TPH2 and psychiatric disorder: Pearson [47] found no significant interactions between TPH2 rs7305115 and childhood trauma in the behavioural approach system related to reward processes and positive feelings; however, Van and Xu [60, 69] both found that TPH2 rs7305115 interacted with childhood trauma in influencing depressive disorders and antidepressant responses, suggesting that mental disorders were influenced by a complex interplay between environmental and genetic factors.