EEG, physiology, and task-related mood fail to resolve across 31 days of smoking abstinence: relations to depressive traits, nicotine exposure, and dependence.

Changes in task-related mood and physiology associated with 31 days of smoking abstinence were assessed in smokers, 34 of whom were randomly assigned to a quit group and 22 to a continuing-to-smoke control group. A large financial incentive for smoking abstinence resulted in very low participant attrition. Individuals were tested during prequit baselines and at 3, 10, 17, and 31 days of abstinence. Abstinence was associated with decreases in heart rate and serum cortisol, a slowing of electroencephalogram (EEG) activity, and task-dependent and trait-depression-dependent hemispheric EEG asymmetries. Differences between the quit group and the smoking group showed no tendency to resolve across the 31 days of abstinence. Trait depression and neuroticism correlated with increases in left-relative-to-right frontal EEG slow-wave (low alpha) activity at both 3 and 31 days of abstinence. In contrast, prequit nicotine intake and Fagerström Tolerance scores correlated with alpha asymmetry and with greater EEG slowing only at Day 3. Thus, the effects of smoking abstinence appear to last for at least several months.

Does noise stress modulate effects of smoking/nicotine? Mood, vigilance, and EEG responses.

Effects of smoking multiple cigarettes on EEG, vigilance, and subjective state were assessed in a repeated measures design where noise level (high versus minimal) was crossed with nicotine dose (quasi-ad lib own versus 1.0 mg FTC nicotine machine-delivered dose versus 0.05 mg FTC nicotine machine-delivered dose). Vigilance was increased by nicotine, but not by noise and there was no noise by dose interaction. Effects of nicotine on EEG varied as a function of dose, noise, hemisphere, time, and eyes-open versus eyes-closed condition. Smoking normal nicotine delivery (0.9-1.1 mg FTC-estimated) cigarettes resulted in decreases in percentages of delta and theta EEG magnitude and increased percentage beta-1 EEG magnitude across conditions and time. Changes in alpha and theta magnitude were dependent on eyes being open versus closed. Hemispheric asymmetries varied as a function of noise and time. Consistent with inverted "U" models, effects of nicotine on EEG were clearly stimulant during the quiet conditions while there were minimal to no differences between nicotine doses during the high-noise conditions. The failure of nicotine to modify mood is interpreted in terms of bioinformational models of nicotine's subjective effects.