Adjustment disorders occur within three months of a life stressor and are characterized by emotions or behaviors that affect a person's ability to function and are excessive in relation to the stressor and resolve within 6 months of the stressor (but Bereavement is not included in this disorder). The symptoms can be acute or chronic and are categorized as: with depressed mood, with anxiety, with mixed anxiety and depressed mood, with disturbance of conduct, with disturbance of conduct and mood, or unspecified.
Reactive depression, also known as adjustment disorder with depressed mood, is the most common form of mood problem in children and adolescents. In children suffering from reactive depression, depressed feelings are short-lived and usually occur in response to some adverse experience, such as a rejection, a slight, a letdown, or a loss. In contrast, children may feel sad or lethargic and appear preoccupied for periods as short as a few hours or as long as 2 weeks. However, mood improves with a change in activity or an interesting or pleasant event. These transient mood swings in reaction to minor environmental adversities are not regarded as a form of mental disorder. (Mental Health: A Report of the Surgeon General)