Psychiatric disorders tend to cause disability and they impair one’s ability to function. But this varies from disability to disability. One would expect the more disabling conditions to disappear. But they do not, and even the less disabling ones remain.

As you can see from this, although depression or substnace abuse does not decrease your chance of mating (we will gloss over the loss of your mate by divorce, which increased depression in men and substance abuse in women) having an anxiety disorder, particularly social phobia, does.

So how do these conditions continue? Well, a recent analysis of the Swedish health system led to the authors concluding.

Nonrandom mating is evident in psychiatric populations both within specific disorders and across the spectrum of psychiatric conditions. This phenomenon may hold important implications for how we understand the familial transmission of these disorders and for psychiatric genetic research.

This is shown by condition in the following table.

There is much talk about assortative mating in social classes. This is (Prof) Ann Althouse’s blog:

The “class divide” in the headline is prompting us to feel bad about male-female equality in marriage, because it means that in one couple 2 high salaries are added together and the next family is stuck pooling 2 low salaries. In the old system, you could have made 2 middling economic units out of these 4 individuals, and now you’ve got one rich-getting-richer couple and one poor-getting-poor couple. Whatever happened to the olden days when a man being rich was like a girl being pretty? The rich man found the most beautiful woman and the family income averaged down, more like that next family.

Now, we’ve got “assortative mating,” in which “people marry others they enjoy spending time with, and that tends to be people like themselves.”

What appears clear is that what happens with the elite also happens with the disadvantaged. We may be assorting people by dysfunction. And, given that there are genetic underpinnings of most anxiety disorders, this could be increase the burden on society, and the unhappiness of the population.

In tradtional society we had less choice as to whom we wed. And that may have been for our good.