Study says obesity, depression linked

CHICAGO — Obesity is strongly linked with depression and other mood disorders, according to a new study by Group Health Cooperative.

Whether obesity might cause these problems or is the result of them is not certain, but there are theories to support both arguments.

Depression often causes people to abandon activities, and some medications used to treat mental illness can cause weight gain. On the other hand, obesity is often seen as a stigma, and overweight people often are subject to teasing and other hurtful behavior.

The study of more than 9,000 adults found that mood and anxiety disorders, including depression, were about 25 percent more common in the obese people studied than in the nonobese. Substance abuse was an exception; obese people were about 25 percent less likely to abuse drugs or alcohol than slimmer participants.

The results appear in the July issue of Archives of General Psychiatry, released Monday. The lead author was Dr. Gregory Simon, a researcher with Group Health in Seattle.

The results "suggest that the cultural stereotype of the jolly fat person is more a figment of our imagination than a reality," said Dr. Wayne Fenton of the National Institute of Mental Health, which funded the study.

"The take-home message for doctors is to be on the lookout for depression among their patients who are overweight," Fenton said.

Both conditions are quite common. About one-third of U.S. adults are obese, and depression affects about 10 percent of the population, or nearly 21 million U.S. adults in a given year.

Previous studies produced conflicting results on whether obesity is linked with mental illness, although a growing body of research suggests there is an association.

The latest study helps resolve the question, said Dr. Susan McElroy, editor of a textbook on obesity and mental disorders.

"This is a state-of-the-art psychiatric epidemiology study that really confirms that there is, in fact, a relationship," she said.

The study was based on an analysis of a national survey of 9,125 adults who were interviewed to assess mental state. Obesity status was determined using participants' self-reported weight and height.

About one-fourth of all participants were obese. Twenty-two percent of obese participants had experienced a mood disorder, compared with 18 percent of the nonobese.