Steven Dubovsky, MD reviewing Kendler KS et al

A dimensional approach might work better than a symptom checklist for diagnosis, treatment, and research.

Some clinicians have questioned the applicability of the DSM-IV's list of nine criteria (which do not drastically differ from the DSM-5 criteria) to the task of diagnosing depression (NEJM JW Psychiatry Jun 19 2002). Researchers analyzed data from a community-based study of 7500 twins to examine how much genetic and environmental factors are shared (common factors) across all DSM-IV depression criteria or specific to different criteria.

In the best-fitting model, criterion-specific genetic factors were associated with clusters of psychomotor and cognitive symptoms; sad mood, anhedonia, and worthlessness; and vegetative symptoms (especially sleep difficulties and fatigue). The genetic factor for psychomotor/cognitive symptoms seemed to reflect nonspecific genetic liability to several internalizing disorders, including anxiety disorders. The neurovegetative genetic factor was most strongly associated with melancholia (as expected, by definition).

Three common environmental factors were identified — one associated with all criteria except guilt and suicidal ideation; another with depression, anhedonia, and decreased concentration; and a third with guilt and suicidal ideation.

Citation(s):

Kendler KS et al. Evidence for multiple genetic factors underlying DSM-IV criteria for major depression. JAMA Psychiatry 2013 Jun 1; 70:599.