The study suggests the approach may do the same in people with autism. It also offers an explanation for why antidepressants do not ease autism traits: They may increase serotonin levels too slowly to be effective.
The researchers used a technique that rapidly increases serotonin levels in the nucleus accumbens, a brain region that mediates social reward.
“Somehow, the release of serotonin in the nucleus accumbens really plays an important role in enhancing sociability,” says lead researcher Robert Malenka, professor of psychiatry and behavioral sciences at Stanford University in California. “The simple hypothesis is it makes the social interaction more reinforcing.”
Decades of research have suggested a connection between serotonin and autism. About 10 years ago, this led researchers to test antidepressants, which increase serotonin levels by blocking its reabsorption into neurons, as a treatment for autism. However, in several trials, antidepressants such as fluoxetine (Prozac) proved ineffective at easing the condition’s features.
The new study suggests that a drug that rapidly activates serotonin receptors would be a more effective way of treating the condition.
“We are only recently starting to understand the mechanisms by which the serotonin system may impact social function and repetitive behavior,” says Jeremy Veenstra-VanderWeele, professor of psychiatry at Columbia University, who was not involved in the work.