Efficacy of quetiapine and risperidone against depressive symptoms in outpatients with psychosis.

Background: The treatment of psychotic symptoms in patients with mood disorders is a complex challenge. Antipsychotic medications in these individuals may be associated with extrapyramidal symptoms (EPS), worsening of depression, and functional impairment. Atypical antipsychotics such as quetiapine and risperidone are associated with a decreased incidence of adverse events such as EPS. The objective of this study was to compare the efficacy and tolerability of quetiapine and risperidone for the treatment of depressive symptoms in outpatients with psychosis.

Method: In this 4-month, multicenter, open-label trial, patients were randomly assigned in a 3:1 ratio of quetiapine to risperidone, and both drugs were flexibly dosed. Eligible patients had psychoses and demonstrated 1 of several DSM-IV diagnoses, including schizoaffective disorder, bipolar I disorder, major depressive disorder, delusional disorder, Alzheimer's dementia, schizophreniform disorder, vascular dementia, and substance abuse dementia. Patients were classified as mood disordered if they had bipolar disorder, major depressive disorder, or schizoaffective disorder. Efficacy was assessed using the Positive and Negative Syndrome Scale and the Clinical Global Impressions scale. The Hamilton Rating Scale for Depression (HAM-D) was used to assess the level of depressive symptoms. The primary tolerability assessment was presence or absence of substantial EPS, defined as EPS severe enough to require an alteration in treatment.

Results: A total of 554 patients were randomly assigned to quetiapine and 175 to risperidone. Mean doses at 16 weeks were 318 mg for quetiapine and 4.4 mg for risperidone. Although both agents produced improvements in mean HAM-D scores, quetiapine produced a greater improvement than risperidone in all patients (p =.0015). Within the mood-diagnosed population, incidences of both substantial EPS (p =.001) and at least moderate EPS (p =.0373) occurred significantly less frequently among patients taking quetiapine. For patients with non-mood diagnoses, incidences of substantial EPS were fewer for patients taking quetiapine than for those taking risperidone (p =.062); however, this was not statistically significant.

Conclusion: These results suggest that quetiapine may be a useful agent in the management of depressive symptoms in patients with psychosis.