Instruments
The following instruments were used: Positive and
Negative Symptom Scale (PANSS; 32). The PANSS
consists of a 30-item,semistructured interview with
the patient on psychiatric symptoms existing the
week prior to the interview,which are rated by the
investigator on a 7-point scale. We used the five
dimensions,derived from a large factor analytic
study (33): positive and negative symptoms,disorganization,
depression and excitement.