Both serotonin and dopamine affect susceptibility to addiction
from Medical Xpress
Serotonin levels during initial drug use are critical to whether someone becomes drug dependent or not. "The higher the serotonin levels someone has, the less likely they will become addicted," says researcher Sarah Bradbury. Once drug use escalates and becomes frequent, the anti-addiction effect of serotonin is decreased. "Another brain chemical, dopamine, seems to be the critical determinant of drug addiction during this phase."
7701 Las Colinas Blvd., Ste. 800, Irving, TX 75063