Conservatives are mentally healthier than liberals

Ed Tom Kowalsky asks:
I've often wondered if mental illness is more common among those who self identify as liberal than those who self identify as conservative. I suspect the answer is a resounding "yes," but I don't know if there is solid evidence justifying my suspicion.
I'm not familiar with the relevant science, but a bit of googling turns up some survey results showing that Republicans are more likely than Democrats are to describe themselves as being in good mental health. Another commenter, JOhn, asserts that liberalism and neuroticism are correlated. From what I'm able to gather, the evidence for that is pretty mixed, but again, I'm really not qualified to speak on the subject.

The GSS is another natural place to turn to in seeking an answer, however, and I am qualified enough to report what its data show! In 2006, it asked respondents if they had ever received treatment for a mental health problem. That's not exactly the same as asking whether or not they had ever suffered from mental health issues--I'd guess, ceteris paribus, liberals are more likely than conservatives are to seek out medical treatment for perceived problems that cover all aspects of personal health, whether they be physical, emotional, or psychological--but it's pretty close.

The question is binary, with respondents simply answering "yes" or "no". The following table shows the percentages of people who report having received treatment for a mental health problem at some point in their lives by political orientation (n = 1,356):


So the GSS provides Ed with at least some evidence that his suspicion is correct.

GSS variables used: MHTRTSLF, POLVIEWS(1-3)(4)(5-7)