In this article, we review the extent of and comorbid conditions associated with psychoactive drug use and disorders among adults aged 50+ years. Adults aged 50 to 64 years are included so that the impact of the “baby-boom” population (i.e., persons born in the post–World War II period, 1946–1964) can be compared with elders aged 65+ years. This review focuses on an understudied area of research: (a) psychoactive drug use defined as illicit drug use or nonmedical use of prescription psychotherapeutic drugs and (b) DSM-IV
drug abuse or dependence (American Psychiatric Association [APA], 2000
). Issues associated with assessment, diagnosis, and treatment also are discussed; suggestions for future research are summarized. Alcohol abuse and dependence are excluded from the review because of an attempt to focus on the “hidden” emerging problems of drug use as opposed to alcohol-related problems.
Older Adults as a Growing At-Risk Population
Older adults constitute a unique, at-risk population for psychoactive drug use. As middle-aged cohorts enter later life, aging-related health and psychosocial conditions can complicate drug use, and medical exposures to psychoactive medications can increase. The number of Americans aged 50+ years is increasing as large numbers of baby boomers reach age 50 years or older, and this cohort uses more psychoactive drugs than older cohorts (Gossop & Moos, 2008
; Han, Gfroerer, & Colliver, 2009a
). Between 1980 and 2007, the number of Americans aged 45 to 64 years increased from 20% to 25%, while the population under 18 years fell from 28% to 25% (Center for Disease Control and Prevention [CDC], 2010
). This trend will continue as life expectancy increases and baby boomers continue to age unless a dramatic period effect emerges to reduce substance use.
In addition, aging-related physiological changes may increase sensitivity to the effects of substance use, medication use can interact with more frequent use of psychoactive drugs by older adults, and chronic medical or psychological conditions can be triggered or worsened by drug use (Dowling, Weiss, & Condon, 2008
; Gossop & Moos, 2008
). For example, because all drugs of abuse act by altering neurotransmission in the brain (predominantly dopaminergic, serotonergic, and glutamatergic systems), aging-related changes to the brain, drug metabolism, and pharmacokinetics (i.e., the process by which a drug is absorbed, metabolized, and eliminated from the body) can place older drug users or abusers at elevated risk for severe neurotoxicity and drug-related adverse consequences (Dowling et al., 2008
Prescriptions of psychoactive medications also may increase the user’s risk for nonmedical use, abuse, or dependence (Culberson & Ziska, 2008
; Voyer, Préville, Cohen, Berbiche, & Béland, 2010
). At least one in four older adults has used psychoactive medications with abuse potential and such use is likely to grow as the population ages (Simoni-Wastila & Yang, 2006
). Unfortunately, nonmedical prescription drug use and abuse have become a major health concern in the United States as shown in rising trends in prescription drug poisoning deaths and emergency department visits (Manchikanti, 2007
). Moreover, the increased supply and availability of controlled substances, either from therapeutic use, prescriptions, or unregulated Internet pharmacies (Manchikanti, 2006
), suggest that older adults are at further risk for exposure to psychoactive drugs.
Taken together, the need for substance abuse care among older adults is expected to increase with time. Older adults who suffer from chronic conditions and seek medical care associated with aging are likely to be affected by drug use–related problems, which may further augment the risk and necessitate unique consideration for treatment (CDC, 2010
; Dowling et al., 2008
). Psychoactive drug use and disorders among older adults, however, remain a neglected area of research (Dowling et al., 2008
; Gossop & Moos, 2008
). Existing studies have focused mainly on alcohol use disorders, and there are few comparable empirical data on psychoactive drug use and disorders (Simoni-Wastila & Yang, 2006
). The American Geriatrics Society has published clinical guidelines for alcohol use disorders in older adults (American Geriatrics Society, 2003
). However, similar guidelines are not available for psychoactive drug abuse. A better understanding of the extent and correlates of psychoactive drug use and abuse can improve early case identification and timely intervention for this vulnerable population. These issues are reviewed and discussed below.
