Long-Term Course of Schizophrenic Illness: Bleuler’s Study Reconsidered

In this study we examined the course of illness in the patients in the schizophrenia study by Manfred Bleuler after we had rediagnosed the patients’ disorders by using both modern diagnostic criteria and those of Eugen Bleuler (the latter operationalized by us). Both the symptoms and the illness course—85% of all patients were followed up for more than 20 years—were well documented. Two investigators scrutinized the written material for each patient independently from each other, and they reached fair to good diagnostic agreement, with kappa coefficients between 0.41 and 0.63. Kappas over 0.60 were obtained for DSM-IV, DSM-III-R, ICD-10, and the RDC, confirming greater reliability of the modern diagnostic systems. Nevertheless, the highest kappa did not exceed 0.63; this was due to the format of our study, which was based on the retrospective evaluation of old clinical records (many of which were initiated in 1910–1920) and other written material and not on the live interviews. Besides, the descriptions were based on partially different psychopathological concepts. All this, however, had no bearing on the determination of course and outcome. In case of diagnostic disagreement, a best-estimate diagnosis was reached and agreed on by both investigators after a thorough discussion.

Depending on the diagnostic system, the diagnosis of schizophrenia was confirmed in 69% to 92% of all patients; the best result (92%) was reached by applying Eugen Bleuler’s criteria used by Manfred Bleuler to define this study sample. Manfred Bleuler was a highly experienced diagnostician, but the concepts of psychiatric disorders and the interpretation of similar symptoms change over time (9). Incidentally, the record information was rich, and it did not favor Bleuler’s criteria, so that we do not think there would be an information bias across the different diagnostic groupings. There was high diagnostic agreement, with kappas between 0.90 and 0.99 for agreement between the four main diagnostic systems (Table 2); these are in correspondence with levels of agreement in similar reports (10). In contrast, Bleuler’s and Schneider’s criteria had poor agreement with all other systems and with each other, reflecting the profound difference in the diagnostic approaches of those two systems. The lack of diagnostic agreement between ICD-10 and Schneider’s criteria is somewhat surprising, as some important ICD-10 schizophrenia items include these criteria.

Altogether, the diagnosis was not confirmed in approximately 30% of the original sample. Compared with study groups in older American studies (5, 11), this is a remarkably low figure, indicating Manfred Bleuler’s reserved attitude toward diagnosing schizophrenia. The majority of patients for whom the diagnosis of schizophrenia could not be confirmed received a diagnosis of schizoaffective disorder (Table 3)—a diagnosis hardly used by Bleuler, even though he admitted that in the course of typical schizophrenic illness, manic and depressive episodes can occur (12).

A minority of these patients received the diagnosis of affective disorder or brief psychotic reaction. Thus, on the whole, there was a certain shift from the schizophrenic to the affective spectrum, reflecting a contemporary diagnostic trend. For a long time cyclothymia was diagnosed only in cases where no schizophrenic symptoms could be verified, and this procedure resulted in widespread overdiagnosis of schizophrenia and underdiagnosis of affective disorders (13). Since the 1970s, diagnostic practice has taken an opposite course, in that schizophrenia is to be diagnosed only when an affective disorder can be excluded without doubt (14). In our study on clinical diagnoses, carried out in another Swiss psychiatric hospital, the same tendency to overdiagnose schizophrenia, to the disadvantage of affective disorders, and to value schizophrenic symptoms over affective symptoms was found (15). The greater appreciation of the importance of affective symptoms and the subsequent shift in diagnostic practice seem to be well justified by the evidence that has emerged from phenomenologic, prognostic, genetic, and possibly treatment-response studies (13). Along with other findings (16), the results of this study demonstrate a less malignant course and a better long-term outcome in schizoaffective than in schizophrenic disorder. Thus, they support the prognostic validity of the distinction of these two disorders. Another finding of the study is in agreement with this conclusion: the group of patients whose schizophrenia diagnosis was not confirmed contained a higher proportion of married or previously married patients, perhaps indicating a better capacity for intimate relationships. It is interesting that all three main contemporary diagnostic systems used in this study (DSM-IV, DSM-III-R, ICD-10) yielded practically identical results, with the exception of the smaller number of brief psychotic disorders diagnosed with ICD-10, reflecting the different requirements for duration of schizophrenic illness.

