They are hard to comfort
Have you noticed no matter how much advice, comfort and guidance you give it's never enough and the behavior hardly improves over time.
To add, it's also why I do not want to deal with people who have poorly managed mental illness, I have dealt with bpd people growing up because I wanted to help them but nothing I ever said was enough. Call me ableist or say mental illness is okay until you show symptoms.. I have tried to be supportive and I grew up needing extra help at school and needing therapy but I don't stay a victim