Teenagers who see themselves as either too heavy or too thin may be at heightened risk of attempting suicide, regardless of what their weight actually is, according to a new study.

The findings, based on a national survey of U.S. high school students, show that perception may trump reality in issues of weight and suicidal behavior, according to researchers at the Centers for Disease Control and Prevention in Atlanta.

They found that among 13,600 high-school students surveyed, those who thought they were “very” overweight, whether or not they actually were overweight, were more than twice as likely as teens who viewed their weight as normal to have considered suicide. Even students who thought they were slightly overweight had a greater tendency toward suicidal thoughts.

Similarly, high schoolers who viewed themselves as slightly or substantially underweight were at increased risk of suicidal thoughts.

However, the teenagers’ actual weight did not affect their risk of suicidal behavior once their perceptions of their weight were taken into account.

It’s not surprising that body perception, even when not in tune with reality, could have a stronger impact on teenagers than their actual weight does, according to lead study author Dr. Danice K. Eaton.

“Their perceptions are their reality,” she noted in an interview.

The findings suggest that “extremes” in a teenager’s weight perception could serve as a warning sign of increased suicide risk, according to Eaton. However, she said, there are many other factors that can sway this risk, and this study was not designed to uncover the reasons for the teenagers’ perceptions.

More research, Eaton said, is needed to look at how kids form their body perceptions, and why for some, these perceptions may contribute to suicidal behavior.

She and her colleagues report the findings in the June issue of the Archives of Pediatrics and Adolescent Medicine.

In an accompanying editorial, Dr. Alain Joffe of Johns Hopkins University in Baltimore agrees on the need for research into which factors - from media images to the influence of friends and parents - help shape teenagers’ body images. He points out that although roughly 72 percent of girls in this study were of normal weight, more than one third described themselves as overweight and 12 percent thought they were underweight.

The study included a nationally representative sample of high-school students who were surveyed on their health-related behavior. Students reported their actual weights and heights and were asked whether they would describe themselves as “very” or “slightly” overweight or underweight, or “about the right weight.” They were also asked whether they had seriously considered or attempted suicide in the past year.

Overall, 14 percent of boys and about 24 percent of girls said they had thought about suicide, while 6 percent and 11 percent, respectively, said they had made a suicide attempt.

The investigators observed some important racial differences. Among black students, those who perceived themselves as overweight were not more likely than their peers to consider or attempt suicide - a finding, the researchers note, that is consistent with studies showing that black women tend to be more accepting of a larger body size.

Though body-image issues are often seen in terms of a teenage girl’s fear of being fat, in this study, perceptions of being underweight were as strongly tied to suicidal behavior as perceived excess pounds were.

Among white, black and Hispanic students alike, those who thought they were very thin were roughly three times more likely to have attempted suicide compared with their peers who thought their weight was about right.

The potential mental-health consequences of feeling underweight, Eaton noted, have not received the same research attention that has gone toward the effects of being or perceiving oneself as overweight.

SOURCE: Archives of Pediatrics & Adolescent Medicine, June 2005.