Introduction: Negative symptoms of schizophrenia often predict an unfavorable clinical outcome. Disturbed dopamine transmission in different brain parts may underlie different aspects of negative symptoms, and the effect of antipsychotics on them may also differ. This pilot study investigated the potentially therapeutic effects of the partial dopamine agonist aripiprazole on different negative symptoms.
Methods: This pilot study randomly assigned patients with schizophrenia (N=40) to either aripiprazole or risperidone. After 6 weeks of treatment, the severity of negative symptoms was determined by the PANSS. Subscales of self-report questionnaires were used to assess differences in initiative, anhedonia, social functioning and subjective well-being.
Results: Patients treated with aripiprazole showed a significant improvement on measures for anhedonia and subjective wellbeing. Negative symptoms in general, lack of initiative and social inhibition were also lower in the aripiprazole treated group, but without reaching statistical significance.
Discussion: According to this pilot study, aripiprazole appears to specifically improve anhedonia and subjective wellbeing compared to risperidone. This may be caused by a specific effect of aripiprazole on the limbic branch of the dopamine system. Future studies should replicate this finding with a larger sample size.