I've been using creatine for years and I've never had any issues with mood while on it. I've heard people claim this before, but I've always dismissed it as placebo effect.
Creatine works in the body by storing energy in phosphate form within the muslce. As your muscle contracts this phosphate is released to provide energy to the cell. It has no direct impact on hormone levels of any kind in the body, although I suppose one could argue that increased energy within the cell is anabolic, but it would have no effect on the endocrine system persay.
IMO, there is either something else causing your mood swings, or perhaps the form of creatine your taking has something else blended in with it. I would look into what other changes you made to your diet and supplimentation within the time period you were using creatine, and make sure to check the label of the creatine you used.
As for your friend who's creatine use
resulted in him being diagnosed for manic depression
thats just not a good possibility. Manic depression can set in at any age, for a host of unknown reasons, and is many times hereditary. But I highly doubt increased atp production in muscle cells would attribute to it. More likely his diagnoses and creatine use were coincidentally at the same time.