I've had a similar situation with my daughter. We used to be very close and gradually she started changing, not just toward me, but everybody and everything. I tried very gently to advise her to seek help, but she is in denial. Never before did she ever raise her voice to me or imply that I was wrong, but this started happening more and more. I tried twice in the past year to tell her she needs help, but both times she got verbally abusive to me and I had to leave abruptly, crying. This person is not my daughter. It has caused me much stress and pain. I was headed into a deep depression anyway, but this hastened it greatly. I got back on meds and seeing doc and am much better now. I have to distance myself from her and her problems right now. I care and love her as much as ever, but I have to take care of me first.

It's hard to let go of someone you care about. If this person is an adult you have to let them make their own mistakes and decisions. Be there if they turn to you, but it is not good for you to worry so much about them. It might feel selfish, and it is in a way, but your first priority is YOU. You cannot help them at all if you fall apart.