Review article
Substance abuse among individuals with intellectual disabilities

https://doi.org/10.1016/j.ridd.2012.02.009Get rights and content

Abstract

Individuals with disabilities are a growing population that confronts multiple disadvantages from social and environmental determinants of health. In particular, the 7–8 million people in the U.S. with an intellectual disability (ID) suffer disproportionately from substance use problems, largely because of a lack of empirical evidence to inform prevention and treatment efforts for them. Although available research could inform future research efforts, studies are scattered across disciplines with the last review synthesizing findings written more than five years ago. To consider more recent findings with earlier works, PubMed, PsychINFO, and Google Scholar were searched and produced 37 peer-reviewed texts across multiple disciplines, 15 from 2006 or later. While the prevalence of alcohol and illicit drug use in this population are low, the risk of having a substance-related problem among ID substance users is comparatively high. Gaps in the research and population subgroups that warrant special attention are identified, such as individuals with borderline and mild ID, individuals with co-occurring mental illness, and individuals who are incarcerated. Compared with substance abusers without ID, ID substance abusers are less likely to receive substance abuse treatment or remain in treatment. Research is needed to better gauge the magnitude of substance use problems, identify prevention strategies, and specify treatment components that meet the unique needs of individuals with ID.

Highlights

► Prevalence of substance use appears low among people with intellectual disabilities. ► Rates of legal substance use may be more similar to rates in the general population. ► Risk of substance abuse is comparatively high among substance users. ► Several subgroups in this group have greater exposure to substance use than others. ► Well-designed, theory-driven studies of substance use are needed for this population.

Introduction

Individuals with disabilities constitute a growing population in the United States. They confront disadvantages from social and environmental determinants of health, including lower educational levels, lower incomes, and higher unemployment, than people without disabilities (Iezzoni, 2011). In particular, people with intellectual disabilities (ID) suffer disproportionately from substance use problems, due largely to a lack of empirical evidence on what substance-related disorder prevention and treatment efforts are effective for them (Cocco and Harper, 2002, Slayter, 2008). Available research is scattered across disciplines, with the last review synthesizing findings written more than five years ago (McGillicuddy, 2006). Researchers suggest that substance use and related problems among people with ID have been understudied. Findings could help inform future research efforts, so recent studies were reviewed to consider with earlier works. While there are still no good, population-based prevalence estimates for substance use or abuse among people with ID, research suggests that prevalence of alcohol and illicit drug use is low, while risk of abuse is relatively high among substance users in this population (McGillicuddy and Blane, 1999, Slayter and Steenrod, 2009). This review identified gaps in research, such as a need to assess the use of readily available substances (e.g., inhalants) in this population (Cocco & Harper, 2002), and subgroups with potentially high vulnerability to substance use problems, such as adolescents and those with a history of involvement with the criminal justice system (Chaplin et al., 2011, Cocco and Harper, 2002).

People with ID have significant limitations in cognitive functioning and adaptive behaviors that relate to everyday social and practical skills. Encompassed by but not the same as a developmental or learning disability (AAIDD, 2012), ID is diagnostically the same as mental retardation but is more respectful and the preferred term to identify the 7–8 million members of this population in the U.S. (HHS, 2012, Schalock et al., 2007). ID diagnoses occur along a spectrum ranging from borderline to severe with the diagnostic and statistical manual of mental disorders (DSM-IV) classifying individuals with an IQ below 20–25 as profound, from 20–25 to 35–40 as severe, from 35–40 to 50–55 as moderate, from 50–55 to approximately 70 as mild, and from 71 to 84 as borderline (APA, 2000). Around 87% of people with ID are only slightly slower than average (HHS, 2012: On-line). Many people with ID live in the community, an improvement over institutionalization, but such integration may increase their exposure opportunities to licit and illicit substances (Slayter, 2006a).

Like ID, substance use operates on a continuum ranging from low (e.g., experimental use) to high, with high-level use defined as abuse or dependence (Brucker, 2007). The DSM-IV defines current substance dependence as a maladaptive pattern of use leading to clinically significant impairment or distress as defined by 3 or more dependence criteria over one year (i.e., tolerance, withdrawal, substance often taken in large amounts or for long periods, persistent desire or unsuccessful attempt to cut down, a great deal of time spent in activities to get the substance, important activities given up, continued substance use despite knowledge of having recurrent physical or psychological problems) (APA, 2000). A substance abuse diagnosis is given when substance users do not meet the criteria for dependence disorder and manifest a maladaptive pattern of use leading to clinically significant impairment or distress as defined by one or more abuse criteria over one year (i.e., a serious problem at home, work, or school caused by using the substance; regular substance use that puts the user in physical danger; repeated use that leads to trouble with the law; problems with family or friends caused by continued use) (APA, 2000).

