Acceptance and Commitment Therapy With Vestibular Rehabilitation for Chronic Dizziness

Inclusion Criteria: * Persistent postural-perceptual dizziness (diagnosed by the diagnostic guideline of ICD-11 beta version at Dec. 2016) * Existing handicap due to dizziness (DHI equal to or more than 16) * Written consent Exclusion Criteria: * Vertigo/dizziness/unsteadiness by organic brain diseases, diagnosed by neuro-otologist * Vertigo/dizziness/unsteadiness explained by only organic cause or drug, diagnosed by neuro-otologist * Physical status inappropriate for psychotherapy or vestibular rehabilitation * Current psychiatric disorder other than anxiety disorders, somatic symptom disorder, or illness anxiety disorder (DSM-5), diagnosed by psychiatrist * History of schizophrenia or bipolar disorder diagnosed by psychiatrist * Increased risk of suicide or self-harm diagnosed by psychiatrist * Started or increased SSRI/Venlafaxine within 1 month before treatment * Any cognitive behavioral therapy or vestibular rehabilitation except this study * Otological surgery or device therapy for dizziness * Insufficient understanding of the Japanese language