Clinical Factors Associated With Treatment Resistance in Major Depressive Disorder: Results From a European Multicenter Study

This study sought to identify specific clinical & demographic factors associated with treatment-resistant depression in a large sample of European patients with major depressive episodes who failed to reach response or remission after at least 2 consecutive adequate antidepressant treatments. 11 variables, including suicide risk, were found to be associated with treatment-resistant depression. Suicidal risk during the depressive episode was found to be associated with a 2.2-fold increased risk of resistance. Suicidal risk included suicide ideation, a suicide attempt in the last month, or a suicide attempt at least once in the lifetime. All of these were associated with treatment-resistant depression but it was difficult to differentiate between variables related to the current episode versus those related to previous suicidality. (23 refs.)