Nicotinic Receptors and Schizophrenia

This study proposes to conduct a clinical trial comparison of olanzapine and the combination of a nicotinic cholinergic agonist, 3-\[2,4-Dimethoxybenzylidene\]anabaseine (DMXB-A) with a dopamine D2 receptor antagonist, the mechanism common to all antipsychotic drugs, to test the hypothesis that 7-nicotinic receptor agonism may be an additional necessary factor that enhances the efficacy of olanzapine that allows its slight superiority to risperidone. This trial would enroll patients taking olanzapine and record baseline measurements of clinical symptoms, cognition, metabolic parameters, and extrapyramidal side effects. The subjects would then be randomized to receive either risperidone or risperidone plus DMXB-A for 6 weeks and then would again have measurements of clinical symptoms, cognition, metabolic parameters and extrapyramidal side effects.