Why is it that so many schizophrenics hear voices telling them to do something violent? Whenever we read about these poor souls, it's because they've heard a voice (usually God's) telling them to burn their neighbor's cat or knife their grandmother. Are there schizophrenics out there who hear voices that say, "This is God. I want you to buy a bouquet of flowers for the mailman," or, "Hello, Jesus here. Just thought you should take the Volvo in for a tune-up"?
-- Eric, via e-mail
After being at the helm of this particular leaky ship for so many decades, I'm more convinced than ever that each of us is some shade of crazy. Just because psychiatrists haven't thought up enough categories to put us in doesn't mean we're home free. And when they do, odds are the psych slots will be misunderstood by the public at large. "Schizophrenic" is a good example. It is characterized by delusions (false beliefs) and/or hallucinations (seeing/hearing things that others don't see or hear) as a result of chemical disruption of brain pathways. It's not curable but is highly treatable and controllable if the right meds are taken faithfully.
Lots of "ordinary" folks believe stuff that's pretty nuts -- the earth's flat; Pluto's a planet; Rufus Wainwright is fun to listen to; obsessive online gaming is a valuable, character-building activity that will serve me well in the future. But society can tolerate these delusions, so Rufus Wainwright fans are not certifiable, just annoying. Schizophrenics' delusions and hallucinations shape behavior that is too out-there for us to deal with. They're not automatically dangerous, just too "different" for their (or our) own good.
Among some schizophrenics' hallucinations are what shrinks call command voices -- a voice telling the person to do something. That something can be good, bad, or indifferent. The content of schizophrenics' delusions and hallucinations are unpredictable and vary from individual to individual. That's one of the characteristics of schizophrenia: very disorganized beliefs and perceptions. Looking at the many studies done of command voices, it's clear that only a minority of schizophrenics have that particular type of hallucination. And of those who do, a smaller percentage yet will actually follow the command. Some will even realize the voices are not real.
Best the docs can tell, a command voice by itself isn't necessarily enough to make a person act. But if the command fits an already existing delusion, and if the person recognizes the command voice, it will have more motivating power. God is a motivator for lots of "ordinary" people; no surprise God's name pops up a lot in hallucinations.
So, say you believe your neighbor's orange tree is giving off evil vapors that cause your daily headaches (delusion). One day, a voice you recognize as your mother's tells you to cut the tree down (hallucination). The two ideas match, you can identify the command voice, so you're more likely to grab your chainsaw and go at it. Given the disorganized nature of schizophrenic thinking, the command voice is just as likely to say, "Give $5 to every homeless person you can find," or "Paint your room purple," or "Stare out the window all day to keep gorillas off the lawn." The content isn't always negative or harmful.
So why do we think it is? You answered your own question. The negative outcomes are the only ones we hear/read about in the news. These days, nothing skews our perception of reality like the media. The few unfortunates we hear about are truly unfortunate and truly dangerous to the target of their delusions or to themselves. Odds are, the person has stopped taking the meds that would help control the behavior.
Schizophrenia isn't the only condition that can cause hallucinations, delusions, or dangerous behavior. More and more, psychiatrists are seeing habitual smokers of the gene-tweaked, ultra-high-THC-content weed who develop similar psychoses. Scarier yet, the condition doesn't seem to be reversible when you stop toking. A mind is a terrible thing to fry.