Benadryl, which contains diphenhydramine, can have notable effects on cognitive function and memory, with varying implications depending on whether it's used short-term or long-term.
In the short term, diphenhydramine can impair mental clarity by affecting alertness, attention, and memory. Many users experience fatigue, drowsiness, and reduced motivation, which can make even simple tasks feel more challenging. This is because the drug’s anticholinergic properties block acetylcholine, a key neurotransmitter important for learning and memory. In older adults, particularly those hospitalized, diphenhydramine has also been linked to delirium, characterized by confusion, disorganized speech, and trouble focusing.
Over the long term, the risks become more serious. Studies suggest that extended use of anticholinergic medications like Benadryl is linked to a higher risk of memory problems and dementia, including Alzheimer’s disease. One theory is that by continuously blocking acetylcholine, the brain may experience changes that contribute to cognitive decline. Some research has also indicated a possible connection between these medications and the accumulation of beta-amyloid, a toxic protein linked to dementia.
Observational studies have found that long-term users of anticholinergic drugs often show greater declines in memory and thinking abilities compared to non-users. However, it’s important to note that these studies show associations, not direct causation. Researchers are still exploring how these drugs might affect brain health, including their impact on inflammation, blood flow, and the brain’s ability to clear harmful proteins.
For older adults or those considering long-term use of Benadryl, these findings highlight the importance of discussing risks with a healthcare provider. While it can be effective for short-term symptom relief, its potential effects on memory and cognition should not be overlooked, especially with prolonged use.
