Deaths caused by drugs and alcohol have reached unprecedented levels in the US,1,2 and in response, researchers have examined a range of characteristics to describe populations at greatest risk for these occurrences.3, 4, 5, 6, 7, 8 A growing body of evidence indicates that there is a strong and positive association between substance misuse and disability status.3,4,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 Disability is the result of an interaction between an individual’s abilities and their environment, which limits participation in a range of activities, rather than an inherent or immutable characteristic of an individual.24 Disability can be categorized by the level and type of difficulty that individuals experience, including auditory, visual, ambulatory, cognitive, self-care and independent living limitations, which prior research shows to vary with age, sex and other demographic characteristics.25 Disability is also associated with lower socioeconomic position, including educational attainment26 and poverty.27 Furthermore, approximately 40% of disabled adults have more than one type of disability,25 which has received limited attention in previous investigations.

The majority of prior studies on disability and substance misuse have assessed substance misuse among adults using a binary indicator of any disability,14, 15, 16,18,22 or by specific singular types of disability.9,10,13,17,19,20,23,28,29 Research which used a dichotomous measure to indicate the presence or absence of any disability, defined as inability to work, the presence of specific conditions, or limitations in performing certain activities,15, 16, 17, 18, 19 reported increased substance misuse among persons with any disability. Other research which assessed specific disabilities, like deafness or blindness, in relation to substance misuse9,13,15,17,23,28 also shows positive associations between the presence of each of these conditions and different types of substance misuse. Specifically, adults with hearing difficulty display increased prevalence of lifetime illicit drug use,17 and opioid-related emergency department visits,23 compared to adults without hearing difficulty. Likewise, adults with vision limitations have reported increased lifetime use of illicit drugs,17 and current opioid use disorder,21 compared to adults without vision limitations. Recently, up to six different disability categories were examined in relation to opioid misuse, with results indicating increased prevalence of opioid use disorder among adults with cognitive,21,30 self-care, and independent living difficulty.30 Similarly, higher rates of substance-related disorders among adults with intellectual disabilities,19,20,29 and alcohol use among young people with emotional and learning disability have been observed.31

There is also limited evidence that people with multiple disabilities are at greater risk for substance misuse than individuals with one disability.11,17,21 In a study of US adults, persons with both vision and hearing loss had a higher prevalence of lifetime drug use, compared to adults with either condition alone.17 Similarly, college students with two or more disabilities have reported increased misuse of drugs and alcohol, compared to college students with one type of disability.11 Lastly, the prevalence of opioid use disorder has been shown to increase with the number of reported disabilities among adults in the general population.21 Thus, the research that has examined the presence of multiple disabilities in relation to substance misuse indicates increased misuse among persons with more than one disability.

Because many of the correlates of disability are also associated with substance misuse, a careful consideration of confounding is required in this area of research. Like disability, substance misuse is associated with age, sex, education and poverty,6,12,15,21,26,27 and these covariates are often included as adjustment factors in statistical modeling.9,15,16,21 The consistent finding of higher rates of disability, but lower rates of substance misuse, among women compared to men,6,14,25,32 also raises the possibility that sex could be an effect modifier of the association between disability and substance misuse.

Although research during the last 20 years has demonstrated a clear link between disability status and substance misuse, most prior studies11,14, 15, 16,18,22 have utilized binary disability measures or focused exclusively on one type of disability.9,13,17,19,20 Recently, some have examined opioid use disorder by disability type,21,30 but not alcohol use disorder or drug use disorder more broadly (i.e. including stimulants and non-opioid tranquilizers). The objective of the current study was to examine which disability types and combinations are associated with the greatest risk for drug and alcohol use disorders, and to evaluate the strength of these associations after controlling for known sociodemographic covariates and considering potential effect modification by sex, which is an especially salient characteristic in disability and substance misuse research.