More American adolescents and young adults are suffering from depression, according to new research from Columbia University Medical Center.

The study, , analyzed data from the National Surveys on Drug Use and Health and found that episodes of depression increased in adolescents from nearly nine per cent in 2005, to more than 11 per cent in 2014.

Results also showed that depression is increasing faster among girls than boys.

In girls, the occurrence of a major depressive episode during a 12-month period increased from 13 per cent in 2005, to 17 per cent in 2014. In boys, it only increased from four per cent in 2005 to six per cent in 2014.

More research is needed to find out why this group is affected more, but experts suggest cyberbullying and negative texting experiences may play a role.