Evidence suggests that nearly half of all mental health problems begin before the age of 14.
Kessler, R., Berglund, P., Demler, O., Jin, R., Merikangas, K., & Walters, E. (2005). Lifetime prevalence and age-of-onset distributions of DSM-IV Disorders in the National Comorbidity Survey Replication. Archives of General Psychiatry, 62(6), 593 – 602.
Côté S.M., Boivin M., Liu X., Nagin D.S., Zoccolillo M., & Tremblay, R.E. (2009). Depression and anxiety symptoms: Onset, developmental course and risk factors during early childhood. The Journal of Child Psychology and Psychiatry, 50(10), 1201-1208.
Sawyer, M. G., Arney, F. M., Baghurst, P. A., Clark, J. J., Graetz, B. W., Kosky, R. J., et al. (2001). The mental health of young people in Australia: Key findings from the child and adolescent component of the national survey of mental health and well-being. Australian and New Zealand Journal of Psychiatry, 35, 806-814.