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Background:
Objectives:
Eligibility:
Design:
Full description
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.
Enrollment
Sex
Ages
Volunteers
Inclusion and exclusion criteria
All participants must be:
Smokers must be:
Nonsmokers must:
EXCLUSION CRITERIA:
Participants will be excluded if they:
Are not suitable to undergo an fMRI experiment due to implanted metallic devices (cardiac pacemaker or neurostimulator, some artificial joints, metal pins, surgical clips or other implanted metal parts), body morphology or claustrophobia.
Have coagulopathies, history of or current superficial, or deep vein thrombosis, or musculoskeletal abnormalities restricting an individual s ability to lie flat for extended periods of time.
Have HIV or Syphilis.
Have any neurological illnesses to include, but not limited to, seizure disorders, migraine (>2/yr or on prophylaxis), multiple sclerosis, movement disorders, or history of significant head trauma, CVA, CNS tumor.
Have other major medical illnesses likely to interfere with study results or safety of an individual during participation.
Have any current major psychiatric disorders to include, but not limited to, mood, anxiety, psychotic disorders, or substance-induced psychiatric disorders.
Regularly use any prescription, over-the-counter or herbal medication that may alter CNS function, cardiovascular function or neuronal-vascular coupling.
Are cognitively impaired or learning disabled.
Significant cardiovascular or cerebrovascular diseases.
INCLUSION CRITERIA (Pilot Studies):
Smokers:
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Data sourced from clinicaltrials.gov
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