Psychiatric Annals

CME Article 

Approach to the Diagnosis of Schizoaffective Disorder

David Beckmann, MD, MPH; Kristina Schnitzer, MD; Oliver Freudenreich, MD, FACLP

Abstract

Diagnosing schizoaffective disorder poses unique challenges due to both its history as a “catch-all” diagnosis and recent changes to the diagnostic criteria. The Diagnostic and Statistical Manual of Mental Disorders, fifth edition, helps to clarify the diagnosis, but issues related to validity and reliability remain. The fundamental approach to diagnosis must be done positively (as opposed to being a diagnosis of exclusion), looking at each feature of a patient's presentation and ensuring that criteria for schizoaffective disorder are met, without symptoms being better explained by a phenomenologically similar yet different psychiatric conditions (and assuming that no medical or toxic condition is responsible). This article presents a straightforward approach to generating and critically assessing a differential diagnosis when schizoaffective disorder is suspected. [Psychiatr Ann. 2020;50(5):195–199.]

Abstract

Diagnosing schizoaffective disorder poses unique challenges due to both its history as a “catch-all” diagnosis and recent changes to the diagnostic criteria. The Diagnostic and Statistical Manual of Mental Disorders, fifth edition, helps to clarify the diagnosis, but issues related to validity and reliability remain. The fundamental approach to diagnosis must be done positively (as opposed to being a diagnosis of exclusion), looking at each feature of a patient's presentation and ensuring that criteria for schizoaffective disorder are met, without symptoms being better explained by a phenomenologically similar yet different psychiatric conditions (and assuming that no medical or toxic condition is responsible). This article presents a straightforward approach to generating and critically assessing a differential diagnosis when schizoaffective disorder is suspected. [Psychiatr Ann. 2020;50(5):195–199.]

Diagnosing schizoaffective disorder has long posed challenges in psychiatric practice.1 Although changes to diagnostic criteria in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5)2 have sought to clarify diagnostic criteria, these changes have not fundamentally resolved issues of validity and reliability for this diagnosis.3 At a minimum, the challenges inherent to the diagnosis of schizoaffective disorder necessitate cautious, discriminate, and accurate use of the diagnostic label, which has important implications for management and prognosis.

The American Psychiatric Association's DSM-5 specifies a diagnosis of schizoaffective disorder based on three key criteria, which are summarized in Table 1 (a fourth criterion, as in many primary psychiatric diagnoses, specifies that the condition cannot be attributable to the effects of substances or general medical conditions).2

Diagnostic Criteria of Schizoaffective Disorder

Table 1:

Diagnostic Criteria of Schizoaffective Disorder

The DSM-5 further subdivides schizoaffective disorder into two subtypes: bipolar type (defined by the presence of at least one manic episode) and depressive type.2

One important and often misunderstood feature of schizoaffective disorder defined by DSM-5 is its reliance on a patient's overall longitudinal disease course (ie, mood symptoms must be present for most of the time). In this regard, schizoaffective disorder differs from the International Classification of Diseases, 11th revision (ICD-11),4 in which schizoaffective disorder is a label only applied to a specific episode.5

Clinically, the difference between schizoaffective disorder and other conditions may be subtle, and the differential diagnosis should be carefully considered. This primarily includes schizophrenia-spectrum disorders, mood disorders, and the presence of both simultaneously. Other considerations in the differential diagnosis of schizoaffective disorder include psychotic disorders that are not well-captured in DSM-5, substance-induced or medically induced symptoms, and other psychiatric syndromes that generate psychotic-like symptoms (Table 2).

