Carrying excess weight is a common problem for many people living with schizophrenia.^1,2 This article looks at why this may be the case and why it is important to try to manage your weight to remain within a healthy range.

What’s the healthy weight?

Before getting into the relationship between schizophrenia and weight gain, it’s worth defining what we mean by healthy weight. Doctors often determine whether someone is of a healthy weight by calculating the body mass index (BMI).³ This is a measure that uses a person’s height and weight to calculate a value that is given in units called kilograms per metres squared (kg/m²).³
 
It is generally agreed that:³

Of course, if someone is very muscular then that may increase their body weight and thus BMI.^3,4 Taking this into account, doctors may consider the person’s overall body frame; their waist circumference; or how much body fat they have.^4,5

https://schizophrenia.life/public/schizophrenia-and-smoking-give-in-or-give-up/Being outside of the healthy BMI range is a frequent finding among people with schizophrenia.¹ In fact, estimates suggest that obesity is twice as common in people with schizophrenia than in the general population.²
 
What is the explanation for this? While medications used to treat schizophrenia are linked to weight gain,⁶ it’s important to note that weight gain and obesity can occur early in the natural course of the disease regardless of any treatment.²
 
Indeed, many people with schizophrenia become overweight before their first episode and they continue to gain weight after the initiation of schizophrenia treatment.² Notably, around two-thirds of individuals experience significant weight gain over the first year of their treatment.²
 
It’s very likely that unhealthy lifestyle habits, such as poor diet, smoking , alcohol use, and not exercising regularly, contribute to weight gain in schizophrenia,⁶ so tackling these may help minimise the effects of weight gain associated with the drugs used to treat schizophrenia.⁷
 
If you are concerned about how the treatment might be affecting your or a loved one’s body weight, talk to a doctor about the available options. There are differences between the various antipsychotic drugs, with some being associated with less weight gain than others.^2,6

Weight gain and obesity are important to address as they not only worsen general health but also have an impact on a person’s self-image and mental wellbeing.^{2,8, 9}
 
Managing obesity is particularly important for people with schizophrenia as they are already at a higher risk for having coexisting health issues than the general population – and being overweight or developing obesity can substantially add to that risk.⁹ Indeed, obesity is an important risk factor for developing both heart disease and type 2 diabetes, and it is a leading cause of premature death. ⁹  
 
Of note, adolescents with psychiatric disorders are a particularly vulnerable group when it comes to obesity and experiencing negative effects on their mental health.¹⁰ Obesity may not only add to the stigma of having schizophrenia, but it may also lower their self-esteem and overall willingness to take antipsychotic medication as presrcribed.¹⁰

Preventing weight gain and obesity is perhaps easier said than done as there are many factors that contribute to someone’s weight.⁸ This includes a person’s metabolism and how quickly their body turns food into energy as much as their lifestyle behaviours, family history, and socioeconomic circumstances.⁸
Weight loss can be achieved with the right support and motivation, however, a combined or integrated approach is recommended.^9.11 This includes lifestyle interventions such as eating a healthy and balanced diet, increasing levels of physical activity and avoiding unhealthy behaviours such as smoking and substance use.^9.11

Some general suggestions for managing weight in schizophrenia include: ^9–11

In additional to talking to a healthcare professional about weight and how it might be affecting you or a loved one, you may find the following good sources of information on general lifestyle advice and weight management.
 
Living with Schizophrenia. Healthy Living: Schizophrenia and Diet
NHS. BMI healthy weight calculator
NHS. 12 tips to help you lose weight
NHS. More ways to kickstart your health.