TUESDAY, April 26 (HealthDay News) -- Severely obese teens are no more likely to be depressed than their normal weight peers, new research suggests.

"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," study author Dr. Elizabeth Goodman, director of the Center for Child and Adolescent Health Policy at Massachusetts General Hospital for Children, said in a hospital news release. "Our findings suggest this assumption is false."

White teens, however, may face a bit of a higher risk, according to the study.

Researchers tracked 51 severely obese teens in grades 7-12 and compared them to a similar group of non-obese teens. The obese teens had a body mass index of 40 or above, which is considered severely obese and in the top 1 percent for their age group.

Teens were assessed for depression at the start of the study and again two and three years later.

The researchers found no link between obesity and depression, although there were signs of a connection in white teens at year three.

"As clinicians, we treat the entire person -- body and mind -- and we can't assume that weight loss will improve all our patients' mental health or that negative feelings run hand-in-hand with obesity," Goodman said. "Body size appears to have a greater impact on feelings of non-Hispanic white teens than non-Hispanic black teens. We should be particularly vigilant about assessing for depression during regular visits among this group."

The study was recently published online in the Journal of Adolescent Health.

More information

For more about obesity in children, visit the U.S. National Library of Medicine.