Cigarette smoking, psychological stress, and cardiovascular arousal

Nicotine reduces discrimination between threat and safety in the hippocampus, nucleus accumbens and amygdala

Nicotine intake is linked to the maintenance and development of anxiety disorders and impairs adaptive discrimination of threat and safety in rodents and humans. Yet, it is unclear if nicotine exerts a causal pharmacological effect on the affective and neural mechanisms that underlie aversive learning. We conducted a pre-registered, pseudo-randomly and double-blinded pharmacological fMRI study to investigate the effect of acute nicotine on Fear Acquisition and Extinction in non-smokers (n = 88). Our results show that nicotine administration led to decreased discrimination between threat and safety in subjective fear. Nicotine furthermore decreased differential (threat vs. safety) activation in the hippocampus, which was functionally coupled with Nucleus Accumbens and amygdala, compared to placebo controls. Additionally, nicotine led to enhanced physiological arousal to learned threats and overactivation of the ventral tegmental area. This study provides mechanistic evidence that single doses of nicotine impair neural substrates of adaptive aversive learning in line with the risk for the development of pathological anxiety.

Smoking, arousal, and affect: the role of anxiety sensitivity

PURPOSE

Despite evidence that smoking elevates peripheral autonomic nervous system activity, cigarette smokers commonly report smoking to reduce negative affect, or "calm down." Studies suggest that anxiety sensitivity is positively associated with the use of anxiolytic substances, but anxiety sensitivity is also characterized by aversive responding to elevations in physiological arousal. As such, anxiety sensitivity may be an important factor in the study of smoking, affect, and arousal.

METHOD

Smokers smoked cigarettes in two experimental sessions: a Stressful Speech Condition and a No Stress Condition. Psychophysiological and self-report served as within-subjects, repeated measures.

RESULTS

Findings revealed that smoking reduced anxiety in high anxiety sensitive smokers who smoked during a stressful situation, but not a no stress situation. Low anxiety sensitive smokers endorsed anxiolysis in both conditions.

CONCLUSIONS

Results suggest that high anxiety sensitive smokers may be sensitive to the physiologically arousing effects of smoking in low stress, low arousal, situations.

Adolescent stress and future smoking behaviour: a prospective investigation

OBJECTIVE

Adolescent stress has been retrospectively associated with various measures of smoking behaviour in school-aged samples. The present study sought to extend this to a prospective investigation in order to examine the possibly formative influences of stress on the onset of smoking in adolescents.

METHOD

A 12-month follow-up study related sources and degree of adolescent stress measured at study commencement with the onset of smoking behaviour 12 months later in a large cohort of adolescents attending Australian secondary schools.

RESULTS

Adolescent stress was only weakly related to smoking onset in adolescent males and even this could possibly be explained by other factors. In adolescent girls, however, prospective associations were stronger and more broadly represented across the various domains of adolescent stress, suggesting that stress may exert a formative influence on smoking onset for girls.

CONCLUSION

Management strategies for adolescent stress may be an affective target for smoking prevention programs among adolescent girls.