Millions of people take medication every day to manage allergies, sleep problems, depression, bladder conditions, and other health concerns. While these medicines can provide important benefits, some may affect memory, concentration, or alertness, particularly in older adults.

Researchers have also investigated whether long-term use of certain medications is associated with an increased risk of dementia. Some studies have found associations, especially with medications that have strong anticholinergic effects.

However, it is important to understand that an association does not prove that a medication causes dementia. The risks vary depending on the specific drug, dosage, duration of use, age, medical history, and other factors.

Here are eight medication categories worth understanding and discussing with a healthcare professional.

1. Certain Antidepressants

Antidepressants are used to treat depression, anxiety disorders, and other mental health conditions. Some older antidepressants, particularly tricyclic antidepressants such as amitriptyline, have strong anticholinergic effects.

Acetylcholine is a chemical messenger involved in memory, attention, and learning. Blocking its activity can contribute to confusion, drowsiness, and difficulty concentrating, especially in older adults.

Observational research has found an association between long-term use of certain anticholinergic antidepressants and dementia. However, depression itself can affect cognitive function, making it difficult to determine how much of the observed association is attributable to medication.

What to do: If you notice new memory problems, discuss your medication with your prescriber. Never stop taking an antidepressant abruptly without medical guidance.

2. Older Antihistamines for Allergies

Some older antihistamines, including diphenhydramine and chlorpheniramine, can cause drowsiness and have anticholinergic effects.

These ingredients may appear in allergy medicines and certain nighttime cold or sleep products.

Potential effects include:

• Sleepiness and reduced alertness.
• Difficulty concentrating.
• Confusion, particularly in older adults.
• Short-term memory difficulties.

Long-term exposure to certain anticholinergic medicines has been associated with dementia in observational studies, although findings vary by drug and exposure level.

What to do: Check the active ingredients in over-the-counter products and ask a pharmacist whether a less sedating alternative may be appropriate.

3. Bladder Control Medications

Medications such as oxybutynin are used to treat overactive bladder and urinary urgency. Some drugs in this category block acetylcholine receptors, which help regulate bladder contractions but also play a role in brain function.

Possible side effects include dry mouth, constipation, blurred vision, and confusion.

Certain bladder antimuscarinics have been associated with an increased risk of dementia in observational studies, particularly with greater cumulative exposure. This does not mean every bladder medication carries the same risk or that everyone who takes one will develop dementia.

What to do: If you take a bladder medication and are concerned about memory changes, ask your healthcare professional whether alternative treatments are suitable.

4. Benzodiazepines for Anxiety

Benzodiazepines, including diazepam and lorazepam, are prescribed for certain anxiety disorders and other medical conditions.

These medications slow activity in the central nervous system and may cause drowsiness, impaired coordination, and problems forming new memories.

Older adults can be especially sensitive to these effects. Studies investigating benzodiazepines and dementia have produced mixed results, and a direct causal relationship has not been established.

What to do: Ask your prescriber to review the benefits and risks if you use these medications regularly. Never stop long-term benzodiazepines suddenly, because withdrawal can be dangerous.

5. Prescription Sleep Medications

Some sleep medicines, including zolpidem and related drugs, can cause next-day drowsiness, impaired attention, and memory difficulties.

These effects may increase the risk of falls and accidents, especially among older adults.

Evidence linking sleep medications to dementia is complex. Sleep problems can sometimes precede a dementia diagnosis, and people taking these medicines may have other health conditions that influence their risk.

What to do: Discuss persistent insomnia and medication use with your healthcare professional. Cognitive behavioral therapy for insomnia, known as CBT-I, may be an effective option for many people.

6. Certain Antipsychotic Medications

Antipsychotics such as risperidone and olanzapine are prescribed for specific psychiatric conditions and, in selected circumstances, severe behavioral symptoms.

Some can cause sedation, movement problems, dizziness, and changes in alertness.

In older adults with dementia, antipsychotics carry additional risks, including an increased risk of stroke and death in certain circumstances. These medications require careful clinical assessment and monitoring.

The underlying psychiatric or neurological condition may also affect cognition, so the effects of medication must be considered in context.

What to do: Discuss new confusion, excessive sleepiness, or other changes with the prescribing clinician. Do not change the dose independently.

7. Certain Antiepileptic Medications

Antiepileptic medications are used to control seizures and may also be prescribed for other conditions, including certain types of nerve pain or mood disorders.

Depending on the medicine and dose, some can cause sleepiness, dizziness, slowed thinking, or difficulty concentrating.

Observational studies have reported associations between some anticholinergic antiepileptic drugs and dementia, but findings differ across medications and do not establish that these drugs directly cause dementia.

What to do: If you experience cognitive changes, ask your clinician to review your treatment. Never stop an antiseizure medication suddenly without medical supervision, because doing so can trigger seizures.

8. Certain Parkinson’s Disease Medications

Some medicines used to treat Parkinson’s disease have anticholinergic effects. They may help manage particular movement symptoms but can also cause confusion, memory difficulties, or hallucinations, particularly in older adults.

Parkinson’s disease itself can affect cognitive function, making careful assessment especially important.

Not all Parkinson’s medications have the same effects, and treatment decisions depend on the person’s symptoms, age, and medical history.

What to do: Report new cognitive or behavioral changes to your neurologist or prescriber. Do not stop Parkinson’s medication without professional guidance.

Does a 33% Increase in Risk Mean You Will Develop Dementia?

No. A relative increase in risk does not mean that an individual has a 33% chance of developing dementia.

For example, a hypothetical 33% relative increase from a baseline risk of 3% would raise that risk to approximately 4%, an absolute increase of one percentage point. This is only an illustration, not an estimate of the risk associated with any particular medicine.

The actual risk depends on the drug, dose, duration of use, age, medical history, and other factors.

Furthermore, many medication studies are observational. They can identify associations but cannot always distinguish the effects of a medicine from the effects of the condition for which it was prescribed.

Warning Signs That Deserve Attention

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