Cognitive and psychomotor effects of adjunctive aripiprazole or paliperidone in patients of schizophrenia receiving olanzapine: a double blind placebo controlled clinical study

Background: Emergence of atypical antipsychotics has revolutionized the treatment of schizophrenia by exploiting dual actions on serotonin as well as dopaminergic receptors. Still, monotherapy with these agents is insufficient to control cognitive and psychomotor as well as positive and negative symptoms. Hence combination therapy with antipsychotics is common in clinical practice. Objective of current study is to compare the effects of addition of aripiprazole or paliperidone on cognition and psychomotor functions in schizophrenia receiving olanzapine. Methods: This is prospective, double blind, placebo controlled, parallel group study in 90 patients of schizophrenia showing partial or no response to olanzapine measured by Positive And Negative Symptoms Score (PANSS) scale. They were randomly divided to receive adjuvant aripiprazole, paliperidone or placebo for 6 weeks. Results: Combination of aripiprazole and olanzapine shows significant improvement in most of the cognition and psychomotor parameters like attention, perception, verbal memory, thinking and processing as well as motor speed while combination of paliperidone and olanzapine is associated with improvement in only some of the cognitive and psychomotor parameters such as attention, perception and verbal memory only. Both the combinations are efficacious in controlling positive and negative symptoms of schizophrenia as assessed by PANSS scale. Conclusions: The best augmenting strategy with for olanzapine nonresponsive patients will be D2 receptor partial agonist like aripiprazole rather than D2 antagonist like paliperidone and other atypical antipsychotic agents for better improvement in cognition and psychomotor domains. [Int J Basic Clin Pharmacol 2014; 3(1.000): 130-138]