Outcomes and Challenges of Motivational Interviewing in Dual Diagnosis Treatment-A Systematic Review

Motivational interviewing (MI) is a client centered counseling approach which aims to promote behavior change by enhancing patient motivation through the exploration and resolution of ambivalence. This type of psychotherapy, initially designed for the treatment of substance use disorders (SUD), is now seen as an effective way to manage chronic physical and psychiatric diseases. Patients with Dual Diagnosis (DD), people who simultaneously have a SUD diagnosis and a mental illness, are a complex group of psychiatric patients who have a particularly low treatment engagement. It was hypothesized that MI could be a valuable add-on therapy for DD patients. This review summarizes the main findings of randomized controlled trials applying MI to patients' psychiatric diagnoses and substance use. We aim to clarify previous inconsistent results regarding MI effectivity in this complex and challenging disorder.

The systematic literature search of PubMed/MEDLINE, Web Of Science and Scopus followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The final selection for this systematic review comprised exclusively of randomized controlled trials (RCTs) comparing MI alone or integrated into routine care. All patients included in the selected studies were over 16 years old. The studies' quality assessment was conducted with the Jadad Scale.

8 RCTs were included in this review. The patients who underwent MI interventions showed an improvement in functioning, psychiatric symptoms, medication compliance and substance use, although without statistical significance. The number of relapses, total days in relapse and alcohol binge days showed a significant improvement in favor of the intervention group (p = .002, Bellack et al., 2006; p = .006, Haddock et al., 2003; and p = .02).

Although there was a clear improvement in most of these outcomes, most studies failed to detect significant results. A significant clinical outcome of MI application was found in lower relapse occurrence and alcohol abuse. The disparity of findings may be due to the disorder's heterogeneity, and/or to methodological limitations. Our results emphasize the need for more methodically sound RCTs with adaptable characteristics specific to the pairing of psychiatric disease and substance abuse.