Challenges to recognizing the problem
There are no screening protocols in the clinical setting that are designed specifically for detecting illicit substance abuse among older adults. Furthermore, diagnosis can be easily overlooked because the signs and symptoms of illicit substance use can be mistaken for other illnesses. To complicate matters further, older adults often do not disclose their substance use, understate it, or even try to explain away their symptoms.1 Many older adults live alone, which may increase their risk of receiving no treatment.14
Older adults generally experience reduced tolerance to the effects of illicit substances because of age-related physiologic changes, such as decreases in renal functioning, motor functioning, and cardiac output; altered liver metabolism of certain drugs; and elevated blood glucose levels.15 As a result, symptoms of illicit substance use could be mistaken for dementia or other forms of cognitive impairment.1,16
Although not designed specifically for older adults, an evidence-based screening instrument, such as the CAGE Questionnaire Adapted to Include Drugs, may be helpful in identifying substance abuse in these patients. Urine and/or serum drug screening, along with obtaining a comprehensive history from a trustworthy source, is useful for diagnosis.
Pharmacologic treatments
Research evaluating the use of medication for treating substance abuse specifically in older adults is extremely limited; studies have focused primarily on younger patients or mixed-age populations. Treatments that have been shown to be effective for younger patients may or may not be effective for older adults.
Marijuana. There are no FDA-approved treatments for marijuana abuse. An open-label study found that N-acetylcysteine, 1,200 mg twice a day, resulted in a significant reduction in marijuana craving as measured by the 12-item version of the Marijuana Craving Questionnaire.17 In a double-blinded placebo-controlled study, adolescents who were dependent on marijuana who received N-acetylcysteine, 1,200 mg twice a day, were more than twice likely to stop marijuana use compared with those who received placebo.18 Some researchers have proposed that N-acetylcysteine may prevent continued use of marijuana via glutamate modulation in the nucleus accumbens. Animal models have demonstrated that chronic drug self-administration downregulates the cystine-glutamate exchanger in the nucleus accumbens, and that N-acetylcysteine upregulates this exchanger, which reduces reinstatement of drug seeking.Further studies are needed to verify this speculation.