Opioid and Dopamine Genes Interact to Predict Naltrexone Response in a Randomized Alcohol Use Disorder Clinical Trial

Epigenetic moderators of naltrexone efficacy in reducing heavy drinking in Alcohol Use Disorder: a randomized trial

Polymorphisms in genes associated with opioid signaling and dopamine reuptake and inactivation may moderate naltrexone efficacy in Alcohol Use Disorder (AUD), but the effects of epigenetic modification of these genes on naltrexone response are largely unexplored. This study tested interactions between methylation in the μ-opioid receptor (OPRM1), dopamine transporter (SLC6A3), and catechol-O-methyltransferase (COMT) genes as predictors of naltrexone effects on heavy drinking in a 16-week randomized, placebo-controlled trial among 145 treatment-seeking AUD patients. OPRM1 methylation interacted with both SLC6A3 and COMT methylation to moderate naltrexone efficacy, such that naltrexone-treated individuals with lower methylation of the OPRM1 promoter and the SLC6A3 promoter (p = 0.006), COMT promoter (p = 0.005), or SLC6A3 3' untranslated region (p = 0.004), relative to placebo and to those with higher OPRM1 and SLC6A3 or COMT methylation, had significantly fewer heavy drinking days. Epigenetic modification of opioid- and dopamine-related genes may represent a novel pharmacoepigenetic predictor of naltrexone efficacy in AUD.

Agreement between DSM-5 and DSM-IV measures of substance use disorders in a sample of adult substance users

BACKGROUND

In DSM-5, definitions of substance use disorders (SUD) were changed considerably from DSM-IV, yet little is known about how well DSM-IV and DSM-5 SUD diagnoses agree among substance users. Because data from many studies are based on DSM-IV diagnostic criteria, understanding the agreement between DSM-5 and DSM-IV SUD diagnoses and reasons for discordance between these diagnoses is crucial for comparing results across studies.

MEASUREMENTS

Prevalences and chance-corrected agreement of DSM-5 SUD and DSM-IV substance dependence were evaluated in 588 substance users in a suburban inpatient addiction program and an urban medical center, using a semi-structured interview (PRISM-5). Alcohol, tobacco, cannabis, cocaine, heroin, opioid, sedative, and stimulant use disorders were examined. Cohen's kappa was used to assess agreement between DSM-5 and DSM-IV SUD (abuse or dependence), DSM-5 SUD and DSM-IV dependence, and DSM-5 moderate/severe SUD and DSM-IV dependence.

RESULTS

Agreement between DSM-5 and DSM-IV SUD was excellent for all substances (κ = 0.84-0.99), except for cannabis and tobacco (κ = 0.75; 0.80, respectively). The most common reason for diagnostic discrepancies was a positive DSM-5 SUD diagnosis but no DSM-IV diagnosis, due to the lowered DSM-5 SUD threshold. Agreement between DSM-5 SUD and DSM-IV dependence was excellent for all substances (κ = 0.88-0.94), except for alcohol, tobacco, and cannabis (κ = 0.63-0.75). Agreement between moderate/severe DSM-5 SUD and DSM-IV dependence was excellent across all substances.

CONCLUSION

While care should be used in interpreting results of studies using different methods, studies relying on DSM-IV or DSM-5 SUD diagnostic criteria offer similar information and thus can be compared when accumulating a body of evidence.