Differential diagnosis of childhood depression: using comorbidity and symptom overlap to generate multiple hypotheses.

Childhood depression is often found to share symptoms and coexist with several other childhood disorders and physiological conditions, leading to diagnostic errors and possibly inappropriate treatment. Literature relevant to the differential diagnosis of childhood depression is reviewed with particular attention given to the similarities and differences between depression and coexisting conditions such as anxiety disorders, conduct disorders, and attention deficit hyperactivity disorder. The characteristics of childhood depression are compared and contrasted with other possible coexisting disorders. Diagnostic reasoning, confirmatory bias, and the advantages of considering multiple hypotheses when diagnosing depression are discussed.