The A (minor) allele is associated with:
- A= lower production of TPH2 protein and therefore less serotonin [R].
- Decreased scores on a go-no go task, which measures a participant's capacity for sustained attention and response control/inhibition [R].
- 1.5X risk for bipolar disorder (883 Russian patients) (R).
- Decreased cortisol and ACTH stimulation (R).