To assess cross-sectional remission of schizophrenia symptoms in patients treated with quetiapine or haloperidol.

Retrospective analyses were conducted on ITT data from all relevant randomised, double-blind studies in the AstraZeneca clinical trial database: a 6-week fixed-dose study (5077IL/0013; Arvanitis et al, Biol Psychiatry 1997;42:233-246); an 8-week fixed-dose study (5077IL/0052; Emsley et al, Int Clin Psychopharmacol 2000;15:121-131); a 6-week flexible-dose study (5077IL/0014; Copolov et al, Psychol Med 2000;30:95-105); a 52-week flexible-dose study (5077IL/0050; Jones and Brecher, Eur Psychiatry 2006;21:S91), of which 12-week data were included in the analysis. Patients in these studies had acute schizophrenia (CGI-S≥4, BPRS≥27 or PANSS≥60) or were partial responders to previous antipsychotics. Cross-sectional remission criteria were as defined by Andreasen et al (Am J Psychiatry 2005;162:441-449), apart from duration (6-12 week data were used). An alternative definition of remission was the proportion of patients with CGI-S≤3.

Data from 791 quetiapine- and 586 haloperidol-treated patients were analysed. Mean quetiapine/haloperidol doses in studies 0013, 0014, 0050 and 0052 were: 379/12, 455/8, 431/13 and 600/20 mg/day. In three studies (0013, 0014 and 0050), cross-sectional remission (modified Andreasen criteria) was similar for quetiapine (13-32%) and haloperidol (14-32%). CGI-S remission rates were also comparable (quetiapine 23-40%; haloperidol 24-43%) in these studies. In study 0052, more quetiapine patients achieved cross-sectional remission (Andreasen 32%, CGI-S 41%), compared with haloperidol patients (Andreasen 25%, CGI-S 30%).

Cross-sectional remission rates with quetiapine or haloperidol were largely comparable, based on either the modified Andreasen (without time element) or the CGI-S criteria.