If you want to assess whether you are actually speaking out loud or not, (whether people are lying to you when they say your are not), just get a cheap tape recorder or put your phone on record, and have it run near you when you're thinking.
I'm sorry, but there are actually no doctors on this website. Once upon a time there were, but not for a long time. Just folks who take an interest or have experiences and want to help. I have no idea why anyone would lie to you about it. That's a pretty vast conspiracy you're talking about. But I'm not there, so I can't know. If you've ended up in mental hospitals something pretty miserable is going on with you. I'm not sure bad acid trips cause problems per se unless you take a whole lot of it at one time or take several different types of drugs in the same day. The big problem is that acid isn't acid anymore, it's a mixture of stuff some of which is probably LSD but much of what is speed and other things to cut it with that are less expensive and make it go farther for the seller. In the earliest days of using LSD, and in its continued use in medical settings by a few psychiatrists, it was pure and didn't really cause problems. I never took it but I was a young man in that time and it wasn't until it became more popular that the LSD began to be mixed with speed, and that prevents you from talking yourself down and keeps you stoned for a long time. That can be very scary. But it's more of a PTSD type reaction than your brain being permanently damaged most likely, and so you can get over it with the exception, as I said, of some who took a whole lot of it at one time or mixed it with a lot of other drugs. I did know a couple of people who did this and they did get long-term problems. Also, there is no normal. Some very "normal" people talk to themselves. I have done it most of my life when thinking, especially when I'm writing fiction or working out a problem. If you're doing it all the time, I can see how that would be disturbing to those around you, but if they're saying you're not doing it, maybe you're not. Again, don't know. You're there, nobody else is. I would try to focus more, though, not on that but on the thoughts you're having that make you unhappy. If you can learn not to do that through therapy and, if necessary, medication, you might get past this. None of us knows the future, but you're young and adaptable so give yourself a fighting chance and do whatever you need to do to get the help you need. Got my fingers crossed. Peace.