TPH2 gene variation and conflict processing in a cognitive and an emotional Stroop task.

Evidence suggests that a promoter polymorphism of the tryptophan-hydroxylase 2 gene (TPH2 -703 G/T) is associated with executive control functions. The current study aimed to clarify whether this relation is restricted to a purely cognitive domain or whether such an effect can also be observed in the processing of emotional material. In a sample of 89 student subjects, a 'cognitive' and an 'emotional' Stroop paradigm were applied to measure processing of cognitive and affective conflicts. Our results suggest an impact of the TPH2 -703 G/T polymorphism on executive control in both, the cognitive as well as the emotional task. In detail, homozygous carriers of the T allele showed decelerated responses in low-conflict conditions, pointing to a rather abnormal functioning of higher-order control mechanisms. Thus, the present investigation is consistent with previous behavioural studies and adds further evidence for the impact of serotonin at the interface of cognition and emotion.