Though it sounds silly today, that is the way the mental health community thought. Depression is difficult to recognize in children. Estimates are that 10 percent of children will suffer a depressive episode before age 12. Children usually don't have the capacity to step back and recognize that the way they are feeling is not normal for them. The symptom picture of depression in children and adolescents is also confusing because they cannot express their feelings as directly as adults.
Irritability is a key indicator.
Children may seem easily frustrated, cranky or moody. Boys may simply appear unusually angry or sullen. Untreated, depression can be permanently devastating to children. Depression is very tough on family members. Usually there is not a dramatic change in personality but often a slow, insidious process which makes it difficult to recognize that something is really wrong.