Description

• A primary mood disorder characterized by sadness and/or irritable mood with impairment of functioning, abnormal psychological development, and a loss of self-worth, energy, and interest in typically pleasurable activities
• Dysthymic disorder is differentiated from major depression by less intense symptoms that are more persistent, lasting at least 1 year.
• The depressive disorder NOS (not otherwise specified) is diagnosed when an adolescent presents with depressive symptoms, but does not meet the criteria for other diagnoses.
• Treatment-resistant depression is a failure of treatment with 2 antidepressants administered in adequate dosage for at least 6 weeks.
• Adolescents with depression are likely to suffer broad functional impairment across social, academic, family, and occupational domains along with a high incidence of relapse, and a high risk for substance abuse and other psychiatric comorbidity.

Epidemiology

Incidence
During adolescence, 20–25%; many do not receive appropriate care.

Prevalence
2–4% of adolescents; twice as common in females

Risk Factors

• Increased 3–6× if 1st-degree relative has a major affective disorder; 3–4× in offspring of parents with depression
• Prior depressive episodes
• History of low self-esteem, anxiety disorders, attention deficit hyperactivity disorder (ADHD), and/or learning disabilities
• Hormonal changes during puberty
• Female gender
• Low socioeconomic status
• General stressors: Adverse life events, difficulties with peers, loss of a loved one, academic difficulties, abuse, chronic illness, and tobacco abuse

Genetics
A 76% concordance rate is found in monozygotic twins reared together and a 67% concordance rate among those reared apart, along with a 19% concordance rate in dizygotic twins reared together.

General Prevention

Insufficient evidence for universal depression prevention programs (psychological and social) (1)[B]. Small benefit to regular exercise in preventing episodes of depression (2)[B]:

• Some evidence indicates that child and adolescent mental health can be improved by successfully treating maternal depression (3).
• Agency for Healthcare Research and Quality (AHRQ) recommends the screening of adolescents (12–18 years of age) for major depressive disorder when systems are in place to ensure accurate diagnosis, psychotherapy (cognitive-behavioral or interpersonal), and follow-up (4)[B].

Pathophysiology

Unclear, low levels of neurotransmitters (serotonin, norepinephrine) may produce symptoms; decreased functioning of the dopamine system also contributes.

Etiology

External factors may affect neurotransmitters/independently affect depression.

Commonly Associated Conditions

• Eating disorders (especially bulimia)
• Alcohol and substance abuse
• Anxiety and somatization disorders
• Behavioral disorders (i.e., ADHD, oppositional-defiant disorder, conduct disorder)
• Learning disorders
• Headaches