Elsevier

Psychiatry Research

Volume 143, Issues 2–3, 30 August 2006, Pages 255-287
Psychiatry Research

Invited review
Schizoaffective disorders are psychotic mood disorders; there are no schizoaffective disorders

https://doi.org/10.1016/j.psychres.2005.08.012Get rights and content

Abstract

Schizoaffective disorder (SA D/O), introduced in 1933 by Dr. Jacob Kasanin, represented a first, modest change in our concept about the diagnoses of psychotic patients away from the beliefs of E. Bleuler, i.e., that hallucinations and delusions define schizophrenia, and toward the recognition of a significant role for mood disorders. SA D/O established a connection between schizophrenia and mood disorders, traditionally considered mutually exclusive, a connection that has strengthened progressively toward the diagnostic unity of all three disorders. A basic tenet of medicine holds that if discrepant symptoms can be explained by one disease instead of two or more, it is likely there is only one disease. The scientific justification for SA D/O and schizophrenia as disorders distinct from a psychotic mood disorder has been questioned. The “schizo” prefix in SA D/O rests upon the presumption that the diagnostic symptoms for schizophrenia are disease specific. They are not, since patients with severe mood disorders can evince any or all of the “schizophrenic” symptoms. “Schizophrenic” symptoms mean “psychotic” and not any specific disease. These data and a very low interrater reliability for SA D/O suggest that the concepts of SA D/O and schizophrenia as valid diagnoses are flawed. Clinically SA D/O remains popular because it encompasses both schizophrenia and psychotic mood disorder when there is a diagnostic question. We present a review of the literature in table form based on an assignment of each article assigned to one of five categories that describe the possible relationships between SA D/O, schizophrenia and psychotic mood disorders. We conclude that the data overall are compatible with the hypothesis that a single disease, a mood disorder, with a broad spectrum of severity, rather than three different disorders, accounts for the functional psychoses.

Introduction

To understand how schizoaffective disorder (SA D/O) became established as a major psychiatric disease and the role it played in the conceptual shift in the diagnoses of psychotic patients away from schizophrenia and toward psychotic mood disorders, an overview of the development of schizophrenia and mood disorders is helpful. In the late 19th century Kraepelin described two separate psychiatric disorders based on his belief that the degree of symptom severity and chronicity differentiated the two: dementia praecox, soon renamed schizophrenia by Bleuler (1911/1950), and manic-depressive insanity, now called bipolar disorder (Kraepelin, 1913, Kraepelin, 1920). Bleuler (1911/1950) contended that his disease, schizophrenia, was the most common mental illness after mental retardation and alcoholism. Bleuler and later Schneider (1959) defined schizophrenia by the presence of the psychotic symptoms of hallucinations, delusions, disorganization and catatonia, although Bleuler's concept was considerably broader. These authors minimized or discounted the diagnostic importance of mood symptoms when psychotic features were present. In contrast to schizophrenia, the course of mood disorders was thought to be acute and brief with a limited degree of severity. The dichotomy of schizophrenia and mood disorders has been a cornerstone of Psychiatry, reinforced by the academic emphasis that the former is a “disorder of thought” while the latter is a “disorder of emotions.” Despite the lack of an objective, reproducible pathophysiology, schizophrenia and bipolar disorder became established as “bona fide” diseases along with syphilis, which unified a wide array of symptoms and diseases, and other infectious diseases whose pathophysiologies were elucidated during the latter half of the 19th century.

In 1933 Dr. Jacob Kasanin first used the term “acute schizoaffective psychoses” in the title of his article in the American Journal of Psychiatry (Kasanin, 1933). Dr. Kasanin was the Clinical Director of the state hospital in Rhode Island and was supported by a research grant from the Rockefeller Foundation to study schizophrenia. In his article he summarized the cases of nine hospitalized patients initially diagnosed with dementia praecox or schizophrenia. He concluded that they differed enough from “classical” schizophrenia, as described by Kraepelin (1913) and Bleuler (1911/1950), that a compromising diagnostic name was needed. The Kasanin patients suffered from hallucinations and/or delusions but were different because they suffered an acute onset of symptoms, had distinct and prominent manic and/or depressive symptomatology, had active social and premorbid personalities, and had only brief periods of psychosis lasting weeks to a few months and recovered to lead successful lives. SA D/O was considered an intermediary diagnosis with patients generally having outcomes better than patients diagnosed with schizophrenia but worse than those with mood disorders. The naming of SA D/O was the first shift in the concept about the diagnoses of psychotic patients away from Bleuler's view that 100% of psychotic patients are schizophrenic and toward the recognition of psychotic mood disorders. SA D/O formed a link between schizophrenia and mood disorders leaving a gap that has progressively closed. The “schizo” prefix of SA D/O was maintained in keeping with the concept that hallucinations and/or delusions were disease-specific for schizophrenia. At that time prominent mood symptoms only warranted an intermediary diagnosis and not a more radical shift to the diagnosis of psychotic affective disorder. Outside of Dr. Kasanin's realm of influence, however, such patients were usually diagnosed schizophrenic because they suffered from hallucinations and/or delusions. Bleuler's and Schneider's (1959) concepts dominated the field, especially in the U.S., and some of Schneider's “first rank symptoms” continue to be critical among the diagnostic criteria for schizophrenia (DSM-IV-TR, 2000) (Table 1,b).

