child under bed representing childhood trauma link to mental health

Experts understand that trauma and obesity are common among people with various mental health concerns and may be associated with mental illness.

While trauma typically precedes the onset of a mental health disorder, the cause-effect relationship between obesity and mental illness is unclear.

In other words, here’s the question researchers still need to answer:

Does obesity increase the likelihood that people will develop certain mental health challenges, or do struggles with mental health undermine a person’s ability to maintain a healthy weight?

In addition to attempting to clarify the link between weight problems and mental health struggles, researchers are now exploring how all three of these concerns – trauma, obesity, and mental illness – may influence each other.

Obesity and Mental Illness

In May 2023, the open access journal Translational Psychiatry published a study that explored the link between obesity and mental illness. This study involved a massive dataset, including information from more than 3.1 million patients who received inpatient care at Austrian hospitals between 2003-2014.

The introduction to this study noted the following about the prevalence of both obesity and mental health concerns throughout the world:

  • Experts estimate that more than 33% of the global population is overweight.
  • About 25% of people throughout the world will struggle with at least one mental illness over the course of their lifetime.
  • About 40% of people who are either overweight or obese have a mental health disorder.

Noting that “the question of cause and consequence [between obesity and mental illness] remains to be resolved,” the researchers stated that rising rates of overweight and obesity justified an in-depth analysis of the connection between these two conditions.

After stratifying the study’s subjects by age and gender, the researchers compared rates of both physical and mental health conditions (as established in the ICD-10) between patients with obesity and patients without obesity.

They also charted when the date of diagnosis, which allowed them to track whether the obesity occurred prior to or after the physical or mental health disorder.

Here’s what they found.

Obesity and Mental Health Disorders

  • Among all age groups, patients with obesity showed higher rates of depressive disorders, anxiety disorders, schizophrenia, and schizoaffective disorder.
  • The risk of anxiety disorders was about twice as high among patients with obesity. This variance was consistent across all age groups.
  • Within the 20-29 age group, the rate of depression was more than two times higher among patients with obesity. This gap narrowed among patients in older age ranges.
  • The highest rates of co-occurring obesity and schizophrenia or schizoaffective disorder appeared in the 20-29 age range. As with depression, the risk gap between the obese and non-obese groups narrowed with age.

The researchers also found that, among patients who had obesity and a co-occurring mental health disorder, about one-third were diagnosed with both conditions during the same hospital visit.

  • Among those who received diagnoses during different visits, the majority received an obesity diagnosis first, and a mental health diagnosis second.
  • The two exceptions to this pattern included schizophrenia and schizoaffective disorder. In most cases, people with both conditions received the schizophrenia/schizoaffective diagnosis first.

Of course, neither of these findings establishes an incontrovertible cause-effect relationship, but they do give some credence to the view that obesity can elevate the likelihood that a person will develop a mental health disorder later in life.

“From a clinical point of view, these results emphasize the need to raise awareness of psychiatric diagnoses in obese patients and, if necessary, to consult specialists at an early stage of diagnosis,” Michael Leutner, one of the researchers, said in a Neuroscience News article about his team’s study.

Trauma and Obesity

Though the Austrian study clearly established that obesity and mental illnesses frequently co-occur, it is less conclusive about why this phenomenon is so common.

Joseph Lloyd Davies, a lecturer in applied psychiatry at the UK’s Cardiff Metropolitan University, believes that trauma may be to blame, especially if that trauma occurs during a person’s childhood.

In a May 2023 article on the website The Conversation, Davies discussed what he described as “a body of research that suggests childhood trauma has a big part to play” in the elevated rates of obesity among people with serious mental illnesses (SMIs).

Davies’ article included the following findings from previously published studies:

  • About 47% of Welsh people have a history of abuse, neglect, or other adverse childhood experiences (ACEs) – but among those who have received care in a forensic psychiatric hospital, the ACE rate is 70%.
  • Having a history of four or more ACEs doubles the likelihood that a person will follow a nutritionally poor diet. Having a history of multiple ACEs is also associated with a 46% greater risk of obesity during adulthood.

Davies theorized that people who have endured multiple ACEs often turn to binge eating in a misguided attempt to cope with their emotional distress:

“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 centers of the brain.”

Following Davies’ logic, untreated childhood trauma can predispose people to myriad mental health challenges, while self-defeating coping mechanisms can lead to weight-control problems.

This supposition is supported by a July 2022 study in the journal Eating and Weight Disorders.

The authors of that study, which involved an assessment of 514 overweight or obese adults aged 18-30, concluded that “individuals who experience traumatic events during childhood may turn to the consumption of food as a maladaptive coping mechanism, which over time often leads to weight gain and the onset of overweight or obesity.”

Trauma, Obesity, and Mental Illness

While Davies’ article and the July 2022 study suggest that trauma can raise a person’s risk for obesity, the link unfortunately doesn’t stop there. Other researchers previously documented the degree to which obesity increases the likelihood that someone will experience stigma, discrimination, and other potentially traumatizing experiences.

In September 2019, the journal Obesity Reviews published a meta-analysis on this topic. This report was based on a review of 105 studies that involved more than 59,000 participants.

The authors of this analysis reported that prior research has linked weight stigma with a variety of negative mental health issues, including:

  • Anxiety disorders
  • Depressive disorders
  • Dysfunctional/disordered eating
  • Diminished quality of life
  • Poor self-esteem
  • Decreased body satisfaction
  • General psychological distress

The authors also found that the intensity of a person’s mental health struggles correlated to the amount and severity of the stigma they perceived. Unfortunately, they noted, most healthcare professionals who work with overweight and obese patients focus on weight loss, not the mental health impact of weight stigma.

“Education about overweight and weight stigma as well as policies to protect people with overweight against stigma is an important challenge for better mental health on a global level,” they wrote.

Trauma, Obesity, and Treatment for Mental Illness

Documenting the connections among trauma, obesity, and mental illness can be valuable for promoting awareness. But how can clinicians put this information into practice in a way that benefits individuals in crisis?

Here are three ways that mental health professionals are using this knowledge to improve patient experience and treatment outcomes.

Trauma, Obesity, and Mental Health: How Clinicians Help

  • Embrace a trauma-informed approach to treatment, which is based on the knowledge that most patients who receive mental health care are likely to have a history of trauma.
  • Acknowledge that weight stigma can be a traumatizing experience that may cause or exacerbate symptoms of anxiety, depression, PTSD, and other mental health concerns.
  • Understand that effective mental health treatment should address the impact that obesity and other weight-related concerns may have on a person’s psychological well-being.

This is yet another reminder of the value of a truly comprehensive approach to mental health treatment. When treatment professionals consider their patient’s mental health challenges in the context of their physical, social, and emotional well-being, they will be better prepared to develop the customized solutions that can empower the patients to achieve the best possible quality of life.