WEDNESDAY, June 18 (HealthDay News) British researchers say they have discovered a means of anticipating how people might behave during a psychotic episode.

The study, by a team at the University of Cambridge, found that patterns of normal brain activity may predispose individuals to different psychosis symptoms.

The researchers compared the brain activity of 15 healthy volunteers before and after they were given ketamine, a psychosis drug that mimics schizophrenia symptoms.

Increased brain activity during some tasks in the normal state predicted behaviors after the participants were given ketamine. For example, those who showed more frontal and temporal brain activity while imaging the sounds of voices in their normal state were more likely to experience strange perceptions after taking ketamine.

In addition, volunteers who showed increased activity in these brain regions while trying to complete simple sentences were more likely to have disordered thoughts after they took the drug.

The temporal lobe is involved in speech, hearing and memory. The frontal lobe is involved in planning, decision-making and correcting and troubleshooting errors.

The findings show why schizophrenia symptoms vary widely and may suggest new personalized diagnosis and treatment approaches, the researchers said.

"Our findings may provide a vulnerability marker to predict psychotic symptoms induced by drugs or disease. This perhaps raises the prospect of early intervention strategies targeted toward schizophrenia patients' individual patterns of symptom vulnerability," study leader Dr. Paul Fletcher said in a prepared statement.

The study is published in the June 18 issue of The Journal of Neuroscience.

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