Because the literature on substance use among people with ID is scattered across disciplines, we reviewed it to identify common findings and gaps in the knowledge concerning substance use problems that will inform future research, intervention, and health policy efforts. This paper considers epidemiological findings from U.S. and non-U.S. studies, explores substance use disorders with co-occurring mental health disorders, incarceration, and other substance use consequences for this population with emphasis of findings from 2006 or later. The paper concludes with recommendations for future research and policy.

Section snippets

Material and methods

Searches of PubMed, Google Scholar, and PsychINFO using keywords, such as intellectual disability; mental retardation; and alcohol abuse; produced 37 journal articles and 2 dissertations on substance use and related problems among people with ID from the past 30 years. Of the 27 texts that reported original research; 14 were from studies outside the U.S. Most studies used community-based samples; included a small sample size (n  200); considered the use of certain substances only (e.g., alcohol;

Epidemiology of substance use, U.S. studies

Provided for comparison, information in Table 1 is from the National Survey on Drug Use and Health (NSDUH), an ongoing annual national survey of approximately 67,500 individuals to assess incidence and prevalence of substance use, abuse, and dependence among non-institutionalized Americans aged 12 years or older. Table 2 reports information from the Monitoring the Future Survey (MTF), an annual national survey of substance use and related attitudes among students in 8th, 10th, and 12th grades.

Conclusions

People with disabilities are a growing health disparities population (Iezzoni, 2011). People with ID face more severe mental, physical, and social consequences from substance use related problems than members of other groups, but substance use problems and associated treatment needs among members of this population are understudied. Well-designed, theory-driven studies of large samples are needed to establish base rates of substance use and disorders (abuse or dependence) for this population

Role of the funding source

This work is made possible by research grants from the U.S. National Institute on Drug Abuse of the National Institutes of Health (R21DA027503, R33DA027503, R01DA019623, R01DA019901; PI: Li-Tzy Wu). The sponsoring agency had no further role in the writing of this paper or the decision to submit the paper for publication. The opinions expressed in this paper are solely those of the authors.

Disclosures

None.

References (55)

  • A. Burtner et al.

    Tobacco and the institutionally mentally retarded: Usage choices and the ethical considerations

    Special Care in Dentistry

    (1995)
  • Centers for Disease Control and Prevention [CDC]. (2012). CDC grand rounds: Prescription drug overdoses: A U.S....
  • L. Christian et al.

    Drug abuse in persons with mental retardation: A review

    American Journal of Mental Retardation

    (1997)
  • K. Cocco et al.

    Substance use in people with mental retardation: A missing link in understanding community outcomes?

    Rehabilitation Counseling Bulletin

    (2002)
  • S.A. Cooper et al.

    Mental ill–health in adults with intellectual disabilities: Prevalence and associated factors

    British Journal of Psychiatry

    (2007)
  • L. Degenhardt

    Interventions for people with alcohol use disorders and an intellectual disability: A review of the literature

    Journal of Intellectual and Developmental Disabilities

    (2000)
  • D. DiNitto et al.

    Drinking patterns of mentally retarded persons

    Alcohol Health and Research World

    (1983–1984)
  • R. Edgerton

    Alcohol and drug use by mentally retarded adults

    American Journal of Mental Deficiency

    (1986)
  • E. Emerson et al.

    Self-reported smoking and alcohol use among adolescents with intellectual disabilities

    Journal of Intellectual Disability

    (2005)
  • W. Fidler et al.

    Smoking: A special need?

    British Journal of Addiction

    (1992)
  • J. Gress et al.

    Substance abuse differences among students receiving special education school services

    Child Psychiatry and Human Development

    (1996)
  • M. Harris et al.
  • N. Hymowitz et al.

    Cigarette smoking among patients with mental retardation and mental illness

    Psychiatric Services

    (1997)
  • L.I. Iezzoni

    Using administrative data to study persons with disabilities

    Milbank Quarterly

    (2002)
  • L.I. Iezzoni

    Eliminating health and health care disparities among the growing population of people with disabilities

    Health Affairs (Millwood)

    (2011)
  • L.D. Johnston et al.

    Monitoring the future national survey results on drug use, 1975–2010: Vol. I, Secondary school students

    (2011)
  • E. Kalyva

    Prevalence and influences on self-reported smoking among adolescents with mild learning disabilities, attention deficit hyperactivity disorder, and their typically developing peers

    Journal of Intellectual Disability

    (2007)
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