There is a group of illnesses which disrupt the functioning of the brain so much, they cause a condition called psychosis. When someone experiences psychosis they are unable to distinguish what is real — there is a loss of contact with reality. Most people are able to recover from an episode of psychosis.
Psychosis is very misunderstood and people think you can easily control an episode of psychosis. This isnt the case speaking from experience and being educated on the matter.
Warning signs for a psychosis include confused thinking, delusions and hallucinations. Psychosis can happen regularly for someone and can come on when you least expect it. You can see the warning signs, but due to it being beyond control they can come on at any time. People think psychosis just happens when drug use is involved and this is far from the truth.
Psychosis is minimised with techniques such as meditation and community support. Because people don't understand it unless they experience it, psychosis is viewed as dangerous and scary. Please note all rational thinking is not present in a psychosis and its not the person who is experiencing it fault.