Studies in the general population show cannabis use has a beneficial effect on metabolic disorders. Given the increased cardiometabolic risk in patients with psychotic disorders, as well as their prevalent use of cannabis, we aim to investigate whether such effects are also evident in these patients.

3176 patients with chronic psychotic disorders from mental health institutions in the Netherlands were included in the study. With multivariate regression analyses we examined the effects of cannabis use on metabolic risk factors; BMI, waist circumference, blood pressure (BP), cholesterol, HDL-C, LDL-C, triglycerides, glucose and HbA1c. Age, sex, smoking, alcohol use and antipsychotic drugs were included as confounders. Next, we examined change in metabolic risk factors after one-year follow up for cannabis users, non-users, discontinuers and starters.

We found a significant negative association between cannabis use and BMI (p=0.003), waist circumference (p>0.001), diastolic BP (p=0.015) and HbA1c (0.004). One year later, patients who had discontinued their cannabis use had a greater increase of BMI (p=0.002) and waist circumference (p=0.011) than other patients. They also had a greater increase of diastolic BP than non-users (p=0.036) or starters (p=0.004).

Discontinuation of cannabis use increased metabolic risk. To stop cannabis use is often an important treatment goal, because it reduces psychotic symptoms. However, physicians should be aware of the increased metabolic risk in patients who discontinue the use of cannabis. Extra attention should be paid to monitoring and treatment of metabolic parameters in these patients to prevent cardiovascular diseases and premature cardiovascular mortality.