Cannabis cravings predict cigarette use in schizophrenia: a secondary analysis from two cannabis abstinence studies

Background: People with schizophrenia have high rates of cannabis use disorder (CUD) as well as co-use of tobacco. Tobacco may be used to alleviate cannabis cravings.Objectives: We conducted a secondary analysis of 7 and 28 days of cannabis abstinence from two datasets of participants with CUD with and without schizophrenia to assess cannabis craving, cannabis use in grams per day (GPD) and cigarettes per day (CPD).Methods: We recruited 49 participants (schizophrenia n = 29; control n = 20; 2% female) with CUD. All participants received weekly behavioral support sessions to assist with cannabis abstinence/reduction. GPD and CPD were assessed with the 7-day Timeline Follow-back; the Marijuana Craving Questionnaire (MCQ) assessed compulsivity, emotionality, expectancy and purposefulness subscales. Effects of GPD and MCQ subscales on CPD at days 7 and 28 were assessed with analysis of covariance.Results: At day seven, participants with schizophrenia scored higher on compulsivity (t = 2.72, df = 46.8, p < .01), emotionality (t = 2.48, df = 45.2, p = .02), and purposefulness (t = 2.32, df = 39.41, p = .02) craving subscales than control participants. There was a significant interaction between high purposefulness craving and low GPD on high CPD at day seven (F1,23 = 4.76, p = .039) and day 28 (F1,13 = 7.02 p = .02) in schizophrenia participants but not control participants.Conclusion: We found preliminary evidence that due to cannabis craving intensity, people with schizophrenia and CUD may use more cigarettes when reducing cannabis use, as compared to CUD participants without schizophrenia. Strategies to manage cannabis craving and avoid increasing tobacco use will be useful to implement in intervention strategies.