Presentation and course of major depressive disorder during childhood and later years of the life span.

OBJECTIVE: To examine whether major depressive disorder (MDD) in childhood, adolescence, and adulthood represents essentially the same diagnostic entity.
METHOD: Recent publications on clinically referred patients with MDD that met certain selection criteria were examined to abstract information on six phenomenological features of the disorder: episode number, symptom presentation, psychiatric comorbidity, recovery from the index episode, recurrence of MDD, and switch to bipolar illness. The studies included both inpatients and outpatients with an age range of 6 to 80+ years.
RESULTS: Synthesizing the information across broad age groups revealed that clinically referred depressed youths, compared with adults and the elderly, are almost exclusively first-episode probands, evidence comparable symptom pictures, have similar rates of psychiatric comorbidity, recover somewhat faster from their index episode of MDD, have a similar recurrence rate, and are at greater risk for bipolar switch.
CONCLUSIONS: MDD in clinically referred youths is similar in many regards to MDD in adults and the elderly. However, the findings that the risk of recurrent MDD among children approximates the rate among adults but, on average, about 20 years earlier in their lives, and that youths with unipolar depression convert to bipolar illness more frequently than do adults, suggest that very early onset MDD is a particularly serious form of affective illness.