Can people with Severe Mental Illness experience less weight loss after metabolic surgery?
Metabolic (bariatric) surgery is an effective treatment for severe obesity, but not everyone loses the same amount of weight. Research suggests that people with severe mental illness (SMI) — such as schizophrenia, bipolar disorder, or major depression — may have slightly less weight loss after surgery compared to people without these conditions. This does not mean surgery is ineffective for people with SMI, but it is important to understand the potential difference and discuss it with your healthcare team.
What the research says
A rapid review and meta-analysis of 23 studies found that people with mental illness (including SMI) had slightly lower weight loss after metabolic and bariatric surgery compared to those without mental illness 1. The effect size was small but statistically significant (standardized mean difference -0.33, 95% CI -0.53 to -0.13) 1. This means that on average, people with mental illness lost a bit less weight, but the difference was not large enough to say surgery is not worthwhile.
The review also found that other conditions like type 2 diabetes and sleep apnea were linked to slightly less weight loss, while hypertension, dyslipidemia, and metabolic syndrome did not show a significant difference 1. The evidence for mental illness came from studies with moderate heterogeneity, meaning results varied across studies 1.
It is important to note that SMI is associated with higher rates of other long-term conditions, such as chronic kidney disease and cardiovascular disease, which can also affect surgical outcomes 73. However, the specific impact of SMI on weight loss after surgery is not fully understood, and more research is needed. The meta-analysis did not separate SMI from other mental illnesses, so the findings may apply broadly 1.
What to ask your doctor
- Based on my mental health condition, what weight loss results can I realistically expect from metabolic surgery?
- Are there any special precautions or follow-up plans for people with severe mental illness before and after surgery?
- How will my psychiatric medications be managed around the time of surgery, and could they affect weight loss?
- Should I see a dietitian or mental health professional before surgery to help optimize my outcomes?
- What support services are available after surgery to help me maintain weight loss and manage my mental health?
This question is drawn from common patient questions about Psychiatry and answered using cited medical research. We do not provide individualized advice.