It appears that doctors can predict psychosis with great accuracy in troubled teens before they may actually develop the full-blown disorders. This is based on a specific combination of risk factors. Once the criteria for risk was noticed, almost 80 percent of the patients were diagnosed with a psychotic disorder such as schizophrenia within just 2 and a half years.
Study researcher Tyrone D. Cannon, Ph.D., of the University of California, Los Angeles, said that those patients who showed early symptoms of psychosis along with a family history of psychotic disease, while exhibiting a decline in social function, were very likely to be diagnosed with the full-blown disorder within a couple years. Unusual thoughts or an unhealthy level of paranoia are examples of early symptoms which may show psychosis.

In the predictive model created by Cannon and his associates, a sudden drop in academic average or substance abuse were also observed as risk factors.   
"When a kid who is pretty connected with his peers and doing well at
school suddenly withdraws and is having unusual thoughts or becomes highly suspicious, it should not be ignored," said Cannon.

291 high-risk teens were recruited by Cannon, co-author Robert Heinssen, Ph.D. of the National Institute of Mental Health (NIMH), and other associates from 7 research centers.
The teens were called “high-risk” due to the symptoms they had which were related to psychosis, yet they were not diagnosed with a psychotic disorder.
Cannon further described alterations in perception, like hearing strange noises or seeing images that appeared and disappeared, as a characteristic of a progressing psychosis.
35 percent of those teenagers who participated in the study and exhibited a risk factor had a psychotic illness within two and a half years.
If the results are confirmed, this could mean that doctors would be able to find out which teens would be at risk for psychotic diseases much sooner. They could get the proper attention much sooner in order to stop the progression of their psychotic illnesses.
Heinssen commented that early treatment with the proper medication can lead to more promising results. Yet this still doesn’t mean that medication need be applied to patients without the active psychosis developed within them.
Heinssen remarked, "Treatment should begin as soon as a person crosses that threshold from pre-psychosis to active psychosis. But active psychosis is often present for weeks and even months before drugs are given."