a very close friend of mine has it - and if she comes off her medication, lithium base, all hell can break loose. She's been sectioned some 8 times - I've been there for one of them and it's certainly not pretty. I sympathise with you.
The thing that really helps her is that she, her hubby and her kids (now adults and with their own children), have a team to call on (any of them if they have concerns) if she starts to slide either wat, a police rep, doctor specialising in bp, a psychiatrist and a nurse) and they can help nip things in the bud and keep her on more of an even keel in the emotional tunnel that most of us experience - and that's the way I describe it, they have far higher ceilings and deeper floors - and being on the ceiling is as dangerous as being deep down in depression..... She's in Surrey, not sure where you are Smow, but worth asking about this form of support.