A Transdiagnostic pilot study of the efficacy of respiratory rate–based biofeedback in the treatment of depressive symptoms

There remains a need to identify short-term, safe interventions for depressive symptoms that can be integrated into standard treatment without imposing a substantial burden on patients or clinical staff. Aims This study evaluated the efficacy of respiratory rate–based biofeedback as an adjunctive intervention for depressive symptoms in hospitalized patients with mental disorders. Methods This prospective pilot study included 84 patients diagnosed with depressive or anxiety disorders. In the intervention group, participants received biofeedback therapy once daily for 10 days in addition to standard pharmacotherapy. The comparison group received pharmacotherapy alone. Results The adjusted between-group difference in the total Montgomery–Asberg Depression Rating Scale (MADRS) score after 3 weeks of treatment was 2.18 points (95% CI [0.17;4.18]; p = 0.034). Among study completers, 40% of patients in the biofeedback group met the criterion for treatment response, compared with 28% in the comparison group; the number needed to treat (NNT) was 9. The addition of biofeedback therapy to standard treatment was not associated with a greater reduction in anxiety symptoms. No clinically prominent adverse events were reported. Conclusions Adding biofeedback therapy sessions to standard treatment resulted in a small reduction in depressive symptoms compared with standard therapy alone. These findings support consideration of respiratory rate–based biofeedback as a potential adjunctive intervention that may enhance the effectiveness of treatment for depressive symptoms in inpatient settings within routine clinical practice. Trial registration The study was registered retrospectively (https://doi.org/10.17605/OSF.IO/R38YW; 2026, February 12).