SY22-5 * NICOTINE AND COGNITION IN SCHIZOPHRENIA

Abstract

Nicotine binds to presynaptic nicotinic acetylcholine receptors (nAChRs) in the brain and facilitates the release of acetylcholine, dopamine, serotonin, glutamate and other neurotransmitters known to be involved in cognitive processes. Nicotine systems in the brain play an important role in the neural basis of memory and attention. Smoking is highly prevalent in schizophrenia, and there is evidence for beneficial effects on neurocognition. Nicotine exposure to non-smoking schizophrenia patients and nicotine application after abstinence to smoking schizophrenia improved attention deficits. The study analyzing the interactional effects of diagnosis of schizophrenia and smoking history suggested a positive effect of smoking history on divided attention in schizophrenia patients. Clinical studies using transdermal nicotine patches have demonstrated the efficacy of nicotine in improving cognitive performance, particularly sustained attention in nonsmokers with schizophrenia. Mecamylamine, a nAChR antagonist, worsened performance of attention compared to varenicline, a nAChR partial agonist, in schizophrenia. There was a treatment by diagnosis interaction, such that mecamylamine worsened performance of sustained attention compared to placebo and varenicline in schizophrenia patients, effects not observed in controls. These findings support a role for nAChRs in attention and suggest that those with schizophrenia may be particularly sensitive to nAChR blockade.