Neurophysiological and Immunological Effects of the Transition From Combustible to Electronic Cigarettes

Participants who are current cigarette smokers will be randomly assigned to either the experimental or control groups. Following a baseline psychiatric assessment session, subjects will return to the study center for two to three additional follow-up visits.

During the second visit, all subjects will undergo a functional magnetic resonance imaging (fMRI) scanning session, during which they will perform a series of functional neuroimaging tasks designed to examine the neural substrates involved in visceral interoception and eating behavior. Prior to the start of the scan session, blood samples will be collected from each subject, for the measurement of bio-markers related to nicotine use and peripheral inflammation. After the end of the second visit, subjects within the experimental group will be asked to switch from combustible to electronic cigarettes. Subjects within the control group will continue to smoke combustible cigarettes as previously.

During the third visit, which will follow two to eight weeks after the second visit, all subjects will provide a second blood sample and complete a second fMRI scan session. Both groups of participants will complete the same fMRI tasks as they did during the second visit.

• Electronic Cigarette (Other): eGo-type electronic cigarette with a supply of 18mg/ml nicotine solution
• Tobacco Cigarette (Other): Smoke own brand of cigarette as previously

Primary outcomes

• Change in overall levels of peripheral inflammatory cytokines [2-8 weeks]: A composite measure of change in overall blood serum levels of multiple peripheral cytokines (CRP, TNF-alpha, sVCAM, IL-1RA, IL-6) between study visits two and three.

Secondary outcomes

• Change in cotinine levels [2-8 weeks]: Change in serum cotinine levels between study visits two and three.
• Frequency of Electronic Cigarette use [2-8 weeks]: Daily use of electronic cigarette between study visits two and three.
• Change in exhaled Carbon Monoxide [2-8 weeks]: Change in exhaled Carbon Monoxide between study visits two and three.
• Frequency of Tobacco Cigarette use [2-8 weeks]: Average number of tobacco cigarettes smoked between study visits two and three.
• Change in Blood Oxygen Level-Dependent (BOLD) resting state functional connectivity during fMRI [2-8 weeks]: Difference in resting-state functional connectivity between brain regions, measured by z-scores of correlated spontaneous fluctuations of the BOLD fMRI signal, between study visits two and three.
• Change in BOLD fMRI response during interoception [2-8 weeks]: Difference in the brain's hemodynamic response during a task of interoceptive attention to visceral signals, measured by percent change of the BOLD fMRI signal, between study visits two and three.
• Change in BOLD fMRI response to food pictures [2-8 weeks]: Difference in the brain's hemodynamic response to viewing pictures of appetizing food, measured by percent change of the BOLD fMRI signal, between study visits two and three.

Sex: All, ages: 18 Years to 50 Years, accepts healthy volunteers

Inclusion Criteria:

* current cigarette smokers who have smoked for at least one year
* right-handed adults
* able to provide written informed consent

Exclusion Criteria:

* use of anticonvulsant, stimulant, or antipsychotic medication for 3 weeks prior to scanning
* any medical conditions or medications likely to influence cerebral blood flow or neurological function including cardiovascular, respiratory, endocrine and neurological diseases
* any history of drug (other than nicotine) or alcohol abuse within 1 year
* current pregnancy or breast feeding
* primary language other than English
* meeting general MRI exclusion criteria such as magnetic implants or claustrophobia
* Past history of any axis I psychiatric condition, other than major depressive disorder and post-traumatic stress disorder
* Current major depression or post-traumatic stress disorder
* Serious suicidal ideation

• William K Simmons, Ph.D, Principal investigator, Laureate Institute for Brain Research