To cut my friend off

I would fade her out. Stop checking up on her when she says she's in a bad place. She doesn't respond anyway and then she's on facebook talking to others and going out on dates so she isn't in that bad a way.
If she phones when you are watching a film, don't pick up. And don't ring her back later. She does the same to you when she ignores you for months on end, leaving you to worry about her.
She has you exactly where she wants you and can drop you and take up with you again whenever she feels like it.

Let her go. You have been very patient and understanding and your posts show that you are trying to be very fair, given her problems. But she worries you with talking about self harm, then ignores you when you tries to check she's OK. Then goes silent on you but not others. Then she's ringing every day and interrupting you when you're trying to relax and watch a film. Who needs that crap? Leave her to her mum, her other friends and the mental health professionals. Find friends who help you flourish and whose effort is equal to yours.

Are you happy with the periods when she’s calling you every day?

I agree- there is a manipulative quality here that indicates this isnt just about her being mentally unable to communicate. The fact she's able to go on dates etc but happy to ignore you and then literally say this is game playing and power play.

She's doing it because you're letting her. The comment about her silence is so blatantly manipulative – she's goading you to complain and then when you do she'll cut you off again and she won't be the bad guy. This isn't about her mental health – it's about her toying with you. I think she's getting a kick out of it.

She's not your friend. For the sake of your own mental health you should ignore her messages when she gets in touch again.

Lots of people have friendship tiers. The people she keeps in contact with regardless of how she is feeling emotionally are her top tier friends. You fall somewhere below that.

I would be ok with that, happy enough to be more acquaintance than friend, providing her expectations of me matched that. I’d be happy to meet up for a coffee, have a cheerful chat, but if she veered the conversation into deeper territory I would say that I’m not the person she needs to be talking to, she has friends she is closer to for that.

Issues with friends who have poor mental health are posted here quite frequently. I think it should be borne in mind that while we shouldn’t be unkind to people with mental health issues, few of us are qualified to know how to handle it effectively. And none of should be expected to hold an acquaintance’s mental health as more important than our own.

Dump her.

She's treating you like garbage.

If this was just about her needing space due to MH issues then she wouldnt be behaving in the ways you describe on social media or socialising with others etc

Mental health isnt an excuse to treat people like utter shit or as if you are a toy she can just pick up and put down whenever she feels like it.

You have the choice now- let this BS continue to harm you or end it now.

well in that case I’d be more relieved than jealous and pity the other friends she was off loading to!

OP… do you have a wide circle of friends? Close friends? Why not just focus your energy on them

It’s pretty clear that OP just wanted to make clear that she is not jealous of this ‘friend’ messaging other friends, it’s just the unfairness of the ‘friend’ being in contact with other friends online and via text and yet ignoring OP.

I've been her in this situation, and it's difficult to explain how depression makes you a very fairweather friend in a lot of cases and I've definitely lost friends as a result of it.

The one thing I'll say having been on the other side of it - it's actually ok for you to prioritise yourself and not keep giving in an uneven relationship. I don't actually resent any of the friends I lost when I was at my worst because I understand now how difficult I was.

You'll feel like you have to stick around and put up with it because she's unwell, but you don't. While a certain amount of understanding is nice, you don't have to accept being picked up and put down like a toy when it suits her, even if she's not doing it out of malice. It's ok to choose yourself and distance yourself from her, it's not entitled to want your friendships and relationships to be balanced and equal.

But she’s done this so many times and she always comes back and then acts like nothing has happened.

well presumably because you let her

You mention jealous a few time

why on earth would you be jealous of her?

As someone who has ADHD task avoidance and hates texting, I still say dump her as a friend.

Because when my ADHD is so bad that I don’t text for weeks, I would never do hurtful things like post online and text some friends but not others.

You have been patient and very reasonable.

Sounds like she has family and friends so you should feel zero guilt. Stop messaging her and next time she messages, tell her the uncertainty around when she is going to respond is giving you anxiety and so it might be best to not be contact anymore and that you wish her all the best.

And then block and delete her on everything.

Doesn’t it look like she doesn’t want to be friends with you and hasn’t wanted to be for some time now?

You have become the therapy or dumping ground friend. She's using you as the go to for negative moaning but when she's upwards and presenting a good face she'll go to others, the one's she wants to impress and have fun with. It sounds like she's exhausting to you and not someone you have fun with you provides you with support and positivity so for those reasons I would drift away. She's not a friend.

Or Narcissists? Or people with narcissistic traits? I think sociopaths are quite rare? Although im no expert!

The only inference you can draw from her being socially and emotionally active with friends but not with you, is that she doesn't want to be friends with you any more.

Don't flog a dead horse

The only people I’ve ever known do this are sociopaths.