MHM Magazine

Issue 2 | 2025 | MENTAL HEALTH MATTERS | 17 MHM The woman sitting opposite me reaches for the box of tissues and takes a deep breath before answering my question. “I started gaining weight after I was put on antidepressants in my mid-20s. I’d struggled with my weight as a child but managed to lose quite a bit in high school when my mom took me with to her Weight Watcher’s meetings. But when I presented with my first episode of depression and my doctor started me on medication, I ballooned. It’s been a daily struggle since then and I’ve tried everything to lose weight. I have yo-yo dieted for years but no matter what I do, I just can’t keep it off.” Unfortunately, this patient’s story is not unique. The mechanisms underlying the relationship between mental illness and early onset and sustained weight gain are multi-factorial and involve both biological and psychological factors, superimposed on the background of social health determinants, medication used to treat serious mental illness (SMI) and their metabolic side effects. Despite an increase in our understanding of obesity, our ability to accurately define the disease is currently lacking. The Canadian Adult Obesity Clinical Practice guidelines have made some headway in trying to refine a definition. They describe obesity as a “complex disease in which abnormal or excess body fat impairs health. The effects of which can also impair quality of life and reduce life span”. Importantly, they have also highlighted it is a “progressive” and “relapsing” chronic disease that should alert health care providers to the importance of long-term treatment. Notably, body mass index (BMI) is not part of this definition. Although BMI does have value on a population level and does correlate with an increasing risk of the metabolic complications of excess adiposity, it should not be seen as the sole indicator of health but rather a flag to identify patients to initiate a discussion about further testing. Patients with SMI have a 2-to- 3-fold increase in mortality compared to the general population with a predicted 10-to- 20-year reduction in lifespan. This excess death is mostly driven by a significantly increased risk of cardiovascular disease (CVD). Some reasons that may account for this “CVD-gap” are an increase in traditional risk factors such as smoking, type 2 diabetes mellitus (T2DM) and importantly, obesity. This is mirrored by under- recognition and suboptimal management of these risk factors in this vulnerable population. Risk of depression in people living with obesity (PLWO) and normal weight individuals: A meta-analysis of 17 epidemiological studies published in 2010 reported that the odds of depression in people living with obesity (PLWO) are 18% higher than those without [odds ratio (OR) 1.18). In women with obesity, odds are 32% higher than those without obesity. Male gender did not influence risk. Large epidemiological surveys have shown the lifetime odds of depression are significantly greater in patients with class III obesity (body mass index > 40kg/m2 ) versus those with a normal body weight. The NHANES (National Health and Nutrition Examination Survey) reported an OR of 2.60 and NESARC and OR of 2.00. It’s therefore imperative that suitable screening for mental health disorders (most notably depression and anxiety) should be undertaken in PLWO as part of standard of care. Prevalence of obesity in patients with SMI: The prevalence of overweight and obesity are 25-60% for bipolar disorder, 30- 70% for schizophrenia and 20-50% for those with depression. Links have also been made between overweight and obesity and binge eating disorder (BED), attention deficit disorder (ADHD) and post-traumatic stress disorder (PTSD). Psychiatric medications and weight gain: a necessary evil? There is a clear, irrefutable link between psychiatric medications and weight gain. While this link has mostly been studied in patients using anti-psychotics, pharmacotherapy used to treat bipolar disorder, depression and Dr Jocelyn Hellig Specialist Physician and Endocrinologist, Claremont, Cape Town OBESITY IN THE PSYCHIATRIST’S OFFICE MHM | 2025 | Volume 12 | Issue 2 | Obesity in the psychiatrist’s office MHM