Cariprazine vs Risperidone for Negative Symptoms

Methods: Study subjects had a diagnosis of schizophrenia (DSM-IV-TR) with a duration of ≥2 years and had been clinically stable for ≥6 months but continued to have a Positive and Negative Syndrome Scale (PANSS) negative symptom score of ≥24 plus a score of ≥4 on at least 2 of the 4 core negative PANSS symptoms: blunted affect, passive social withdrawal, lack of spontaneity, and flow of conversation. Those with a history of nonresponse to risperidone or who had received the drug within the prior 6 weeks were excluded. Participants were randomly assigned to double-blind treatment with either cariprazine or risperidone. During the first 2 post-randomization weeks, study medications were cross-titrated with patients' previous antipsychotics. Following the taper, patients received monotherapy for 26 weeks at target dosages of 4.5 mg/day cariprazine or 4 mg/day risperidone. Patients could receive lorazepam or a similar agent for agitation, sedatives for sleep, or a limited number of agents for extrapyramidal symptoms, but no other psychotropics were permitted. The primary efficacy outcome was change from randomization to treatment week 26 in the PANSS factor score for negative symptoms.