A twin study of communication disturbances in schizophrenia

Relatives of schizophrenia patients have demonstrated several different typ es of subtle communication disturbances. This study used twin methodology t o address the question of whether certain of these disturbances might be re flective of genetic vulnerability. Verbatim interviews from a sample of mon ozygotic and dizygotic twins in which at least one member of each twin pair had a diagnosis of schizophrenia were rated for three different types of r eferential communication disturbances. Monozygotic versus dizygotic nonschi zophrenic co-twins were compared on each type of disturbance. Associations between the language variables and object sorting test performance also wer e examined. Differences among subjects in levels of global psychopathology were controlled. Schizophrenic participants showed higher levels of communi cation disturbance than nonschizophrenic co-twins. One type of communicatio n failure, the "missing information" reference, discriminated monozygotic f rom dizygotic nonschizophrenic co-twins. This type of failure was associate d with specific types of errors on the object sorting test. These findings suggest that missing information references may be an expression of schizop hrenia-related genetic vulnerability.