Here, we aim to investigate the effect of pharmacogenetic-informed dose adjustment of the antidepressants escitalopram and sertraline or the antipsychotics risperidone and aripiprazole according to the latest state-of-the-art international dosing recommendations for CYP2C19 and CYP2D6 metabolizer status in patients with mood-, anxiety- or psychotic disorder. This evidence concerns the gene CYP2C19 and psychotic disorder.