Problematic cannabis use in young adults who screen positive for ADHD: Subgroup analysis from the three-armed randomized controlled CANreduce 2.0 trial of web-based self-help with adherence focused guidance (Preprint)

BACKGROUND Prevalence rates for lifetime cannabis use and cannabis use disorder are much higher in people with attention deficit hyperactivity disorder (ADHD) than those without. CANreduce 2.0 has been shown to be generally effective at reducing cannabis use in cannabis misusers. This self-guided web-based intervention (duration=6 weeks) consists of modules grounded in motivational interviewing and cognitive behavioral therapy. OBJECTIVE To evaluate whether CANreduce 2.0 affects cannabis use patterns and symptom severity in adults screening positive for ADHD more than in those who do not. METHODS Ninety-four adults with ADHD (using the Adult ADHD Self-Report screener) and 273 without who had enrolled in the active intervention arms of CANreduce 2.0 were compared regarding the frequency and severity of cannabis use (number of days used in the preceding 30 days, cannabis use disorder identification test [CUDIT] score and severity of dependence scale [SDS]) at baseline and 3-month follow-up. Secondary outcomes included scores for the Generalized Anxiety Disorder and Center for Epidemiological Studies Depression scales, and data on retention, intervention adherence, and safety. RESULTS Both groups reported significantly reduced frequency and severity of cannabis use (reduction in consumption days: ADHD 11.53±9.28, no-ADHD 8.53±9.4; SDS: ADHD 3.57±3.65, no-ADHD 2.47±3.39; CUDIT: ADHD 6.38±5.96, no-ADHD 5.33±6.05), as well as anxiety (ADHD 4.31±4.71, no-ADHD 1.84±4.22) and depression (ADHD 10.25±10.54, no-ADHD 4.39±10.22). Those with ADHD also reported significantly decreased ADHD scores (4.65±4.44). No significantly different decrease was detected between the two subject groups in any of the outcome variables. ADHD symptom severity at baseline was not associated with reduced cannabis use frequency or severity but was linked to greater reductions in depression (Spearman rho=.33) and anxiety (Spearman rho=.28). Individuals with ADHD were significantly less likely to fill out the consumption diary, but the association between continuous ADHD symptom severity and retention (Spearman rho=-.10) was non-significant. There also was no significant difference in the number of completed modules (ADHD 2.10±2.33, no-ADHD 2.36±2.36) and no association with ADHD symptom severity (Spearman rho= -.09). The same was true for the rate of adverse effects. CONCLUSIONS Cannabis users with ADHD may benefit from CANreduce 2.0 to decrease the frequency and severity of cannabis dependence and attenuate symptoms of depression and ADHD-related symptoms. This web-based program’s advantages include its accessibility for remote users and a personalized counselling option that may contribute to increased adherence and motivation to change among program users. CLINICALTRIAL This trial is registered at ISRCTN with the number ISRCTN11086185 as well as accessible at http://www.isrctn.com/ISRCTN11086185.