Which discovery led to the hypothesis that Tourette's patients may have an excess of the chemical dopamine?
a. Haloperidol helps control Tourette's symptoms.
b. Ritalin helps control Tourette's symptoms.
c. Tourette's has the same symptoms as schizophrenia, a disorder with an excess of dopamine.
d. Tourette's has the same prognosis as other disorders that have an excess of dopamine.