A prospective 12-year study of subsyndromal and syndromal depressive symptoms in unipolar major depressive disorders

Arch Gen Psychiatry. 1998 Aug;55(8):694-700. doi: 10.1001/archpsyc.55.8.694.


Background: Investigations of unipolar major depressive disorder (MDD) have focused primarily on major depressive episode remission/recovery and relapse/recurrence. This is the first prospective, naturalistic, long-term study of the weekly symptomatic course of MDD.

Methods: The weekly depressive symptoms of 431 patients with MDD seeking treatment at 5 academic centers were divided into 4 levels of severity: (1) depressive symptoms at the threshold for MDD; (2) depressive symptoms at the threshold for minor depressive or dysthymic disorder (MinD); (3) subsyndromal or subthreshold depressive symptoms (SSDs), below the thresholds for MinD and MDD; and (4) no depressive symptoms. The percentage of weeks at each level, number of changes in symptom level, and medication status were analyzed overall and for 3 subgroups defined by mood disorder history.

Results: Patients were symptomatically ill in 59% of weeks. Symptom levels changed frequently (1.8/y), and 9 of 10 patients spent weeks at 3 or 4 different levels during follow-up. The MinD (27%) and SSD (17%) symptom levels were more common than the MDD (15%) symptom level. Patients with double depression and recurrent depression had more chronic symptoms than patients with their first lifetime major depressive episode (72% and 65%, respectively, vs 46% of follow-up weeks).

Conclusion: The long-term weekly course of unipolar MDD is dominated by prolonged symptomatic chronicity. Combined MinD and SSD level symptoms were about 3 times more common (43%) than MDD level symptoms (15%). The symptomatic course is dynamic and changeable, and MDD, MinD, and SSD symptom levels commonly alternate over time in the same patients as a symptomatic continuum of illness activity of a single clinical disease.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Antidepressive Agents / therapeutic use
  • Chronic Disease
  • Depressive Disorder / classification
  • Depressive Disorder / diagnosis*
  • Depressive Disorder / drug therapy
  • Dysthymic Disorder / classification
  • Dysthymic Disorder / diagnosis
  • Dysthymic Disorder / drug therapy
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Prospective Studies
  • Recurrence
  • Severity of Illness Index


  • Antidepressive Agents