EMDR's Neurobiological Mechanisms of Action: A Survey of 20 Years of Searching

Historically, mechanisms of action have often been difficult to ascertain. Thus far, the definitive discovery of eye movement desensitization and reprocessing (EMDR)'s underlying mechanisms has been equally elusive. We review the neurobiological studies of EMDR, as well as the theoretically driven speculative models that have been posited to date. The speculative theoretically driven models are reviewed historically to illustrate their growth in neurobiological complexity and specificity. Alternatively, the neurobiological studies of EMDR are reviewed with regard to their object of investigation and categorized as follows: findings before and after EMDR therapy (neuroimaging and psychophysiological studies) and findings during the EMDR set (psychophysiological, neuroimaging, and qEEG studies).