The image in the mirror and the number on the scale both count

"Parents often worry about overweight girls' mental health, but our findings show that it is girls who have a healthy weight but perceive being overweight who are most likely to feel depressed," said Jason N. Houle, graduate student in sociology and demography.

In the past, researchers have looked at the consequences for adolescents of actually being overweight and they looked at how adolescent perceptions of their weight influenced their lives. But, "focusing on the intersection of weight and weight perceptions better shows which adolescents are at risk of depressive symptoms than an approach that treats both predictors as independent, unrelated constructs," the researchers report in the current issue of the Journal of Health and Social Behavior.

"Clinicians cannot assume that healthy weight adolescents know their weight is healthy or feel good about it," said Michelle L. Frisco, assistant professor of sociology and demography.

Eighty percent of girls who are overweight know that they are overweight, but 40 percent of boys who are overweight do not think they are overweight. This reinforces the idea that while the medical and public health world knows what overweight and obese means, the public may not. Also, there is more to the problem than simple physiology; psychology plays an important part.

The researchers found that female weight pessimists -- girls who thought they were overweight but were normal weight -- or boys who were actually under weight were at high risk for depressive symptoms.

"For boys it is slightly different," said Houle. "There is a similar pattern with weight pessimists, but underweight boys are extremely distressed. Underweight boys are far more likely to be distressed than boys who are heavier."

The researchers looked at data from 6,557 male and 6,126 female participants who were part of the Wave II of the National Longitudinal Study of Adolescent Health. This dataset included the participants' actual weight; whether they thought they were under, over or about the right weight; and their scores on the Center for Epidemiologic Studies Depression Scale, a questionnaire that identifies depressive symptoms. High values on the scale correlate well with clinical diagnoses of depression. Their analysis accounted for socioeconomic factors, parental obesity, health status, physical activity, race, ethnicity and family structure.

"We were trying to identify kids who were not doing well psychologically," said Molly A. Martin, assistant professor of sociology and demography. "Small blips do not count. The way the questions are worded, it has to be caused by something more than 'my boyfriend left me'."

The researchers suggest that in the past focus may have been placed on the wrong adolescents.

"We focus on how overweight girls feel," said Martin. "But they may not suffer as many symptoms as we suspected. Past researchers may have missed the key group: normal weight girls who think they are overweight, and underweight boys."

The researchers looked at two approaches to the problem. One approach suggests that conditions are additive, so that an overweight girl who thinks she is overweight would suffer double jeopardy because she has two negatives to her credit. The other approach, health congruency, is based on the degree to which actual health and perceived health match.

The team's results show that health congruency is the theory that works in this case. Realists, those whose perceptions match reality, are relatively unscathed, while those who pessimistically perceive in the mirror something that is not verifiable on the scale are most at risk for depressive symptoms.

"Society emphasizes healthy body image, but it also equates thinness with beauty," said Frisco. "These mixed messages may produce weight pessimism that is distressing for adolescents."

On the other hand, according to Houle, "Overweight teenagers may not be as emotionally troubled as we think."

The National Institute of Child Health and Human Development supported this work.