The overall aim of this project is to evaluate the effect of progressive nicotine reduction in cigarettes on smoking behavior, toxicant exposure and psychiatric symptoms in smokers with comorbid mood and/or anxiety disorders.~To do so, we will randomly assign 200 adult smokers with a unipolar mood and/or anxiety disorder within the past year to smoke research cigarettes that will contain either a) Usual Nicotine Content (UNC): nicotine content similar to their preferred usual brand of cigarettes, or b) Reduced Nicotine Content (RNC): nicotine content per cigarette is progressively reduced from approximately 11.6 mg to 0.2 mg per cigarette over 18 weeks. All subjects will participate in baseline periods prior to double-blind randomization to assess normal smoking behavior and then to establish ability to tolerate research cigarettes prior to randomization.~A total of 280 participants will be enrolled in the study at two sites with the aim of randomizing 200 who complete the baseline phase. 100 participants will be enrolled in the randomized phase at Penn State Hershey and 100 at the Massachusetts General Hospital site. Participants will be started on the study protocol during Baseline I and Baseline II but will be removed from the study if they are not able to comply with the protocol. We expect that approximately 40 participants at each site drop out from the study prior to randomization (due to inability to comply with study protocol).~It is our hypothesis that nicotine intake, as measured by plasma cotinine concentration, will decline as a function of cigarette nicotine content in the RNC group. Further, it is our hypothesis that by gradually reducing the nicotine content of the cigarettes in a step-wise fashion, there will not be significant increases in biomarkers of tobacco smoke exposure, severity of nicotine withdrawal symptoms, mood and anxiety symptomatology or protocol non-adherence over time in the experimental group (RNC) as compared with the UNC control group.
The overall aim of this project is to evaluate the effect of progressive nicotine reduction in cigarettes on smoking behavior, toxin exposure and psychiatric symptoms in smokers with comorbid mood and/or anxiety disorders.~Smokers with mood and/or anxiety disorder will smoke research cigarettes that will contain either a) nicotine content similar to their preferred usual brand of cigarettes, or b) nicotine content per cigarette that is progressively reduced from approximately 11.6 mg to 0.2 mg per cigarette over 18 weeks.~It is our hypothesis that nicotine intake will decline as a function of cigarette nicotine content in the Reduced Nicotine Content group without significant increases in tobacco smoke exposure, severity of nicotine withdrawal symptoms, mood and anxiety symptomatology or protocol non-adherence over time in the Reduced Nicotine Content group as compared with the control group.