Memory Digest

Reversible Causes of Memory Problems

Not all memory loss is dementia. Vitamin B12, thyroid problems, medications, depression, sleep apnea and normal pressure hydrocephalus can all be treated.

Last reviewed: October 2026

When memory problems appear, many people fear the worst. But a range of conditions can cause memory and thinking problems that improve with treatment. Truly reversible dementia is uncommon, but finding and treating these factors often helps—even in someone who also has Alzheimer's. This is one of the most important reasons to see a doctor rather than assuming it's "just age."

Medications

Medicines are among the most common and fixable causes. Culprits include:

• Anticholinergic drugs – some older allergy and sleep medicines (such as diphenhydramine, found in many "PM" products), bladder medicines (such as oxybutynin), some antidepressants, and certain stomach and muscle relaxant medicines.
• Benzodiazepines (such as lorazepam, diazepam, alprazolam) and "Z-drug" sleeping pills
• Opioid pain medicines
• Some seizure medicines, steroids and others
• Combinations of many medicines (polypharmacy)

The American Geriatrics Society's Beers Criteria lists medicines that older adults should generally avoid. Never stop a medicine on your own—some must be tapered—but do bring every pill bottle, including over-the-counter products and supplements, to your doctor and ask for a review.

Vitamin B12 deficiency

Low B12 can cause memory problems, confusion, depression, numbness and tingling, and balance problems. It is more common with age, in people taking metformin or long-term acid-reducing medicines, in vegans, and after stomach surgery. A simple blood test checks it; treatment is with supplements or injections. Early treatment works best.

Thyroid problems

An underactive thyroid (hypothyroidism) can cause slowed thinking, poor memory, fatigue, depression and weight gain. An overactive thyroid can cause anxiety, poor concentration and confusion. A blood test (TSH) checks it, and treatment usually improves symptoms.

Normal pressure hydrocephalus (NPH)

NPH is a buildup of cerebrospinal fluid in the brain's cavities (ventricles). It classically causes three problems, sometimes summarized as "wet, wobbly and wacky":

• Walking problems – a slow, shuffling, "magnetic" gait, often the first sign
• Urinary urgency or incontinence
• Thinking problems – slowness, apathy, poor attention

It is diagnosed with brain imaging and tests such as removing some spinal fluid to see if walking improves. Some people improve significantly with a surgically placed shunt that drains extra fluid. Walking usually responds best; early treatment gives the best results.

Depression and anxiety

Depression can cause poor concentration, slowed thinking and memory complaints—sometimes called "pseudodementia." It often improves with treatment such as therapy, medication and exercise. Depression can also be an early sign of dementia, so follow-up is important.

Sleep problems and sleep apnea

Untreated sleep apnea deprives the brain of oxygen and restful sleep and is linked to memory and attention problems. Treatment such as CPAP can improve alertness and thinking. Chronic insomnia also affects memory. See Sleep and Memory.

Other treatable causes

• Infections – urinary infections and pneumonia can cause sudden confusion (delirium); syphilis and HIV can also affect thinking.
• Hearing and vision loss – make it harder to take in information and can look like memory loss.
• Alcohol – heavy drinking damages memory; thiamine (B1) deficiency can cause serious memory disorders.
• Dehydration, low sodium, kidney or liver problems, low or high blood sugar
• Subdural hematoma – a slow bleed on the brain surface, sometimes after a minor fall, especially in people on blood thinners.
• Brain tumors – uncommon, but imaging can find them.
• Stress, grief and burnout

What a check-up usually includes

A good evaluation for memory problems typically includes a medication review, blood tests (including B12, thyroid, blood count, metabolic panel), screening for depression, a hearing and vision check, questions about sleep and alcohol, and often a brain scan. See Getting a Diagnosis.

The bottom line

Don't assume memory loss is untreatable. Ask your doctor: "Could anything else be causing this?" Even when dementia is present, treating these conditions can make thinking clearer and life better.

Sources

1. National Institute on Aging: Memory Problems, Forgetfulness, and Aging
2. Mayo Clinic: Dementia—causes (conditions that can be reversed)
3. NINDS: Normal Pressure Hydrocephalus
4. American Geriatrics Society 2023 Beers Criteria (medications to avoid in older adults)

Not medical advice. This article is general information, not a diagnosis or treatment plan for any individual. Talk with a doctor about your situation.

Related articles

• Normal Aging vs. Memory Problems
• Delirium vs. Dementia
• Getting a Diagnosis
• Alzheimer's Disease
• Frontotemporal Dementia