The psychosis continuum and categorical versus dimensional diagnostic approaches

Abstract

This overview briefly presents recent thinking on the dimensional approach to understanding psychotic experiences. First, evidence is provided for a continuum of psychosis ranging from self-reported infrequent psychotic symptoms in the general population, to schizotypal traits, to schizotypal personality disorder, and finally to full-blown psychosis resulting in a diagnosable primary psychotic disorder. Variation within each of these types of psychotic experience is discussed. Then, a comparison is presented between categorical and dimensional approaches to the diagnosis of psychosis by highlighting four advantages of each approach. In doing so, it is emphasized that the categorical approach is beneficial primarily in terms of reliability, whereas the dimensional approach would enhance validity.

Factor structure of the French version of the Hypomanic Personality Scale (HPS) in non-clinical young adults

“…HPS Total score and two subscales out of three (Excitement and Mood Volatility) were linked to another measure of personality referred to as schizotypal personality. Schizotypal traits are frequently found in the general population [36][37][38][39] and are viewed as the subclinical expression of the "schizophrenia spectrum" [40,41]. Indeed, this result is consistent with a newly emerging area of research that defends the idea of a continuum between the bipolar and schizophrenia spectra [42][43][44][45].…”

Bridging the Gaps in the Study of Typical and Atypical Cognitive Development: A Commentary

“…The two most commonly used systems, the Diagnostic and Statistical Manual for Mental Disorders -5th Edition (DSM-V; APA, 2013) and the World Health Organization (WHO) International Classification of Diseases and Health-Related Problems (WHO, 2016), treat disorders as categories based on a set of defining features. This categorical approach to the assessment of psychological disorders has continued to dominate the fields of psychology and psychiatry, despite considerable research demonstrating that most presenting symptoms exist on a continuum and that most mental disorders are manifestations of an isolated number of underlying dimensions (Esterberg & Compton, 2009;Lahey et al, 2008)-a point we will return to in the next section.…”

Schizophrenia spectrum disorders

“…There is increasing support of a dimensional conceptualisation of psychosis (Esterberg & Compton 2009) but convention dictates categorisation of these disorders based on major signs and symptoms.…”