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-D(total 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-D(total 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: DRKS00004803at drks-neu.uniklinik-freiburg.de, German Clinical Trials Register (registration date 2016-02-02), retrospectively registered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12906-017-1676-5) contains supplementary material, which is available to authorized users.