Science has known for a long time that schizophrenic patients are two to three times more likely to carry antibodies to T. gondii than are controls who are not schizophrenic. Furthermore, antipsychotic drugs that block the action of dopamine, such as haloperidol, commonly used in the treatment of schizophrenia, are also effective in combating toxoplasmosis in both rats and people. And some infected adults go on to develop psychotic symptoms similar to schizophrenia. Little is known about the mode or site of action of this pathogen in the human brain. The exact link between T. gondii and psychiatric diseases is tantalizing but remains murky.