Janusz Rybakowski: 120 years of the Kraepelinian dichotomy of "endogenous psychoses" in historical perspective

Janusz Rybakowski’s reply to Barry Blackwell’s comment


        Thanks to Barry Blackwell for his thoughtful comments on the relation of my essay on the 120th anniversary of the Kraepelinian dichotomy to the present DSM classification. As I pointed out, the conceptualization of "dementia praecox" and "manisch-depressives Irresein" practically paved the way to psychiatric diagnosis and treatment in the 20th century and some elements have remained still valid.

        The features of Kraepelinian dichotomy have been present in the newest versions of the American DSM classification, including DSM-5. In the latter, the subjects of the Kraepelinian classification are included in three classes of disorders named "Schizophrenia Spectrum and Other Psychotic Disorders," "Bipolar and Related Disorders" and "Depressive Disorders," actually making a kind of "trichotomy." From the point of view of the Kraepelinian concept it would be interesting to explore the intermediate areas between these three classes, i.e., between schizophrenia and bipolar disorder and between bipolar disorder and major depressive disorder. More than 30 years ago Timothy Crow (1986) even proposed a continuum between schizophrenia, schizoaffective disorder, bipolar disorder and unipolar depression.

        The seminal article of Kasanin (1933) on schizoaffective disorder was published more than 80 years ago, however, the studies on schizoaffective disorders appearing also in the 21st century have not brought about any definite conclusions as to its nosological classification.  In the DSM-5 this entity is included in the schizophrenia spectrum. However, a  diagnostic and therapeutic question may be asked whether schizoaffective disorder could be more properly included in bipolar and related disorder, on account of its periodic course and the long-term use of the first and second generation mood-stabilizers (Rybakowski 2018) in its treatment.

        Kraepelin lumped together bipolar and unipolar mood disorders under the umbrella of "manisch-depressives Irresein." However, owing to a clinical astuteness of other German psychiatrists such as Karl Kleist and Karl Leonhard, the differentiation between these disorders has been made. The most important for this distinction were the works of Jules Angst and Carlo Perris, both published in 1966, in which each of them, independently of each other, reported on a different occurrence of mental disorders in the families of patients with unipolar and bipolar affective disorder (Angst 1966; Perris 1966). Since then, the specifier for bipolar disorder has been the occurrence of (hypo)mania, reflected in DSM-5 where bipolar disorder (with mania) and major depressive disorder (without mania) constitute separate classes.

        There are, however, several premises showing a relationship between bipolar disorders and depressive disorders. Not infrequently, a diagnostic conversion from depression into bipolar disorder in the course of the illness is needed. Angst, Sellaro, Stassen and Gamma (2005) noticed that such a phenomenon pertains to 1.5% of depressive patients per year. Similar figures were obtained in a Polish study (Dudek, Siwek, Zielińska et al. 2013) (1.7%), and in the meta-analysis of Baldessarini, Faedda, Offidani et al. (2013) (1.79%). Furthermore, using the tools for measuring bipolarity, such as the Hypomania Checklist-32 and the Mood Disorder Questionnaire, demonstrated bipolarity features in a proportion of patients with major depression (Rybakowski, Dudek, Pawłowski et al. 2011). Such patients are characterized, among others, by the worse response to antidepressant drugs (Rybakowski 2012).   Coming back to Kraepelin's concept, it should be mentioned that in recent years, a neo-Kraepelinian approach to mood disorders has emerged. According to it, the most cyclic and recurrent forms of unipolar depression should be included in a bipolar spectrum (Saggese, Lieberman and Goodwin 2006). This was also reflected in the second edition of the Goodwin-Jamison book titled Manic-depressive illness. Bipolar disorders and recurrent depression (Goodwin and Jamison 2007). Therefore, it would be conceivable that in "Bipolar and Related Disorders," a category of "bipolar spectrum" could be established where a proportion of patients with major depressive disorder can be included.


Angst J. Zur Ätiologie und Nosologie endogener depressiver Psychosen. Springer, Berlin, 1966.

Angst J, Sellaro R, Stassen HH, Gamma A. Diagnostic conversion from depression to bipolar disorders: results of a long-term prospective study of hospital admissions. J Affect Disord 2005; 84:149-57.

Baldessarini RJ, Faedda GL, Offidani E, Vázquez GH, Marangoni C, Serra G, Tondo L. Antidepressant-associated mood-switching and transition from unipolar major depression to bipolar disorder: a review. J Affect Disord 2013; 148:129-35.

Crow TJ. The continuum of psychosis and its implication for the structure of the gene. Br J Psychiatry 1986; 149:419-29.

Dudek D, Siwek M, Zielińska D, Jaeschke R, Rybakowski J. Diagnostic conversions from major depressive disorder into bipolar disorder in an outpatient setting: results of a retrospective chart review. J Affect Disord 2013; 144:112-15.

Goodwin FK, Jamison KR. Manic-Depressive Illness. Bipolar Disorders and Recurrent Depression. Second Edition. Oxford University Press. Oxford, New York, 2007.

Kasanin J. The acute schizoaffective psychoses. Am J Psychiatry 1933; 90:97-126.

Perris C. A study of bipolar (manic-depressive) and unipolar recurrent depressive psychoses: I: Genetic investigation. Acta Psychiatr Scand 1966; 42 (Suppl.194):15-44.

Rybakowski JK, Dudek D, Pawłowski T, Lojko D, Siwek M, Kiejna A. Use of the Hypomania Checklist-32 and the Mood Disorder Questionnaire for detecting bipolarity in 1051 patients with major depressive disorder. Eur Psychiatry 2011; 27:577-81.

Rybakowski JK. Bipolarity and inadequate response to antidepressant drugs. Clinical and psychopharmacological perspective. J Affect Disord 2012; 136:e13-e19.

Rybakowski JK. Meaningful aspects of the term 'mood stabilizer'. Bipolar Disord 2018; 20:391-2.

Saggese JM, Lieberman D, Goodwin FK. The role of recurrence and cyclicity in differentiating mood disorder diagnoses. Primary Psychiatry 2006; 13:43-8.


April 16, 2020