I had a Britney style breakdown after my divorce. Can I win back custody after losing it in New York

It is very difficult to win back custody after losing it for a significant period of time. Especially where the children are very young. The court has an interest in preserving the stability in children’s lives. That being said, if you lost custody because of a mental breakdown, the court is likely to want a thorough pyschiatric evaluation before even entertaining the notion of returning custody to you.
But depending on how long the children have been with the other party, your chances of getting custody back could be jeopardized. Would it be in the children’s best interest to uproot them? If the children seem well adjusted, and the law guardian recommends that custody remain with the other custodial parent, you will have an uphill battle getting the children back.
But if circumstances have changed with the other custodial parent for the worse, and with you for the better, you stand a chance of getting your children back.
Will Britney ever get custody back? It’s hard to say. I don’t think it is impossible. Now that her father is her permanent conservator, it does lend some appearance of stability to their lives. She is the monied spouse so the children will arguably have a higher standard of living with her. But the court is not going to restore custody to her just because she had more money than Kevin. That is why there are child support laws. So the children can still live at the standard they would have had the marriage stayed in tact.
But if Kevin gets more “unfit” as time goes on, and Britney is in a stable marriage situation, and she has no more outburts, and her father remains her conservator, with good lawyers she may be able to bring in psychiatrists who will strongly recommend custody to the mother.
Certainly, as the children grow older, they may want to live with their mother, and their wishes start to take on more weight as they grow older. The court would have to take their wishes into consideration.
So can you get custody back? It depends. How long has your situation been going on? How old are the children? What is their living arrangement now? How deep are your pockets? Who is the judge? Who is the law guardian? Can you get everybody to root for you? If yes, then maybe you can get custody back. If not, I doubt it.