Which neurotransmitter is decreased in Alzheimer's disease?

In Alzheimer's disease, there is a significant decrease in the neurotransmitter acetylcholine. This decline is particularly impactful because acetylcholine is a crucial neurotransmitter involved in memory and learning. The cholinergic hypothesis of Alzheimer's disease suggests that the loss of acetylcholine is central to the cognitive deficits observed in patients.

Researchers have noted that neuronal loss in specific areas of the brain, particularly those associated with memory, affects cholinergic pathways. This is why acetylcholine is critically linked to the symptoms seen in Alzheimer's disease, including difficulties with memory formation and retrieval. Treatments for Alzheimer's often target this neurotransmitter system to help mitigate cognitive decline.

While other neurotransmitters, such as dopamine, norepinephrine, and serotonin, may also play roles in various psychological and cognitive functions, the distinct and documented decrease of acetylcholine in Alzheimer's makes it the most relevant answer in this context.