Conceptualizing problematic use of medicinal Cannabis: Development and preliminary validation of a brief screening questionnaire

The use of Medicinal Cannabis (MC) for treating chronic pain is increasing, globally, yet the definition of problematic MC use remains unclear. Defining problematic use of cannabis in medical and non-medical contexts may be fundamentally different since individuals prescribed MC often experience physical dependence, which do not necessarily imply pathology. We aimed to conceptualize problematic use of MC and develop a brief questionnaire for identifying and quantifying problematic MC use. Content validation used a broad definition of problematic substance use, adapting and compiling an initial list of 36 items from various sources: (a) screening tools for assessing problematic prescription opioid medication use; (b) screening tools for problematic recreational cannabis use and (c) qualitative interviews with MC patients. 390 American self-identified chronic pain patients holding a MC card rated each item from the initial list on a 5-point frequency scale and filled out questionnaires assessing various clinical outcomes. Following initial item titration, a multi-group measurement invariance comparison strategy, using two external indicators: alcohol-related problems and depression, resulted a final eight-item list that met fit quality in a baseline model, presented excellent internal consistency reliability (α = 0.929), and significantly correlated with anxiety and low quality of life. Items in the final list related predominantly to negative consequences of MC use. Problematic use of MC is characterized by negative physiological, social, emotional and functional consequences. The final eight-item list was named the Medicinal Cannabis Negative Consequences Scale (MCNCS), emerging as a brief measure for problematic MC use and demonstrating preliminary reliability and validity, which could aid clinicians and researchers.