There are fewer more frightening or challenging psychiatric conditions for a family to face than psychosis, an extreme mental state in which impaired thinking and emotions cause a person to lose contact with reality. This could mean hearing or seeing things that aren’t there (hallucinations), or believing things that aren’t true (delusions).
The illness most often associated with psychosis, schizophrenia, usually doesn’t show up until very late adolescence or early adulthood. Recently, however, experts in the field have been working to identify high-risk kids who show symptoms that could serve as early warning signs of psychosis, and several academic centers have been set up to focus on this crucial period when it may be possible to change the trajectory of mental illness.
http://www.childmind.org/en/posts/articles/2015-7-20-warning-signs-psychosis-schizophrenia-teens