Physiological, Cognitive and Cerebral Activity Changes as a Function of Cigarette Smoking (With or Without Nicotine) and Tobacco Abstinence

Objective: To compare the effects of complete abstinence or smoking denicotinized research cigarettes to smoking ad libitum nicotinized research cigarettes on the following measures: withdrawal symptoms and quality of sleep; MAO-A and MAO-B activities; hormonal responses (HPA, HPT); mood, cognitive and psychometric performance; functional brain activity, and physiological responses. Study Population: Participants are 125 men who are at least 18 years old, report smoking at least 15 cigarettes per day, have not used any illicit drug except marijuana in the past year, have no history of drug or alcohol dependence, and have already experienced tobacco withdrawal symptoms when they had no access to cigarettes. Design: Smokers will be randomized into one of the following 3 groups: a) complete tobacco abstinence for 8 days; b) denicotinized research cigarettes for 8 days, or c) control group smoking nicotinized research cigarettes during the entire study (16 days). Because there are few studies comparing functional brain activity in smokers and nonsmokers, a group of nonsmokers will serve as a control group for the brain imaging studies. Outcome Measures: Withdrawal symptoms, mood, quality of sleep, cognitive performance, temperature, blood pressure and heart rate, MAO-A parameters: plasma DHPG (dihydroxyphenylglycol), HVA (homovanillic acid), 5HIAA (5-hydroxyindolacetic acid); MAO-B parameters: urinary excretion of phenylethylamine, platelet MAO-B activity; hormonal parameters: serum ACTH, cortisol, TSH, thyroxine, triiodothyronine; EEG; cigarette liking; expired air CO; and functional brain activity.