The continuity in adulthood of major depressive disorder (MDD) first arising before puberty is largely unknown. This information could guide early treatment and clarify the appropriateness of including children with MDD in genetic studies.
Eighty-three subjects with onset of MDD, 44 subjects with anxiety disorder and no MDD, and 91 subjects with no evidence of past or current psychiatric disorders were assessed by two psychiatrists before puberty (Tanner stage <III) and were evaluated 10 to 15 years later as adults by an independent team without knowledge of the initial diagnosis.
The clinical outcome of children with prepubertal-onset MDD in adulthood includes a high risk of suicide attempts (nearly 3-fold compared with normal controls and 2-fold compared with children with anxiety) and bipolar disorder. Compared with controls, both the children with MDD and those with anxiety went on to have increased risk of substance abuse and conduct disorder but not other disorders, increased use of long-term psychiatric and medical services, and overall impaired functioning. Children with prepubertal-onset MDD with a recurrence of MDD during follow-up had higher rates of MDD in their first-degree relatives.
There is high morbidity in clinically referred children with prepubertal-onset MDD and anxiety, but continuity and specificity of MDD or anxiety disorder in adulthood is less clear. Caution is warranted in selecting clinically referred children with prepubertal-onset MDD for inclusion in genetic studies unless they have a family history of MDD and recurrence of MDD over time.