The course and the outcome of illness could be reviewed for 202 of the 205 patients in the original sample (Table 4). The majority of Bleuler’s original patients, 58%, presented an undulating illness course; 22% of the patients had a severe end state, and 22% recovered. Similar results have been reported elsewhere: continuous hospitalization for 19% and recovery for 19% were found in one study (17), and recovery and a functionally adequate outcome were reported for one-third of the patients in another study (18). The results indicate that in patients diagnosed with schizophrenia according to the criteria of DSM-IV, DSM-III-R, ICD-10, and RDC there is a slight shift in the distribution of the types of illness course; the proportion of patients with a simple (unremitting) course and chronic onset increased, whereas the proportion of patients with an undulating (episodic) course and recovery decreased. However, the distribution of patients among the eight types of illness course did not significantly differ between Bleuler’s original sample and the patients rediagnosed with the other diagnostic systems (Table 4).

On the other hand, in all groups whose schizophrenia diagnosis was confirmed by modern diagnostic systems (but not with Bleuler’s and Schneider’s criteria) the number of patients with an undulating course and the number who recovered were disproportionally lower and the numbers who had a simple course with chronic onset and who had a severe end state were disproportionally higher than in Bleuler’s original sample (Table 5). In contrast, undulating course was identified in over 80% of all patients for whom the diagnosis of schizophrenia was not confirmed, and only patients with an undulating course recovered. Also, few of these patients showed a simple course with chronic onset (about 10%); they fell ill earlier, and fewer were single. Incidentally, a lower proportion of single people was also found in the original sample in patients who had a simple course and chronic onset of disease; in this context, it is important that the age at illness onset for these patients was significantly higher. The latter is an unexpected finding that, however, should not be overvalued; age at illness onset was not associated with worse end state in spite of the high association between course and outcome. The appearance of Bleuler’s symptoms seems to characterize an earlier schizophrenia onset, and Schneider’s symptoms seem related to later onset.

In summary, it is fair to say that the modern diagnostic criteria for schizophrenia identify a more homogenous group of patients. Stricter operationalized diagnostic criteria for schizophrenic illness tend to identify a population of patients with a greater tendency toward chronicity and less frequent recovery. Nevertheless, as our data and those of Harding et al. (5) demonstrate, the more stringent criteria fail to produce a uniformly poor outcome: half of our patients with a confirmed schizophrenia diagnosis had an undulating illness course, and 12%–15% recovered (see Table 4). It is important to point out that the assessment of the final outcome required that the same condition be maintained over 5 years, a criterion also applied to other severe illnesses, such as cancer. A severe end state was reached by 27% to 28% of these patients. However, we must not forget that the study terminated in 1965, before the large-scale deinstitutionalization took place and before other modern therapeutic methods were introduced. Differences in therapeutic policies and programs contribute to differences in clinical outcome (19), which improved significantly in the course of the last century (20). Beyond that, for many patients the therapeutic response to neuroleptics would have been compromised by their long previous duration of illness.

In conclusion, we confirmed that in diagnosing the patients in his original sample, Manfred Bleuler relied heavily on the basic schizophrenic symptoms delineated by Eugen Bleuler. Compared with the main modern diagnostic systems (DSM-IV, DSM-III-R, ICD-10, RDC), Bleuler advocated a broader schizophrenia concept; for about 30% of his patients the diagnosis of schizophrenia could not be confirmed. Between the main diagnostic systems applied there was a high degree of diagnostic agreement; in contrast, Schneider’s and Bleuler’s criteria identified different patient groups.

In the majority of patients for whom a diagnosis of schizophrenia could not be confirmed, the diagnosis of schizoaffective disorder or brief psychotic reaction was given. The majority of these patients showed undulating illness course with recovery—a finding confirming the validity of the distinction of these disorders from schizophrenia.

A total of 58% of the patients of Bleuler’s original sample showed an undulating illness course; 22% developed severe end states, and 22% recovered. In the smaller group of all patients with a confirmed diagnosis of schizophrenia (atypical courses included), an undulating illness course was observed in about 48%–49% and the proportion of patients with severe end state increased to 27%–28%. Recovery occurred in 12%–15% of all patients; thus, even a patient diagnosed with schizophrenic illness according to DSM-IV or ICD-10 has a chance to recover.

On the whole, the prognosis of the patients with a diagnosis of schizophrenia according to modern criteria appears worse; nevertheless, half of them still show an undulating illness course, and some 25%–30% of the latter recover.

The high proportion, 27%–28%, of patients with severe end state in the group with confirmed schizophrenia must be seen against the background of the therapeutic possibilities available in the 1940s to 1960s.

Received Oct. 9, 2002; revision received April 8, 2003; accepted June 20, 2003. From the Psychiatric Hospital, University of Zurich. Address reprint requests to Dr. Modestin, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, CH-8029 Zurich, Switzerland; [email protected] (e-mail). The authors thank Prof. D. Umbricht for his comments.