The rate of personality disorders among drug users is estimated to be up to 50%. The co-occurrence of personality disorders among drug users can potentially lead to increased symptom severity, resistance to treatment, and increased risk of relapse. Using the systematic review method, in the present study, the efficacy of the dual focus schema therapy (DFST) in the treatment of substance use disorders with personality disorders was investigated. Using two databases, namely ScienceDirect and noormags, five eligible articles were reviewed that evaluated the efficacy of dual focus schema therapy (DFST) using case study and randomized controlled trial (RCT). The results showed that despite the positive and promising therapeutic results in the two case studies, three RCT studies showed the least useful results for the efficacy of the dual focus schema therapy (DFST) and that the dual focus schema therapy (DFST) is not a more effective option compared to the other forms of intervention, and more accurate evaluation requires further RCTs
