Background
Estimating the likelihood of future major depressive episodes (MDEs) would assist clinicians in decision-making regarding the optimal length of treatment for MDE. Unfortunately, little data are available to guide clinical practice.
Methods
We followed 200 females and 152 males who responded to treatment for a MDE for 2 years to determine risk factors for future MDE. Cox Proportional Hazard Regression modeled time to first relapse into MDE and mixed effect logistic regression modeled monthly depression status.
Results
Females were more likely than males to experience a MDE in any month of the study, and marginally more likely to experience a relapse. By 12 months, 60% of females had relapsed compared to 51% of males (median time to relapse 8 vs 13 months, respectively). Several factors predicted worse outcome for both men and women: reported childhood abuse, earlier age of onset of first MDE, Bipolar Disorder, unemployment, and more years of education. For females, but not males, suicidal ideation predicted MDE relapse and both suicidal ideation and prior suicide attempts were associated with more time in a MDE.
Limitations
The naturalistic treatment of participants, exclusion of individuals with current comorbid alcohol or substance use disorder, and a follow up period of two years are limitations.
Conclusions
Women are more vulnerable to relapse and spend more time depressed compared to men. Identification of general and sex-specific risk factors for future depression may provide clinicians with useful tools to estimate need for ongoing pharmacotherapy in MDE.