Impairments in Executive Functioning in Patients with Comorbid Substance Use and Personality Disorders: A Systematic Review.

Objective: The purpose of this systematic review was to examine the evidence for impaired executive functioning in patients diagnosed with a dual pathology of personality disorder (PD) and substance use disorder, and to identify whether differences exist in comparison to those with a single diagnosis. Methods: A systematic search was conducted to identify studies using measures of executive functioning in patients with PD-substance use disorder dual pathology. Sixteen studies were selected. Results: The results indicate that dual pathology patients with Cluster C personality disorder do not differ from controls, and that the presence of dual pathology does not influence the updating domain of executive functioning. The findings were inconclusive with regard to dual pathology patients with Cluster B personality disorders. Whilst the various studies consistently show that these patients show worse performance than the control groups, here are contradictory results with regard to whether Cluster B personality disorders add more alterations in executive functioning to those that already appear in substance use disorder. Conclusions: The results suggest the need for further research that more adequately controls variables such as time in treatment, medication, and sample size, whilst there is also a need to employ longitudinal designs that include more patients from Clusters A and C.