Emotionally controlled decision‐making and a gene variant related to serotonin synthesis in women with borderline personality disorder

The Iowa Gambling Task (IGT) was used to examine (i) social decision-making in women with borderline personality disorder (BPD), and (ii) the relationship between impaired decision-making and the tryptophan hydroxylase-1 (TPH-1) gene, involved in serotonin synthesis. Forty-two women with BPD and a history of suicide attempts were genotyped, and the frequency of a TPH-1 haplotype previously uniquely associated with BPD was calculated. The BPD group scored significantly lower than a control group in the IGT. Furthermore, the TPH-1 haplotype displayed a significantly higher frequency in BPD participants with impaired decision making, compared to BPD participants with normal scores. These findings suggest that impaired decision-making as determined by the IGT is a feature of BPD and may be (i) associated with serotonin dysfunction, and (ii) possibly relevant for suicidal behavior.