Projected Drug Use Trends Among Older Adults
Because of the concern that the aging baby-boom population will place increasing demands on the substance abuse treatment system in the next few decades, Gfroerer and Epstein (1999)
used data from marijuana users in the 1995–1996 National Household Survey on Drug Abuse (NHSDA) to generate the first estimates of the number of illicit dug users who will need drug abuse treatment for the years 2000 through 2020. Because the baby-boom cohort uses more drugs than previous cohorts, the proportion of adults aged 50+ years who will need substance abuse treatment is projected to increase from 4% in 1995 to 17% to 34% by 2020. Although Blacks generally have a low rate of lifetime marijuana use, the national data suggest that older black adults will have a higher probability of needing substance abuse treatment than their White counterparts (Gfroerer & Epstein, 1999
Subsequently, Colliver, Compton, Gfroerer, and Condon (2006)
used data from the 1999–2001 NHSDA to estimate the number of past-year illicit/nonmedical drug users aged 50+ years of age in 2020. Past-year marijuana use among adults aged 50+ years is estimated to increase from 1.0% (719,000 users) in 1999–2000 to 2.9% (3.3 million) in 2020. This increase is considered a combined effect of the increase in rate of use and a projected 51.8% increase in the civilian noninstitutionalized population in this age group. In addition, use of any illicit drug is estimated to increase from 2.2% (1.6 million) to 3.1% (3.5 million), and nonmedical use of prescription drugs (opioids, sedatives, tranquilizers, and stimulants) is projected to increase from 1.2% (911,000) to 2.4% (2.7 million). The majority of past-year users of marijuana (87%) or prescription drugs (77%) in 2020 will be White; older Blacks will be as likely as older Hispanic to use marijuana (6% vs. 5%) or prescription drugs (9% vs. 10%); there will be no gender differences in use of these drugs.
More recently, Han, Gfroerer, Colliver, and Penne (2009b)
estimated the number of adults aged 50+ years with a past-year substance use disorder (alcohol/drug abuse or dependence) in 2020. By using more current data from the 2002–2006 National Surveys on Drug Use and Health (NSDUH), the number of adults aged 50+ years with a substance use disorder (alcohol or drugs) is projected to double from 2.8 million (annual average) in 2002–2006 to 5.7 million in 2020. Increases are projected for all examined gender, racial/ethnic, and age groups. The majority of individuals with a substance use disorder is projected to be male (71%) and White (76%); Blacks (10.5%) and Hispanics (10%) will have similar numbers of persons with a substance use disorder. Such increases are reported to be a combined effect of a 39% population increase and a 44% increase in the rate of past-year substance use disorders. However, the number of adults aged 50+ years with a substance use disorder may exceed the estimated 5.7 million because these estimates don’t include potentially high-risk older adults who reside in institutions, and the data used to derive the estimates are based on self-reports, which may be influenced by respondents’ underreporting (Gfroerer, Penne, Pemberton, & Folsom, 2003
; Han et al., 2009b
In summary, the only national study of projections for substance use disorders reveals that the number of individuals with a substance use disorder among adults aged 50+ years is expected to increase for all gender and racial/ethnic groups (Whites, Hispanics, Blacks, and others) in the next decade (Han et al., 2009b
). Overall, older men are more likely than older women to have a substance use disorder. However, due to a lack of distinction between illicit and prescription drug use disorders, gender and racial/ethnic differences in specific drug use disorders remain unclear.
Surveys of the General Population
Adults aged 50 to 64 years use more psychoactive drugs than older groups (Blazer & Wu, 2009a
). Han and colleagues (2009a)
examined the national trends of drug use among adults aged 50 to 59 years in the 2002–2007 NSDUH to clarify their patterns of drug use. Between 2002 and 2007, the rate of past-year use increased from 3.1 % to 5.7% for marijuana and 2.2% to 4.4% for nonmedical prescription drug use. Overall, 9.4% of adults aged 50 to 59 years in 2007 used an illicit or nonmedical drug in the past year. Their analyses also confirmed that the increase in drug use between 2002 and 2007 was driven primarily by the aging of the baby-boom cohort. Characteristics associated with continued drug use in this age group include male gender, unmarried status, early onset of drug use, residence in the western region, less education, low-income status, unemployment due to disability, recent alcohol or tobacco use, having a major depressive episode in the past year, and rare attendance of religious services (Han et al., 2009a
In addition, by comparing the data from the 1991–1992 National Longitudinal Alcohol Epidemiologic Survey (NLAES) and the 2001–2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), Compton, Grant, Colliver, Glantz, and Stinson (2004)
found that the rate of past-year marijuana use between 1991–1992 and 2001–2002 had increased in the 45 to 64 age group for women (from 0.3% to 0.7%), men (from 0.8% to 2.5%), Whites (0.5% to 1.6%), and Blacks (1% to 1.9%). Of all past-year marijuana users aged 18+ years, there was an increase in past-year marijuana use disorders among Blacks (from 21.2% to 38.6%) and Hispanics (from 23.7% to 37.1%). Owing to the sample size of the 65+ age group, detailed comparisons for this group are precluded.
