/s44271-025-00245-2
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