A GROWING body of evidence links weight and mental illness, and now, a major UK study confirms the connection lasts for years. Researchers found that people with severe mental illness gained significantly more weight over 15 years than the general population, yet received no more referrals to weight management services.
Long-Term Link Between Weight and Mental Illness
The relationship between weight and mental illness is complex and deeply concerning. Individuals diagnosed with schizophrenia spectrum disorders, bipolar disorder, or related psychoses often face rapid weight gain following antipsychotic treatment. While medications are vital for symptom control, their metabolic effects can lead to obesity and associated health risks. The new research highlights how these physical health challenges persist well beyond the early years after diagnosis, underscoring a longstanding gap in holistic care for those with mental illness.
Tracking Weight Trajectories and Service Access
Using data from over 113,000 individuals registered at 1,454 primary care practices across England, the population-based cohort study examined weight and mental illness over a 15-year period. Of the total participants, 23,025 had severe mental illness, including schizophrenia (47.9%) and bipolar disorder (51.9%). People with severe mental illness gained an average of 2.10 kg in the first year and 5.55 kg after 15 years, compared with 0.58 kg and 1.62 kg, respectively, among those without such diagnoses. Despite being 10% more likely to receive weight management advice, there was no corresponding increase in referrals to formal weight management services. The findings suggest that while clinicians recognise the problem, practical support remains insufficient.
Implications for Clinical Practice and Policy
The authors call for earlier and sustained interventions, including routine metabolic monitoring and proactive referrals to weight management services. Integrating physical and mental healthcare could prevent long-term cardiometabolic complications and reduce preventable mortality in this underserved group. For clinicians, these findings emphasise the need for coordinated care pathways that address both mind and body.
Reference
Lee CL et al. Weight trajectories and access to weight management services in individuals with severe mental illness in the UK: a population-based, matched cohort study. The Lancet Psychiatry. 2025;12(10):736-45.
