Several groups of medicines have been associated with a higher risk of dementia or cognitive decline, particularly with long-term use. But an important distinction is that an association does not prove the medicine causes dementia. Many studies are observational, and the underlying condition being treated can itself affect dementia risk.
1. Anticholinergic medicines — the strongest concern
These block acetylcholine, a chemical important for memory and thinking. Examples include some medicines used for:
- Overactive bladder
- Certain allergies
- Motion sickness
- Depression
- Some Parkinson’s symptoms
- Some stomach or intestinal problems
Long-term or high cumulative exposure has been repeatedly associated with increased dementia risk. A recent umbrella review found moderate-certainty evidence for this association.
2. Benzodiazepines
These include medicines such as diazepam, lorazepam and alprazolam, commonly prescribed for anxiety, insomnia or seizures.
Long-term use has been associated with dementia in observational research, although researchers cannot confidently say the medicines themselves cause dementia.
3. Z-drugs and other sedative medicines
Sleep medicines such as zolpidem and related drugs have also been associated with dementia in observational studies. The evidence is less certain than it is for anticholinergics.
4. Some hormone treatments
Androgen-deprivation therapy, used in certain prostate cancers, has been associated with increased dementia risk in observational research. Evidence concerning hormone therapies overall is complicated and depends heavily on the specific drug, dose, timing and patient population.
What about antidepressants, antipsychotics and acid-reducing medicines?
The evidence is much less straightforward. Current reviews have not established that these groups generally cause dementia. For some medications, the condition being treated may partly explain the observed association.
