I think the passage about Sirius in Azkaban is really gripping. He is not affected by the Dementors at all, which shows that he is not evil, and in his mind he will always be optimistic. All the other prisoners have had their happiness drawn out of them by the Dementors, but Sirius' mental health is a lot different from theirs, thus the Dementors can't get to him.
I think Azkaban is a prison that tortures people. It's definitely not a mental health prison because it does the opposite of helping mental health. It makes people crazy with the Dementors because they suck all the happiness out of people. They make people depressed which is what JK Rowling based them off of.
Azkaban is the complete opposite of a mental health prison in the sense that it completely destroys a prisoner's mental health. However I can imagine that the sense of feeling trapped inside the building is similar
- We know what the Dementors represent, but is there more beyond that?