Because of few empirical estimates for specific type of drug use among adults aged 50+ years, Blazer and Wu (2009a
examined the prevalence of past-year use and disorders for specific drugs by analyzing the pooled data from the 2005–2006 NSDUH. The investigators found that adults aged 50 to 64 years were more likely than those aged 65+ years to use marijuana (3.9% vs. 0.7%) and cocaine (0.7% vs. 0.04%) in the past year and that the rates of past-year use of inhalants, hallucinogens, methamphetamine, and heroin were very low (<0.2%) among noninstitutionalized adults aged 50+ years. Adjusted logistic regression found that age 50 to 64 years, male gender, separated/divorced/widowed status, never-married status, and past-year major depression increased odds of marijuana use; age 50 to 64 years, male gender, native American status, Black race, not employed status, separated/divorced/widowed status, never-married status, and past-year major depression increased odds of cocaine use. Overall, 11.7% of past-year drug users (marijuana, cocaine, inhalants, hallucinogens, methamphetamine, and heroin) aged 50+ years met DSM-IV
criteria for a past-year drug use disorder. Among past-year marijuana users aged 50+ years, 4.5% met criteria for a past-year marijuana use disorder; among past-year cocaine users aged 50+ years, 43.9% met criteria for a past-year cocaine use disorder. It is important to note that these estimates cannot be applied to institutionalized older adults as they are not included in the national surveys (Blazer & Wu, 2009a
Using the data from the 2005–2006 NSDUH, Blazer and Wu (2009b)
also examined nonmedical prescription drug use among adults aged 50+ years. In a national sample of civilian noninstitutionalized adults, past-year nonmedical use of prescription opioids (1.4% in adults aged 50+ years) was more prevalent than nonmedical use of prescription sedatives (0.14%), tranquilizers (0.46%), and stimulants (0.16%). Several groups showed elevated odds for nonmedical opioid use, including adults aged 50 to 64 years (1.9 %), men (1.7%), American Indians/Alaska natives (9.0%), alcohol users (1.7%), marijuana users (10.7%), and adults with past-year major depression (2.9%). Propoxyphene, hydrocodone, oxycodone, and codeine products were the opioid products commonly used for nonmedical reasons. The majority (88%) of nonmedical opioid users reported that their first nonmedical opioid use occurred in adulthood (51% at age 18–39 years; 16% at age 40–49 years; 21% at age 50+ years); 50% of all users reported using nonmedical opioids on 12+ days in the past year (M
= 34.84 days). Although the overall past-year prevalence of prescription opioid use disorders among all adults aged 50+ years was low (0.13%), the risk of prescription opioid dependence was comparatively high (one in 13 users; 7.6%) compared with the risk for abuse (1.7%) among nonmedical opioid users.
In addition to prescription opioids, benzodiazepines have received more research attention than other prescription psychoactive drugs (Culberson & Ziska, 2008
). Benzodiazepines are among the most prescribed psychiatric medications (Grohol, 2010
). Approximately 9% to 54% (M
= 32%) of elderly adults have used benzodiazepines in a given year (Llorente, David, Golden, & Silverman, 2000
). Despite the high prevalence of use, existing studies have focused primarily on factors and adverse effects associated with their prescription use. There is a paucity of information on nonmedical benzodiazepine use and abuse/dependence in the elderly (Llorente et al., 2000
). Research findings from benzodiazepine-using outpatients (N
= 599) have shown that a longer duration or higher dose of benzodiazepine use increases the odds for developing benzodiazepine dependence (Kan, Hilberink, & Breteler, 2004
). In a recent survey of community-dwelling elderly adults aged 65+ years in Canada (n
= 2,798), 3.3% of women and 0.8% of men met DSM-IV
criteria for past-year benzodiazepine dependence (Préville et al., 2008
). Of the subsample of benzodiazepine users aged 65+ years, about 1 in 10 (9.5%) met criteria for benzodiazepine dependence (Voyer, Préville, Roussel, Berbiche, & Beland, 2009
). Women and those who had cognitive impairment, panic disorders, or suicidal ideations had elevated odds of developing dependence on benzodiazepines (Voyer et al., 2009
Last, cross-national studies provide some evidence that adult Americans use more illicit drugs than adults in other countries. Recent analyses of selfreported drug use data from the 54,068 respondents in the World Health Organization (WHO) World Mental Health Surveys (WMH) showed that, except for one country (New Zealand) that suggested a similar high rate of drug use, illicit drug use generally was more prevalent in the United States than in the other countries (Degenhardt et al., 2010
). In the overall 18+ age group, 40.9% of Americans used marijuana and 18.7% used other illicit drugs by age 29 years, while the corresponding rate for adults in other countries (excluding New Zealand) was 0.3% to 18.4% and 0.2% to 4.9%, respectively. In the 45 to 59 age group, 40.7% of Americans used marijuana and 15.7% used other illicit drugs by age 29 years, while the corresponding rate for adults in other countries (excluding New Zealand) was 0% to 13.0% and 0% to 2.4%, respectively.
