The result is a deluge of tics. Other research indicates that tics are related to higher than normal levels of dopamine production and use. Perhaps there is a larger than normal number of dopamine-producing brain cells. Maybe the individual cells have an abundance of sites, or terminals, that release dopamine. A new imaging study examined tic severity by comparing younger individuals with TS to older patients.
Tics often become milder as patients age.
The researchers found that in specific brain areas, the younger group had a greater number of molecules known as dopamine transporters than did controls. Once dopamine carries out a task, a dopamine transporter, which resides at the terminals, shuttles the chemical back into the cell that produced it so it can be used again. Other research indicates that dopamine is not the only TS instigator. For example, one new study compared individuals with TS to those without the disease and found a difference in the number of transporters for another chemical, serotonin, but no significant difference in the density of dopamine transporters. Some scientists think that dopamine alterations may be more subtle in the disease and that serotonin plays a larger role.