Dimensions in major depressive disorder and their relevance for treatment outcome

Abstract

Background: Major depressive disorder (MDD) is a heterogeneous disease. More homogeneous psycho(patho)logical dimensions would facilitate MDD research as well as clinical practice. The first aim of this study was to find potential dimensions within a broad psychopathological assessment in depressed patients. Second, we aimed at examining how these dimensions predicted course in MDD.

Methods: Ten psychopathological variables were assessed in 75 MDD inpatients. Factor and regression analyses assessed putative relations between psychopathological factors and depression severity and outcome after 8 weeks of treatment.

Results: A 3-factor model (eigenvalue: 54.4%) was found, representing a psychomotor change, anhedonia and negative affect factor. Anhedonia and negative affect predicted depression severity (R(2)=0.37, F=20.86, p<0.0001). Anhedonia predicted non-response (OR 6.00, CI 1.46-24.59) and both negative affect (OR 5.69, CI 1.19-27.20) and anhedonia predicted non-remission (OR 9.28, CI 1.85-46.51).

Limitations: The sample size of the study was relatively modest, limiting the number of variables included in the analysis.

Conclusions: Results confirm that psychomotor change, anhedonia and negative affect are key MDD dimensions, two of which are related to treatment outcome.

Keywords: Anhedonia; Factor analysis; Major depressive disorder; Outcome; Stress.