How to Identify Treatment-Resistant Depression in Treated MDD
How can clinicians or health systems operationally identify treatment-resistant depression among adults receiving medication treatment for major depressive disorder?
Clinicians and health systems need a consistent way to distinguish patients whose depression has progressed beyond standard first-line pharmacotherapy from those with medication-treated MDD who have not met resistance criteria. This article uses a commonly applied treatment-pattern definition that can support case finding, burden assessment, and population management in adults already receiving antidepressant treatment.
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Start with adults who have medication-treated MDD
Define the eligible population as adults with major depressive disorder who are receiving antidepressant treatment. In the source studies, MDD was identified from ICD-9-CM or ICD-10-CM diagnosis codes in medical claims data, and the workflow was applied only within this medication-treated MDD population.
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Verify two antidepressant courses of adequate dose and duration
Review treatment history to confirm that 2 antidepressant treatment courses of adequate dose and duration have been changed. The article does not provide a dose table or minimum duration threshold beyond stating that adequacy of dose and duration was required, so the classification depends on documenting 2 adequate prior courses rather than simply counting prescriptions.
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Classify TRD when a third treatment course begins
Identify treatment-resistant depression when the patient initiates a third antidepressant treatment course after the 2 prior adequate courses have been changed. Augmentation therapy counts within this third-course definition, so escalation beyond serial monotherapy can meet the operational TRD criterion used in this study.
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Allow limited gaps between consecutive courses
When reconstructing the treatment sequence, allow a treatment gap of up to 180 days between consecutive antidepressant treatment courses. A gap within that window does not break the sequence used to classify TRD in the article's claims-based approach.
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Use a 2-year observation window for non-TRD classification
Classify adults with an MDD diagnosis and antidepressant treatment as having non-TRD MDD if they do not meet the TRD criteria within 2 years of the first antidepressant claim. This creates a defined follow-up window that separates patients who progress to a third course after 2 adequate changes from those who do not.
Clinical Considerations
- The article notes that there is no universally accepted definition of TRD, and prevalence estimates vary widely depending on the criteria used.
- This workflow is based on proxy definitions from treatment patterns because symptom burden was not available in the claims database studies.
- The source definition was developed from claims-based analyses and may not capture clinical response, remission, or the reasons a treatment was changed.
- The study focused on adults with medication-treated MDD, so this operational approach does not address untreated MDD or all patients with MDD in the community.
Bottom Line
In this article, TRD is operationally identified when an adult with medication-treated MDD starts a third antidepressant treatment course, including augmentation, after 2 prior adequate courses have been changed, allowing gaps of up to 180 days and using a 2-year window from the first antidepressant claim.
