Validation of the McIntyre And Rosenblat Rapid Response Scale (MARRRS) in Adults with Treatment-Resistant Depression Receiving Intravenous Ketamine Treatment

BACKGROUND Depression severity and efficacy measurement scales employed for rapid-acting treatments (e.g., ketamine) were initially validated in adults receiving conventional monoamine-based antidepressants. The emergence of rapid-acting antidepressants in psychiatry provides the impetus for outcome measures that have been validated as sensitive to change with rapid-acting treatments. Herein, we provide results validating the McIntyre and Rosenblat Rapid Response Scale (MARRRS). METHODS Adults with treatment-resistant depression (TRD) receiving intravenous (IV) ketamine had depressive symptoms measured with the 16-Item Quick Inventory Depressive Symptoms Self-Report (QIDS-SR-16) and MARRRS at baseline and as a repeated measure across an acute course of four infusions. The MARRRS is a self-report measure assessing depressive symptoms during the past 72 hours. RESULTS Sixty-four patients (Mage = 45.4 ± 13.5) were included. The MARRRS had a high internal consistency across acute infusions as determined by Cronbach's alpha (0.84 to 0.94). There was significant convergent validity between the QIDS-SR-16 and MARRRS total scores across infusions (rs(292) = .87, p < .001); the MARRRS was also sensitive to change (rs(49) = .70, p < .001). Exploratory factor analysis revealed that MARRRS items loaded onto two factors (i.e., dysphoria and psychic anxiety) accounting for 63.4% of the total variance. LIMITATIONS Heterogenous sample of adults with TRD receiving open-label treatment without placebo comparison. CONCLUSION The MARRRS is a brief validated self-report metric of depression symptom severity that is sensitive to change with the rapid-acting antidepressant ketamine. Measuring outcomes with the MARRRS informs treatment progress and facilitates treatment decisions in persons receiving the rapid-acting antidepressant ketamine. Studies of other rapid-acting antidepressants should incorporate outcome measures that are validated as sensitive to change with rapid-acting antidepressants.