They nevertheless provide valuable clues to the dynamics of the onset of psychotic disorder, which may be useful, if not at the level of the general population, certainly at the level of mental health care. Raising the rate of schizophrenia by sample enrichment strategies The sample enrichment strategy basically consists of the creation of a sample with many people at risk by Inhibitors,research,lifescience,medical selectively filtering them out over a range of consecutive referral processes starting in the general population, through to general practioners (GPs) , mental health services, and the early detection clinic. The

sample enrichment strategy is undoubtedly the most widely used approach in the early intervention literature, but possibly also the worst understood, in that the high predictive values obtained in sample enrichment studies are often Inhibitors,research,lifescience,medical wrongly attributed

to some instrument with supposedly high predictive values, whereas in reality they are a function of the sample enrichment strategy itself. For example, several authors have suggested that the high “transition rate” to psychotic illness in individuals exhibiting psychosis-like symptoms is between 40% and 70%, thanks to the use of some prodromal-rating instrument,34,45,46,62,63 Inhibitors,research,lifescience,medical advocating the use of such instruments in order to reduce transition to full-blown illness. However, closer inspection of these data is required, as illustrated by the following example. Inhibitors,research,lifescience,medical In

a recent publication, Klosterkotter et al63 reported a follow-up study of 160 young individuals who were considered to be at risk of developing psychotic illness. The signs and symptoms used to predict transition to schizophrenia were from a list of “basic symptoms.”64 Inhibitors,research,lifescience,medical The presence of any of the baseline basic symptoms was used as a test to predict the onset of psychosis over a mean follow-up period of 9.6 years. The main results are presented in Table IV: the risk of developing schizophrenia, given the presence of a basic symptom described by Huber et al,64 was 77/110 (70%). Therefore, these data apparently predicted the onset of schizophrenia nearly over a 9-year period with 70% accuracy! The question, however, is whether this high predictive accuracy can be completely GSK1349572 mw attributed to these basic symptoms, or whether instead other factors are more important. In reality, only a minor proportion of the predictive value can be attributed to the basic symptoms, because most can be ascribed to the very high baseline rate of schizophrenia in this sample. As can be seen in Table IV, the final rate of schizophrenia in this sample was 79/160 (49%). The conclusion from this is that by chance alone, any subject in this study had a nearly 50% probability of developing schizophrenia anyway.