Polymorphism of the serotonin-2A receptor gene (HTR2A) associated with childhood attention deficit hyperactivity disorder (ADHD) in adult women with seasonal affective disorder

Introduction: Several lines of research point to a possible overlap between seasonal affective disorder (SAD) and attention deficit hyperactivity disorder (ADHD), particularly in females. There is also emerging evidence that variation of the 5-HT2A receptor gene (HTR2A) contributes to both SAD and ADHD. The current study investigated whether variation in HTR2A was associated with symptoms of childhood ADHD in adult women with SAD. Method: Sixty-six women with SAD were administered the Wender–Utah Rating Scale (WURS), which retrospectively assesses childhood ADHD, as part of an ongoing genetic study of SAD. WURS scores were compared across the three genotypic groups defined by the T102C polymorphism of HT2RA. Results: Analysis of variance indicated a significant difference in mean 25-item WURS scores across the three genotypic groups (p=0.035). Post-hoc tests revealed that the C/C genotypic group had a significantly higher mean score than both the T/T group and T/C group. Based on previously established WURS criteria, 38% of subjects with the C/C genotype, and none with the T/T genotype, had scores consistent with childhood ADHD. Limitations: The current sample size is small, and childhood ADHD diagnoses were based on retrospective recall. Conclusion: These preliminary results suggest a possible association between variation in HTR2A, childhood ADHD, and the later development of SAD in women.