My psychiatrist told me that naturally, hair grows in at different times, so when some falls out, other is already growing in. She said that things like Depakote (and also testosterone, which I take) makes more hair grow in and fall out at the same time, so you go through periods of ok hair, and periods of thinning hair. It seems to be true for me (not with depakote but with testosterone), sometimes my hair is thinner and sometimes it's ok.