A new study from Johns Hopkins Medicine has found a possible link between low serotonin levels and memory problems in older adults.
The study, published in the Journal of Alzheimer’s Disease, looked at people with mild cognitive impairment (MCI), a condition that often comes before Alzheimer’s disease.
Serotonin is sometimes called the “happiness chemical” because it helps with mood and emotions. But it also plays a role in memory and thinking. In this study, researchers wanted to know if low serotonin might be related to memory issues in people with MCI.
The study involved over 90 older adults, including 49 with MCI and 45 healthy individuals. Each person had brain scans at Johns Hopkins between 2009 and 2022.
These scans included MRI and PET scans to look at two things: how much serotonin transporter was in their brain and how much amyloid-beta (Aβ) protein they had. Aβ is a protein that builds up in the brains of people with Alzheimer’s disease.
The results showed that people with MCI had up to 25% lower levels of serotonin transporter in key brain areas related to memory, emotion, and thinking. They also had more amyloid protein than the healthy adults.
According to Dr. Gwenn Smith, who led the research, this finding is important. Even when they took into account other signs of brain aging and Alzheimer’s, lower serotonin levels still matched up with memory problems. This could mean serotonin is playing a bigger role in cognitive health than we previously thought.
Mild cognitive impairment is an early warning sign. People with MCI might be more forgetful, struggle to find words, or lose their sense of smell. Understanding what causes these changes could help doctors catch Alzheimer’s earlier and maybe slow it down.
The researchers are careful to say that this study only shows a connection—not proof that low serotonin causes memory loss. More studies that follow people over time are needed to find out if serotonin levels drop before other Alzheimer’s symptoms appear.
Past studies in mice at Johns Hopkins showed that serotonin loss came before big buildups of amyloid protein. This loss is also linked to mood problems like depression and anxiety. So, boosting serotonin might help with both memory and mood.
In the future, the researchers plan to track people with MCI over time and watch how their serotonin, Aβ, and another protein called Tau change. They also want to test new kinds of antidepressants that might improve both memory and mood.
This research could lead to better ways to treat or prevent Alzheimer’s by acting early and focusing on brain chemicals like serotonin. It also shows how important it is to pay attention to early signs of memory loss and take brain health seriously.
If you care about Alzheimer’s disease, please read studies about the protective power of dietary antioxidants against Alzheimer’s, and eating habits linked to higher Alzheimer’s risk.
For more health information, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.
For more information, the full study can be found in the Journal of Alzheimer’s Disease.
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