Certain commonly prescribed medications have been associated with an increased risk of dementia, particularly when used over extended periods or in high doses. These drugs often possess anticholinergic properties, meaning they block acetylcholine—a neurotransmitter crucial for memory and cognitive function. Older adults are especially vulnerable due to natural declines in acetylcholine levels.

1. Anticholinergic Drugs

Medications with anticholinergic effects, such as first-generation antihistamines (e.g., diphenhydramine), tricyclic antidepressants (e.g., amitriptyline), and certain bladder medications (e.g., tolterodine), have been linked to an increased risk of dementia. A study found that long-term use of these drugs was associated with a 50% higher risk of developing dementia. The risk escalated with prolonged use, particularly when taken daily for three years or more.
Healthline

2. Benzodiazepines

Benzodiazepines, including medications like lorazepam (Ativan) and alprazolam (Xanax), are commonly prescribed for anxiety and insomnia. Prolonged use has been associated with an increased risk of dementia. A study indicated that individuals using benzodiazepines for more than six months had an 84% higher risk of developing Alzheimer’s disease compared to those who did not use these medications.
Harvard Health

3. Gabapentin