Taken together, in the civilian noninstitutionalized older population, adults aged 50 to 59 years (the baby-boom cohort) use more illicit or nonmedical drugs than older groups; marijuana and cocaine are the most commonly used illicit drugs, and opioid analgesics are the prescription medications most commonly used for nonmedical reasons. Among older past-year illicit drug users, close to 12% develop a DSM-IV
drug use disorder; among older past-year nonmedical prescription opioid users, 9% to 10% develop a DSM-IV
prescription opioid use disorder (Blazer & Wu, 2009a
Admissions to Substance Abuse Treatment Facilities
Admission data from the Treatment Episode Data Set (TEDS) can be used to monitor characteristics of older adults who seek treatment for substance abuse (Substance Abuse and Mental Health Services Administration [SAMHSA], 2008
). TEDS provides an annual compilation of admission (rather than individual-level) data on demographics and substance abuse problems of people admitted to substance abuse treatment facilities receiving some public funding. In 2005, admissions for adults aged 50+ years accounted for about 10% of the 1.8 million treatment admissions for substance abuse reported to TEDS (SAMHSA, 2007a
). In line with study results from national surveys of the general population (Blazer & Wu, 2009a
; Han et al., 2009a
), adults aged 50 to 59 years are more likely than adults 60+ years of age to use substance abuse treatment. Adults aged 50 to 59 years accounted for 83% of all admissions aged 50+ years. There are also important race/ethnicity-by-age differences in admissions: the proportion of admissions among Whites increased gradually with age strata (55% in the 50–54 age group vs. 66% in the 70+ age group), whereas the proportion of admissions among Blacks decreased with age strata (30% in the 50–54 age group vs. 14% in the 70+ age group). Alcohol, opioids/heroin, and cocaine are the most commonly reported primary substances of use in the 50 to 59 age group; they accounted for 55% to 62%, 19% to 22%, and 10% to 13% of all admissions, respectively. More adults aged 50+ years received substance abuse care in an ambulatory setting (55% to 63%) than in a detoxification (27% to 32%) or rehabilitation/residential (10% to 15%) setting.
Trend data from TEDS not only suggest a changing profile of substances used but also confirm an increased trend in drug abuse among older adults. Admission data for adults aged 65+ years showed that, between 1995 and 2005, the proportion of admissions for alcohol as the primary substance of use had decreased from 84.7% to 75.9%, whereas the proportions of admissions had increased significantly for opioids/heroin (from 6.6% to 10.5%), cocaine (2.1% to 4.4%), and sedatives (0.5% to 1.3%; SAMHSA, 2007b
). Similarly, Lofwall, Schuster, and Strain (2008)
found that admissions to substance abuse treatment facilities among adults aged 50+ years had increased significantly between 1992 and 2005; in 2005, 61% of admissions in the 50–54 age group and 45% of admissions in the 55+ age group reported illicit drug use (mainly heroin and cocaine). The increase in drug use also paralleled higher rates of admissions for combined alcohol and drug use, for drug use only, and for use of multiple substances over time; there was a decreased trend in admissions for use of alcohol only. Specifically, increased rates of admissions for drug use-related admissions were noted among Blacks aged 55+ years, Whites aged 50+ years, older adults (50+ years) with 12+ years of education, or those whose admissions involved criminal justice referrals (Lofwall et al., 2008
Data from TEDS also showed important differences and similarities between the characteristics of older (55+ years) versus younger (30–54 years) admissions (Arndt, Gunter, Acion, 2005
). Compared with younger admissions, a higher proportion of older admissions reported alcohol as the primary substance of use (76.3% vs. 50.5%), had no prior treatment episodes (43.2% vs. 36.9%), and used only one substance at admission (77.1% vs. 46.0%); a lower proportion reported using opioids/heroin (14.3% vs. 21.1%) and cocaine/crack (5.4% vs. 16.8%). However, older admissions were similar to younger admissions in daily use of primary substance of use (55.6% vs. 51.4%) and criminal justice referrals to treatment (25.4% vs. 28.0%). Both groups also were most likely to report opioids/heroin and cocaine/crack as their primary illicit drugs of use. There are also gender differences among older admissions. Compared with older male admissions, a higher proportion of female admissions attended college, were White, identified alcohol as the primary substance of use, and initiated substance use at a later age (Arndt et al., 2005
In summary, consistent with study results from surveys of the noninstitutionalized population, findings from treatment-seeking populations indicate an increasing trend of drug use/abuse. Older admissions associated with combined alcohol and drug use and with drug use alone have increased, while older admissions associated with alcohol use alone have decreased. Alcohol, opioids/heroin, and cocaine are the primary substances most commonly used by older adults in substance abuse treatment.