Development and validation of the Comprehensive Cannabis Motives Questionnaire (CCMQ).

Background: Existing scales that measure cannabis use motives have failed to incorporate the full range of motives that underpin cannabis consumption, especially with the increased use of medical cannabis. The current research aimed to develop a novel, psychometrically robust scale that comprehensively measures cannabis use motives. Here, we report the development and validation of the Comprehensive Cannabis Motives Questionnaire (CCMQ).

Method: Cannabis users completed a 45-item questionnaire measuring a range of cannabis use motives. A UK English-speaking sample (n = 450) provided data for exploratory factor analysis. A second UK English-speaking sample (n = 200) was used for confirmatory factor analysis. Test-retest reliability was based on a third English-speaking sample (n = 45) who completed the revised, 41-item CCMQ twice across 2 weeks. A US-based sample (N = 216) was used to test measurement invariance of the scale across countries.

Results: Exploratory and subsequent confirmatory factor analysis provided an eight-factor solution. The eight factors were food, medicinal, sleep, social, high, coping, conformity and creative. All the factors had good to excellent internal reliability with McDonald's ω ranging between 0.85 and 0.97. Test-retest reliability was obtained for the revised 41-item questionnaire (Intraclass correlation's 0.5+ for Total Cannabinoid Eating Experience Questionnaire and each subscale). The eight factors were correlated with Cannabis Use Disorder Identification Test - Revised to assess relationships with problematic use. Finally, strict measurement invariance was achieved in comparisons between males and females and a UK sample against a US sample.

Conclusion: The CCMQ provided a valid, reliable assessment of the motivations that underlie cannabis use.