Schizophrenic delusions: the detection of warning signals.

Schizophrenic delusions are important target symptoms for treatment. This study aims to identify predictors of delusion formation. Two samples of schizophrenic patients (total n = 131) are examined prospectively every second week during a period of 6 months. In one sample (n = 60) delusion formation (n = 27; 45%) is correlated significantly with a change in score of eight individual items from the Early Signs Scale (ESS): sleep, anxiety, concentration, irritability, coping, tiredness, depression and confusion. These eight items form the Warning Signals Scale (WSS). The predictive validity of the scale is tested in another sample (n = 71), of which 43 patients (61%) have reemergence of delusions. A criterion cut-off score of > or = 5 points combines an acceptable sensitivity (77%) and specificity (68%). The scale is acceptable to patients, manageable for clinicians, and it has a high degree of predictive validity and reliability. This makes it relevant for implementation in ordinary clinical practice.