Aripiprazole is a D2 and D3 receptor partial agonist that is unlike other second generation antipsychotics. The effectiveness of aripiprazole with regard to neurocognitive function and its adverse effects is unclear. The present study evaluates the comparative efficacy, effects on neurocognitive function, and adverse effects of aripiprazole and risperidone in the treatment of hospitalized patients with schizophrenia. This double-blind, cross-over study included 23 patients with schizophrenia who were randomly assigned to be treated first with either aripiprazole or risperidone. After eight weeks on one medication, the patients were switched to the other medication for eight weeks. The patient assessment included the Positive and Negative Syndrome Scale (PANSS), neurocognitive assessments, and adverse events including extrapyramidal symptoms, vital signs, electrocardiogram, and clinical laboratory tests. The study findings indicated that psychopathology assessed with the PANSS, extrapyramidal symptoms and other adverse effects did not differ between aripiprazole and risperidone for the subjects remaining in treatment. In the neurocognitive assessments, the score for disinhibition with aripiprazole was significantly lower than with risperidone (p<0.05). In addition, serum prolactin levels were significantly lower with aripiprazole (p<0.001). The treatment drop-out rate was higher for patients receiving aripiprazole than risperidone.
In comparing aripiprazole and risperidone, risperidone is better from the viewpoint of treatment continuation. On the other hand, some adverse effects, such as hyperprolactinemia and disinhibition, are less severe with aripiprazole. Thus, for certain applications, aripiprazole may be a beneficial new treatment option for schizophrenia.