The method of Eye Movement Desensitization and Reprocessing (EMDR) is an integrative and well structured psychotherapeutic treatment which has received approval as an efficacious evidence-based approach for posttraumatic stress disorder (PTSD). EMDR, as a psychotherapeutic technique, accelerates the accessing and reprocessing of traumatic materials and supports the brain to release the nervous system from these traumatic experiences by means of normal handling of emotional information. Due to the fact that up to 40% of individuals with PTSD turn to substance abuse in their lifetime, EMDR is effective in the treatment of SUD especially in case of unsolved traumata, which are keeping up the vicious circle of SUD. Furthermore several studies suggest that EMDR is effective in addiction treatment by significantly reducing substance craving and thus also the rate of relapse, extending consecutive sobriety, as well as more than twice as many graduates in EMDR integrated programs. However, the evidence of the efficacy and effectiveness of EMDR on addiction treatment is still limited, because many findings are preliminary as being narratively or just case-study based or paying less attention to the role of emotions. Therefore, the purpose of this study is to further explore and determine the effectiveness of EMDR for the regulation of emotional processes in long-term addiction treatment.