Dopa decarboxylase and tyrosine hydroxylase gene variants in suicidal behavior

The dopaminergic system has been previously associated to behavioral facilitation and aggression, hence making the pathway a good candidate for suicidal behavior. We studied gene variants in the tyrosine hydroxylase (rs3842727, rs6356) and DOPA decarboxylase (rs1451371, rs1470750, rs998850) genes in a sample of 571 individuals consisting of 167 German suicide attempters (affective spectrum n = 107, schizophrenia spectrum n = 35, borderline personality disorder n = 25), 92 Caucasian individuals who committed suicide and 312 German control subjects. TH variants were not associated with suicide (uncorrected P = 0.023) and related traits. Some marginal associations could be observed for DDC with suicide, violence, anger, and aggression. In conclusion, our study does not support the involvement of TH gene variants as major contributors to suicide, whereas DDC variants could mediate some features related to suicide and be involved in violent suicidal behavior.