The Complex Latent Structure of Attenuated Psychotic Symptoms: Hierarchical and Bifactor Models of SIPS Symptoms Replicated in Two Large Samples at Clinical High Risk for Psychosis

Henry R Cowan; Trevor F Williams; Vijay A Mittal; Jean Addington; Carrie E Bearden; Kristin S Cadenhead; Tyrone D Cannon; Barbara A Cornblatt; Matcheri Keshevan; Diana O Perkins; Daniel H Mathalon; William Stone; Scott W Woods; Elaine F Walker

doi:10.1093/schbul/sbae042

The Complex Latent Structure of Attenuated Psychotic Symptoms: Hierarchical and Bifactor Models of SIPS Symptoms Replicated in Two Large Samples at Clinical High Risk for Psychosis

Schizophr Bull. 2024 May 10:sbae042. doi: 10.1093/schbul/sbae042. Online ahead of print.

Authors

Henry R Cowan^{1

2}, Trevor F Williams³, Vijay A Mittal^{3

4}, Jean Addington⁵, Carrie E Bearden^{6

7}, Kristin S Cadenhead⁸, Tyrone D Cannon^{9

10}, Barbara A Cornblatt¹¹, Matcheri Keshevan¹², Diana O Perkins¹³, Daniel H Mathalon¹⁴, William Stone¹², Scott W Woods¹⁰, Elaine F Walker¹⁵

Affiliations

¹ Department of Psychiatry and Behavioral Health, The Ohio State University, Columbus, OH, USA.
² Department of Psychology, Michigan State University, East Lansing, MI, USA.
³ Department of Psychology, Northwestern University, Evanston, IL, USA.
⁴ Departments of Psychiatry and Medical Social Sciences, Northwestern University, Evanston, IL, USA.
⁵ Department of Psychiatry, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
⁶ Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA.
⁷ Department of Psychology, University of California Los Angeles, Los Angeles, CA, USA.
⁸ Department of Psychiatry, University of California San Diego, San Diego, USA.
⁹ Department of Psychology, Yale University, New Haven, CT, USA.
¹⁰ Department of Psychiatry, Yale University, New Haven, CT, USA.
¹¹ Department of Psychiatry Research, Zucker Hillside Hospital, Glen Oaks, NY, USA.
¹² Department of Psychiatry, Harvard Medical School at Beth Israel Deaconess Medical Center and Massachusetts General Hospital, Boston, MA, USA.
¹³ Department of Psychiatry, University of North Carolina, Chapel Hill, Chapel Hill, NC, USA.
¹⁴ Department of Psychiatry, University of California San Francisco, San Francisco, CA, USA.
¹⁵ Department of Psychology, Emory University, Atlanta, GA, USA.

PMID: 38728417
DOI: 10.1093/schbul/sbae042

Abstract

Background and hypothesis: The Structured Interview for Psychosis-Risk Syndromes (SIPS) and other assessments of psychosis risk define clinical high risk for psychosis (CHR) by the presence of attenuated psychotic symptoms. Despite extensive research on attenuated psychotic symptoms, substantial questions remain about their internal psychometric structure and relationships to comorbid non-psychotic symptoms.

Study design: Hierarchical and bifactor models were developed for the SIPS in a large CHR sample (NAPLS-3, N = 787) and confirmed through preregistered replication in an independent sample (NAPLS-2, N = 1043). Criterion validity was tested through relationships with CHR status, comorbid symptoms/diagnoses, functional impairment, demographics, neurocognition, and conversion to psychotic disorders.

Study results: Most variance in SIPS items (75%-77%) was attributable to a general factor. Hierarchical and bifactor models included a general factor and five specific/lower-order factors (positive symptoms, eccentricity, avolition, lack of emotion, and deteriorated thought process). CHR participants were elevated on the general factor and the positive symptoms factor. The general factor was associated with depressive symptoms; functional impairment; and mood, anxiety, and schizotypal personality diagnoses. The general factor was the best predictor of psychotic disorders (d ≥ 0.50). Positive symptoms and eccentricity had specific effects on conversion outcomes. The deteriorated thought process was least meaningful/replicable.

Conclusions: Attenuated psychotic symptoms, measured by the SIPS, have a complex hierarchical structure with a strong general factor. The general factor relates to internalizing symptoms and functional impairment, emphasizing the roles of general psychopathological distress/impairment in psychosis risk. Shared symptom variance complicates the interpretation of raw symptom scores. Broad transdiagnostic assessment is warranted to model psychosis risk accurately.

Keywords: attenuated psychotic symptoms; bifactor; comorbidity; general factor; hierarchical factors.

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Grants and funding

U01MH081984/MH/NIMH NIH HHS/United States