Analysis of association of clinical correlates and 5-HTTLPR polymorphism with suicidal behavior among Chinese methamphetamine abusers

Substance use disorders are familial, and genetic factors explain a substantial degree of their familial aggregation. Methamphetamine (MAP) abusers are commonly noted as having psychosis, depression and suicidal behavior. The goals of the present study were (i) to investigate relations of clinical correlates, such as gender, drug use behavior, psychiatric comorbidity and psychiatry family history, with suicidal behavior among Chinese MAP abusers; and (ii) to investigate whether there is an association between a polymorphism in the promotor region of the serotonin transporter gene (5-HTTLPR) and suicidal behavior among Chinese MAP abusers. A total of 439 MAP abusers from a hospital and detention center in Taipei were interviewed with the Diagnostic Interview for Genetic Study and the Family Interview for Genetic Study. The 5-HTTLPR polymorphism was compared between 94 MAP abusers with suicide attempts and 294 MAP abusers without suicide attempts, for whom DNA data were available. The results of the present study indicate that among MAP abusers in Taiwan, suicide attempts were significantly related to female gender, history of MAP-induced psychotic disorder, history of MAP-induced depressive disorder, and family history of psychotic disorders. Among suicide attempters, the attempters with moderate to severe lethality used higher MAP doses than those with minimal to mild lethality. In the present sample the triallelic 5-HTTLPR polymorphism (S, L_G, L_A) was not associated with MAP-induced depressive disorder, MAP-induced psychotic disorder or suicidal behavior, but studies with larger sample sizes are warranted before excluding the role of the 5-HTTLPR polymorphisms in suicidal behavior among MAP abusers.