ABSTRACT
OBJECTIVES: The diagnosis of schizoaffective disorder (SAD) is well established in clinical practice but is heavily disputed on theoretical grounds. We analyzed the extent and direction of diagnostic shift in SAD patients. METHODS: We searched Medline, Embase, and PsycINFO systematically for all studies documenting two diagnostic assessments at different points in time (rediagnosis studies) and used meta-analytic methods to quantify diagnostic shift. Multiple prespecified and post-hoc subgroup analyses (e.g., rater blinding) and meta-regressions (e.g., year of publication) were carried out. RESULTS: We included 31 studies out of 4,415 articles screened: 27 studies on the shift from and 23 studies on the shift to SAD (median time span was two years). A total of 36% of patients with a diagnosis of SAD at first assessment switch, many to schizophrenia (19%), 14% to affective disorders, and 6% to other disorders. Among patients diagnosed with SAD at second assessment, 55% had received a different diagnosis at first assessment, a large portion of whom had been initially diagnosed with affective disorder (24%), schizophrenia (18%), and other disorders (12%). CONCLUSIONS: Diagnostic shift in SAD patients is substantial. Psychiatrists need to reassess the diagnosis during the course of the illness and to adjust treatment. Slightly more diagnoses of SAD are changed to schizophrenia than to affective disorders, and among patients rediagnosed with SAD, fewer have been diagnosed with schizophrenia than with affective disorders. Thus, at the diagnostic level, there seems to be a slight trend toward schizophrenia during the course of functional psychoses.
Subject(s)
Psychotic Disorders/diagnosis , Diagnosis, Differential , Female , Humans , Male , Mood Disorders/complications , Mood Disorders/diagnosis , Mood Disorders/psychology , Psychotic Disorders/classification , Psychotic Disorders/psychology , Schizophrenia/diagnosis , Schizophrenic PsychologyABSTRACT
OBJECTIVES: Schizoaffective disorder is a frequent diagnosis, and its reliability is subject to ongoing discussion. We compared the diagnostic reliability of schizoaffective disorder with its main differential diagnoses. METHODS: We systematically searched Medline, Embase, and PsycInfo for all studies on the test-retest reliability of the diagnosis of schizoaffective disorder as compared with schizophrenia, bipolar disorder, and unipolar depression. We used meta-analytic methods to describe and compare Cohen's kappa as well as positive and negative agreement. In addition, multiple pre-specified and post hoc subgroup and sensitivity analyses were carried out. RESULTS: Out of 4,415 studies screened, 49 studies were included. Test-retest reliability of schizoaffective disorder was consistently lower than that of schizophrenia (in 39 out of 42 studies), bipolar disorder (27/33), and unipolar depression (29/35). The mean difference in kappa between schizoaffective disorder and the other diagnoses was approximately 0.2, and mean Cohen's kappa for schizoaffective disorder was 0.50 (95% confidence interval: 0.40-0.59). While findings were unequivocal and homogeneous for schizoaffective disorder's diagnostic reliability relative to its three main differential diagnoses (dichotomous: smaller versus larger), heterogeneity was substantial for continuous measures, even after subgroup and sensitivity analyses. CONCLUSIONS: In clinical practice and research, schizoaffective disorder's comparatively low diagnostic reliability should lead to increased efforts to correctly diagnose the disorder.
Subject(s)
Bipolar Disorder , Depressive Disorder, Major , Psychotic Disorders , Schizophrenia/diagnosis , Bipolar Disorder/diagnosis , Bipolar Disorder/psychology , Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/psychology , Diagnosis, Differential , Humans , Psychotic Disorders/diagnosis , Psychotic Disorders/psychology , Reproducibility of ResultsSubject(s)
Bipolar Disorder , Depressive Disorder, Major , Psychotic Disorders , Schizophrenia/diagnosis , HumansABSTRACT
OBJECTIVES: Reliability of schizoaffective disorder (SAD) diagnoses is low in adults but unclear in children and adolescents (CAD). We estimate the test-retest reliability of SAD and its key differential diagnoses (schizophrenia, bipolar disorder, and unipolar depression). METHODS: Systematic literature search of Medline, Embase, and PsycInfo for studies on test-retest reliability of SAD, in CAD. Cohen's kappa was extracted from studies. We performed meta-analysis for kappa, including subgroup and sensitivity analysis (PROSPERO protocol: CRD42013006713). RESULTS: Out of > 4000 records screened, seven studies were included. We estimated kappa values of 0.27 [95%-CI: 0.07 0.47] for SAD, 0.56 [0.29; 0.83] for schizophrenia, 0.64 [0.55; 0.74] for bipolar disorder, and 0.66 [0.52; 0.81] for unipolar depression. In 5/7 studies kappa of SAD was lower than that of schizophrenia; similar trends emerged for bipolar disorder (4/5) and unipolar depression (2/3). Estimates of positive agreement of SAD diagnoses supported these results. LIMITATIONS: The number of studies and patients included is low. CONCLUSIONS: The point-estimate of the test-retest reliability of schizoaffective disorder is only fair, and lower than that of its main differential diagnoses. All kappa values under study were lower in children and adolescents samples than those reported for adults. Clinically, schizoaffective disorder should be diagnosed in strict adherence to the operationalized criteria and ought to be re-evaluated regularly. Should larger studies confirm the insufficient reliability of schizoaffective disorder in children and adolescents, the clinical value of the diagnosis is highly doubtful.
Subject(s)
Bipolar Disorder/diagnosis , Depressive Disorder, Major/diagnosis , Psychotic Disorders/diagnosis , Schizophrenia/diagnosis , Adolescent , Adult , Child , Diagnosis, Differential , Female , Humans , Male , Reproducibility of Results , Young AdultABSTRACT
Schizoaffective disorder is a common diagnosis in clinical practice but its nosological status has been subject to debate ever since it was conceptualized. Although it is key that diagnostic reliability is sufficient, schizoaffective disorder has been reported to have low interrater reliability. Evidence based on systematic review and meta-analysis methods, however, is lacking. Using a highly sensitive literature search in Medline, Embase, and PsycInfo we identified studies measuring the interrater reliability of schizoaffective disorder in comparison to schizophrenia, bipolar disorder, and unipolar disorder. Out of 4126 records screened we included 25 studies reporting on 7912 patients diagnosed by different raters. The interrater reliability of schizoaffective disorder was moderate (meta-analytic estimate of Cohen's kappa 0.57 [95% CI: 0.41-0.73]), and substantially lower than that of its main differential diagnoses (difference in kappa between 0.22 and 0.19). Although there was considerable heterogeneity, analyses revealed that the interrater reliability of schizoaffective disorder was consistently lower in the overwhelming majority of studies. The results remained robust in subgroup and sensitivity analyses (e.g., diagnostic manual used) as well as in meta-regressions (e.g., publication year) and analyses of publication bias. Clinically, the results highlight the particular importance of diagnostic re-evaluation in patients diagnosed with schizoaffective disorder. They also quantify a widely held clinical impression of lower interrater reliability and agree with earlier meta-analysis reporting low test-retest reliability.