Those who argue that anti-social personality disorder, a common characteristic among killers, is a form of mental illness, will also concede that these people are not hospitalized for their condition, and are able to function in the world. The disorder is not diagnosed until the person is incarcerated for violent activities. Even after the diagnosis of anti-social personality disorder, there is little that can be done to treat the person. Incarceration is the only means of protecting others from sociopaths who have killed. Paranoid schizophrenia, however, is a treatable disease, but in severe cases the patient must be closely monitored in a hospital-like setting.
Medication helps, but paranoid schizophrenics can easily stray from treatment if left on their own.
Unlike anti-social personality disorder, paranoid schizophrenia is usually diagnosed before violence occurs. Dr. Lunde, who examined John Linley Frazier, Herb Mullin, and Edmund Kemper, has said that among the small proportion of murderers who are mentally ill, the single most common disorder is paranoid schizophrenia. Mullin s propensity toward violence was grimly evident to many, but there was nothing that could be done to keep him institutionalized. If his parents had the funds, they would have kept him in a hospital. If the hospitals who has held Mullin had the authority, they would have kept him in treatment.