It happens for men, just that it is a low conversion rate. The conversion rate is even higher for women who are pregnent or breastfeeding, which makes sense from an natural adaptation point of view. You can also elevate the level of DHA in chicken eggs (up to a point) by feeding the chickens flax seed in their diet. Seems like DHA is nutritious for any young, growing brains.
The key thing about the ALA conversion in women is that you're not going to OD on it. Having too much DHA gives you insomnia (though, that is not such a bad thing if by circumstances, you are already sleep deprived).
I havn't seen any papers on it, but my personal experience is that the ratio of DHA to EPA is also important for mental health. EPA seems to help with smoothing out burnout and protect against spiraling into depression.
