Thought disorder or allusive thinking in the relatives of schizophrenics? A response to Callahan, Madsen, Saccuzzo, and Romney.

Romney and Saccuzzo et al. (J Nerv Ment Dis 176:364-367; 368-371, 1988) disagreed concerning the need for further studies investigating the presence of thought disorder and associative cognitive dysfunction in relatives of schizophrenics. Saccuzzo et al. were concerned at the variations in the results of previous studies. Methodological issues relevant to such variation are discussed. It is pointed out that the study (McConaghy J Neurol Neurosurg Psychiatry 22:243-246, 1959) initiating psychometric investigation of cognitive processes of relatives of schizophrenics was based on the belief that what was familially transmitted was not thought disorder, but a nonpathological looseness of associations, shown also by a percentage of normal subjects. This looseness was later termed allusive thinking. It was considered that allusive thinking acted as an inherited predisposition to schizophrenia. It required the addition of impairment of abstract thinking to constitute the characteristic thought disorder originally described by Bleuler. To account for the significant degree of thought disorder found in 6% to 12% of normal subjects, some researchers now accept that thought disorder exists in normal subjects on a continuum with schizophrenic thought disorder. It is suggested that replication of a later study demonstrating familial transmission of allusive thinking in university students and their parents could aid in clarifying the significance of the findings of increased incidence of looseness of associations in the families of schizophrenics.