Staging of depressive disorders: Relevance of resistance to treatment and residual symptoms.

Background: Clinical staging model for depression helps to better define the clinical situation of patients. The objectives of this study are: to correlate the Hetrick's staging model of depression with the severity of depression, associated disability, and resistance to treatment in the established disease stages and to test the modification introduced by our group consisting in the introduction of a substage for recurrence from a previous episode that was stabilized with a complete remission.

Methods: A Cross-sectional study with 133 adult subjects having a current and primary diagnosis of Depressive disorder was developed. Patients were classified according to the model and assessed with: 17-item Hamilton Depression Scale (HAM-D), Clinical Global Impression (CGI); Global Assessment of Function (GAF); Maudsley Staging Method for treatment resistance (MSM) and Sheeham Disability Schedule (SDS).

Results: The variable that best contributes to the differentiation between clinical stages, in established Depression, is resistance to treatment evaluated by the MSM. Correlations between MSM and the clinical stages were statistically significant between most pairs of stages. Finally, we showed preliminary data in order to prove that a differential sub-stage for recurrent depression with and without inter-episodic remission in the current heuristic models could be a possible stage for better define depression staging model.

Conclusions: Resistance to treatment should be included in the definition of clinical stages in established depression. Despite the difficulty of establishing a valid model for the staging of depression, it can certainly add great value to diagnosis, therapeutic interventions and clinical research.