The researchers say adolescent insomnia symptoms are associated with depression, suicide ideation and attempts, and the use of alcohol, cannabis and other drugs such as cocaine.

The study is unique in that it the first to examine over a lengthy period, insomnia in adolescents both in association with mental health problems during adolescence and as a risk factor for mental health problems in young adulthood.

The findings suggest that adolescents with insomnia have more than double the risk of developing mental health problems and such problems may be more severe.

It appears that adolescents with the symptoms of insomnia are 2.3 times more likely to develop depression in early adulthood than adolescents without symptoms of insomnia.

This was more so if the insomniacs used alcohol, cannabis and other drugs as these factors made it more likely they would suffer from depression, suicide thoughts, and suicide attempts.

Though the study excluded any participants with a diagnosed mental health problem at baseline, the insomnia group was still significantly more likely to develop depression.

Gender differences emerged for alcohol use, cannabis use, non-cannabis drug use, and depression - with males significantly more likely to endorse alcohol use, cannabis use, and the use of other drugs, while females were twice as likely to develop depression.

Lead investigator and author Dr. Brandy M. Roane, from the University of North Texas says the study suggests adolescents with insomnia are more prone to developing mental disorders, in particular depression and previous research in adults has apparently found similar results.

The study involved 4,494 adolescents between 12 and 18 years of age at the beginning of the study, from 145 schools and 3,582 young adults between the ages of 18 and 25 years in a six-to-seven year follow up - 9.4 percent of the adolescents had insomnia symptoms.

The researchers say the information discovered during this study could potentially provide parents, educators and mentors with a sign of a risk factor for the development of mental health issues.

Insomnia symptoms were categorized as having trouble falling asleep every day or almost every day - binge drinking was defined as drinking five or more alcoholic beverages in a row, and suicide ideation was based on whether or not a participant had endorsed having thoughts of suicide in the last year.

The study appears in the current issue of the journal Sleep.