The research found that girls were nearly twice as likely to think about suicide if they had only a few friends and felt isolated from their peers. Girls were also more likely to consider suicide if their friends were not friends with each other.
These relationship factors had no significant effect on whether boys considered suicide.
"Close friendships appear to be much more important for adolescent girls than they are for boys, and problems with these relationships have major impacts on girls' mental health," said James Moody, co-author of the study and assistant professor of sociology at Ohio State University.
"Boys tend to hang out in groups, and close relationships do not seem to be as important to them."
Another key finding was that there was no way to tell which teenagers who are thinking about suicide will actually attempt it.
Moody conducted the study with Peter Bearman of the Institute for Social and Economic Research and Policy at Columbia University. Their findings appear in the January 2004 issue of the American Journal of Public Health.
The researchers used data on 13,465 adolescents in grades 7 through 12 from across the United States. The students participated in the National Longitudinal Survey of Adolescent Health. They completed a survey in school and then were interviewed in their homes one year later. They were asked, among many other things, about their friendships, whether they had thought about suicide in the past year and whether they had attempted suicide in the past year.
Moody said he wasn't surprised that friendships played a larger role for girls than for boys, but he was surprised at the size of the difference.