Serotonin is a chemical produced by nerve cells. Its role is to send signals between nerve cells, transporting messages. It can be found predominantly in the digestive system, the central nervous system and also in blood platelets. But, some experts believe that high serotonin levels could be linked to autism.
Serotonin is best known for its role in reducing depression and anxiety, but it also serves a purpose in healing wounds, stimulating nausea, maintaining bone health, controlling bowel movements and more.
What is less discussed is serotonin’s link to autism. This began to be discussed several decades ago, in 1961, when a study was conducted on 23 autistic people. Results revealed that 6 of them presented a significantly higher level of serotonin in their bloodstream. Based on this discovery, other studies continued to be made. It has consistently been reported that 1 out of 4 autistic people has a high level of serotonin.
High serotonin levels might cause autism, but more studies are needed to confirm that
After several observations, scientists tried to come up with an explanation for the high levels of serotonin in autistic people. According to them, serotonin is made in the gut and then transported to blood cells using particular proteins called “serotonin transporters.” People who have autism may have inherited certain types of these proteins that have a higher ability for transportation.
Based on these theories, people on the autistic spectrum could be treated with an antidepressant. Studies show a decrease in repetitive behavior in autistic adults treated with antidepressants. Even more, the active ingredient in the drug “ecstasy” seems to diminish social anxiety, raising serotonin levels in the brain.
Some scientists decided to take their research one step further, exploring the effects of antidepressants in-utero. However, results were not precise, as they could not differentiate the effects of the treatment to the effects of the mother’s depression. It seems that children born in a family with a history of depression have more chances of being on the spectrum.
Currently, more researchers are conducting experiments on mice to determine if drugs that activate serotonin receptors make the subject more sociable.