1.Causal effects of fluid intelligence on psychiatric disorders
Sunyeup KIM ; Gahyun KIM ; Minyoung KIM ; Kyung-Hun SUNG ; Seunghyup LEE ; Youngoh BAE ; Seung Won LEE
Precision and Future Medicine 2026;10(1):27-38
Purpose:
Fluid intelligence (FI), a core cognitive function involved in reasoning and problem-solving, has been linked to psychiatric outcomes in observational studies. However, causal inferences remain challenging due to confounding and reverse causation. This study aimed to investigate the causal effects of FI on 10 major psychiatric disorders using Mendelian randomization (MR).
Methods:
We performed a phenome-wide association study-based two-sample MR analysis to evaluate the effects of genetically proxied FI on 10 psychiatric disorders. Genome-wide association study summary statistics were obtained from large-scale European cohort studies. The inverse-variance-weighted method served as the primary analytical method, and complementary sensitivity analyses were conducted to assess pleiotropy and heterogeneity.
Results:
Higher FI was causally associated with a reduced risk of attention-deficit/hyperactivity disorder (ADHD) (odds ratio [OR], 0.72; P< 0.001), schizophrenia (OR, 0.69; P= 0.016), and post-traumatic stress disorder (PTSD) (OR, 0.93; P= 0.006). In contrast, FI was positively associated with an increased risk of autism spectrum disorder (ASD; OR, 1.43; P < 0.001) and anorexia nervosa (OR, 1.39; P= 0.005). No significant associations were observed for major depressive disorder, anxiety disorder, bipolar disorder, obsessive-compulsive disorder, or postpartum depression. Sensitivity analyses supported the robustness of these findings, with no evidence of directional pleiotropy or undue influence of individual single-nucleotide polymorphisms.
Conclusion
This study provides genetic evidence that higher FI exerts divergent causal effects across psychiatric disorders, protective in externalizing and stress-related conditions (ADHD, PTSD, and schizophrenia) but associated with an increased risk of neurodevelopmental and internalizing conditions (ASD and anorexia nervosa). These findings highlight the need for a nuanced understanding of cognitive capacity in psychiatric vulnerability and guide preventive strategies tailored to disorder-specific cognitive profiles.
2.Risk of Psychiatric Disorders Following Carpal Tunnel Syndrome: A Nationwide Cohort Study
Youngoh BAE ; Chaeyoon KANG ; Hohyun JUNG ; Seung Won LEE
Psychiatry Investigation 2026;23(1):30-37
Objective:
Despite the suspected link between carpal tunnel syndrome (CTS)—a common neuropathy—and psychiatric issues, long-term evidence, especially in Asia, remains scarce. This study investigated the long-term incidence of depression, anxiety, somatoform, and sleep disorders after CTS diagnosis in a South Korean nationwide cohort.
Methods:
Using the Korean National Health Insurance Service cohort (2002–2013), newly diagnosed CTS patients (2004–2013) were identified following a 2-year washout period. Each CTS patient was propensity score-matched 1:10 with non-CTS controls based on demographics and health status. Cox proportional hazards regression yielded adjusted hazard ratios (aHRs) for incident depressive, anxiety, somatoform, and sleep disorders over up to 10 years of follow-up.
Results:
Compared to controls, CTS patients had significantly elevated risks for all outcomes: depressive disorders (aHR, 1.59; 95% confidence interval [CI], 1.45–1.74), anxiety disorders (aHR, 1.41; 95% CI, 1.31–1.52), somatoform disorders (aHR, 1.38; 95% CI, 1.23–1.55), and sleep disorders (aHR, 1.36; 95% CI, 1.25–1.49). Risk was notably higher in individuals aged <60 years for all disorders. Males showed higher risks for depression, anxiety, and sleep disorders, while females had a slightly higher risk for somatoform disorders.
Conclusion
This comprehensive, longitudinal study indicated that CTS is associated with an increased long-term risk of psychiatric disorders. The findings emphasize comprehensive management strategies that integrate mental health screening and interventions tailored to age and sex among patients with CTS.
3.Coincidental Nasopharyngeal Carcinoma and Ventral Foramen Magnum Meningioma:Case Report and Review of the Literature
Youngoh BAE ; Wonwoo OH ; Yeongu CHUNG ; Yu Sam WON ; Je Beom HONG
Brain Tumor Research and Treatment 2022;10(1):55-60
Multiple primary tumors at adjacent site are rare. We report a rare case of coincidentally found nasopharyngeal cancer and ventral foramen magnum meningioma. The 68-year-old male patient presented with a year history of ataxia. Radiological examination revealed lesions in the nasopharyngeal space and ventral foramen magnum. A needle aspiration biopsy for nasopharyngeal space and surgical removal for foramen magnum lesion were performed. The pathological diagnoses were nasopharyngeal cancer and meningioma, respectively. The concomitant occurrence of these two tumors is very rare and there is no known association between these two tumors. We report a case of ventral foramen magnum meningioma simultaneously present with nasopharyngeal carcinoma.

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