Suicidal behaviour runs in families and the existence of genetic vulnerability to suicidality is well-established. Mental disorders, especially depression, are present in more of 90% of suicides. The incidence of treatment emergent suicidal ideation in major depression (MDD) varies from 4% to 20%, depending on the definition of suicidal ideation and sample characteristics.

In the present study, we further elucidated the impact of depression candidate genes in treatment emergent suicidal ideation in MDD. One hundred-seventy MDD patients were collected in the context of a resistant depression study and treated with antidepressants at adequate doses for at least 4 weeks. MDD subjects were genotyped for SNPs within the COMT gene, BDNF, DTNBP1, 5HT1A, 5HT2A, GNB3, GRIK4, PTGS1, PTGS2, CREB, and cytochrome P450 CYP1A2, CYP2C9, CYP2C19 and CYP2D6 gene. Response, remission and treatment resistance, as well as suicidality information derived from Mini International Neuropsychiatric Interview (MINI) and Hamilton Rating Scale for Depression (HAM-D) were recorded.

A quantitative and measure of suicidal behaviour was defined using the Hamilton rating scale (score 0 to 4) and the MINI-item (yes/no) on suicidality in a large cohort of depression cases. In addition, we tested for association with ‘serious suicidal attempts’ corresponding to a HAMD score of 4 (discrete trait analyses). Results of this candidate gene approach in treatment emergent suicidal ideation in MDD will be presented and discussed.