Differences between chronic and nonchronic depression: Systematic review and implications for treatment

Abstract

Background: There is still uncertainty if and to what extent chronic depression (CD) presents with specific features especially in contrast to the nonchronic course of major depressive disorder (non-CD). This systematic review aims to summarize the existing literature regarding sociodemographic factors, psychopathology, and course of disease in patients with CD in comparison to patients with non-CD. Methods: A structured database search (MEDLINE, PsycINFO, Web of Science, CENTRAL) was performed. All studies comparing CD with non-CD patients were included. Twenty-eight studies, including cohort studies, cross-sectional studies, and observational studies, were identified in which both subgroups were diagnosed according to DSM-IV or DSM-5, respectively. Primary outcome were group comparisons focused on sociodemographic factors, childhood adversity, onset of the disorder, comorbidities, severity and course of the depressive symptoms, and specific psychopathology. Results: Patients with CD had an earlier onset of depressive symptoms, higher rates of psychiatric comorbidities, and a complicated treatment course (e.g., higher rates of suicidality) compared to non-CD. We also found some evidence for specific features in the psychopathology of CD patients (submissive and hostile interpersonal styles) in contrast to non-CD patients. Results were inconsistent with regard to childhood maltreatment. No differences were found regarding the severity of depressive symptoms and most sociodemographic factors. Conclusion: Despite some inconsistencies, the results of this review verified important differences between CD and non-CD. However, future research is needed to characterize especially the specific psychopathology of CD in comparison to non-CD patients to develop more tailored treatment strategies.