The house attached to ours has been owned for about 15 years by a landlord who specialises in providing accommodation to young people coming out of care for the first time or with mental health issues needing a "half-way house" between hospital and moving on. Which means the landlord has to be good, legally compliant and above board and all the rest or he doesn't get tenants referred to him any more. Basically he's the opposite of the "bad landlord/Rachman" figure.
 
We have never had a problem with any of those tenants at all. What can happen is sometimes other people latch on to someone and basically abuse the situation in all kinds of ways. If professionals aren't involved resolution can be slow and very difficult if not impossible. I have worked with a lot of mentally ill people, never had a problem and would be happy to have most of my ex-clients as a neighbour, but moving next to what you describe isn't something I'd knowingly do.
 
There was once an almost continual middle of the night party and music noise issue with a young guy who worked for the landlord staying there for a few weeks. He had a lot of mates who treated the house like a party venue. I was tempted to retaliate via the nuclear option and dig out the Orange, Fuzz Face and Telecaster, crank everything to 11, prop guitar against speaker and go away for the weekend but Mrs TLW though that would have been a Really Bad Idea.
 
So had to settle for a quiet world with the landlord instead. Which did the trick. But when the problem is an owner-occupier things are much stickier.

tlw
 If professionals aren't involved resolution can be slow and very difficult if not impossible. I have worked with a lot of mentally ill people, never had a problem and would be happy to have most of my ex-clients as a neighbour, but moving next to what you describe isn't something I'd knowingly do.
 

Thanks tlw, your post was really helpful. I'm a teacher in my day job, and I've worked with students with mental health issues. I too see no problem with living next to a person who is supervised by a professional. I even teach some of those types of professionals.
The issue here is that we cannot get clear information about this guy. He lost his mother 4 years ago and that's when things got really bad, but, by all accounts, there were issues before she passed away with her complaining to him about bringing certain types back to the house. His father (who we see around town) has washed his hands of him. The mother's sister is in some type of tutor role, but the woman is in her 70s, she cannot look after him forever. We also know that there are people living in the apartment with him, but no-one in the block knows who they are, they come and go at night, and often leave the TV on until the morning full blast - they are basically night animals.
When people looked into his 'record' they found everything clean. No criminal record, no record of detox or recovery, but when know he is on a disability pension at the age of 30. My wife saw him too and said that he is really in bad shape, but no-one can say if this is a health issue or a drug issue - he's been found face down in the garden before, the ambulance is often called out to his flat......basically, there are so many 'buts' in this equation that I just cannot take the risk.
Thanks again for your rational reply.