For example, substance abuse is often self-medication for depression. Younger adolescents may be less able to explain inner feelings or moods for developmental reasons, whereas mid- and older adolescents may believe that to do so is weak. Depression in adolescence is overlooked at least as often as in other age groups. Depression should be considered when a previously well-performing youth does poorly in school, withdraws from society, or commits delinquent acts. Diagnostic categories and treatment of adolescent depression are similar to those of adult depression.
Bipolar disorder is rare before puberty.
Symptoms, Signs, and Diagnosis Depressive manifestations in adolescents, especially when accompanied by stuporous or psychotic episodes, often herald the onset of bipolar disorder. Mania in adolescents is commonly confused with schizophrenia because it often takes the form of an excited psychotic attack. A cyclical pattern of retarded depression and an accelerated psychosis with good premorbid and intermorbid functioning strongly favor the diagnosis of bipolar disorder. Because prevention of disruptive psychotic episodes is important, lithium, valproate, or carbamazepine should be initiated after a single manic episode or psychotic mixed state in an adolescent or young adult with a family history of bipolar disorder. Valproate is preferred over lithium by many physicians because of its familiarity from epileptic management, but it may cause liver damage, particularly in younger children.