Deviate from the norm
If person exhibit behaviors, thinking that are way too far from the norm, then it could be mental illness like seeing ghosts or God or wanting to harm someone or hearing voices, or seeing things going into their body and seeing things real in front of them. These could result from being high on drugs. Too much drugs can cause a person to hallucinate, and see weird things that seem real but are not real.
If they have harmful thoughts about people or their own family member or themselves, then it could be from mental illness. No normal person would sit around and think about harming him or herself or other people. This is bizarre and they will need help.
If a person truly believe in something and they’re absolutely not true and unheard of then they have metal illness. I know a person that think food is harmful so he had been starving himself to death and then ended up in the hospital for at least six months and still would not eat and they have to feed it into his nose. Yes, there are people out there who would have such a fixed beliefs system like him. There are some that are afraid of being overweight, like anorexic people, and that is mental illness, or those that are afraid of germs, like OCD people, are mental illness. My own family members suffered terribly from OCD, they cleaned like a thousands time a day and even at three in the morning, and they do it because they like to torture the other family members with their habits. So they actually enjoy harming other people.
If a person is talking to someone and there appears to be no one in front of them, they are hallucinating. Hallucinations can be resulted from drugs. Often, people can think that you’re a devil and harm you. There have been many cases where people with schizophrenia who murdered their family members and then mutilate them because they thick that they’re the devil.
They could be suffering from mental disorder if they have extreme thinking like the Pakistanis people harming them so they go after them. Recently, there was one massacre in UK, where a person goes after so many Muslims because he think that they’re all terrorists and are harmful to him and other people around him. Obviously, this is extreme thinking. An example of the attack of Arizona congress woman lately was from a mentally ill person. You could look at his face and know that he’s not normal. He looks like a freak. People that think too extreme can be unsafe.
If they appear to be disoriented most of the time, then there are problems with them. If they can’t walk, can’t talk, then they apparently can’t think straight either and any thinking out of them can be wrong.
If they think that they’re the king of a country, or a princess and they dress like that all year round, then they have mental illness. I’ve seen a lady in my town, where she thought of herself as a king and she only wear king clothing like and hats, and king cane, and yellow and golden cape and walk around all year round. I think this is mental illness. Another person I know thinks that she’s an angel falling from heaven and that she knows everything about everyone, this is apparent mental illness. She’s a mortal, living and breathing.