The Older Brain on Drugs: Substances That May Cause Cognitive Impairment

Jenny Rogers, MD; Bonnie S. Wiese, MD; Kiran Rabheru, MD, CCFP, FRCP


Geriatrics and Aging. 2008;11(5):284-289. 

In This Article

Abstract and Introduction


Alcohol, recreational drugs, over-the-counter, and prescription medications may cause a range of cognitive impairments from confusion to delirium, and may even mimic dementia. Moderate to high alcohol consumption is one of the often overlooked risk factors for development of dementia and cognitive impairment among older adults. Substances such as opioids, benzodiazepines, and anticholinergics pose a particular risk of cognitive impaiment and the risk increases when these are combined with multiple medications, as polypharmacy is common in patients over 65. A substance-induced dementia may have a better prognosis compared to other types of dementia, as once the instigating factor is gone, the cognition often improves.


When assessing cognition in older adults, it is important to consider that a variety of substances may cause both permanent and reversible cognitive impairment. Alcohol abuse may cause dementia or dementia-like syndromes. Recreational drugs, as well as over-the-counter (OTC) and prescription medications, may cause a range of cognitive impairments from confusion to delirium, and may even mimic dementia. Polypharmacy (defined as use of more than five drugs), which is common among older adults, increases the risk of adverse interactions that may interfere with cognition.[1,2,3] A careful assessment of drug, alcohol, prescription, and nonprescription substance use can therefore allow for modifiable risk factors for cognitive impairment to be identified and addressed.


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