Differential Diagnosis of Schizoaffective Disorder

Table 2:

Differential Diagnosis of Schizoaffective Disorder

Experts in the field have debated (long before DSM-5) to what extent schizoaffective disorder is a discrete entity versus a clinical manifestation that exists on a spectrum between mood and psychotic disorders.6,7 One reason for the evolution of schizoaffective disorder's diagnostic criteria is the increasing recognition that Kraepelin's8 dualistic distinction between mood disorders (characterized by a better prognosis) and psychotic disorders (characterized by more avolition and difficulties with emotional expression and cognition) in 1920 is not as dichotomous as he believed.3,9

Approach to Diagnosis

Diagnosing schizoaffective disorder is an exercise in rigorously applying the DSM-5 criteria, a seemingly simple but often challenging strategy. Historically, at least some skepticism directed toward schizoaffective disorder has resulted from its being diagnosed in a less systematic way. It has often been a “catch-all” diagnosis when other pieces do not fit (eg, a patient with bipolar disorder whose psychosis during mood episodes is prominent, or a patient with schizophrenia who experiences significant periods of depression). Schizoaffective disorder has also been used to mitigate the implications of other diagnoses. For example, patients who meet criteria for schizophrenia may be given a diagnosis of schizoaffective disorder if their symptoms are less severe, or if there is another reason to suspect a favorable prognosis. The presence of substance use may muddy a diagnostic picture and result in a clinician applying schizoaffective disorder as a way of hedging diagnostic certainty. Finally, as schizoaffective disorder features prominent mood and psychotic symptoms, it became an easy label to apply to a patient who has both types of symptoms, particularly one who is not well known to the clinician and when viewed from a cross-sectional perspective during an episode of acute illness.

These diverse and nonstandardized paths to a schizoaffective disorder diagnosis have undermined its reliability. To avoid this, schizoaffective disorder needs to be diagnosed positively (instead of using it as a diagnosis of exclusion) by using DSM-5 criteria rather than resorting to this diagnosis when there is a lack of diagnostic clarity or in the face of the presence of multiple symptom clusters. If no diagnosis fits properly, DSM-5 diagnoses such as “unspecified psychotic disorder” should be used.

The practice of evidence-based medicine necessitates that a diagnosis be as accurate as possible, as diagnosis drives management and prognosis. As with most of psychiatry, the first step in diagnosis is ruling out secondary (ie, medically and substance-induced) causes of psychopathology. This involves taking a thorough patient history, as well as basic laboratory testing. Assuming “organic” etiologies have been ruled out, rigorously approaching the diagnosis of schizoaffective disorder is essentially the process of systematically applying the DSM-5 criteria (ie, demonstrating that past and present symptoms fit these criteria better than anything else on the differential).

The diagnostic categories with the most overlap with schizoaffective disorder (and, therefore, most likely to cause confusion) are schizophrenia, other schizophrenia-related conditions, and primary mood disorders with psychosis (bipolar disorder with psychosis, major depressive disorder with psychotic features). Indeed, as has been discussed, schizoaffective disorder may actually represent an intermediate illness on a spectrum that encompasses all of these diagnostic categories.3

Schizophrenia

Differentiating schizoaffective disorder from schizophrenia may be the most common diagnostic challenge. Both diagnoses hinge on the same criterion, namely the presence of psychotic symptoms (Table 1). It is tempting to think the distinction is easily made by the presence or absence of mood symptoms, but this is not so clear cut: the presence of some mood symptoms in schizophrenia is common. Perhaps 15% of patients with schizophrenia have symptoms of depression, even if the criteria for a full mood episode are not met.10 For a diagnosis of schizoaffective disorder, these symptoms must rise to that of a full mood episode; furthermore, criteria for a mood episode must be met the majority of the time that a patient is symptomatic.

Schizophrenia-Related Conditions

Whenever schizophrenia is being considered as a diagnosis, other related disorders (such as schizophreniform disorder or brief psychotic disorder, both of which are similar to schizophrenia but resolve after a shorter periods of time) should also be considered. Like schizophrenia, these do not prominently feature mood symptoms; distinguishing schizoaffective disorder from each of these should be similar to the process of distinguishing it from schizophrenia (ie, on the basis of also meeting criteria related to the presence of mood episodes).

