New research out of the University of North Texas shows an association between adolescent insomnia and the use of alcohol, cannabis and other drugs, the authors said.

Scientists led by Brandy M. Roane studied 4,494 adolescents ages 12 to 18, with follow-up interviews six to seven years later. They found that adolescents who reported experiencing insomnia symptoms -- having trouble falling asleep every day or almost every day -- were more likely to use alcohol, marijuana and cocaine during the study period.

The insomnia group was also 2.3 times more likely to develop depression in early adulthood than adolescents without symptoms of insomnia.

Males were more likely to use alcohol and other drugs, while the depression rate was higher among women.

The findings will be published in the Oct. 1, 2008 issue of the journal Sleep.