A - 24 Treatment Response to Internet-Delivered Cognitive Behavioral Therapy for Depression in Multiple Sclerosis

Abstract Objective A recent randomized-controlled (phase III) clinical trial examined the efficacy of an internet-delivered cognitive behavioral therapy (iCBT) intervention designed to treat depressive symptoms in persons with multiple sclerosis (PwMS). Significant mean reductions in depressive symptoms were found in the stand-alone iCBT and guided-iCBT conditions compared to the control group. The purpose of the current study was to identify the proportion of PwMS who responded to iCBT (stand-alone and guided) for depression compared to a waitlist control group. Method 224 PwMS completed the Beck Depression Inventory-II (BDI-II) to measure depression severity at baseline and post-intervention. Reliable change index (RCI) scores for depressive symptoms were calculated for each participant. Clinical significance was determined using the 95th percentile cutoff (RCI = ± 1.96). Results Combining the stand-alone and guided-iCBT (n = 147) groups, 89 PwMS (61%) demonstrated a reliable decrease in BDI-II scores, whereas 58 PwMS (39%) did not show a reliable decrease. For waitlist controls (n = 77), 19 PwMS (25%) showed a reliable decrease in BDI-II scores, χ2(2, N = 224) = 33.82, p < 0.001, φ = 0.39. Conclusions We found that the iCBT treatment was highly effective, with 61% of PwMS showing a reliable decline in depressive symptoms compared with only 25% of waitlist controls. Still, generally consistent with previous research, almost 40% of PwMS did not respond to iCBT for depression. Future work will investigate baseline cognitive, psychosocial, and disease-related predictors of response to iCBT to better understand treatment outcomes and possible targets to optimize interventions for depression in MS.