What is the ruling on one who abandoned prayer due to severe suffering from obsessive-compulsive disorder and the effect of nerve medications that cause prolonged sleep, and is she sinful?

Allah does not burden a soul beyond its capacity. A sleeping person is excused for missing a prayer due to the hadith: "Whoever sleeps through a prayer or forgets it, let him pray it when he remembers it." There is no negligence in sleeping.

She must make up the missed prayers, and she should appoint someone to wake her up if she is able to wake up. Otherwise, there is no sin upon her, and she should make them up when she wakes up.

As for prayers intentionally omitted, she must make them up, repent, and seek forgiveness. The view of the majority is more cautious regarding their making up.