Cannabis-Using Schizophrenia Patients Gained Less Weight on Antipsychotics
First-episode schizophrenia patients who tested positive for cannabis gained significantly less weight during 12 months of antipsychotic treatment compared to non-users, with no significant difference in metabolic markers.
Quick Facts
What This Study Found
There was a significant group-by-time interaction (p=0.002): cannabis-negative patients showed greater BMI increases over 12 months than cannabis-positive patients. Post hoc tests showed the cannabis-negative group had significant increases in fasting glucose, triglycerides, and decreased HDL cholesterol, while the cannabis-positive group showed no significant changes in these markers.
Key Numbers
109 patients total: 40 cannabis-positive, 69 cannabis-negative. Significant group-by-time interaction for BMI (p=0.002). More cannabis-negative patients had elevated waist circumference at endpoint (p=0.003).
How They Did This
109 minimally treated first-episode patients with schizophrenia-spectrum disorders received standardized depot antipsychotic treatment over 12 months. 40 tested positive for cannabis at any point; 69 tested negative at all time points. Repeated measures compared BMI, fasting glucose, and lipids over time.
Why This Research Matters
Antipsychotic-induced weight gain is a major side effect that contributes to cardiovascular disease and treatment non-adherence. Understanding why some patients gain less weight could lead to better metabolic management strategies.
The Bigger Picture
While acute cannabis use stimulates appetite, chronic use may actually suppress it. This study adds clinical evidence to population-level findings linking regular cannabis use with lower obesity rates, specifically in a context where weight gain is a major clinical concern.
What This Study Doesn't Tell Us
Observational within a treatment study - cannot prove cannabis caused the weight difference. Cannabis users may have different lifestyle factors (diet, smoking). Urine testing only indicates recent use, not quantity or frequency.
Questions This Raises
- ?Is the weight difference directly caused by cannabis or by associated lifestyle factors?
- ?Could cannabinoid-based medications be developed to counteract antipsychotic weight gain?
- ?Does the metabolic benefit outweigh the psychiatric risks of cannabis use in schizophrenia?
Trust & Context
- Key Stat:
- Cannabis-positive patients showed significantly less BMI increase over 12 months (p=0.002) and fewer metabolic changes than cannabis-negative patients.
- Evidence Grade:
- Moderate - prospective cohort with standardized treatment and objective cannabis testing, but observational comparison with potential confounders.
- Study Age:
- Published in 2018.
- Original Title:
- Effects of cannabis use on body mass, fasting glucose and lipids during the first 12 months of treatment in schizophrenia spectrum disorders.
- Published In:
- Schizophrenia research, 199, 90-95 (2018)
- Authors:
- Scheffler, F, Kilian, S, Chiliza, B, Asmal, L, Phahladira, L, du Plessis, S, Kidd, M, Murray, R M, Di Forti, M, Seedat, S, Emsley, R
- Database ID:
- RTHC-01826
Evidence Hierarchy
Enrolls participants and follows them forward in time.
What do these levels mean? →Frequently Asked Questions
Does cannabis affect weight gain from antipsychotics?
This study found that schizophrenia patients who tested positive for cannabis gained significantly less weight during 12 months of antipsychotic treatment. They also showed fewer negative metabolic changes in blood sugar and cholesterol.
Does chronic cannabis use affect body weight?
While cannabis acutely stimulates appetite ("the munchies"), this and other studies suggest chronic use may actually be associated with lower body weight. The mechanisms are not fully understood.
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Cite This Study
https://rethinkthc.com/research/RTHC-01826APA
Scheffler, F; Kilian, S; Chiliza, B; Asmal, L; Phahladira, L; du Plessis, S; Kidd, M; Murray, R M; Di Forti, M; Seedat, S; Emsley, R. (2018). Effects of cannabis use on body mass, fasting glucose and lipids during the first 12 months of treatment in schizophrenia spectrum disorders.. Schizophrenia research, 199, 90-95. https://doi.org/10.1016/j.schres.2018.02.050
MLA
Scheffler, F, et al. "Effects of cannabis use on body mass, fasting glucose and lipids during the first 12 months of treatment in schizophrenia spectrum disorders.." Schizophrenia research, 2018. https://doi.org/10.1016/j.schres.2018.02.050
RethinkTHC
RethinkTHC Research Database. "Effects of cannabis use on body mass, fasting glucose and li..." RTHC-01826. Retrieved from https://rethinkthc.com/research/scheffler-2018-effects-of-cannabis-use
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.