BACKGROUND: Delusions are a common transdiagnostic feature of psychotic disorders, and their treatment remains suboptimal. Despite the pressing need to better understand the nature, meaning, and course of these symptoms, research into the lived experience of delusional phenomena in psychosis is scarce. Thus, we aimed to explore the lived experience and subjective apprehension of delusions in help-seeking individuals with psychosis, regardless of diagnosis and thematic content of the delusion. METHODS: In our systematic review and qualitative evidence synthesis, we searched MEDLINE, Embase, PsycINFO, CINAHL, and Web of Science for qualitative studies published in English from database inception, with the last search on Sept 9, 2021. Grey literature search and hand-searching of relevant journals were also done. Studies were eligible if they provided an analysis of lived experience of delusions or predelusional phenomena presented from the perspective of individuals (age 14-65 years) who had developed a clinical high-risk stage of psychosis, or a diagnosable affective or non-affective psychotic disorder (as clinically defined, self-reported, or assessed within the primary study). Studies with only a subset of relevant participants were eligible only if data for the population of interest were reported separately. Studies that did not discriminate between the experience of delusion and other positive symptoms (eg, hallucinations) were included only if data for delusions were reported separately or could be extracted. First-person accounts (and author interpretations) discussing changes in the sense of self, lived world, and meaning in relation to delusions were extracted and synthesised using a novel thematic synthesis approach informed by a critical realist stance and a phenomenological theoretical framework. Analytic themes were developed into a new overarching framework for understanding the emergence of delusional phenomena. The study was registered with PROSPERO, CRD42020222104. FINDINGS: Of the 3265 records screened, 2115 were identified after duplicate removal. Of these, 1982 were excluded after title and abstract screening and 106 after full-text eligibility assessment. Of the 27 studies entering quality assessment, 24 eligible studies were included in the qualitative evidence synthesis, representing the perspectives of 373 help-seeking individuals with lived experience of delusions in the context of psychosis. Gender was reported as male (n=210), female (n=110), transgender (n=1), or not reported (n=52). Only 13 studies reported ethnicity, with White being predominant. The age of most participants ranged from 15 to 65 years. We found no eligible studies investigating subclinical or predelusional experiences in at-risk mental state populations through qualitative methods. Most studies were undertaken in western, educated, industrialised, rich, and democratic (WEIRD) societies, and most included participants had received or self-reported a diagnosis within the schizophrenia spectrum. Studies differed in relation to whether they focused on one kind or theme of delusion or delusional phenomena more generally as a unified category. Three superordinate themes relating to experiential changes and meanings in delusion were identified: (1) a radical rearrangement of the lived world dominated by intense emotions; (2) doubting, losing, and finding oneself again within delusional realities; and (3) searching for meaning, belonging, and coherence beyond mere dysfunction. Based on the review findings and thematic synthesis, we propose the Emergence Model of Delusion to advance understanding of delusional phenomena in psychosis. INTERPRETATION: Delusions are best understood as strongly individualised and inherently complex phenomena emerging from a dynamic interplay between interdependent subpersonal, personal, interpersonal, and sociocultural processes. Integrative approaches to research on delusion, which consider their potential adaptiveness and favour explanatory pluralism, might be advantageous. Effective clinical care for individuals with psychosis might need adapting to match more closely, and take account of, the subjective experience and meaning of delusions as they are lived through, which might also help redress power imbalances and enduring epistemic injustices in mental health. FUNDING: Priestley Scholars, Wellcome Trust.
458 - 476
Adolescent, Adult, Aged, Delusions, Emotions, Female, Humans, Male, Middle Aged, Psychotic Disorders, Qualitative Research, Schizophrenia, Young Adult