SA D/O became firmly established as a recognized disorder with the publication in 1952 of the first Diagnostic and Statistical Manual for Mental Disorders (DSM), the official and widely respected guide to the nomenclature and definitions of psychiatric diseases. The DSM-I (1952) and the DSM-II (1968) defined “schizoaffective schizophrenia” as the “category for patients showing a mixture of schizophrenic symptoms and pronounced1 elation or depression.” Two subtypes were described: excited and depressed. Despite the centrality of mood symptoms, SA D/O was defined as a subtype of schizophrenia, not a subtype of the mood disorders. The placement of SA D/O in the DSM and in textbook chapters on schizophrenia reflected the influence of Bleuler and Schneider and inhibited the consideration of SA D/O as a psychotic mood disorder. An additional modest but temporary shift occurred in 1980.

In the DSM-III-R (1980)SA D/O was moved out of the chapter on schizophrenia and into a separate section called “psychotic disorders not elsewhere classified.” This reflected a resurgence in the movement away from the Bleuler/Schneider concept. No diagnostic criteria were given for SA D/O in the DSM-III, but mood-incongruent hallucinations or delusions were emphasized as indicating schizophrenia, not SA D/O. Data now document that mood-incongruent delusions and/or hallucinations are disease non-specific because incongruency occurs often in patients with psychotic mood disorders (Carpenter et al., 1973, Tohen et al., 1992). The placement of SA D/O in the DSM-III represented the greatest shift in any edition of the DSM toward moving SA D/O away from schizophrenia. The DSM-III-R (1987) reversed the DSM-III trend and moved SA D/O back into the chapter on schizophrenia where it remains today in the DSM-IV-TR (2000) (Table 1,b). SA D/O has never been placed in the chapter on mood disorders in any edition of the DSM. Another index of the acceptance and clinical popularity of SA D/O may be reflected by the number of citations in the scientific literature.

Based on a PubMed literature search for articles citing SA D/O, the diagnosis was little used between the mid-1930s and the mid-1960s despite its description in 1933 and inclusion in the DSM from 1952 (Table 2, Fig. 1). This may reflect the prevalence of Bleuler's influence reinforced by that of Schneider in 1959. The next notation to “schizoaffective psychoses” following Kasanin's appears to have occurred in 1943 when Cobb (1943) used this term in his textbook to include both schizophrenia and manic-depressive illness under one diagnosis. Cobb may have been the first to imply that these two diseases were one.

The number of PubMed citations sharply increased in 1965 and 1966, plateaued or decreased slightly in the 1970s and remained stable until 1999 when the number of articles about SA D/O increased substantially again through 2005 (Table 2, Fig. 1). The decrease in the 1970s may reflect the influence of a number of publications that questioned the validity of SA D/O and schizophrenia (Kendell and Gourlay, 1970a, Kendell and Gourlay, 1970b, Fowler et al., 1972, Carlson and Goodwin, 1973, Szasz, 1976, Procci, 1976, Pope and Lipinski, 1978). The popularity of the diagnosis was also demonstrated clinically in the 1980s and 1990s when a substantial percentage of functionally psychotic inpatients on some units received a diagnosis of SA D/O. By this time, in many clinical environments, patients with hallucinations and/or delusions plus disturbances of mood received the diagnosis of SA D/O rather than the more traditional diagnosis of schizophrenia or of a psychotic mood disorder. These changes in the diagnoses of psychotic patients represented further movement away from schizophrenia and toward psychotic mood disorders. Clinically SA D/O has likely been broadly embraced as a “diagnostic compromise” between schizophrenia and mood disorders. The diagnosis of SA D/O often has been used when the physician is unsure if the psychotic patient with a disturbance of mood suffers from schizophrenia or a psychotic mood disorder. Doubt about the correct diagnosis commonly occurs when a psychotic patient presents with mood symptoms but has a past history of inpatient admissions with the diagnosis of schizophrenia. SA D/O appears to solve this diagnostic dilemma but may not serve such patients well with respect to their pharmacological management and other aspects of their lives.

