Higher intelligence and complex behaviors are correlated with increased mental illness
the verdict
REFUTED
the evidence says no
refutedsupported
the weight of evidence
1 source for · 1 against
Available literature evidence directly refutes the claim that higher intelligence is a risk factor or positively correlated with an increased prevalence of psychiatric disorders.
The gut-brain axis (GBA) is a complex, bidirectional communication network critical to integrating central nervous system functions with gastrointestinal (GI) health. This review examines how disruptions to the GBA during the critical early-life developmental window - a period of rapid neurogenesis and microbial colonization - contribute to long-term neurocognitive and psychiatric vulnerabilities. Evidence from animal models demonstrates that early-life stress, antibiotics, and infection induce sustained neuro-inflammation and alter microglial function, leading to long-term behavioral and cognitive impairments in adulthood. Human studies corroborate these findings, revealing that severe early GI insults, such as necrotizing enterocolitis, confer a high risk (40%) of global neurodevelopmental impairment and specific attention deficits. Chronic inflammatory conditions similarly impact the central nervous system: A high burden of early severe enteric infection is an independent risk factor for diminished intelligence quotient (IQ) and executive function, while conditions like celiac disease and inflammatory bowel disease are associated with persistent deficits in attention, processing speed, memory, and executive function. These clinical outcomes are strongly linked to systemic inflammation [elevated interleukin-6, kynurenine-to-tryptophan (Kyn:Trp) ratio], micronutrient deficiencies (iron, vitamin B12, folate), and structural white matter changes in the brain. Furthermore, chronic GI disease imposes a significant psychiatric burden, with high comorbidity of anxiety and depression often mediating poor health-related quality of life, particularly in pediatric inflammatory bowel disease. The findings underscore the necessity for a shift in clinical practice: Chronic GI disease in early life must be recognized as a red flag for neurocognitive risk. We advocate for a multidisciplinary approach encompassing early neurodevelopmental follow-up for high-risk groups and routine screening for cognitive and emotional comorbidities. Future research must focus on long-term prospective cohorts, identifying precise mechanistic biomarkers (metabolomics, microbiome signatures), and conducting interventional trials targeting the GBA to mitigate these long-term functional consequences.
rol group [ 6 , 7 ]. We find that high intelligence is not a risk factor for psychiatric disorders and even a protective factor for general anxiety. Higher intelligence was associated with a decrease in trauma exposure, and consequently PTSD. This is consistent with previous findings [ 29 ] and with the association of childhood trauma with lower intelligence [ 40 ].
With regard to somatic disorders, we replicate the increased risk of allergies in individuals with high intelligence [ 2 , 41 ]. One possible explanation for this association is that allergies and intelligence share neural correlates [ 42 ]. Another possibility is that more intelligent individuals with a higher g -factor live in more urban areas [ 43 ], where allergies are more prevalent [ 44 ], or that individuals with high intelligence are more aware of allergic symptoms and have better access to health care. However, the prevalence between groups did not differ across all allergies (e.g., asthma and hay fever rhinitis).
In line with a previous literature review [ 27 ], the risk of myopia was greater for individuals with high intelligence. While near-work activities (e.g., reading and computer use) seem to be a risk factor for myopia [ 45 , 46 ], this association appears to be distinct from that of higher intelligence and education level [ 22 ]. Although additional years of education contribute to an increase in the risk of developing myopia [ 47 ], most of the evidence points towards shared genetic factors between intelligence and myopia [ 22 ], which is consistent with our observation that the risk of myopia associated with a high g -factor only slightly decreased when adjusting for educational attainment.
Our results indicate more afternoon–evening chronotypes in individuals with high intelligence than in individuals with average intelligence, which could be explained by differences in the work schedules of the different g -factor groups [ 28 ]. In line with a previous study [ 30 ], we find that ind