TRD eligibility assessment

The manuals converge on the core idea that TRD eligibility assessment depends on confirming a depressive disorder diagnosis, checking current episode severity, and verifying a history of inadequate treatment response before baseline. Across the extracts, the manuals recommend using structured clinical assessment to confirm DSM-5 major depressive disorder, then applying severity thresholds and treatment history criteria to establish that the participant meets study entry requirements. They also agree that prior antidepressant failure must be documented carefully, with attention to both the number and adequacy of prior trials. The sources consistently refer to at least two failed antidepressant treatments or equivalent inadequate response, and they all treat baseline eligibility as contingent on the participant still meeting the protocol-defined TRD definition at the point of enrolment. The manuals differ in the exact operational details. One source specifies DSM-5 MDD without psychotic features confirmed by clinical assessment and MINI, plus IDS-C30 thresholds and special rules such as late-onset depression exclusions and rescreening. Another includes unipolar and bipolar depression, defines sufficient prior exposure by dose and duration, and uses Hamilton Depression Scale response and suicidal ideation criteria.