Homogeneity and heterogeneity in schizophrenia.

Summary.-This scudy provides a description of replicated findings of Limited heterogeneity in DSM-111 schizophrenics. Based now on a sample of 145 schizophrenics in 1984 and 182 in 1991 it is suggested that the diagnosis is primarily given to chronic patients with poor prognoses, in turn restricting the utility of a process-reactive conceptualization of schizophrenia. Schultz and Herron (1979) compared abilities of 12 process-reactive measures to predict symptom improvement in schizophrenics at 3- and 6-17-10, intervals. Six were successful predictors; however, in a follow-up study by Cheselka, Herron, Poland, and Schultz (1984) which retained the most promising measures from the previous study and added newly developed measures, gave disappointing results. While four measures showed some significant predictive ability, there was no consistency. The differing results appeared to be due to the Schultz and Herron (1979) study having a DSM-I1 sample while the Cheselka, et al. (1984) sample contained DSM-I11 patients (American Psychiatric Association, 1980). In the former there was sufficient heterogeneity to ensure a range of predictive scale and improvement scores, but the DSM-111 sample was overwhelmingly process, thereby limiting the possibility of improvement and prediction of change. These mixed results suggested the need for a study of the entire schizophrenic spectrum to increase the heterogeneity of patients and the possible utility of the process-reactive dimension. Diamond (1991) attempted this with nine process-reactive measures and a sample utilizing schizotypal personality disorders, schizoaffective and schizophreniform disorders, brief reactive psychosis, and schizophrenia. The criterion of improvement was symptom change at two follow-ups, 9 months or discharge if that occurred before 9 months or 18 months. Only one measure, the Maine Paranoid Scale (Magaro, Abrams, & Cantrell, 1981) successfully predicted outcome, but only at the second 18-mo. follow-up. As in the Cheselka, et al. (1984) study, the sample again appears to be the issue. First, it was difficult to obtain a spectrum, because of the total sample of 182, 138 were diagnosed as schizophrenia, with 1 brief reactive, 3 schizophreniform and 3 schizotypal, and 37 schizoaffective disorders. This pattern prevailed in both follow-ups, with 85 of 110 in the first and 54 of 72 in the second, diagnosed as schiozophrenia. These results raise a question as to the range of schizophrenic types that can be found within what was predominantly a chronic state hospital population. The next problem was that the majority of patients scored in the process or in-between group on most of the scales. For example, on the Phillips scale (Harris, 1975) only 31 subjects were classified as reactive, with 66 as process and 85 were in-between reactive and process. Five of the other scales had at least 123 process patients at baseline, with follow-ups also having a majority of process patients. Exceptions to the uneven distribution of process and reactive patients were marital status and chronicity, both having even splits, though the criteria used appeared to inflate the number of reactives, and by follow-ups the samples became primarily process. Heterogeneity was restricted; so, in turn, was the predictive ability of process-reactive measures, with less than 1% improvement found at each follow-up.