The Identification and Validation of Distinct Depressive Syndromes in a Population-Based Sample of Female Twins

Since Aubrey Lewis' classic study there has been debate about whether the distinction between depressive subtypes is categorical or dimensional.^1-6A recent article by Kendler et al⁷supports a categorical classification of depressive subtypes. Using a different means of validating nosological distinctions, our group reached similar conclusions and we think it relevant to review the similarities and differences between our...