Medical Causes of Psychosis: Lessons for Individuals with Attenuated Psychosis Syndromes

Abstract

This chapter addresses the possible medical causes of the clinical high-risk (CHR) state or one type of attenuated psychosis syndromes (APS), consistent with the theme of this volume. The definition and characterization of the at-risk state continue to evolve; in DSM-5, the APS category is subsumed under 'conditions for further study'. This syndrome, based on subthreshold psychotic symptoms (in severity or duration), has been associated with an increase in the risk of development of a full-fledged psychotic disorder within the next year. Symptoms include subthreshold delusions, hallucinations/perceptual abnormalities, or disorganized speech/communication. The incorporation of this diagnosis reflects the growing movement focused on identification of at-risk individuals, with early diagnosis and treatment to prevent or limit severity of a psychotic disorder. This chapter first reviews the criteria for at-risk populations, including clinical high-risk (CHR) and ultrahigh-risk (UHR) individuals. It then outlines the clinical features of different medical diagnoses that can present with APS symptoms. Finally, the chapter discusses the approach to diagnosis of these disorders, with an emphasis on differentiation from a primary CHR illness. (PsycInfo Database Record (c) 2022 APA, all rights reserved)