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Medically reviewed by Danesh Alam MD, DFAPA, DFASAM
Yes, drug use, heavy drinking, and some medicines can cause memory and thinking problems that look like dementia. Doctors call this a substance- or medication-induced neurocognitive disorder. The main causes are long-term heavy alcohol use, strongly anticholinergic medicines, sedatives such as benzodiazepines, and inhalants. Some cases improve once the cause is stopped, but some, such as Korsakoff syndrome, leave lasting damage.
The earlier the cause is found, the better the chance of improvement. If someone becomes confused suddenly, over hours or days, treat it as an emergency and call 911. For questions about a possible poisoning or overdose, call Poison Help at 1-800-222-1222.
What is drug-induced dementia?
"Drug-induced dementia" is a common search phrase, not a formal diagnosis. In the DSM-5, the clinical term is substance/medication-induced major or mild neurocognitive disorder. It describes memory and thinking problems caused by alcohol, a drug, or a medicine that last beyond the period of intoxication or withdrawal. MSD Manual: Substance-related psychiatric disorders.
"Major" means the problems interfere with daily life. "Mild" is closer to what the National Institute on Aging calls mild cognitive impairment: more memory or thinking trouble than others the same age, while the person can usually still manage daily tasks. Dementia is not a normal part of aging. NIA: Memory problems, forgetfulness, and aging.
Is it the same as pseudodementia?
No. Pseudodementia is an informal clinical term for dementia-like memory problems caused by depression or other psychiatric conditions, not by a drug or by brain degeneration. Gen Psychiatr: What do we know about pseudodementia?.
Is there such a thing as drug-induced Alzheimer's?
Not as a proven cause. Some medicines, including strong anticholinergics and benzodiazepines, have been linked in large studies to a higher chance of a later dementia or Alzheimer's diagnosis. Those studies show associations, not proof that a drug caused the disease, as explained below.
How common is it?
It is hard to measure and often missed. A 1994 review found "a paucity of data" on how often it happens. Drug Safety: Drug-induced dementia, 1994. A 1999 review found that medication toxicity was behind 2 to 12 percent of cases of suspected dementia. Drugs and Aging review, 1999. There is no good current estimate.
What drugs can cause symptoms of dementia?
This list covers the substances and medicines most often linked to lasting memory and thinking problems.
- Alcohol. Long-term heavy drinking changes brain cells and is the best-studied cause.
- Strongly anticholinergic medicines. These include older allergy and sleep medicines such as diphenhydramine and doxylamine, bladder medicines such as oxybutynin and tolterodine, tricyclic antidepressants such as amitriptyline, paroxetine, some antipsychotics, and muscle relaxants such as cyclobenzaprine. 2023 AGS Beers Criteria.
- Benzodiazepines and "Z-drugs." Examples include sleep medicines such as zolpidem and eszopiclone.
- Inhalants. Long-term use of solvents such as toluene can damage the protective coating around nerve fibers.
- Methamphetamine and heavy cannabis use. Both are linked to memory and learning problems, though the evidence on lasting harm is weaker.
- Opioids, corticosteroids, and some stomach acid medicines. These are better known for causing sudden confusion (delirium) than lasting decline.
Anticholinergic medicines
In a Seattle study of 3,434 adults aged 65 and older, people with the highest long-term use of strong anticholinergics had about a 54 percent higher risk of dementia. That level was roughly equal to taking a medicine such as oxybutynin 5 mg or doxepin 10 mg every day for more than three years. JAMA Internal Medicine: Anticholinergics and dementia, 2015; full text.
A larger English study found a similar pattern for several, but not all, classes of anticholinergic medicines. JAMA Internal Medicine: Anticholinergics and dementia, 2019.
These are observational studies, so they cannot prove the drugs caused dementia. Early, undiagnosed illness can itself lead to more prescriptions, which can make a drug look riskier than it is. J Epidemiol Community Health: Prescriptions and dementia.
Benzodiazepines and sleep medicines
Benzodiazepines clearly affect memory and attention while people take them. The American Geriatrics Society advises that adults 65 and older generally avoid them because they raise the risk of cognitive impairment, delirium, falls, and car crashes, and gives the same advice for Z-drugs. 2023 AGS Beers Criteria.
Whether they cause dementia is unsettled. A Canadian study linked long-term use to Alzheimer's, though the authors noted the medicine might be an early marker of the disease. BMJ: Benzodiazepines and Alzheimer's, 2014. A Seattle study found no rise in risk with the heaviest use and concluded its results "do not support a causal association." BMJ: Benzodiazepines and dementia, 2016. A 2018 review found some memory and attention problems may persist after people stop. Archives of Clinical Neuropsychology: Lasting effects of benzodiazepines.
Opioids
Opioids can cause confusion and delirium, especially in older adults. 2023 AGS Beers Criteria. Evidence of lasting dementia risk is limited: one large study found "little evidence of long-term cognitive harm specific to opioids." J Am Geriatr Soc: Prescription opioids and risk of dementia.
Inhalants, methamphetamine, and cannabis
Inhalants. NIDA calls brain and nerve damage perhaps the most significant toxic effect of long-term inhalant use. Long-term use "can cause memory, attention, and judgement problems," and a single use can be fatal. NIDA: Inhalants.
Methamphetamine. Some studies link long-term use to reduced cognitive function, including trouble with verbal learning and memory loss, though NIDA says more research is needed. NIDA: Long-term effects of methamphetamine misuse.
Cannabis. Frequent or heavy use has been linked to problems with learning and memory, and regular heavy use in adolescence is associated with effects on working memory and processing speed. NIDA: Cannabis (marijuana).
