Alcohol use disorder and associated physical health complications and treatment amongst individuals with and without opioid dependence: A case-control study

Background: Dependence upon one substance may increase vulnerability for dependence on other substances. This study aimed to i) examine the association between opioid dependence and alcohol use and dependence; and ii) identify demographic, mental health, substance use, and alcohol-related withdrawal, physical health complications, and treatment correlates of comorbid alcohol and opioid dependence versus the former only. Methods: In this case-control study, 1475 participants with opioid dependence recruited from opioid substitution therapy (OST) clinics and 516 non-opioid dependent matched participants completed a structured interview covering psychiatric history, substance dependence, child maltreatment, and history of alcohol use. Analyses were mainly concentrated on cases (n = 696) and controls (n = 194) reporting lifetime alcohol dependence. Results: Cases with opioid dependence had higher rates of lifetime alcohol dependence than controls. Binary logistic regression analyses showed comorbid cases reported greater socio-economic disadvantage, poorer psychiatric history, greater incidence of dependence on other substances, earlier onset of regular drinking and alcohol dependence, and greater severity of alcohol dependence (relative to controls with alcohol dependence only). Comorbid cases were also more likely to report endorsement of certain DSM-IV criteria (i.e., legal problems due to alcohol and desire/inability to cut down use), specific withdrawal symptoms (e.g., tachycardia, hallucinations), using other substances to relieve withdrawal symptoms, and experiencing liver disease/jaundice. Rates of lifetime treatment engagement were low overall. Conclusions: Though strongly associated with alcohol dependence and alcohol-related harms, people with a history of opioid dependence have complex social and clinical backgrounds, which appear to be important factors associated with higher levels of alcohol dependence.