Measuring change in cannabis use

We examined the ability of the Cannabis User Disorders Identification Test – Revised (CUDIT-R) to detect change in a treatment sample, including correlation with changes in other clinically relevant areas of functioning, and to determine reliable and clinically significant change thresholds. 133 cannabis-using patients taking part in a treatment trial for concurrent substance use and mood disorder were administered the 8-item CUDIT-R at baseline, 6 and 12 months, in addition to assessment of current cannabis use disorder, mood, alcohol use, motivation and employment status. Significant reductions in CUDIT-R scores were observed and were correlated with change in cannabis diagnosis, and improvement in mood. Higher motivation at baseline predicted greater reduction in CUDIT-R score. Reliable change was identified as occurring when CUDIT-R score changed by two or more, while clinically significant change, benchmarked against an increase or decrease of one DSM-IV cannabis dependence symptom, was equated to a CUDIT-R score changing by 3 or more points.