Insomnia treatment effects among young adult drinkers: Secondary outcomes of a randomized pilot trial.

BACKGROUND Cognitive behavioral therapy for insomnia (CBT-I) has moderate-to-large effects on insomnia among young adult drinkers, with preliminary data indicating that improvements in insomnia may have downstream effects on alcohol-related consequences. However, the mechanism(s) by which insomnia treatment may facilitate reductions in alcohol-related problems is unclear. Secondary outcome data from a randomized pilot trial were used to examine CBT-I effects on four proposed mediators of the insomnia/alcohol link: alcohol craving, delay discounting, negative affect, and difficulties with emotion regulation. METHODS Young adults (ages 18 to 30 years) with insomnia who reported 1+ binge drinking episode (4/5+ drinks for women/men) in the past month were randomized to receive CBT-I (n = 28) or to a sleep hygiene control (n = 28). Outcomes were assessed at baseline, after 5 weeks of treatment, and at 1-month posttreatment. RESULTS Relative to those in sleep hygiene, CBT-I participants reported greater decreases in alcohol craving (d = 0.33) at the end of treatment and greater 1-month posttreatment decreases in delay discounting of large rewards (d = 0.42). CBT-I did not have a significant effect on delay discounting of smaller rewards or momentary negative affect. There was also no significant treatment effect on difficulties with emotion regulation, although findings were confounded by a significant group difference at baseline in difficulties with emotion regulation. CONCLUSIONS Treatment of insomnia may lead to improvements in alcohol craving and delay discounting of large rewards among young adult drinkers with insomnia. Additional research examining whether improvement in insomnia is a mechanism for improvement in addiction domains is warranted.