Insomnia is associated with psychological distress in individuals with methamphetamine dependence

IntroductionMethamphetamine dependence is associated with psychological distress (stress, anxiety, and depression). Insomnia is common in this population, yet its association with distress remains underexplored. This study examined the relationship between insomnia severity and psychological distress in treatment-seeking individuals with methamphetamine dependence.MethodsThis is a secondary cross-sectional analysis of baseline data from 152 participants enrolled in a randomised controlled trial of lisdexamfetamine versus placebo for methamphetamine dependence. Insomnia severity was assessed using the Insomnia Severity Index (ISI), and distress was measured via the Depression Anxiety and Stress Scale (DASS-21). Associations were analysed using Spearman's correlations and regression models adjusted for demographics, methamphetamine use, concomitant medication, and co-occurring distress.ResultsInsomnia severity showed moderate correlations with depression, anxiety, stress, and total distress (ρ = 0.46-0.59, p < .001). In adjusted models, insomnia remained associated with distress: each 1-point ISI increase related to a 2.1-2.5% rise in DASS-21 depression and stress scores (β = 0.021-0.025, p = .003-.007), and a 6.5% increase in total scores (β = 0.063, p < .001); the association with anxiety was attenuated.ConclusionsOur study identified insomnia as an independent correlate of psychological distress in treatment-seeking individuals with methamphetamine dependence. Findings underscore sleep problems' relevance and support further research into sleep-focused interventions.