A perspective different to others in this thread. As someone who has been in your roommate's position before.

Unless he was physically violent to you, you calling the mental health team (and therefore the police) on him escalated this situation. Obviously he would be angry with you, because you essentially had him arrested. His reactivity to this in of itself is not a sign of mental illness. If you put yourself in his shoes, you would be angry or annoyed too.

Additionally, you could have been more descriptive about his behavior. That he believes reality is an illusion is not necessarily a sign of mental illness. For all we know he could have had a glimpse of satori (ironic given your username). That statement about reality is described in countless spiritual and religious texts by people far wiser and more intelligent than either of us.

However, him talking to himself and not sleeping could be a sign of mental illness. Not sleeping itself could even be the cause, and not the effect of mental illness. As in, maybe he stopped sleeping well on the first day, and then the second, and so on, causing this weeklong incident, and sleeping normally would bring everything back to normal. We don't know if this was the case.

If I were you, as a friend, I would apologize for causing him to be arrested and thrown in hospital (even if you don't believe you're at fault or have done anything wrong) and at least let him stay in the house you shared for a couple of months before making any drastic moves like kicking him out. Treat him normally, as you did before this incident. Don't treat him with kid gloves or as a crazy person. This incident could very well be a one off...or it could be the start of long term mental health issues, which can be resolved but would require some more understanding from you. From there on, make a decision about whether you want to continue living with him given what has transpired. You have to be careful about not blowing this one week, or even a couple of days out of proportion and ruining his life and career. Treat it just as an anomaly, don't share what happened with anyone unless you have permission from him.

I'm speaking as someone who's gone through what your roommate has gone through and recovered. A lot of armchair mental health professionals in this thread are providing extremely poor advice here; advice that's only likely to exacerbate what's happened.

For example:

- Kicking him out of the house

Refusing to have him back in the house is basically the same as indefinitely extending his stay at the hospital - possibly one of the worst things you can do from my perspective. Unless he's actively physically violent, which it doesn't sound like he is - why on earth would you refuse to have him back for at least several weeks?

- Breaking off ties with him

Ridiculous, treat him as the friend he has always been to you. There's no need to worry about your safety unless he is actively physically violent to you. If he starts talking about reality, why not humor him out try and understand exactly what he's saying or looking it up?

- Telling his workplace about what happened

You mentioned you phoned his workplace regarding his absence. I hope you kept the details general and didn't tell them about him being hospitalized. That's a decision for him to make later when he is feeling better.

You sound like a good guy. The best thing you can do for him is to keep a level head yourself and be a good friend while maintaining some kind of detachment and distance. The most likely outcome statistically is him recovering - it will just take some time. Just my two cents.