Efficacy of vestibular stimulation treatment in the depressive phase of bipolar disorder: study protocol for a randomized, double-blind, controlled trial

Background and objectives: Bipolar disorder (BD) is a neuropsychiatric disorder characterized by the oscillation of mood states between hypoactive/pessimistic (depressive phase) and hyperactive/optimistic states (manic/hypomanic phase). Previous studies evidenced that a particular technique of neuro-vestibular stimulation is an effective treatment for major depression. This study will investigate the efficacy of the said vestibular stimulation technique in the depressive phase of BD, and will compare it with sham vestibular stimulation. Design: A double-blind, randomized controlled study. Methods: One hundred and twenty patients with bipolar type I or II, currently undergoing a depressive phase, will be randomized into the experimental group ( n = 60) or control group ( n = 60), receiving three sessions of real/sham vestibular stimulation. Outcome measures: The primary outcome is the change in Montgomery Asberg Depression Rating Scale scores from baseline to post 4 and 12 weeks. The secondary outcome is the vestibular activity assessed at baseline, post 4 and 2 weeks. Discussion: Currently, no treatment has proved efficacy for bipolar depression. Studies have demonstrated that lateralized neuro-vestibular stimulation is an effective treatment for mayor depression but has not been studied in the depressive phase of bipolar disorder. This investigation will give the first evidence supporting or denying the use of vestibular stimulation treatment in BD depression. Ethics and dissemination: This study protocol was approved by the Ethics Committee of SSMO (Servicio de Salud Metropolitano Oriente) in Santiago, Chile (approval No. 08032016) on March 8, 2016. The results of the study will be published in scientific journals and other media. Trial registration: ClinicalTrials.gov Identifier: NCT02778256.