Objective: In the general population cannabis use is associated with better cardiometabolic outcomes. Patients with severe mental illness frequently use cannabis, but also present increased cardiometabolic risk factors. We explore the association between cannabis use and cardiometabolic risk factors in patients with severe mental illness.

Method: A total of 3169 patients with severe mental illness from a Dutch cohort were included in the study. The association of cannabis use with body mass index, waist circumference, blood pressure, cholesterol, triglycerides, glucose, glycated hemoglobin and Positive and Negative Syndrome Scale was examined with separate univariate AN(C)OVA. Changes in metabolic risk factors and Positive and Negative Syndrome Scale were examined after a follow-up interval of 9-24 months, for patients who continued, discontinued, started or were never using cannabis between the two assessments.

Results: Cannabis users at baseline had lower body mass index, smaller waist circumference, lower diastolic blood pressure, and more severe psychotic symptoms than non-users. Patients who discontinued their cannabis use after the first assessment had a greater increase in body mass index, waist circumference, diastolic blood pressure and triglyceride concentrations than other patients, and the severity of their psychotic symptoms had decreased more compared to continued users and non-users.

Conclusion: Extra attention should be paid to the monitoring and treatment of metabolic parameters in patients who discontinue their cannabis use.