Effect of progesterone administration in male and female smokers on nicotine withdrawal and neural response to smoking cues: Role of progesterone conversion to allopregnanolone

This double-blind, randomized, placebo-controlled crossover study examined whether use of allopregnanolone instead of progesterone during a brief abstinence period had a therapeutic effect in 39 male and female smokers, including whether the effect was different in females versus males. As part of the study, participants completed two ad lib smoking sessions, with expired CO levels measured before and after each session using the Vitalograph BreathCO carbon monoxide monitor.