problems other than PTSD." A 2021 major review that included randomized controlled trials, group studies, and case studies that specifically did not focus on the use of EMDR in the treatment of trauma or PTSD, found that EMDR may be beneficial in at least fourteen conditions that included: addictions, somatoform disorders, sexual dysfunction, eating disorders, disorders of adult personality, mood disorders, reaction to severe stress, anxiety disorders, performance anxiety, Obsessive-Compulsive Disorder (OCD), pain, neurodegenerative disorders, mental disorders of childhood and adolescence, and sleep. The authors concluded that "Results shed light on several aspects that support the interest of its practice in mental health care." Mechanism Possible mechanisms Incomplete processing of experiences in trauma Many proposals of EMDR efficacy share an assumption that, as Shapiro posited, when a traumatic or very negative event occurs, information processing of the experience in memory may be incomplete. The trauma causes a disruption of normal adaptive information processing, which results in unprocessed information being dysfunctionally held in memory networks. According to the 2013 World Health Organization practice guideline: "This therapy [EMDR] is based on the idea that negative thoughts, feelings and behaviours are the result of unprocessed memories." EMDR allowing correct processing of memories EMDR is posited to help in the correct processing of the components of the contributing distressing memories. EMDR may allow the client to access and reprocess negative memories (leading to decreased psychological arousal associated with the memory). This is sometimes known as the Adaptive Information Processing (AIP) model. Proposed mechanisms by which EMDR achieves efficacy The mechanism by which EMDR achieves efficacy is unknown, with no definitive finding. Several possible mechanisms have been posited; EMDR may impact working memory. If a patient performs bilateral stimulation task while remembering the trauma, the amount of information they can recall is reduced, which makes the resulting negative emotions less intense, and more bearable. This is seen by some as a 'distancing effect'. The client is then able to re-evaluate the trauma and to process it correctly. EMDR may enable ‘dual attention’ in which the trauma is recalled whilst also remaining aware of the present. Connectivity among several brain regions has been found to be changed by bilateral eye movement and by EMDR. In one 15 person study, EMDR was found to lead to reduced connectivity between some brain areas. These changes may cause EMDRs efficacy. EMDR efficacy has been linked to the Zeigarnik effect