DRD4 receptor gene exon III polymorphism in inpatient suicidal adolescents

Some studies have suggested possible association of the dopamine receptor subtype 4 (DRD4) gene exon III 48 bp repeat polymorphism with novelty seeking behavior. As suicidal behavior in adolescents is linked to risk taking behavior, we evaluated the association of suicidality with DRD4 polymorphism in Israeli inpatient suicidal adolescents. Sixty-nine inpatient adolescents who recently attempted suicide were assessed by structured interview and rating scales for detailed clinical history, diagnoses, suicide intent and risk, impulsivity, violence, and depression. The frequency of DRD4 alleles was compared between the suicidal inpatients and 167 healthy control subjects. No significant association between the DRD4 polymorphism and suicidal behavior was found. Analysis of the suicide-related measures demonstrated a significant difference in depression severity between suicidal inpatients homozygote and heterozygote for the DRD4 alleles (p=0.003). The relevance of this finding to increased depression severity in suicidal adolescents, if replicated, is as yet unclear.