Treating Comorbid Obesity in Mental Illness

The incidence of obesity in Americans may be as high as 35%, and among Americans who have a psychiatric disorder, obesity may range from between 40% and 50%. Many psychiatric conditions, like binge eating disorder, have an obvious link to obesity, but the link is not as clear in other disorders.1

In a cross-sectional epidemiologic survey published in 2006 in the Archives of General Psychiatry, researchers analyzed data on obesity from more than 9,000 respondents with a psychiatric disorder. Obesity, defined as having a body mass index of 30 or greater, was associated with about a 25% increased chance of having a mood or anxiety disorder. Odds of having depression, bipolar, and panic disorder were also higher in those with obesity.2

A review of obesity management in psychiatric practice by Susan L. McElroy, MD, professor of psychiatry and chief research officer at the Lindner Center of HOPE at the University of Cincinnati, Ohio, notes that although the causality is difficult to determine, the association is striking. “Eighty percent of patients seeking treatment for binge eating disorder are obese. Obesity is also quite common in mood disorders, especially bipolar disorder, major depression, and atypical depression,” says McElroy.3

The Complex Relationships Between Obesity and Psychiatric Disorders

“Depression can cause inactivity which can lead to obesity, and atypical depression can cause increased appetite, McElroy says. “It has been shown in many studies that sleep disturbance can lead to obesity. These relationships seem clear. But there may also be a bidirectional relationship. Stigma of obesity or the inflammatory burden of obesity may have some causal effects for some psychiatric disorders.”

“Psychiatric medications are another major cause of obesity,” says Gail L. Daumit, MD, MHS, associate professor of medicine, psychiatry, epidemiology, and mental health at Johns Hopkins Bloomberg School of Public Health. “The older mood stabilizing drugs and antidepressants are very likely to cause obesity.

“Some of the newer antidepressants are less likely,” she continues. “It can be quite complicated when you have a patient on multiple drugs. In some cases, you can switch to other drugs. In some cases you can’t. Atypical antipsychotics like clozapine cause obesity, but there are no substitute drugs to use.”4

Is Obesity a Mental Health Disorder?

According to DSM-5, a mental disorder is a syndrome of disturbed cognition and control. Substance abuse and many eating disorders are included in DSM-5. With obesity, there is often a lack of ability to control behavior that is harmful.5

“In fact,” says McElroy, “DSM-5 considered adding obesity as a mental health disorder but rejected the idea. There are some good arguments on both sides. There is a growing consensus that obesity is a prominent contributor to mental health disorders and a frequent complication.”

The discussion centers around stigma: Would classifying obesity as a mental health disorder add to the stigma, or might it encourage people to consider obesity a disease, much like addiction, that is more about brain chemistry than willpower? This is still a topic of debate.

How Should Obesity and Psychiatric Disorders Be Managed?

“It is hoped that any doctor managing a patient with obesity and a psychiatric disorder would take responsibility for managing obesity as part of psychiatric management. Just like managing any other dual diagnosis, you will be unlikely to make progress on either disorder unless you treat both,” says McElroy.

If a safe and effective drug to manage obesity existed, it would probably be the most prescribed drug in history. Although there are a few drugs that can be used for obesity in psychiatric patients, they are not well researched. “That’s because psychiatric patients are routinely excluded from most obesity drug trials,” McElroy adds.

An option is bupropion (Zyban), one of the few antidepressants that may cause modest weight loss. Lorcaserin (Belviq) is a serotonergic drug that may be used as an adjunct to diet and exercise for obesity, but it has not been established whether this drug is safe to use with antidepressants and antipsychotics. It has also been associated with serotonergic syndrome. “A drug combination of naltrexone and bupropion has shown some benefit in the treatment of binge eating disorder,” says McElroy.

Psychosocial Management of Obesity

Almost all experts agree that psychosocial interventions are the first and best ways to manage obesity in mental health. “The first order of business is to stop weight gain. After that you need a lot of empathy and patience. Cognitive-behavioral therapy, sleep hygiene, exercise, and nutrition education are all important,” says McElroy.

Daumit’s research centers on behavioral interventions for weight loss. “Many doctors do not feel comfortable managing weight loss along with mental illness. But our research shows that even in severely mentally ill patients, changes can be made,” she says.

A 2013 study from Daumit included 291 obese patients with serious mental illness. This was the first large weight loss study to include people with schizophrenia, bipolar disorder, and major depression. Subjects were divided into a weight management intervention group and a control group. Interventions focused on simple messages and goals, not on counting calories. After 18 months, the intervention group lost seven more pounds than the control group.6

“If you concentrate on simple goals like exercising, avoiding junk food and sugary beverages, [limiting] portion size, and [eating] lots of fruits and vegetables, you can achieve a healthier lifestyle and weight loss in this patient population. That can mean less stigma and better outcomes,” Daumit says.

Chris Iliades, MD, is a full-time freelance writer based in Cape Cod, Massachusetts.

This article was medically reviewed by Pat F. Bass III, MD, MS, MPH.


  1. McElroy SL. Medical Management of Obesity in the Psychiatric Practice. White Paper. Psychiatric Times. Oct. 1, 2014. (
  2. Simon GE, et al. Association Between Obesity and Psychiatric Disorders in the US Adult Population. Arch Gen Psychiatry. 2006;63(7):824-830. doi:10.1001/archpsyc.63.7.824. (
  3. Susan L. McElroy, MD, Chief Research Officer, Lindner Center of HOPE, Professor of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine.
  4. Gail L. Daumit, MD, MHS, Associate Professor of Medicine, Psychiatry, Epidemiology, Health Policy and Management and Mental Health, Johns Hopkins Medical Institutions, Division of General Internal Medicine, and Associate Director, Welch Center for Prevention, Epidemiology and Clinical Research.
  5. Pierre JM. “Is Obesity a Psychiatric Disorder?” June 24, 2014. (
  6. Serious mental illness no barrier to weight loss success. News Release. ScienceDaily. March 21, 2013. (