Background: Recently, the "Remission in Schizophrenia Working Group" proposed remission criteria consisting of a reduction to mild levels on key symptoms for at least 6 months.
Aims: This study applied these remission criteria to a large first-episode psychosis sample in order to (1) determine the rates of remission; (2) explore predictors of remission; and (3) test the external validity of these criteria.
Methods: We analyzed data from 462 subjects with a first-episode of psychosis who participated in a long-term, multinational, randomized, double-blinded trial of risperidone and haloperidol over 2 to 4 years.
Results: At some time point in the study 323 (70%) of the 462 subjects had a reduction to mild levels on the key symptoms as measured by the PANSS although only 109 (23.6%) maintained this level for at least 6 months thereby meeting remission criteria. The two strongest predictors of remission were shorter duration of untreated psychosis (p=0.01) and treatment response at 6 weeks (p=0.001). Compared to non-remitted patients, those in remission experienced greater improvement on all PANSS subscales (p<.0001), CGI-S (p<.0001), better quality of life (p=0.006), fewer relapses (p<.0001), displayed a more favorable attitude towards their medication (p=.002), had lower EPS levels according to the ESRS (p=<.0001) and received lower doses of antipsychotic medication (p=0.003). The remission and non-remission groups did not differ significantly regarding composite cognitive scores, suicidality and body mass index.
Conclusions: The results suggest that the remission criteria, although based solely on core symptom improvement, can effectively identify patients who have a more favorable overall outcome.