Effect of Cognitive Behavioral Therapy for Insomnia on Alcohol Treatment Outcomes Among US Veterans: A Randomized Clinical Trial

IMPORTANCE: Three of 4 adults in treatment for alcohol use disorder (AUD) report symptoms of insomnia. Yet the first-line treatment for insomnia (cognitive behavioral therapy for insomnia, CBT-I) is often delayed until abstinence is established. OBJECTIVE: To test the feasibility, acceptability, and preliminary efficacy of CBT-I among veterans early in their AUD treatment and to examine improvement in insomnia as a mechanism for improvement in alcohol use outcomes. DESIGN, SETTING, AND PARTICIPANTS: For this randomized clinical trial, participants were recruited through the Addictions Treatment Program at a Veterans Health Administration hospital between 2019 and 2022. Patients in treatment for AUD were eligible if they met criteria for insomnia disorder and reported alcohol use in the past 2 months at baseline. Follow-up visits occurred posttreatment and at 6 weeks. INTERVENTIONS: Participants were randomly assigned to receive 5 weekly sessions of CBT-I or a single session about sleep hygiene (control). Participants were asked to complete sleep diaries for 7 days at each assessment. MAIN OUTCOMES AND MEASURES: Primary outcomes included posttreatment insomnia severity (assessed using the Insomnia Severity Index) and follow-up frequency of any drinking and heavy drinking (4 drinks for women, ≥5 drinks for men; number of days via Timeline Followback) and alcohol-related problems (Short Inventory of Problems). Posttreatment insomnia severity was tested as a mediator of CBT-I effects on alcohol use outcomes at the 6-week follow-up. RESULTS: The study cohort included 67 veterans with a mean (SD) age of 46.3 years (11.8); 61 (91%) were male and 6 (9%) female. The CBT-I group included 32 participants, and the sleep hygiene control group 35 participants. Of those randomized, 59 (88%) provided posttreatment or follow-up data (31 CBT-I, 28 sleep hygiene). Relative to sleep hygiene, CBT-I participants reported greater decreases in insomnia severity at posttreatment (group × time interaction: −3.70; 95% CI, −6.79 to −0.61) and follow-up (−3.34; 95% CI, −6.46 to −0.23) and greater improvements in sleep efficiency (posttreatment, 8.31; 95% CI, 1.35 to 15.26; follow-up, 18.03; 95% CI, 10.46 to 25.60). They also reported greater decreases in alcohol problems at follow-up (group × time interaction: −0.84; 95% CI, −1.66 to −0.02), and this effect was mediated by posttreatment change in insomnia severity. No group differences emerged for abstinence or heavy-drinking frequenc