Lexical Cohesion and Formal Thought Disorder During and After Psychotic Episodes

Speech samples obtained from schizophrenics, manics, schizoaffectives, and normal subjects were compared for the amount of lexical cohesion both within and between clauses. Two speech samples were obtained for each patient: one shortly after admission to a psychiatric hospital and another several weeks following discharge. All of the psychiatric patients showed evidence of formal thought disorder at admission, and all three groups showed a significant decline in the extent of thought disorder at follow-up. There were no differences between groups with regard to between-clause lexical cohesion at either point in time. Within-clause lexical cohesion did distinguish among the psychiatric groups at the first assessment interval; schizophrenics showed less within-clause lexical cohesion than the manics or schizoaffective patients. The manics and the schizoaffectives showed a significant decline in the amount of within-clause lexical cohesion from initial assessment to follow-up. The schizophrenics exhibited a modest decline in the amount of between-clause lexical cohesion.