Examining correlates of cannabis users' engagement with a digital intervention for substance use disorder: An observational study of clients in UK services delivering Breaking Free Online

Background: Cannabis is among the most widely used drugs, with the literature demonstrating that cannabis use disorder (CUD) may be more prevalent than previously thought. Research should explore novel approaches to behavioral support to meet treatment need, including computer-assisted therapies such as Breaking Free Online (BFO). This study aimed to understand how participants' baseline sociodemographic and clinical characteristics are associated with engagement with BFO, and how both participants' characteristics and their engagement may be associated with cannabis use and biopsychosocial functioning at follow-up. Methods: An observational study with 1830 individuals presenting to UK-based publicly funded treatment services who reported cannabis as their primary problem substance and engaged with BFO as a self-directed intervention. Results: Moderate-severe depression/anxiety (51%) and elevated severity of cannabis dependence scores (39%) characterized the baseline sample. Women demonstrated greater clinical complexity at baseline than men. Baseline mental health and biopsychosocial functioning were associated with whether participants completed a follow-up assessment. Among 460 participants who completed a follow-up assessment, intervention engagement was positively associated with self-reported quality of life and biopsychosocial functioning at follow-up. Conclusions: Cannabis users demonstrated substantial clinical complexity at baseline, with depression/anxiety and biopsychosocial functioning being associated with BFO engagement. Greater BFO engagement was also associated with better quality of life and biopsychosocial functioning at follow-up. Some groups, including those with greater mental health and biopsychosocial impairment at baseline and women, may require support to engage with BFO to maximize clinical benefits.