Depression increases your risk of...depression

Why is it that news about postpartum depression seems so often to fall in the no-shit-sherlock category?

Check out this item: “Psychiatric history affects 'baby blues,' study says.
Mental health issues may increase postpartum suicide risk.” Um—it took researchers with master’s degrees to figure this out?

Then again, read deeper and you find more to undermine conventional wisdom than to reiterate common sense. Midway down the article I see this: Rates of suicide attempts by women after giving birth is much lower than in the general population.

This does make sense; most women, even depressed ones, feel an obligation to their newborns to stay alive. Still, you might think from all the publicity about postpartum depression that women were at high risk of suicide after pregnancy.

Talk about postpartum depression is a strange mixture of the deadly obvious repackaged as profound scientific insight and thoroughly bogus leaps of logic repackaged as unquestionable science. This says to me that we’re thoroughly confused about postpartum depression. And "mental illness" in general, for that matter. My favorite billboard ever, which I used to pass by daily on my way to work, is "Number one cause of suicide: Untreated depression." Can we say tautology, class?