Substance use among individuals with intellectual disabilities living independently in Flanders

Over the past decades, there has been increased scientific and clinical interest in substance use among individuals with intellectual disabilities (ID). Despite raised interest and awareness in the topic, lack of supportive data on prevalence and risk factors highlights the need for ongoing research. The aims of this cross-sectional multicenter study were to examine the nature and extent of substance use in individuals with ID living independently, to investigate group differences in substance use and related problems, and to explore the role of substance-related knowledge and attitudes in substance use behaviors.

Participants were 123 individuals with mild to moderate ID receiving support from independent living services. Data were gathered by means of a structured interview strategy (i.e. the Substance Use and Misuse in Intellectual Disability-Questionnaire; SumID-Q).

Findings revealed that rates of lifetime use of licit and illicit substances were higher than those found in earlier studies among individuals with ID and the general population. While cannabis use was the only illicit substance reported, current tobacco and alcohol use were shown to be highly prevalent (48%-45.5%). Rates for the latter were similar to earlier studies among community samples of individuals with ID. In contrast to our hypotheses, few group differences in substance use behaviors were observed. Male gender was associated with age of onset of alcohol and tobacco use and tobacco use-related problems, while younger age was found to be associated with lifetime use of cannabis. No evidence was found regarding the role of knowledge; however, smokers and alcohol users rated tobacco and alcohol use more positively.

This study demonstrated that individuals with ID living independently use a wide range of licit and illicit substances and present divergent levels and patterns of substance use. Notwithstanding the role of personal choice in substance use, more research is needed to better understand the nature and extent of substance use and related problems, as well as the role of substance-related knowledge and attitudes in individuals with ID.