Could Low Serotonin Levels Drive Alzheimer’s Disease?

Past studies have noted that people with Alzheimer’s disease have less serotonin in their brains than other adults. The chemical monitors and regulates appetite, mood, sexual function, sleep and more in the body. Recent studies now suggest that low serotonin levels may be more than a side effect of Alzheimer’s – it may actually drive the disease.Could Low Serotonin Levels Drive Alzheimer's Disease?

Learn more about the most recent study and how it may affect Alzheimer’s drug research.

The Relationship Between Alzheimer’s and Serotonin Levels

While the cause of Alzheimer’s is still unknown, researchers are dedicated to understanding the pathology of the disease and how genetic, molecular and neurological components contribute to its development and progression. Past studies have shown that people with Alzheimer’s have less serotonin in their brains a neurotransmitter which regulates appetite, mood, sleep and sexual function. Other past studies have shown that a decrease in monoaminergic neurons (the neurons that regulate serotonin and other neurotransmitters) are linked to an increase in beta-amyloid plaque in the brain. Researchers are not sure if the lack of serotonin and its regulators are a cause or effect of Alzheimer’s.

Now, a new study from the Johns Hopkins University School of Medicine in Baltimore confirms that serotonin levels play a crucial role in the pathology of Alzheimer’s, even suggesting the chemical may drive the disease and not just be a side effect of living with it.

The study used positron emission tomography (PET) scans to evaluate the brains of 56 participants. Researchers divided the participants into two groups one group with mild cognitive impairment (MCI) and one group with healthy adults (the control group). Using radioactive carbon, researchers were able to trace the activity of serotonin and its transmitters during the scans, finding that those with MCI had 38% less than their healthy counterparts.

Furthermore, researchers compared the results of cognitive testing with PET scan results and found that those with MCI performed 37% worse in verbal memory and had 18% less serotonin than the control group.

Targeting Serotonin Transmitters

Gwenn Smith, Ph.D., first and corresponding author of the study, and a professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine says:

“Now that we have more evidence that serotonin is a chemical that appears [to be] affected early in cognitive decline, we suspect that increasing serotonin function in the brain could prevent memory loss from getting worse and slow disease progression.”

While more research needs to be done to understand how serotonin behaves in a brain with Alzheimer’s, this study suggests that serotonin levels may be a therapeutic target for future drug trials.

Were you surprised to hear a loss of serotonin could affect Alzheimer’s? We’d like to hear your thoughts on the study in the comments below.

Related Articles:

Please leave your thoughts and comments

  • Margaret Atienza

    My mother’s alzheimers is moderately advanced — almost all the time suffers from anxiety, very agitated, obsessive-compulsive moods. Recently her neurolgist prescribed seroquel in order to control these symptons. However I read that seroquel block serotonin, isn’t this contradictory to studies about low level of serotonin being or could be the cause of alzheimer’s? It will be most appreciated if anyone can share their knowledge on this.

    • Debbi

      I would question the seroquel! Last I knew Seroquel was absolutely not recommended for patients with dementia or Alzheimer’s! My mother was given that when she went into a care facility and several months later I read an article on the dangers of Seroquel in the elderly with Alzheimer’s. It is used to control behavior but can result in major personality changes and cause death! I insisted this medication be discontinued immediately. They did follow our wishes and prescribed another anti anxiety medication. My mother was much more herself and did quite well for many years.

      • Debbi

        My mother was taking an antidepressant as well as Aricept for quite a few years before needing to enter a care facility and these medications were continued. I feel very strongly that these played a significant role in delaying the progression of this sad and difficult disease.

  • KNRover

    I have the same question as Margaret A. I was also going to ask “where can one buy seratonin supplements, or is that not possible”? And after reading the findings of John Hopkins, I’m confused. I.e., they say “the chemical may drive the disease.” “Driving” something generally means “keeping it going”. . . the LAST thing we want to do with Altzheimer’s.

  • WildLandLover

    My father, who has what I would call mild to moderate cognitive impairment, was recently prescribed generic Lexapro for depression. It was explained to us it would help increase the levels of serotonin, and honestly, besides his mood being better, his overall memory seems better as well.

    He still has trouble with his eyes and is having increasing trouble with his fingers, but the decline in his cognitive abilities seems to have slowed some and is better than it was a few weeks ago.

    Perhaps the depression was causing some of the memory problems?

  • Zupamum

    I am 62 and have some mild cognitive decline. I have never been a sleeper. When I close my eyes my brain continues to be on overdrive and I often see flashes of color pulsing. I was diagnosed with ADHD as an adult about 30 years ago and take Vyvanse presently early morn. I I would love to have my serotonin level tested and if low do something about it! I really would love someone to do a pet scan on my brain to see if there is a visible problem! The mystery of Alzheimer’s needs to be cracked and a successful drug needs to be developed either to slow down the decline or better yet fix the effected brain!

  • Jeff

    My wife developed PCA-Bensons syndrome are rare ALZ variant after 11 years on Effexor. I am wondering what the contribution may have been.

About The Author

Profile photo of Alissa Sauer