Use and Co-Use of Alcohol and Cannabis Following Physical Pain in the Daily Life of Community Adults Engaged in Regular Substance Use

Objective: Alcohol and cannabis are often perceived as pain-relieving. However, minimal work has examined whether people use and co-use these substances following pain in daily life. Method: Forty-six adults reporting weekly use of alcohol and/or cannabis completed a 60-day ecological momentary assessment protocol, answering at least four daily reports on their alcohol and cannabis use and pain (nassessments = 10,769 over 2,656 days). We examined whether self-reported pain so far that day (cumulative-average pain) was associated with subsequent alcohol and cannabis use and same-occasion co-use. Models also addressed whether associations differed for initiating versus continuing a use episode. Hypotheses were preregistered. Results: A multinomial multilevel model found that cumulative-average pain was associated with a greater likelihood of same-occasion co-use in the continuation phase but not the initiation phase, compared to no use (OR = 1.48,95% CI [1.06, 2.06], p = .023) and alcohol use (OR = 1.52, CI [1.03, 2.26], p = .037). Cumulative-average pain was largely not associated with alcohol-only and cannabis-only use. After alcohol use, greater pain was associated with cannabis use (OR = 1.37, CI [1.11, 1.70], p = .004), but not the reverse. Secondary analyses found greater previous-occasion (not cumulative) pain was associated with initiation of alcohol use and number of drinks, and initiation and continuation of cannabis use, but not number of cannabis hits. Conclusions: Although not all hypotheses were supported, pain was associated with subsequent substance use in this sample engaged in regular substance use and not recruited for chronic pain. Cumulative pain may be particularly related to alcohol-cannabis same-occasion co-use, which may increase the risk of substance use-related problems over time.