Lead author Dr. Elizabeth Goodman, director of the Center for Child and Adolescent Health Policy at Massachusetts General Hospital, analyzed the relationship between severe obesity and depressive symptoms in a community-based sample of non-Hispanic black and white adolescents.
The study included 51 severely obese participants -- body mass index equal to or greater than 40 -- between grades 7-12 and an equal number of non-obese matched controls.
Study participants were defined as having high depressive symptoms if they used antidepressant medication or had assessment scores at or above a level known to predict major depressive disorder, Goodman says.
"People assume that all obese adolescents are unhappy and depressed; that the more obese a teen may be, the greater the impact on his or her mental health," Goodman says in a statement. "Our findings suggest this assumption is false."
The study, published in the Journal of Adolescent Health, found no relationship between participants' weight status and the likelihood of being depressed.
However, the researchers found an association between obesity and higher depressive symptoms, but only in white participants and only at the three-year assessment, not at baseline or at two years.