Executive function at baseline and follow-up in opioid maintenance patients and its relation to psychiatric comorbidity and substance use patterns.

BACKGROUND

Research investigating executive functions in opioid-dependent patients undergoing opioid maintenance treatment (OMT) is scarce. This study aimed to assess executive function in patients with opioid use disorder at treatment initiation and one-year follow-up, exploring its correlation with psychiatric comorbidity within the patient group. Additionally, associations between executive functions and factors such as age at substance use initiation, duration of substance use, and current substance use were explored.

METHODS

Forty-nine adults (mean age: 40.6 [11.4]) with opioid use disorder initiating OMT participated in a naturalistic study with a one-year follow up. Participants underwent subtests of the Delis-Kaplan Executive Function System (D-KEFS) and self-assessed their cognitive function using the BRIEF-A form. Psychiatric diagnoses were determined using MINI, while symptoms of personality disorders were assessed using the SCID II screening form. Blood and saliva samples were collected for alcohol and drug markers.

RESULTS

Most participants exhibited impaired Cognitive flexibility (67%), with varying levels of impairment in Verbal fluency and problem-solving functions (25-30%). The majority rated their executive functions as poor. At the one-year follow-up, Verbal fluency had improved (p <.05), but other executive functions remained unchanged. Stimulant use was associated with reduced Verbal fluency and Cognitive flexibility (p <.1). Older age and longer substance use duration correlated with poorer Verbal fluency (p <.05), while earlier onset of substance use correlated with poorer self-reported executive functioning (p <.05) but unexpectedly with better Cognitive flexibility (p <.1). Symptoms of borderline personality disorder was related to poorer self-reported executive functioning (p <.001), symptoms of Narcissistic Personality Disorder was related to poorer Cognitive flexibility (p <.1), and symptoms of Antisocial Personality Disorder was related to better problem-solving (p <.1).

CONCLUSIONS

Executive function impairment is common in patients starting OMT, with specific functions more affected. The varied results of correlations between psychiatric comorbidity, substance use, and executive function indicate patient heterogeneity. While some executive functions show slight improvement over time, complex functions appear resistant to change, suggesting lasting damage which may influence treatment outcomes. Overall, patient variability in executive function highlights the need for personalized treatment approaches in OMT.