Is it possible to diagnose schizophrenia at the start of the initial prodromal phase prior to the first psychotic manifestation?

In the international research on schizophrenia, the early detection and int ervention already in the initial prodromal phase prior to the first psychot ic manifestation has become one of the main aims in recent years, Therefore , in the present study, the diagnostic efficiency of initial prodromal symp toms was examined prospectively for the first time ever. At index-examinati on, patients were examined with the 'Bonn Scale for the Assessment of Basic Symptoms - BSABS' and the ninth version of the 'Present State Examination - PSE 9'. At that time, none of the 160 patients had shown psychotic sympto ms, but in 110 of the cases prodromal symptoms were found. At the reexamina tion that took place in average 9.6 years later, patients were explored wit h regard to a meantime transition to a first psychotic episode applying the same instruments as at index-examination. 79 of the 160 patients (49.38%) had developed a schizophrenic disorder according to DSM-IV-criteria in the catamnestic interval. In general, the 66 assessed prodromal symptoms exhibi ted a high sensitivity (.98), a high negative predictive power (.96) and a low percentage of false-negative predictions (1.3%), but lower values of sp ecificity (.59) and positive predictive power (.70) as well as a higher per centage of false-positive predictions (20.6%). However, for a subset of mai nly cognitive prodromal symptoms with a sensitivity sufficient for diagnost ic criteria, high specificities (.85 -.91) and positive predictive powers ( .71 -.91) as well as satisfactory percentages of False-positive predictions (7.5% -1.9%), and good classification rates (81.25 %) were found. The results show that the applied conceptualisation of prodromal symptoms t hat originates in the German psychopathological tradition is indeed useful for an early detection of psychoses. By assessing those prodromal symptoms, which were proven to be highly predictive, a diagnosis of schizophrenic di sorders already seems possible in the initial prodrome. Thus in future, an early intervention related to them might enable a prevention of first psych otic episodes.