I've never tried the south beach diet (though I really need to try some diet) but my sister in law did and she became so depressed she had to go on meds. When she stopped the low carb diet circuit she could be weaned off her Lexapro.

I attribute it to that since she'd never had depression before (lucky girl) and hasn't had it since.

So much for the low carb diets for me...

Good luck!

Take care.