Abstract
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.