Destination Matters More: Relapse following Hospital-Based Treatment of Substance Use Disorders With and Without Co-Occurring Disorders

Objectives: Addressing substance use in psychiatric care encounters significant barriers, but the emergence of specialized services offers an opportunity to advance and scale up the integration of addiction services within psychiatric settings. However, research gaps still exist in this field, particularly in understanding the substance relapse rates of people with co-occurring disorders after a psychiatric hospitalization. This study aimed to investigate and compare the relapse rates of patients under inpatient care with exclusively addiction-related issues and those with co-occurring disorders after a hospitalization in a psychiatric ward and gain insights into differences in outcomes for these two patient groups. Methods: This retrospective analysis examined electronic medical records of patients admitted to the Acute Psychiatry Ward of the Hospital Clinic of Barcelona with a substance use disorder diagnosis between January 2019 and February 2021. Cox regression was used to identify variables independently associated with the first relapse episode. Results: From a total of 318 admissions (79.2% with psychiatric comorbidity), 76.1% relapsed during the study follow-up, with a median survival time of 54 days. Younger age, female gender, voluntary admission, and outpatient follow-up were independently associated with relapse. The presence of a co-occurring disorder was not associated with relapse. Conclusion: This study highlights the need for interventions aimed at improving post-discharge abstinence rates for addiction-related hospitalizations. It also challenges the notion that co-occurring disorders automatically imply a worsened prognosis and emphasizes the importance of addressing addiction and psychiatric comorbidity in a comprehensive, integrated, and specialized manner.