Psychiatric disorders linked with obesity

By Anne Harding

NEW YORK (Reuters Health) - Obese people are more likely to have a mood or anxiety disorder compared with individuals who are not obese, a new study shows. However, it is not clear if obesity causes these problems or if the psychiatric disorders lead to obesity.

"The street probably goes both ways in terms of which comes first or which causes the other," Dr. Gregory E. Simon of the Center for Health Studies, Group Health Cooperative in Seattle told Reuters Health.

"The people who live with this every day, they know this already," he added. "What we're doing is sort of putting some numbers on it from a public health perspective."

Simon and his team looked at a nationally representative sample of 9,125 men and women who provided detailed information on their mental health in in-person surveys.

People with body mass indexes of 30 or higher were 21 percent more likely to have experienced major depression at some point in their lives compared with slimmer individuals, and obesity boosted lifetime risk of bipolar disorder by 47 percent.

Obese people were also 27 percent more likely to suffer from a panic disorder or agoraphobia, the fear of going places where help might not be available, which typically includes the fear of crowds, bridges or being alone outside.

However, the researchers found, obese people had a 22-percent lower lifetime risk of having a substance abuse disorder.

No differences in these associations were found between men and women.

However, the association between obesity and mood disorders was statistically significant only among non-Hispanic whites and those with 12 or more years of education. Because obesity is less common among those groups, Simon notes, it may be that it is more heavily stigmatized and hence more likely to cause depression.

He and his colleagues are now conducting additional research to investigate the question of how obesity may influence mental health, and vice versa, by looking at diet and physical activity.

SOURCE: Archives of General Psychiatry, July 2006.