Schizophrenia or schizoaffective disorder? A 50-year assessment of diagnostic stability based on a national case registry

Sharon Florentin*, Inbal Reuveni, Paola Rosca, Shlomo Rahmani Zwi-Ran, Yehuda Neumark

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Background: Schizoaffective disorder (SAD) remains a controversial diagnosis in terms of necessity and reliability. Objectives: We assessed diagnostic patterns of SAD and schizophrenia (SZ) among hospitalized psychiatric patients over a fifty-year period. Method: Data from the Israeli National Psychiatric Registry on 16,341 adults diagnosed with SZ or SAD, hospitalized at least twice in 1963–2017, were analyzed. Stability between most-frequent, first and last diagnosis, and diagnostic-constancy (the same diagnosis in >75 % of a person's hospitalizations) were calculated. Three groups were compared: People with both SAD and SZ diagnoses over the years (SZ-SAD), and people with only one of these diagnoses (SZ-only; SAD-only). The incidence of SAD and SZ before and after DSM-5 publication was compared. Results: Reliability between last and first diagnosis was 60 % for SAD and 94 % for SZ. Agreement between first and most-frequent diagnosis was 86 % for SAD and 92 % for SZ. Diagnostic shifts differ between persons with SAD and with SZ. Diagnostic-constancy was observed for 50 % of SAD-only patients. In the SZ-SAD group, 9 % had a constant SAD diagnosis. Compared to the other groups, the SZ-SAD group exhibited a higher substance use prevalence, younger age at first-hospitalization, and more hospitalizations/person (p < 0.0001). The incidence of a first-hospitalization SAD diagnosis increased by 2.2 % in the 4-years after vs. prior to DSM-5. Conclusions: A SAD diagnosis is less stable than SZ. The incidence of a SAD diagnosis increased after DSM-5, despite stricter diagnostic criteria. The SZ-SAD group exhibited the poorest outcomes. SAD may evolve over time necessitating periodic re-evaluation.

Original languageAmerican English
Pages (from-to)110-117
Number of pages8
JournalSchizophrenia Research
StatePublished - Feb 2023

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  • DSM-5
  • Diagnostic stability
  • Reliability
  • Schizoaffective disorder
  • Schizophrenia


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