The sad truth is that most clinical research has absolutely no effect on clinical practice—rarely does a study impact how we diagnose and treat patients. A paper by Morrison and colleagues in the British Medical Journal is that rare exception. For the pleasure of reading it, see: "Early detection and intervention evaluation for people at risk of psychosis: multisite randomized controlled trial."
The authors, from four British universities, investigated the effectiveness of cognitive therapy in preventing psychosis in young help-seeking people. The study compared a group of patients who received cognitive therapy plus monitoring of mental state with a group who received monitoring only.
This one beautiful study has succeeded in definitively answering two of the most timely and consequential questions facing psychiatry today: 1) Is it a good idea to include a "psychosis risk syndrome" in DSM 5? and 2) Can early treatment programs prevent psychosis? The answers to both questions—a conclusive and emphatic No.
First off, the study proves that we don't yet have the basic diagnostic tools needed to build a preventive psychiatry. Fundamental to any meaningful prevention program is the accurate identification of those who are really at risk. This study clearly demonstrates the impossibility of predicting who is (and who is not) likely to become psychotic. It is striking that only 8% of misnamed "ultra high risk" patients actually go on to have a psychotic episode. The unacceptably high false positive rate means that nine of 10 people entered into a psychosis prevention program will be misidentified and told they are at risk (or even worse at "ultra high risk") for eventually becoming psychotic—when quite clearly they are not. There can be no justification for burdening young people with such unnecessary stigma and worries, reduced ambitions, and the risk of receiving potentially dangerous antipsychotic drugs. If they have problems that need addressing, these should be addressed, but not under the misleading and pejorative auspice of their being at "ultra high risk."