Consideration should also be given to psychotic disorders that are not explicitly described in DSM-5. As discussed above, schizoaffective disorder has evolved along with the DSM, partially in an attempt to push back against its “catch-all” status. Other diagnoses not (yet) in the DSM-5 may, in the future, help clarify schizoaffective disorder's place in these organizational schemas. Of note, DSM-5 does allow for syndromes that do not fit neatly into its own criteria, and these entities would be classified as “unspecified psychosis.” In particular, cycloid psychosis and acute and transient psychotic disorders (ATPD) warrant some attention. Although these diagnoses are not in DSM-5, they have been accepted into the World Health Organization's ICD-11.

Cycloid psychosis is characterized by symptoms appearing suddenly (over the course of hours to days) and exhibiting rather diverse clinical psychopathology including perplexity, delusions, hallucinations, anxiety, ecstasy, hyperkinesis, preoccupation with death, and significant mood symptoms.11,12 There are several descriptions of cycloid psychosis presenting with features that are similar to mania,12 and the two could easily be confused. However, cycloid psychosis is characterized by a much more rapid change in symptoms and complete or nearly complete remission of symptoms between episodes. ATPD is a set of conditions that has significant overlap with both cycloid psychosis and the DSM-5's brief psychotic episode.4,13 These diagnoses, however, primarily affect adolescent and adult women and are characterized by brief episodes of psychosis, typically preceded by an acute stressor, and respond robustly to antipsychotic medications. Although mood symptoms are not a core feature of ATPD, acute stressors may simultaneously trigger symptoms related to mood and to psychosis.

Primary Mood Disorders

Bipolar disorder and major depressive disorder with psychotic features may both exhibit psychosis in the context of a major mood episode. Psychosis can be rather prominent and overshadow the underlying mood symptoms. As with the comparison to psychotic disorders, the timing and overlap of symptoms is key. Per the diagnostic criteria of both bipolar disorder and major depressive disorder, psychosis should be present only during major mood episodes (mania or depression).2 Schizoaffective disorder, in contrast, requires a 2-week period of psychosis in the absence of a mood episode. In other words, not all psychosis is driven by the presence of major mood episode.

Symptoms from Comorbid Illnesses

Schizophrenia and mood disorders are no longer considered to be mutually exclusive. For example, one patient may have schizophrenia and simultaneously have intermittent mood episodes sufficient to make a diagnosis of major depressive disorder. However, if this patient did not experience mood symptoms during the majority of his or her illness, it would be more appropriate to diagnose schizophrenia with comorbid major depressive disorder, rather than schizoaffective disorder. To complicate matters, people with schizophrenia commonly experience demoralization, which at times may be accompanied by neurovegetative or negative symptoms that mimic a mood episode; not all such presentations indicate the presence of schizoaffective disorder as conceptualized by DSM-5.14

Other Considerations

Finally, it is worth noting that a variety of illnesses not classified as mood or psychotic disorders can still have elements of psychosis or psychosis-like symptoms. In particular, brief episodes of psychosis can be seen in up to 25% of patients with borderline personality disorder, which may also have significant mood symptoms.15 Trauma-related disorders may also result in brief periods of psychosis.16 These symptoms, however, like cycloid psychosis and ATPD, should be brief with a complete return to the patient's normal functioning between episodes of psychosis, although this baseline may be characterized by other symptoms. For example, a given patient with borderline personality disorder may have features such as impulsivity, poor sense of self, or increased sensitivity to rejection; such features should not resolve when episodes of psychosis do.

Table 3 describes key characteristics that differentiate schizoaffective disorder from each of these other psychiatric conditions.

