Obsessive-compulsive spectrum and serotonin: A genetic association study

Dysfunction in serotonin (5-HT) neurotransmission in obsessive-compulsive disorder (OCD) and obsessive-compulsive personality disorder (OCPD) has been reported. Therefore, genetic variants of serotonergic genes could account for the genetic liability for OCD and/or OCPD. We analyzed an insertion/deletion polymorphism in the promoter region of the 5-HT transporter (5-HTTLPR) and a G to A polymorphism at base position -1438 of the 5-HT2A receptor gene (5-HT2A[-14381G/A). We studied the association of 5-HTTLPR and 5-HT2A[-1438]G/A with OCD, OCPD, and associated features of OCD and OCPD, such as impulsive-aggressive behavior and personality dimensions. One hundred fifty unrelated OCD subjects, 78 patients with OCPD and 140 healthy controls participated in the study. Aggressive behavior was evaluated by the Buss & Durkee Hostility Inventory (BDHI). Personality dimensions were evaluated by the Tridimensional Personality Questionnaire (TPQ). 5-HTTLPR and 5-HT2A[-1438]G/A were genotyped as described elsewhere. No significant differences in genotype or allele frequencies of both 5-HTTLPR and 5-HT2A[-1438]G/A were observed among OCD, OCPD and controls. No significant association was observed between BDHI scores and both 5-HTTLPR and 5-HT2AI-14381G/A genotypes in OCD or OCPD. 5-HTTLPR SS genotype was significantly associated with harm avoidance scores of the TPQ in both OCD and OCPD. The association of 5-HTTLPR with harm avoidance in both OCD and OCPD reflects the importance of defining psychopathological features associated with major psychiatric disorders.