2. Presence of symptoms despite the optimization of the antipsychotic dosage (based on prescriber's judgment) for at least 6 weeks, i.e. a dosage increase cannot be considered due to tolerability issues and/or is judged unlikely to bring sufficient clinical improvement. This will be operationalized by a minimum Negative PANSS score of 20 and at least one item scoring > 4; OR a Positive PANSS score > 20 with at least one item scoring > 4 (e.g. delusion or hallucination), indicating persistent negative symptoms and/or persistent positive symptoms,