Key Features Differentiating Schizoaffective Disorder from Other Illnesses

Table 3:

Key Features Differentiating Schizoaffective Disorder from Other Illnesses

Conclusion

Schizoaffective disorder is a diagnosis that has seen substantial revisions over the past several decades, in part due to its poor reliability and use as a “catch-all” diagnosis, and in part due to the fact that it may represent an intermediate form of psychopathology that exists on a spectrum of mood and psychotic disorders. As our understanding of psychiatric illness evolves—both what can be observed clinically and the underlying disease factors—schizoaffective disorder is likely to go through further revision. In the interim, rigorous application of DSM-5 criteria ensures that this diagnosis is being applied uniformly.

References

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Diagnostic Criteria of Schizoaffective Disorder

Patient must simultaneously meet the primary criterion for schizophrenia (delusions, hallucinations, disorganized speech [at least one of these three must be present], disorganized behavior, and negative symptoms) and meet criteria for a major mood episode (mania or depression with depressed mood)

Delusions or hallucinations must occur in the absence of mood symptoms for at least 2 weeks

Mood episode criteria must be met for the majority of the time someone is actively experiencing symptoms

Symptoms cannot be attributable to substances and/or general medical conditions

Differential Diagnosis of Schizoaffective Disorder

Primary psychotic disorders

Schizophrenia

Schizoaffective disorder

Other schizophrenia-related conditions (schizophreniform disorder, brief psychotic disorder, delusional disorder)

Other (non-DSM) psychotic disorders (cycloid psychosis, acute and transient psychotic disorders)

Primary affective disorders

Bipolar disorder with psychosis

Major depressive disorder with psychotic features

Comorbidity: the simultaneous presence of a mood and a psychotic disorder Other psychiatric illnesses with mood and psychotic-like symptoms

Trauma-related disorders

Borderline, schizotypal, and other personality disorders

Obsessive-compulsive disorder with poor insight

Secondary psychosis (substance-induced, medical/organic)

Key Features Differentiating Schizoaffective Disorder from Other Illnesses

DiagnosisSimilaritiesDifferences
SchizophreniaCriterion A of schizoaffective disorder in DSM-5 except for presence of a mood episode (ie, two of hallucinations, delusions, disorganized speech [at least one of these must be present], disorganized behavior, and negative symptoms), must have prominent symptoms of psychosisMajor mood symptoms must be present for the majority of the illness in schizoaffective disorder
Comorbid schizophrenia and mood disorderProminent mood and psychotic symptomsMajor mood symptoms must be present for the majority of the illness in schizoaffective disorder
Cycloid psychosis/ATPDEpisodes of psychosis with prominent mood featuresPsychosis from cycloid psychosis and ATPD should exist in brief episodes with full resolution
Bipolar disorderMay have depression and/or mania, may have psychosis during major mood episodesIn schizoaffective disorder, psychosis must be present for at least 2 weeks in the absence of a mood episode
MDD with psychosisMay have depression and/or mania, may have psychosis during major mood episodesIn schizoaffective disorder, psychosis must be present for at least 2 weeks in the absence of a mood episode
Authors

David Beckmann, MD, MPH, is a Staff Psychiatrist, First Episode and Early Psychosis Program, Massachusetts General Hospital; and an Instructor of Psychiatry, Harvard Medical School. Kristina Schnitzer, MD, is a Fellow, Public and Community Psychiatry, Massachusetts General Hospital. Oliver Freudenreich, MD, FACLP, is the Co-Director, Schizophrenia Clinical and Research Program, Massachusetts General Hospital; and an Associate Professor of Psychiatry, Harvard Medical School.

Disclosure: Oliver Freudenreich has been a consultant for Alkermes, Neurocrine, Janssen, Novartis, and Roche; has performed contracted research for Otsuka, Janssen, Avanir, and Alkermes; receives royalties from UpToDate, Wolters Kluwer, and Springer; and has received payments from Medscape, Elsevier, and Global Medical Education for writing. The remaining authors have no relevant financial relationships to disclose.

Address correspondence to David Beckmann, MD, MPH, Massachusetts General Hospital, 15 Parkman Street, WACC 812, Boston, MA 02114; email: david.beckmann@mgh.harvard.edu.

10.3928/00485713-20200408-01

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