Yes, it's ableist and, yes, it contributes to the negative stereotype of those of us who hear voices. But instead of fussing about it, I'd like to see it stimulate a conversation between us.
How many of us hear voices telling us to kill ourselves?
How many of us hear voices telling us to kill others?
Of those who have command hallucinations of murder, how many actually commit the deed?
How many of us use our illness as an "excuse" to get out of work or school?
I did a quick Google search and found a few references to a 2000 study which suggested that about 30% of patients heard voices telling them to commit violence and about 22% tried to act on those commands.
A 2008 study suggested that antipsychotic drugs helped prevent such violence and that the risk of compliance increased with age.
This guide lists questions to ask of people who report persecutory or command hallucinations.
This is just a quick look, of course, and no one source should be taken as an ultimate authority without more research; however, we can see that not every person who hears voices - even voices telling them to kill - is dangerous. In fact, the studies suggest that most people are not.
Now I can only speak with authority on my own case. I have had visual hallucinations sporadically and auditory hallucinations constantly since I was very young. I did have some command hallucinations but they didn't instruct me to kill. Some of my hallucinations were persecutory and I did self-harm and attempt suicide a couple times as a result of them. But for the most part, the voices offered either neutral or helpful information. I don't want to make it sound like the voices were a good or wanted thing - they weren't - but they often talked about things in the background while I worked and then burst out with advice. Overall, I'd say that my voices helped me excel as far as competency and output but, when it came to emotional stability, people skills, and ability to go to work, they hurt me a lot.
Then Seroquel came into my life and 99% of the voices went away. It's kind of like waking up to find out that everyone else is gone. The quiet in my mind was almost unbearable and I spent the first year adjusting by listening to music or movies or background noise as much as possible.
I hated my voices and I loved them. I feel like part of me is gone now that they've mostly been stripped away. My inner life is much poorer for seeing them go but at least my waking reality is mine now. And since I don't have to focus on them, I can focus on real people who really matter.
So am I offended by the cartoon? Not really. I don't get offended by much these days unless it's really bad. Is the cartoon funny? I guess that's in the eye of the beholder. Is it helpful? No, not at all. People already think we "psychos" and "schizos" are dangerous and no one seems to care much that the biggest repository of our psychos and schizos are jails.
Should PZ take it down? That's up to him, of course, but I think it would be great if we used the cartoon as a launching pad to really talk about these illnesses and to see those of us who have them as real people rather than just shut the conversation down.