The Double Burden of Diabetes and Severe Mental Illness

Although antipsychotics are the mainstay of treatment in severe mental illness (SMI), their use is associated with an increased risk of diabetes; the prevalence of diabetes is increased 2–3 folds in patients with schizophrenia and bipolar disorder.1,2 Patients with schizophrenia die 15–20 years earlier than the general population, with the leading cause of mortality being cardiovascular disease.3

Epidemiology of diabetes and SMI

Dr. Richard Holt (University of Southampton, UK) shared a rather sobering quote from Henry Maudley, who lived 1835–1918: “Diabetes is a disease which often shows itself in families in which insanity prevails.” In other words, the link between SMI and type 2 diabetes (T2D) has long been known. Precise prevalence rates of T2D in patients with SMI are unclear, as people from this population are often reluctant to participate in epidemiological studies, and as many as 70% may be undiagnosed.1 However, a meta-analysis of 118 studies including 438,245 patients with SMI showed an overall prevalence of 10.2% of T2D.1 The consequences of T2D in this group are more severe, with higher rates of microvascular and macrovascular complications, acute metabolic dysregulation and diabetes-related deaths.2

The prevalence of diabetes is increased 2-3 folds in patients with schizophrenia and bipolar disorder

Improving diabetes outcomes in people with SMI

Dr. Holt pointed out that many factors contribute to the development of T2D in patients with SMI: genetics, gene-environment interactions, inflammation, neuroendocrine mechanisms, poor diet, poverty and deprivation, physical inactivity, taking antipsychotic medication and smoking.1,2 In order to improve outcomes, health care providers must intervene in this complex cycle wherever possible. Dr. Holt recommends an integrated approach, consisting of better screening, lifestyle counselling/modifications, psychotherapeutic interventions and addressing health inequities experienced by patients living with SMI. For instance, patients with SMI receive inferior cancer care, cardiovascular care and are screened less for eye and foot comorbidities associated with diabetes.1,4

Changing antipsychotics to one associated with less weight gain may be an option

Pharmacological strategies to improve diabetes outcomes in patients with SMI include changing antipsychotics to one that is less prone to result in weight gain, and possibly using pharmacological agents, such as sodium-glucose cotransporter-2 inhibitors, and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) to support weight loss. 


  1. Presented by Dr. Richard Holt, “The Double Burden of Diabetes and Severe Mental Illness,” at SIRS 2023, Toronto, Canada.
  2. Holt RIG & Mitchell AJ. Diabetes mellitus and severe mental illness: mechanisms and clinical implications. Nat. Rev. Endocrinol. 2015;11:79-89.
  3. Presented by Dr. Margaret Hahn, “The Double Burden of Diabetes and Severe Mental Illness,” at SIRS 2023, Toronto, Canada.
  4. Mitchell AJ, Malone D & Doebbeling CC. Quality of medical care for people with and without comorbid mental illness and substance misuse: systematic review of comparative studies. BJPsych. 2009;194:491-499.