Augmenting single-session behavioral activation for depression with delta-beta tACS: Preliminary investigation of a double-blind placebo-controlled randomized pilot clinical trial

Single-session behavioral activation (BA) and transcranial alternating current stimulation (tACS) are promising interventions for major depressive disorder (MDD). However, the synergy of combined single-session BA and tACS has not yet been evaluated. This pilot study assessed whether tACS augments the efficacy of single-session BA in individuals with MDD. N = 30 (M_age=36, SD=15; 70 % female) participants with MDD were randomized to receive either: 1) tACS with BA or 2) sham tACS with BA. Change in depression and anhedonia symptoms were assessed (preregistration: NCT05693922). Clinician-rated depression and anhedonia showed significant effects of time, but no significant differences between conditions, with the exception of dysphoria. Specifically, between baseline and two-week follow-up, those in the verum condition demonstrated significantly less dysphoria than those in the sham condition; however, these significant differences did not maintain at one-month follow-up. While preliminary, this is the first study to assess the augmentation of psychotherapy with tACS for MDD and it further serves as a template for future studies using combined interventions to treat depression.