CYP2D6 and psychiatric disorder: The polymorphic enzyme CYP2D6 plays a key role in the metabolism of around 25% of all clinically used drugs, among which many are used in treatment of psychiatric diseases (Ingelman-Sundberg, 2005; Milosavljevic et al., 2020; van Schaik et al., 2020; van Westrhenen et al., 2020).