REACTION-TIME ANALYSIS IN SCHIZOPHRENICS WITH NEGATIVE SYMPTOMS USINGAN ELECTROPHYSIOLOGICAL APPROACH

20 postacute schizophrenic patients with predominantly negative sympto ms and 21 age and sex matched normal controls were investigated in a P 300 paradigm with simultaneous measurement of EP, EMC and behavioural reaction time. The steps of central information processing were operat ionalised by the following measures: input processing time (IPT): N1-l atency; central processing time (CPT): N1-latency until EMC-onset; mot or execution time (MET): EMC-onset until onset of target behaviour. Fo r the schizophrenic group we found a pattern of significant deviations with reduction of the N1-, N2- and P3-amplitude, prolongation of the central processing, motor execution and behavioural termination time. The largest loss of time however was found for the central information processing time (203.1 +/- 72.9 vs. 113.1 vs. 20.2 ms, p = 0.000). In the control group the EMC reaction started 12.4 ms before the N2 peak , in the schizophrenic group 63.5 ms after the N2 peak (p = 0.02). Sum ming up, these findings are compatible with the assumption of a multip le functional deficit of central information processing in schizophren ia.