CYP2D6 and schizophrenia: <b>Conclusions</b>: In adolescent schizophrenia, the CYP2D6-reduced metabolizer status is the strongest independent predictor of long-term QoL impairment, associated primarily through a substantially higher burden of treatment-related adverse effects (metabolic, endocrine, neurological, and sedative) rather than through persistence of psychotic symptoms alone.