Noninvasive brain stimulation combined with evidence-based psychotherapy for psychiatric disorders: A meta-analysis of optimal implementation parameters.

Evidence-based psychotherapies are first-line treatments for psychiatric disorders, yet response rates remain suboptimal. Noninvasive brain stimulation (NIBS) may augment psychotherapy by modulating treatment-engaged circuits. We conducted a systematic review and meta-analysis of randomized controlled trials comparing active NIBS plus evidence-based psychotherapy versus sham NIBS plus psychotherapy. We searched six databases through February 2025, screening 1017 records. Twenty-eight trials (31 treatment arms; 1506 participants) met inclusion criteria. Active NIBS combined with psychotherapy produced significantly greater symptom improvement than sham NIBS with psychotherapy (SMD = -0.38, 95% CI [-0.68, -0.08]), with substantial heterogeneity. Moderator analyses revealed critical implementation parameters: repetitive transcranial magnetic stimulation (rTMS) showed significant benefit while transcranial direct current stimulation did not. Non-concurrent delivery showed significant effects; concurrent delivery did not. Cognitive behavioral therapy (CBT) combined with NIBS showed significant benefit; other psychotherapy modalities did not. Human-delivered psychotherapy significantly enhanced outcomes; computerized formats did not. Significant effects were observed only for anxiety disorders (SMD = -0.70, 95% CI [-1.26, -0.14]). While there was a null finding for depression, it likely reflects insufficient statistical power rather than true ineffectiveness. Secondary analyses found no significant effects on executive functioning or quality of life. Treatment integrity was under-reported: only 39.3% of studies used fully manualized protocols and 10.7% documented therapist adherence. Timing and modality are largely confounded in the current evidence base, and priming versus consolidation effects cannot be distinguished. These findings provide an evidence-based framework for optimizing combined treatment protocols and highlight the need for standardized psychotherapy fidelity monitoring.