The definition and meaning of treatment-resistant depression

Most patients treated for an episode of unipolar or bipolar major depressio n are treatment resistant in the sense that the majority do not achieve ful l remission with the first somatic or psychosocial treatment they receive. Little attention has been given to formalizing criteria for evaluating the nature and extent of treatment resistance, even though determining the adeq uacy and outcome of prior treatment trials is key in clinical decision maki ng about subsequent treatment. Furthermore, determining the adequacy of pri or treatment is essential since substantial evidence indicates that large n umbers of depressed patients are under-treated, resulting in prolonged epis odes and the appearance of "pseudoresistance." Adequacy of antidepressant t reatment trials should be defined in terms of thresholds for the dosage and duration of medication, adherence, and clinical outcome. The Antidepressan t Treatment History Form is presented as one method to formalize the evalua tion of treatment adequacy and treatment resistance.