This study aims to characterize the effect of smoking on stress-induced allopregnanolone (ALLO) response in women by menstrual phase. The investigators hypothesize that women who smoke will have a blunted ALLO response to stress.

Cigarette smoking persists as the leading cause of preventable morbidity and mortality. Thus, finding ways to maximize quitting behavior is critical. Women have a more difficult time achieving smoking abstinence than men. The risk for smoking relapse appears to vary by menstrual phase such that the follicular phase is associated with greater risk compared to the luteal phase. Women are also more likely to smoke in response to stressful stimuli than men. Allopregnanolone (ALLO) is a stress-reducing neuroactive steroid that is primarily metabolized from the sex hormone progesterone and, therefore, varies by menstrual phase in women. Recent preclinical literature has indicated that ALLO may protect against drug abuse behaviors. Unfortunately, ALLO remains largely unexplored in clinical samples containing women.

In this study we aim to characterize the effect of smoking on stress-induced ALLO response in women by menstrual phase. To achieve this goal, we will recruit a sample of premenopausal women who smoke (n=30) and do not smoke (n=30) to participate in a controlled cross-over study. All participants will complete two four-hour lab sessions timed to occur in the Follicular (F; low ALLO) and Luteal (L; high ALLO) menstrual phases. Each lab session will contain an acute stressor along with a timed series of assessments including blood samples (for ALLO measurement) and self-report of mood and perceived stress.

Inclusion Criteria:

• Female between the ages of 18-40 years old
• Stable physical/mental health,
• Self-report of regular menstrual cycles,
• Self-report of either smoking either current or never smoking,
• English fluency,
• Ability to provide informed consent

Exclusion Criteria:

• Self-report of current use of illicit drugs, other tobacco products, nicotine, or smoking cessation medications,
• Current or recent pregnancy or breastfeeding,
• Current or recent use of exogenous hormones (including birth control pills),
• Current or recent use of psychotropic medications.

Women between the ages of 18 and 40 who either smoke or do not smoke.