I am on sabbatical from teaching to work with chronically mentally ill patients in a hospital setting. The patients I encounter are fortunate to have a high level of skilled care and treatment of their illnesses, and society is safer for this. A common trait among the majority of schizophrenic patients I've observed is internal stimuli in the form of command hallucinations. It's almost always God who speaks directly to the patient, and He often demands that they do something that has terrible consequences. They have no choice but to obey.
When appropriately treated, most often with medication, the patient is able to regain a sense of control and personal agency. Violent behavior is regulated. The voices quiet down.
When our politicians state "I am driven with a mission from God -- 'George, go and end the tyranny in Iraq'" or attribute the slaughter of our schoolchildren to our having "systematically removed God from our schools," in the absence of mandated involuntary medication for elected officials, let's remember that we are not all hearing the same voices.