Preliminary evidence suggests that MDD may be increasing in the pediatric population in a cohort fashion. Risk factors for recurrent illness include a positive family history for affective disorder, female gender and psychosocial adversity, including important losses. Major depression in the pediatric population is readily diagnosable using DSM-IV criteria, i.e. the criteria sets work. Nevertheless, there are clear age-related differences between children, adolescents and adults in depressive symptoms and associated features. For example, adolescents are more likely to complain of feeling sad without looking sad, whereas younger children and adults also look sad when depressed.
Irritability also seems to be a much more prominent symptom in pediatric than in adult depression.
Like other disorders, major depression is commonly comorbid with other internalizing and externalizing disorders. The anxiety disorders often precede MDD, especially in younger children. Subtle anxiety symptoms sometimes remain when depressive symptoms resolve, and may form the nidus for a recurrent depressive episode. Conduct disorder and substance abuse may pose a significant problem in depressed adolescents. Comorbid disruptive behaviors may signal comorbid bipolarity in a substantial number of depressed acting out youth.