There are two additional sets of diagnostic criteria that define SA D/O, and they differ from the criteria of the DSM. The Research Diagnostic Criteria (RDC) (Feighner et al., 1972, Spitzer et al., 1978) and the International Classification of Diseases, 10th edition (ICD, 1992) criteria for SA D/O are broader and capture a more heterogeneous population than that identified by the DSM. For example, the RDC, which are frequently used in research, require only one “schizophrenic” symptom for a diagnosis of SA D/O rather than the two necessary using the DSM. Thus patients diagnosed using DSM criteria are more severely affected. The concordance between the RDC and the ICD criteria is higher (kappa is 0.69) than that between the DSM and either the RDC or the ICD (Berner and Lenz, 1986). The RDC are less clear regarding the relationship of SA D/O to schizophrenia and to mood disorders, while the ICD-10 (1992) has moved SA D/O from the section on schizophrenia into a separate category, somewhat similar to the DSM-III (1980). Like the DSM, the ICD has never placed SA D/O with mood disorders. Despite the differences across these three sets of diagnostic criteria, the basic, core criteria for SA D/O are similar in that all three are based on the assumption that the diagnostic criteria for schizophrenia are disease specific (Table 1). Since the DSM criteria are more stringent than either the RDC or ICD criteria, if the DSM criteria are flawed, the ICD and the RDC are expected to be similarly flawed (as discussed below).

After 72 years, SA D/O remains firmly established in the psychiatric nomenclature as demonstrated by the continued diagnosis and treatment of patients and lectures and publications about SA D/O (Table 2, Table 3, Fig. 1). The literature on SA D/O is extensive. Since 2000 there have been at least 4338 articles published that refer to SA D/O and the trend is upwards (Table 2, Fig. 1). Much of the literature has focused on the relationship of SA D/O to schizophrenia and psychotic mood disorders.

Section snippets

Possible relationships between SA D/O, schizophrenia and mood disorders

It is evident from discussion in the literature concerning the potential links between SA D/O, schizophrenia and mood disorders that several possibilities exist:

First, as taught by Bleuler (1911/1950) and reinforced by Schneider (1959) and others, it is possible that SA D/O is really schizophrenia and SA D/O is an unnecessary redundancy since hallucinations and delusions are present. Bleuler and Schneider essentially stated that there is no non-schizophrenic, functional psychosis.

A second

A review of the literature on the phenomenology of SA/DO; the assignment of studies to one or more of five categories (Table 3)

A PubMed search for SA D/O articles revealed over 23,800 references that mention SA D/O from 1949 to the present. Over 480 had SA D/O in the title and 256 of these examined the relationships between SA D/O, schizophrenia and mood disorders by contrasting the symptoms, the course of the disorders, outcomes, responses to treatment, degree of insight into illness, the risks of concordance among first-degree family members, genetics, epidemiology, neuroimagery, auditory evoked potentials, brain

Support for the hypothesis that a single disease accounts for functionally psychotic patients, not three

A basic tenet of medicine holds that if a wide spectrum of symptoms can be explained by one disease instead of two or more, it is likely that the variety of symptoms represents only one disease. An early example of such diagnostic unification was the recognition that multiple, widely different symptoms and diagnoses were caused by a single organism, a treponema. The acceptance of SA D/O not only added a third psychotic diagnosis to the already established disorders of bipolar and schizophrenia,

The U.S. and U.K. concepts of the causes of psychoses

In contrast to academic and clinical Psychiatry in the U.S., in the U.K. there has been an emphasis upon the recognition of mood symptoms in psychotic patients for some time (Cooper et al., 1972). In the British literature, Kendell and Gourlay, 1970a, Kendell and Gourlay, 1970b, in referring to psychotic patients with mixed symptomatology opined that “most American psychiatrists—gloss over affective symptoms and regard the illness as a form of schizophrenia differing in no significant respect

Influences that may have moved the diagnosis of psychotic patients toward mood disorder diagnoses in the 1970s in the U.S.

Three developments in the 1970s may have influenced American Psychiatry to move further away from the concepts of Bleuler and Schneider and toward diagnosing psychotic patients with mood disorders: 1) data from genetics, epidemiology and psychopharmacology strengthened support for a scientific basis for bipolar disorder as a distinct disease (Goodwin and Jamison, 1990) (see below); 2) the efficacy of lithium, especially for bipolar disorder, was demonstrated and publicized (Baldessarini, 1970);

Clinical studies compatible with a single disease to account for the three psychoses

Schizophrenia and SA D/O were described and codified when their characteristics and criteria were thought to be specific. The limitations of symptom severity and chronicity, initially considered narrow for mood disorders, have been eliminated. Mood disorders can evince the severity of symptoms, the chronicity and the epidemiological characteristics formally held as unique to schizophrenia. Several studies find a unimodel distribution of symptoms among schizophrenia and bipolar disorders,

Selected family and genetic studies compatible with a single disease to account for the three psychoses

