Something in New Mexico's water?

Another crack in the it’s-our-crazy-hormones theory of women’s minds:

As the Our Bodies, Ourselves blog notes, a Center for Disease Control survey has found that postpartum depression is much more commonly experienced by women who also experienced emotional, traumatic, partner-related, and financial stressors during pregnancy, and those who were physically abused during pregnancy were more likely to report symptoms of depression. Women who were younger, less-educated, and who received Medicaid at the time of delivery were also more likely to report symptoms. And rates of reported symptoms of depression varied from 11.7 percent in Maine on up to 20.4 percent in New Mexico. (As I mentioned in an earlier post, poverty also correlates with higher rates of postpartum depression.)

No surprises here, except you should be surprised if you believe the line that postpartum depression just is a hormone imbalance. If postpartum depression is a hormone imbalance, is there something in the water in New Mexico that sends hormones out of whack? And exactly how do receiving Medicaid and not having a Harvard diploma cause hormone imbalances? And if they do, just how relevant is the hormone imbalance to the problem?

To be clear, I’m not arguing that hormones play no role in postpartum depression. I’m sure they do. But I’m not sure which is the cart and which the horse—are whacked-out hormone levels the cause or the effect of being depressed, or some bit actor in the causal drama? I find the theory that our mental lives just are flows of chemistry to be incoherent. Maybe emotions feel like they’re about things in the world at least largely because they are. Like maybe it’s hard to be a mother in this society, and that can get a woman down, even make her crazy.