Description

In the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR), major depressive disorder is characterized by a distinct period of at least 2 wk (an episode, Table 24-1) in which there is a depressed or irritable mood that is present for most of the day nearly every day, and/or loss of interest or pleasure in nearly all activities. There also are associated vegetative and cognitive symptoms, including disturbances in appetite, sleep, and energy; impaired concentration; and thoughts of worthlessness, guilt, and suicide. To meet the syndromal diagnosis, 5 or more symptoms (including depressed or irritable mood or loss of interest or pleasure) must be present and must represent a distinct change from previous functioning, cause clinically significant distress or impairment, not be better accounted for by bereavement or by other psychiatric disorders, and not be due to the direct physiologic effects of a substance or a general medical condition.

Major depressive disorder is categorized as mild if few symptoms in excess of those required to make the diagnosis are present and the symptoms result in only minor functional impairment, and it is categorized as severe if several symptoms in excess of those required are present and the symptoms markedly interfere with functioning. Severe major depression is subcategorized as occurring with or without psychotic features (hallucinations or delusions). Moderate major depression is intermediate between mild and severe.

Overall, the clinical presentation of major depressive disorder in children and adolescents is similar to that in adults. The prominence of the symptoms can change with age; somatic complaints, irritability, and social withdrawal may be more common in children (who are less able to verbalize their feeling states), and psychotic and melancholic symptoms or suicidal behavior may be more common in adolescents.

Epidemiology

The prevalence of major depressive disorder is estimated to be approximately 2% in children and 4-8% in adolescents, with a male-female ratio of 1 : 1 during childhood and 1 : 2 during adolescence. The risk of major depression increases by a factor of 2 to 4 after puberty, and the cumulative incidence by age 18 yr is approximately 20%.

Differential Diagnosis

A number of psychiatric disorders, general medical conditions, and medications can generate symptoms of depression and irritability and must be distinguished from the depressive disorders. The psychiatric disorders include anxiety (Chapter 23), attention-deficit/hyperactivity disorder (ADHD) (Chapter 30), disruptive behavior (Chapter 27), developmental disorders (Chapter 28), substance abuse (Chapter 108), and adjustment disorders. Medical conditions include neurologic disorders, endocrine disorders, infectious diseases, tumors, anemia, uremia, failure to thrive, chronic fatigue disorder, and pain disorder. Medications include narcotics, chemotherapy agents, cardiovascular medications, corticosteroids, and contraceptives. The diagnosis of a depressive disorder should be made after these other explanations for the observed symptoms have been ruled out.

Comorbidity

Major depressive and dysthymic disorders (Chapter 24.3) often co-occur with other psychiatric disorders, and both can occur concurrently (double depression). Depending on the setting and source of referral, 40-90% of youths with a depressive disorder have other psychiatric disorders, and up to 50% have 2 or more comorbid diagnoses. The most common comorbid diagnosis is an anxiety disorder, followed by disruptive behavior, ADHD, and substance use disorder.

Clinical Course

The median duration of a major depressive episode approximates 8 mo for clinically referred youths and 1 to 2 mo for community samples. Prepubertal depressive disorders can exhibit more heterotypic than homotypic continuity; thus, depressed children may be more likely to develop nondepressive psychiatric disorders in adulthood than depressive disorders. Adolescents might exhibit greater homotypic continuity, with the probability of recurrence of depression reaching 70% after 5 yr. Between 20% and 40% of these adolescents develop a bipolar disorder (Chapter 24.2), and the risk is higher among adolescents who have a high family loading for bipolar disorder, who have psychotic depression, or who have had pharmacologically induced mania.

Sequelae

Approximately 60% of youths with major depression report thinking about suicide, and 30% actually attempt suicide (Chapter 25). The risk of suicidal behavior increases if there is a history of suicide attempts, exposure to adverse psychosocial circumstances, a family history of suicidal behavior, or comorbid psychiatric disorders. Youths with depressive disorders are also at high risk of substance abuse, impaired academic performance, impaired family and peer relationships, and poor adjustment to life stressors, including physical illness.

Etiology and Risk Factors

Major depression is a highly familial disorder, with both genetic and environmental influences. Environmental influences include parental psychopathology, impaired parenting, dysfunctional families, parent figure changes, loss of a parent, physical and sexual abuse, neglect, social isolation, lack of social supports, exposure to domestic and community violence, and other correlates of disadvantaged socioeconomic status. Longitudinal studies have suggested the greater importance of environmental influences in children who become depressed compared to adults who become depressed.

Prevention

Several experimental trials have demonstrated the effectiveness of cognitive-behavioral strategies in preventing the escalation of sub-syndromal to syndromal depression. These strategies include identifying negative mood states, linking mood states to environmental or cognitive precipitants, avoiding situations that are typically stressful, correcting automatic negative attributions, scheduling pleasurable activities, developing competencies to enhance self-esteem, and developing learning skills to deal with adversity. Other strategies that can prove helpful include lifestyle modification (e.g., regular and adequate sleep, exercise, and relaxation) and involvement with supportive mentors and peers.

Early Identification

Clinicians should screen all children and adolescents for the key depressive symptoms of sad mood, irritability, and anhedonia (Table 24-2). A diagnosis of a depressive disorder should be considered if these symptoms are present most of the time, affect the child’s functioning, and are beyond what would be expected for the given circumstances. The use of standardized depression rating scales (Chapter 18) designed for self- or parent report can be helpful in the screening process. If the screening indicates clinically significant depressive symptoms, the clinician should refer to a specialist for a comprehensive diagnostic evaluation to determine the presence of depressive and other comorbid psychiatric and medical disorders. The evaluation must include assessment of the potential for harm to self or others.

Table 24-2 SCREENING AND TREATMENT FOR MAJOR DEPRESSIVE DISORDER IN YOUTHS