CHICAGO – People who are overweight are not more jolly, according to a study that instead found obesity is strongly linked with depression and other mood disorders.
Whether obesity might cause these problems or is the result of them is not certain, and the research does not provide an answer, 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 non-obese.
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 Cooperative in Seattle, a large nonprofit health plan. Obesity and depression both 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 including depression, although a growing body of research suggests there is an association.
This latest study helps resolve the question, said Dr. Susan McElroy, a psychiatry professor at the University of Cincinnati and 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.