Classification and Staging of Treatment-Resistant Depression

Introduction to Staging Models

The Maudsley Staging Method (MSM) is the preferred instrument for classifying Treatment-Resistant Depression (TRD) due to its prospective validation and predictive utility, as recommended by 69% of experts 2
Five validated staging models exist to classify TRD, including the Antidepressant Treatment History Form (ATHF), Thase and Rush Staging Model (TRSM), European Staging Model, Massachusetts General Hospital Staging Model (MGH-s), and the Maudsley Staging Method (MSM) 1, 2

The Antidepressant Treatment History Form (ATHF) defines adequate treatment as ≥4 weeks duration and does not directly correspond with the number of treatment failures, with predictive validity confirmed in three prospective ECT studies 1
The Thase and Rush Staging Model (TRSM) stages patients according to the number of antidepressant classes that failed, with Stage II corresponding to two treatment failures, and does not consider psychotherapy failures 1, 3
The European Staging Model requires a minimum of two treatment failures for all TRD stages and defines Chronic Resistant Depression (CRD) as resistance beyond 12 months 1, 3
The Massachusetts General Hospital Staging Model (MGH-s) is primarily based on the number of prior antidepressant failures without class hierarchy and considers treatment optimization, augmentation/combination strategies, and prior failed ECT 1, 3
The Maudsley Staging Method (MSM) uniquely includes disease characteristics such as duration of illness and symptom severity at baseline, making it the most comprehensive assessment 1, 3

The Maudsley Staging Method (MSM) is the only model with prospective validation demonstrating good predictive validity, and is recommended as the preferred staging instrument for clinical trials 1, 2
The ATHF demonstrates good reliability and predictive validity specifically for ECT outcomes, while the TRSM, European Model, and MGH-s lack systematic validation studies 1, 3
The American Psychiatric Association recommends careful treatment history documentation or structured staging tools, such as the ATHF, TRSM, European Model, MGH-s, or MSM, to confirm treatment resistance in clinical practice 4, 5