Insomnia in stimulant use disorders: Prevalence and associations with negative affect.

Research suggests that sleep disturbances are common among people who use psychostimulants, including cocaine use and methamphetamine use. These sleep disturbances hinder recovery, heighten relapse risk, and worsen physical and mental health outcomes. This study aimed to estimate the prevalence and severity of insomnia among individuals who use cocaine and methamphetamine and to explore potential psychological factors that are associated with more severe insomnia. The sample included participants who completed in-person screening assessments for ongoing studies at an outpatient research clinic. As a part of this screening, participants completed the Insomnia Severity Index (ISI) and validated assessments of psychological domains related to negative affect, such as distress tolerance, anhedonia, emotion regulation, and posttraumatic stress symptoms. Regularized regression identified and retained the most important psychological variables for predicting the presence of clinically-significant insomnia. Results indicated that the prevalence of clinically significant insomnia was 36.6 % in those who use cocaine and 44.7 % in those who use methamphetamine, and the prevalence of subthreshold insomnia was 35.3 % in individuals who use cocaine and 39.3 % in individuals who use methamphetamine. Regression results indicated that depression symptoms were the strongest predictor of insomnia severity, along with difficulties in emotion regulation and posttraumatic stress symptoms. Similarities and differences between cocaine and methamphetamine subgroups were also identified. These results suggest that insomnia in individuals who use cocaine and methamphetamine may be shaped by a collection of modifiable psychological processes, and highlight the need for tailored, integrated interventions that address sleep, affective functioning, and trauma-related processes within stimulant-focused SUD treatment.