Lack of association between serotonin 5-HT1B receptor gene polymorphism and suicidal behavior

A genetic susceptibility to suicide attempts has been repeatedly suggested by family-, twin-, and adoption-studies. Because elevated impulsive aggression is one of the most prominent characteristics of suicide attempters and aggressive behavior has been reported in 5-HT1B receptor gene knockout mice, the serotonin receptor 1B gene (5-HT1B) is an attractive candidate. The distribution of a polymorphism (G861C) in the 5-HT1B gene was examined in 148 consecutively hospitalized German suicide attempters, and 327 German healthy volunteers randomly recruited from the general population. The controls and their first degree relatives had no history of mental disorders or suicidal behavior. We found no significant difference in allele or genotype frequency between patients and controls. The results did not differ when the patients were divided into several subgroups (gender, suicide attempters with a violent method or suicide attempters with unipolar-, bipolar-, borderline personality-, and schizophrenia spectrum disorders). These findings suggest that the 5-HT1B polymorphism is unlikely to play a major role in the genetic susceptibility to suicide attempts.