How childhood trauma can lead to obesity in people with serious mental illness

Research suggests childhood trauma has a big part to play in obesity. Ken stocker/Shutterstock

People with a serious mental illness (SMI), like schizophrenia, often experience obesity. And in the UK, such people are almost twice as likely to be obese compared to those without a diagnosis.

People with SMI also have a greater risk of having other obesity related illnesses such as type 2 diabetes, respiratory disease, cardiovascular disease and heart failure. The result is a life expectancy that is 15 years less than the general population.

Many experts believe the greater risk of obesity is due to the medications used to treat mental illness. Antipsychotics, for example, have frequently been shown to impact body weight.

But that explanation does not consider the role that deeper psychological factors play in obesity. There is a body of research that suggests childhood trauma has a big part to play too.

Psychological trauma and obesity

Psychologists often refer to the trauma experienced in childhood as “adverse childhood experiences” (ACEs). Such experiences include abuse and neglect (both physical and emotional), mental illness and substance abuse in the home, witnessing domestic abuse and having an incarcerated relative.

This type of trauma is strongly associated with the development of mental illnesses in later life. This may explain why many people who are treated in psychiatric hospitals have had such experiences. For example, 70% of people in forensic psychiatric hospitals have at least one ACE, compared to 47% of the population of Wales.

Research also shows trauma can effect the way people behave. A recent study found someone who has experienced four or more adverse childhood experiences is twice as likely to have an unhealthy diet. This may explain why there is a 46% increase in the odds of adult obesity following exposure to multiple ACEs.

Despite this knowledge, however, little attention is paid by policymakers to the impact childhood trauma can have on obesity in people with serious mental illness.

Why is it that people who experience trauma in childhood have a greater risk of being obese? It is well known that people who have experienced traumatic childhoods engage in behaviour that isn’t particularly healthy, such as self-harming, abusing drugs and binge eating. These people do this as a form of avoidance, to distract themselves from the difficult thoughts and feelings they experience.

The term used to describe this behaviour is “experiential avoidance”.

Eating our emotions

Experiential avoidance can take many forms, but a common method is emotional eating, which is the tendency to eat in response to negative emotions. It is associated with the consumption of tasty food that is high in calories.

When someone emotionally eats, they can experience the numbing of intense negative emotion, can be distracted and feel a sense of comfort. This is because when we eat food with lots of fat and sugar, it activates the reward and pleasure areas centres of the brain. Eating foods high in fats and sugar is fine in moderation, of course. But the positive effects of eating tasty, high calorie foods are often short lived.

Eating food high in sugar and fat activates the reward and pleasure areas centres of our brain.

So, people who engage in experiential avoidance may rely on these foods and consume them to excess. This, according to research, is what can lead to weight gain and obesity.

Currently, the treatment guidelines for people with SMI do not consider the impact that ACEs can have on obesity in this group of people. This is probably due to the emphasis placed on antipsychotic drugs as the main contributor to excessive weight gain.

And despite the negative impact that obesity can have on people with a serious mental illness, psychiatric services often overlook physical health issues because some psychiatric staff feel they are not adequately trained to deal with the physical health of their patients.

To improve physical health in people with a serious mental illness, it is important that mental health professionals and policymakers consider the impact that psychological trauma has on obesity in this group of people.

Promoting a trauma-informed approach to both psychiatric and physical health care is vital. In essence, this would involve care teams having a complete picture of their patient, mentally and physically, and providing adequate training around the impact that psychological trauma can have on a person’s behaviour.

Joseph Lloyd Davies does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

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