How do marijuana and Prozac interact?

I have two friends who were recently diagnosed with depression. They were both prescribed Prozac by their respective doctors. Both of them are heavy marijuana users and both failed to mention that to their doctors. One has been on Prozac for two months and the other for six weeks. I have noticed that their behavior has become strange: mood swings, paranoia, oversleeping, fatigue. They continue taking their Prozac (20 mg a day) and continue smoking pot. I am afraid that there might be some negative interaction between the substances, one being an antidepressant and the other a depressant. Can you provide some insight?


What to do about bleeding nose and gums?

I just came here this fall. Since then, my nose has been bleeding occasionally without any injury. My friend told me it was because of the dry air of U.S. Is he right? How can I prevent this situation? I also have a problem when I brush my teeth. My gums are always bleeding and not just a little!! What should I do? Thanks.