Predicting clinical course in major depressive disorder: The association between DM-TRD score and symptom severity over time in 1115 outpatients.

Background: The Dutch Measure for Quantification of Treatment Resistance in Depression (DM-TRD) is a promising prediction tool for major depressive disorder (MDD) based on variables associated with treatment outcome. The objective of our study was to examine the association between the DM-TRD and clinical course in a large cohort of MDD outpatients receiving treatment as usual. Furthermore, we examined whether the addition of an item measuring the presence of childhood adversity improved this association.

Methods: We included 1115 subjects with MDD (according to the DSM-IV) who were naturalistically treated at seven outpatient departments of a secondary mental healthcare center in the Netherlands. Data on subjects who had a diagnostic work-up between June 2014 and June 2016 were analyzed. Multilevel analyses were performed to examine the association between the DM-TRD score at baseline and clinical course, defined by symptom severity according to scores on the Quick Inventory of Depressive Symptomatology-Self Report (QIDS-SR) over time. We also investigated whether an extra item measuring childhood adversity improved the model.

Results: The model including the DM-TRD and its interaction with time was superior to previous models. The addition of childhood adversity and its interaction with time did not improve the model.

Conclusions: In depressed outpatients receiving treatment as usual, the solid longer-term association between higher DM-TRD scores and worse clinical course supports its usefulness in clinical practice. Childhood adversity did not improve the model value indicating that-counterintuitively-this parameter offers no additional predictive power to the variables included.