Most studies, but not all (Taylor, 1992), reject the idea that these three disorders each “breed true.” Twins and triplets have mixtures of psychotic disorders. Some family studies report that first-degree relatives of patients diagnosed as schizophrenic have an increased incidence of mood disorders and also the reverse. The preponderance of heritability studies reviewed by Taylor (1992) and Kendler et al. (1995) show a higher rate of mood disorders among first-degree relatives of schizophrenic

Selected medication-response studies compatible with a single disease to account for the three psychoses

The dichotomy in responsivity to lithium between schizophrenia and bipolar disorder might initially seem to indicate two separate diseases. However, as introduced above, when symptom severity is viewed along two axes: one for psychotic symptoms and the other for mood symptoms, this dichotomy may resolve. These two severity axes may appear inversely related because when psychotic symptoms predominate, mood symptoms may be obscured while mood symptoms will be more evident when psychotic symptoms

Recent basic science data from selected studies supporting a single disease to account for the three psychoses

There is a recent, rapidly expanding and provocative literature from diverse basic science laboratories that demonstrates surprising similarities between schizophrenia, SA D/O and psychotic mood disorders, similarities that should not occur even from selected studies, if these are three distinct disorders. One author has recently stated that, “…of the (eleven) chromosome loci attributed to the transmission of schizophrenia and bipolar disorder, eight have been found to overlap…” (Fawcett, 2005

The continuum or “dimensionally similar” theory is compatible with one disease to account for the three psychoses

The very nature, naming and development of SA D/O as a disease concept speaks to a continuum between schizophrenia and mood disorders. Several authors, including Crow, 1986, Crow, 1990a, Crow, 1990b and Taylor (1992) have stated more forcefully than Ketter et al. (2004) their beliefs that the psychotic diseases, traditionally called mood disorders, SA D/O and schizophrenia, represent a spectrum of severity. The continuum is one of severity of psychotic symptoms, not one of diseases. Psychotic

Flawed diagnostic criteria for SA/DO

About two decades ago, “affective” disorders were renamed “mood” disorders (DSM-III-R, 1987). SA D/O could have morphed to “schizomood disorder” but has not. The sixth position noted above contends that the DSM-IV-TR (2000) diagnostic criteria A and B that establish SA D/O as a separate disease are flawed (Table 1,a). DSM criterion A for the diagnosis of SA D/O depends on two parts—Part 1: the presence of a major depressive, a manic or a mixed episode, i.e., a mood disorder, that is concurrent

If one disease, why not SA/DO or schizophrenia?

According to several selected reviews and other reports, symptoms, course, outcome, epidemiology, heritability, responses to treatment and the results of several basic science studies are similar if not indistinguishable between the three psychotic diseases, suggesting only one disease and not three (Table 3). If only one, which one and why? In addition to the flaws in the diagnostic concepts of schizophrenia and SA D/O detailed above, SA D/O appears to have no validity as a disease as judged

Scientific basis for a “bona fide” psychiatric disease

Since there are no pathophysiological tests that are diagnostic for any psychiatric disorder including bipolar disorder, strict criteria are necessary to scientifically support the existence of such diseases (Feighner et al., 1972, Winokur, 1973, Welner et al., 1979, Procci, 1976). These include: 1) symptoms that are clearly unique; 2) consistent epidemiology; 3) consistent response to medications (some that relieve and others that exacerbate symptoms); 4) consistent course and outcome; 5)

Psychotic patients with no obvious mood symptoms

There will certainly be a finite number of psychotic patients with no obvious mood symptoms or obvious signs of an organic etiology at any time. We suggest these patients be diagnosed temporarily with “psychotic disorder not otherwise specified” (DSM #298.9) while subtle mood symptoms and organic causes are explored further. Overemphasis on the psychosis and underemphasis on mood symptoms during the initial diagnostic interview may explain some of these cases (Kendell and Gourlay, 1970a,

Liabilities for misdiagnosing a psychotic mood disorder

Does it matter what diagnosis we use, schizophrenia, SA D/O or a psychotic mood disorder? A diagnostic classification of disorders that is non-data based does not serve our profession or our patients well. Good scientific practice dictates the establishment of specific and objective diagnostic criteria before naming a new disease. This was not the case in Psychiatry with either schizophrenia or SA D/O (or bipolar disorder initially). Since the diagnostic criteria for SA D/O “build” on the

Summary/Conclusions

This review of the functional psychoses is one of many over the past 40 years. Some past reviews have reached more definitive conclusions than have others. We approached our review with a goal of critically assessing a broad literature that addresses the issue of the relationships between SA D/O, schizophrenia and mood disorders. When the data reviewed seemed to warrant a definitive statement, we have stated such in an attempt to avoid ambivalence in our conclusions. We did not focus

Acknowledgments

The authors acknowledge technical assistance of Anita Swisher.

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