Prevalence and assessment of self-disorders in the schizophrenia spectrum: a systematic review and meta-analysis

Abstract

Self-disorders have been proposed as the "clinical core" of the schizophrenia spectrum. This has been explored in recent studies using self-disorder assessment tools. However, there are few systematic discussions of their quality and utility. Therefore, a literature search was performed on Medline, Embase, PsychINFO, PubMed and the Web of Science. Studies using these assessment tools to explore self-disorders within schizophrenia spectrum disorders (SSDs) were included. A meta-analysis was performed on the outcomes of total self-disorder score and odds ratios of self-disorders, using Comprehensive Meta-Analysis software. Weighted pooled effect sizes in Hedge's g were calculated using a random-effects model. 15 studies were included, giving a sample of 810 participants on the schizophrenia spectrum. Self-disorders showed a greater aggregation within schizophrenia spectrum groups compared to non-schizophrenia spectrum groups, as measured with the Bonn Scale for the Assessment of Basic Symptoms (Hedge's g = 0.774, p < 0.01) and Examination of Anomalous Self-Experiences (Hedge's g = 1.604, p < 0.01). Also, self-disorders had a greater likelihood of occurring within SSDs (odds ratio = 5.435, p < 0.01). These findings help to validate self-disorders as a core clinical feature of the broad schizophrenia spectrum.

Figure 1

PRISMA flowchart for study selection.

Figure 2

Meta-analysis of the aggregation and likelihood of developing self-disorders in schizophrenia spectrum and control groups, as measured with the Bonn scale for the assessment of basic symptoms (BSABS). Studies are grouped by outcome measure. (a) Describes the standard difference in means for total self-disorder score in schizophrenia spectrum and control groups. (b) Describes the odds ratios of developing self-disorders in schizophrenia spectrum and control groups. Data shown as mean ± SEM of self-disorder scores for (a) and log odds ratio ± SE for (b). Both are representative of two independent samples; values are significant if p < 0.05. BD = bipolar disorder, HC = healthy control, MD = mood disorder, NAP = non-affective psychosis, OCD = obsessive compulsive disorder, OMI = other mental illness, SD = self-disorder, SPD = schizotypal personality disorder, SZ = schizophrenia.

Figure 3

Meta-analysis of the aggregation of self-disorders in schizophrenia spectrum and control groups, as measured with the examination of anomalous self-experiences (EASE). Studies are grouped by the type of self-disorder score reported. (a) Describes the standard difference in means for dichotomous total self-disorder scores in schizophrenia spectrum and control groups. (b) Describes the standard difference in means for continuous total self-disorder scores in schizophrenia spectrum and control groups. Diamonds indicate pooled effect sizes and squares indicate individual study effect sizes. Data shown as mean ± SEM of self-disorder scores and are representative of two independent samples; values are significant if p < 0.05. ASD = autism spectrum disorder, BD = bipolar disorder, FEP = first episode psychosis, FRS = first rank symptoms, HC = healthy control, NAP = non-affective psychosis, OMI = other mental illness, SD = self-disorder, SPD = schizotypal personality disorder, SSD = schizophrenia spectrum disorder, SZ = schizophrenia, UHR = ultra-high risk for psychosis.