4. Which of the following statements reflects "circumstantial evidence" for the dopamine theory ofschizophrenia?
(A) Antipsychotic drugs (neuroleptics) act as dopamine agonists,increasing the amount of dopamine in the brain.
(B) Antipsychotic drugs (neuroleptics) can produce symptoms similar tothose of Parkinson's disease (a disorder due to insufficient dopamine).
(C) The drug L-dopa, a dopamine agonist, is used to treat schizophrenicsymptoms in patients with Parkinson's disease.
(D) Amphetamines, which activate dopamine, can lessen psychoticsymptoms in people with schizophrenia.