Core beliefs in psychosis: a systematic review and meta-analysis
A. Jorovat, Ricardo Twumasi, Andrea Mechelli, Anna Georgiades
Abstract
Increasing interest is growing for the identification of psychological mechanisms to account for the influence of trauma on psychosis, with core beliefs being proposed as a putative mediator to account for this relationship. A systematic review (n = 79 studies) was conducted to summarise the existing evidence base regarding the role of core beliefs/schemas in psychosis, Clinical High-Risk (CHR), and non-clinical samples with Psychotic-Like Experiences (PLEs). Compared to Healthy Controls (HCs), individuals with psychosis experiencing Auditory Hallucinations or Persecutory Delusions had significantly higher scores for negative self and negative other-beliefs and significantly lower scores for positive self and positive other-beliefs. This pattern of core beliefs was also observed for CHR individuals. In contrast, the core belief profile for grandiose delusions was in the opposite direction: higher positive self and positive other-beliefs and lower negative self-beliefs. In non-clinical samples, several factors mediated the relationship between Traumatic Life Events (TLEs) and PLEs, such as greater perceived stress, dissociation, external locus of control, and negative self and negative other-beliefs. Compared to HCs, meta-analyses revealed statistically significant large effects for negative self and negative other-beliefs in Schizophrenia. In CHR, statistically significant large and moderate effects were found for negative self and negative other-beliefs, respectively, along with a moderate negative effect for positive self-beliefs. Core beliefs were found to play a significant role in the development and maintenance of positive symptoms of psychosis. The development of psychosocial interventions that explicitly target negative self and other-beliefs, whilst also enhancing positive self-beliefs are warranted and would innovate CBTp practices.