Alcohol-related dementia and Wernicke-Korsakoff syndrome
Long-term heavy drinking changes brain cells, and an alcohol overdose can cause permanent brain damage. NIAAA: Alcohol and the brain. Alcohol-related dementia tends to start younger than other dementias and often affects memory, planning, and spatial skills. Alzheimer's Research and Therapy: Alcohol-related dementia. In a French study of hospital records, alcohol use disorders were the strongest modifiable risk factor for dementia, and more than half of dementias that started before age 65 were alcohol-related or came with an alcohol use disorder diagnosis. Lancet Public Health: Alcohol use disorders and dementia in France. For more, see our guide to alcohol and memory loss.
Heavy drinking can also lead to Wernicke-Korsakoff syndrome, brain damage linked to a lack of vitamin B1 (thiamine). NIAAA: Wernicke-Korsakoff syndrome. Thiamine deficiency can also follow weight-loss surgery or illnesses that affect absorption. MedlinePlus: Wernicke-Korsakoff syndrome.
- Wernicke's causes confusion, poor coordination or unsteady walking, and abnormal eye movements. NIAAA says it "should be considered a medical emergency." Doctors treat it with vitamin B1 given into a vein.
- Korsakoff's can follow if Wernicke's is not treated quickly. It causes trouble forming new memories and making up stories to fill gaps. NIAAA calls it "not reversible," and MedlinePlus notes that thiamine "often does not restore lost memory."
NIAAA notes that researchers estimate about 80 percent of cases may go undiagnosed. If you see these signs in someone who drinks heavily, call 911 or go to the emergency room.
Drug-induced dementia symptoms vs. delirium
Dementia-type problems develop gradually, over months or years. Signs include:
- Asking the same questions again and again
- Getting lost in familiar places
- Trouble following directions or recipes
- Growing confusion about time, people, and places
- Poor judgment, trouble managing bills, or not taking care of oneself
NIA: Memory problems, forgetfulness, and aging.
Delirium is different. It is sudden, severe confusion that develops over hours to days and comes and goes during the day. Common causes include intoxication, withdrawal, overdose, infections, and medicines such as pain relievers, sedatives, and anticholinergics. MedlinePlus: Delirium.
Delirium is dangerous and often missed, especially when the person seems quiet rather than agitated. In an older adult with new confusion, doctors assume a medical cause until it is ruled out. StatPearls: Delirium.
Is drug-induced dementia reversible?
Sometimes. It depends on the cause and how early it is found.
- Medicine side effects. MedlinePlus lists certain medicines and long-term heavy drinking among causes of dementia that "may be stopped or reversed if they are found soon enough." MedlinePlus: Dementia. Problems from anticholinergic medicines are generally considered reversible after stopping, though long-term dementia risk may not fully go away. JAMA Internal Medicine, full text.
- Alcohol. A growing number of studies show some alcohol-related brain changes can improve, and possibly reverse, with months of sobriety, though how much is not fully understood. NIAAA: Alcohol and the brain.
- Korsakoff syndrome. Memory loss is often permanent.
- Benzodiazepines. Some deficits may persist after stopping, and protracted withdrawal can include memory problems that last weeks to more than a year. FDA: Boxed warning for benzodiazepines.
Full reversal of an established dementia is uncommon. A 2003 analysis of 39 studies found that only 0.6 percent of dementia cases actually reversed. Archives of Internal Medicine: Reversible dementias.
How is it diagnosed and treated?
If memory problems last more than a few weeks, talk with a doctor. Bring a complete list of every prescription, over-the-counter medicine, and supplement, and be honest about alcohol and drug use. A doctor can run tests, check for other treatable causes such as thyroid problems, low vitamin B12, or depression, and may refer to a neurologist. NIA: Memory problems, forgetfulness, and aging.
Treatment means finding the cause and removing or changing it safely:
- Changing medicines under supervision. Do not stop or cut back a medicine on your own. Stopping a benzodiazepine suddenly can cause life-threatening seizures, so it needs a gradual, individualized taper. FDA: Boxed warning for benzodiazepines.
- Stopping alcohol safely. Quitting heavy drinking suddenly can cause potentially life-threatening withdrawal, so get medical help to plan it. NIAAA: Wernicke-Korsakoff syndrome.
- Thiamine when a deficiency is suspected, given promptly by a medical team.
- Treating substance use so the cause does not return.
Alzheimer's medicines such as donepezil are prescribed for mild to moderate Alzheimer's symptoms. There is no evidence they treat drug-related memory problems. NIA: How is Alzheimer's disease treated?. Be wary of memory supplements and brain-training products. NIA warns they "might be unsafe, a waste of money, or both," though a healthy lifestyle and limiting alcohol may help lower risk. NIA: Memory problems, forgetfulness, and aging.
When to call 911
Call 911 for sudden confusion, a suspected overdose, or signs of Wernicke's: confusion, unsteady walking, and abnormal eye movements. For poisoning questions, call Poison Help at 1-800-222-1222. For a mental health or substance use crisis, call or text 988.
Getting help at Ambrosia
If alcohol, drugs, or a medication regimen may be affecting your memory or a loved one's, start with a medical evaluation. Ambrosia can help with the substance use and medication side. Our admissions team can talk through options, including medical detox and alcohol detox, benzodiazepine addiction treatment with a supervised taper, alcohol addiction treatment, and dual diagnosis care for co-occurring mental health conditions.
For older adults, our geriatric behavioral health program treats mental health and substance use concerns, and our deprescribing program offers medically supervised reduction or stopping of psychiatric medications when their risks outweigh their benefits.