Enhancing the efficacy of CBT for patients with unipolar depression by integrating digital interventions into treatment: A pilot randomized controlled trial

Blended cognitive behavioral therapy (bCBT) combines face-to-face therapy with digital elements such as digital health apps. Many researchers and practitioners expect bCBT to be advantageous for treating mental disorders such as depression. Yet, studies comparing bCBT to non-blended face-to-face cognitive behavioral therapy (CBT) are limited and have yielded heterogeneous results. Thus, this pilot study aimed to explore the efficacy and safety of a novel bCBT digital therapeutic for treating unipolar depression in adults combined with face-to-face CBT compared to face-to-face CBT alone (treatment as usual; TAU) in routine care. Patients (N = 80) were randomly assigned to bCBT (n = 41) or standard CBT (n = 39) over 12 weeks. bCBT consisted of weekly face-to-face CBT sessions accompanied by the digital therapeutic elona therapy for use between sessions. Standard CBT consisted of weekly face-to-face CBT sessions, mirroring routine care. A broad set of outcomes were measured at baseline, at six weeks, and at 12 weeks. These outcomes were analyzed with linear mixed models. Improvements in depressive symptoms were descriptively larger for the bCBT group than for the CBT group (BDI-II: d = -.22, PHQ-9: d = -.27). Yet, this difference did not reach statistical significance. bCBT was superior to standard CBT in secondary outcome measures of psychological health (d = .54) and generalized anxiety symptoms (d = -.50). In other secondary outcomes, improvements were also descriptively larger for bCBT than for CBT, but these differences did not reach statistical significance (BAI: d = -.28, PSWQ: d = .28, GSE: d = .31, WHOQOL-BREF physical health scale: d = .28). In sum, this pilot study indicated that bCBT is superior to standard CBT and safe to use in clinical samples. Future research using larger samples is needed to solidify our findings.