SEMANTIC INHIBITION DISORDERS IN SCHIZOPHRENIC-PATIENTS ASSESSED BY ALEXICAL DECISION TASK

Lexical decision tasks were used in 17 schizophrenic subjects and 11 c ontrol subjects, to evaluate the so-called automatic priming of semant ic links, and the controlled processes which involve longer lexical an ticipation strategies. In this type of trial, inhibition in the recogn ition of the target word, when the preceding priming word is not seman tically linked to it, indicates the activation of such controlled proc esses. Postulating that patients in the schizophrenic group were heter ogeneous in terms of cognition, we compared the resultant scores in tw o subtypes of schizophrenic patients: paranoid and hebephrenic (CIM-9 criteria). The study demonstrated that there was a difference in perfo rmance between the schizophrenic subtypes. Although these findings nee d to be confirmed, they demonstrate the necessity of determining indiv idual profiles of patients entering the trial, to take into account th ose of their phenomenological differences that may correspond to diffe rences in cognitive functioning. The results indicate an absence of in hibition, but only in the paranoid group. In these subjects, results w ere consistent with the hypothesis of a failure to set up controlled p rocesses rather than a stronger ''automatic'' activation of the semant ic links. However, as the results were not significant, the hypothesis remains open to further investigation. The reasons for the nonsignifi cance of the results and alternative hypotheses are discussed.