Predictive validation of single-episode uncomplicated depression as a benign subtype of unipolar major depression

To evaluate the predictive validity of a proposed benign major depressive disorder (MDD) subtype, single-episode 'uncomplicated MDD', defined as MDD that remits within 6 months and lacks severe impairment, psychotic ideation, suicidal ideation, psychomotor retardation, and feeling worthless.

Using two-wave National Epidemiologic Survey on Alcohol and Related Conditions data, four groups differing in wave 1 lifetime MDD history (no history [n = 27 609]; single-episode uncomplicated [n = 418]; other single-episode [n = 1943]; multiple episode [n = 2473]) were evaluated for 3-year follow-up rates of major depressive episode (MDE), generalized anxiety disorder (GAD), and suicide attempt.

Follow-up rates for no-MDD-history, single-episode uncomplicated MDD, other single-episode MDD, and multiple-episode MDD, respectively, were depressive episode 6.1%, 6.9%, 19.5%, 27.1%; GAD 2.7%, 4.3%, 7.8%, 11.2%; and suicide attempt 0.3%, 0.1%, 0.8%, 1.7%. For all validators, 3-year rates for single-episode uncomplicated cases were not significantly different from no-MDD-history rates, but significantly lower than both single- and multiple-episode other-MDD rates. Mild MDD, defined by having only five or six symptoms, did not yield similarly benign results; logistic regression showed 'uncomplicated' provides incremental validity over 'mild' in explaining validator rates. Validator differences were not explainable by treatment-rate differences.

Single-episode uncomplicated MDD is a benign subtype lacking typical MDD negative sequelae. The planned DSM-5.1 revision should reinstitute an extended bereavement exclusion applied to all stressors.