E. The symptoms are not better accounted for by bereavement, and the symptoms persist >2 mo or are characterized by marked functional impairment, morbid preoccupation with worthlessness, suicidal ideation, psychotic symptoms, or psychomotor retardation.
Dysthymic disorder and anxiety disorders (prevalence 30% and 80%, respectively), substance abuse (20% to 30%), and disruptive behavior disorders (10% to 20%) are frequent comorbid disorders in depressed children and adolescents. Twenty percent of patients diagnosed with depression develop bipolar disorder (BD); this is more common in cases with a family history of mania or concurrent psychotic features.
The differential diagnoses for MDD are diverse and many. It is always prudent to rule out mood disorder due to a general medical condition or substance-induced mood disorders before considering MDD. Schizophrenia in its initial stages and the dysphoria related to untreated attention-deficit/hyperactivity disorder (ADHD) may also be mistakenly diagnosed as depression. Hypothyroidism, anemia, diabetes, and folate and B12 vitamin deficiencies need to be ruled out.
Dysthymic disorder (prevalence rate 0.6% to 1.7%) is a chronic, milder form of depression characterized by a depressed or irritable mood (subjectively or described by others) present for at least 1 year. Two of the following symptoms are also required: changes in appetite; sleep difficulty, fatigue; low self-esteem; poor concentration or difficulty with making decisions; and feelings of hopelessness. About 70% of children and adolescents with dysthymic disorder eventually develop major depression. The development of MDD after dysthymia is often referred to as double depression.
Atypical depression is MDD characterized by hypersomnia, increased appetite with carbohydrate craving, weight gain, interpersonal rejection sensitivity, and mood reactivity.
Adjustment disorder with depressed mood is the most common depressive disorder in children and adolescents. Symptoms start within 3 months of an identifiable stressor (e.g., loss of a relationship), with distress in excess of what would be expected and interference with social, occupational, or school functioning. Symptoms should not meet criteria for another psychiatric disorder, should not be caused by bereavement, and should not last longer than 6 months after the stressor has stopped.
Seasonal affective disorder is a condition common in northern or extreme southern latitudes, in which depressive symptoms occur in the late fall and early winter when the hours of daylight are shortening.
Depressive disorder not otherwise specified is a diagnosis used when patients have functionally impairing depressive symptoms that do not meet criteria for another condition.
Treatment of depression involves psychopharmacy and psychotherapy. First line antidepressant selective serotonin reuptake inhibitors (SSRIs) have response rates of 50% to 70% despite high-placebo response rate. Fluoxetine is the only agent approved by the U.S. Food and Drug Administration (FDA) for treatment of youth. Citalopram, escitalopram, paroxetine, and venlafaxine have positive clinical trial results as well. An antidepressant should be given an adequate trial (6 weeks at therapeutic doses) before switching or discontinuing unless there are serious side effects. For a first episode of depression in children and adolescents, treatment for 6 to 9 months after remission of symptoms is recommended. Patients with recurrent or chronic depression may need to take antidepressants for extended periods (years or even a lifetime). If a patient does not respond to adequate trials of two or more antidepressants, a child psychiatrist should be consulted. The psychiatrist’s evaluation should focus on diagnostic clarity and psychosocial issues that might be preventing a full response. The psychiatrist may use augmentation strategies that may include lithium, thyroid hormone, lamotrigine, or bupropion.