Is major depressive disorder in adolescence a distinct diagnostic entity?

The concept of major depressive disorder in childhood and adolescence is reviewed and it is suggested that contemporary enthusiasm for this diagnosis may have outrun the evidence that it is a distinct categorical entity. To test the hypothesis that major depression is not a qualitatively distinct disorder in adolescence, but rather a continuously distributed, noncategorical syndrome, the behavioral rating scales (CBCL-P) of 216 hospitalized adolescent patients were analyzed first by principal components analysis and then by cluster analysis. Three behavioral syndromes were isolated by principal components analysis. Of three groups of patients identified by a subsequent cluster analysis, one was consistent with the concept of a categorically distinct "nuclear" depression. However, a noncategorical continuously distributed depressive syndrome appears to affect a larger number of patients in this age group, and the "nuclear" disorder may be less prevalent than is currently assumed. One explanation of these findings would combine a categorical model of nuclear depression with a dimensional model of dysthymia.