Study of the Effects of Mecamylamine and Varenicline in Schizophrenia

We are conducting this study to find out if blocking or partially stimulating the effects of nicotine in the brain can affect memory and concentration. Nicotine is the addictive drug found in tobacco products. Our subjects will be people with and without mental illness (schizophrenia), smokers and non-smokers. We will use a medication called mecamylamine (Inversine) to block the effects of nicotine on the brains of our subjects. We will also use a medication called varenicline (Chantix) to partially increase the effects of nicotine on the brains of our subjects. This study also uses a placebo, a pill that does not have any active ingredients but looks exactly like the mecamylamine and varenicline pills. We will compare the effects of giving mecamylamine or placebo to people who have schizophrenia and people who do not have schizophrenia. We know that people with schizophrenia smoke heavily and find it harder to stop smoking than most other people do. Studies have shown that people with schizophrenia may smoke more because nicotine helps their concentration and memory. We are interested in helping people with schizophrenia smoke less. Mecamylamine blocks the parts of the brain that react to nicotine and varenicline partially stimulates and partially blocks the parts of the brain that react to nicotine. Both medications may decrease the effects that smoking has on the body.