Quetiapine may not differ from typical antipsychotics in the treatment of positive symptoms and general psychopathology. There are no clear differences in terms of the treatment of negative symptoms. However, it causes fewer adverse effects in terms of abnormal ECG, extrapyramidal effects, abnormal prolactin levels and weight gain.
Comparative effectiveness of second-generation antipsychotics and haloperidol in acute schizophrenia.
There is little information on the comparative effectiveness of second-generation antipsychotic agents.
                To determine if any of five second-generation antipsychotics or haloperidol is more effective in treating acutely ill patients with schizophrenia, schizoaffective disorder or schizophreniform disorder.
                A sample of 327 newly admitted patients were randomised to open-label treatment with aripiprazole, haloperidol, olanzapine, quetiapine, risperidone or ziprasidone for a minimum of 3 weeks. Measures of effectiveness were improvement in mental status so that the patient no longer required acute in-patient care, and changes in Brief Psychiatric Rating Scale (BPRS) scores.
                By the first measure, haloperidol (89%), olanzapine (92%) and risperidone (88%) were significantly more effective than aripiprazole (64%), quetiapine (64%) and ziprasidone (64%). Changes in BPRS ratings were not significant among treatments.
                Haloperidol, olanzapine and risperidone are superior to aripiprazole, quetiapine and ziprasidone for the acute treatment of psychosis in hospitalised patients with schizophrenia, schizoaffective disorder or schizophreniform disorder.