I have been on yasmin since august 2004 ( about 4 months) and have experienced a 5 lb weight gain and mild depression. I have tried desogen as well, but that made me cry often, so I asked my dr about yasmin, because I heard it has a diuretic in it which would be beneficial to me ( I compete in fitness competitions and at certain times in the year, must be extremely lean), so I figured the diuretic would ward off unwanted water weight.
I must admit however, that I have a pre-existing thyroid condition of which I take synthetic hormones for. So...It could be that the gain was from my thyroid ( of which my tsh-thyroid stimulating hormone- levels have been off since beginning yasmin) or some combination of the two.
Each person is different. I am off of yasmin for a 3 month trial to see if my depression ( I am seeing a psych too) and tsh levels even out. If they do even out, we know the culprit was the bcp, if they don't well, I would definitely go back on yasmin ( I loved knowing when my period was coming..Like clockwork) and combat whatever has caused my depression and mismanaged tsh levels.
I say talk to your doc, discuss your fears and any past history of health conditions that could interact with the bcps.