Effects of hyperthermic baths on depression, sleep and heart rate variability in patients with depressive disorder: a randomized clinical pilot trial

BACKGROUND Despite advances in the treatment of depression, one-third of depressed patients fail to respond to conventional antidepressant medication. There is a need for more effective treatments with fewer side effects. The primary aim of this study was to determine whether hyperthermic baths reduce depressive symptoms in adults with depressive disorder. METHODS Randomized, two-arm placebo-controlled, 8-week pilot trial. Medically stable outpatients with confirmed depressive disorder (ICD-10: F32/F33) who were moderately depressed as determined by the 17-item Hamilton Scale for Depression (HAM-D) score ≥18 were randomly assigned to 2 hyperthermic baths (40 °C) per week for 4 weeks or a sham intervention with green light and follow-up after 4 weeks. Main outcome measure was the change in HAM-Dtotal score from baseline (T0) to the 2-week time point (T1). RESULTS A total of 36 patients were randomized (hyperthermic baths, n = 17; sham condition, n = 19). The intention-to-treat analysis showed a significant (P = .037) difference in the change in HAM-Dtotal score with 3.14 points after 4 interventions (T1) in favour of the hyperthermic bath group compared to the placebo group. CONCLUSIONS This pilot study suggests that hyperthermic baths do have generalized efficacy in depressed patients. TRIAL REGISTRATION DRKS00004803 at drks-neu.uniklinik-freiburg.de, German Clinical Trials Register (registration date 2016-02-02), retrospectively registered.