A study of psychological therapies for psychosis

Abstract

Study 1: Abstract Aim: The present article provides a meta-analysis of the effectiveness of metacognitive therapy (MCT) for psychosis. Variables such as insight and cognitive bias were also analysed. Method: A systematic search of the literature was completed using the databases: Psychology and Behavioural Sciences Collection, PsycARTICLES and PsycINFO, MEDLINE and ProQuest. The review included 19 studies published between the years 2010 – 2018. Metaanalyses were conducted on positive symptoms (352 participants), negative symptoms (160 participants), general psychopathology (313 participants), delusions (234 participants), insight (219 participants) and cognitive bias (193 participants). Results: The review demonstrates overall statistically significant results which indicate that MCT is an effective treatment for psychosis. This result is classified as having a medium effect size. The largest effect size was for severity of delusions which demonstrated a medium effect. A medium treatment effect size was also found for positive symptoms, negative symptoms, general psychopathology and self-reflection. The effect of MCT on cognitive bias indicate a positive but weak effect and was not statistically significant. Results indicated no difference between gender or age. Conclusion: MCT appears to be an effective treatment for psychosis. Further research is required to determine with more certainty what aspects of cognitive biases are addressed by MCT.

Study 2: Abstract Background: The Schema Mode Inventory (SMI) is a self-report measure used to assess schema modes. Aims: The aim of the study was to explore the psychometric properties and factor structure of the SMI within an Irish population and determine its viability for use for psychotic disorders. Method: 834 participants were recruited online from the general population. A further 19 participants were recruited with a diagnosis of a psychotic disorder. Schema modes were measured in both groups using the SMI. The Community Assessment of Psychic Experiences was utilised to determine symptoms of psychosis. A full psychometric evaluation of the SMI was carried out. Multidimensional Scaling was used to assess the equivalence of the two samples. Results: Confirmatory factor analysis confirms the 14-factor mode model within the general population and good scale score reliabilities. The pattern of inter-scale correlations are consistent with expectations and are equivalent across samples. The multi-dimensional scaling reveals a common underlying structure of the SMI for both samples. However, the psychometric properties of some SMI scale scores are weaker in the psychosis group. Possible reasons for this are discussed. Conclusions: This study represents a preliminary step towards understanding the viability of the schema mode model within the psychosis population. The psychometric results indicated that the SMI is a valuable measure that can be used for mode assessment within Ireland and possibly for psychotic disorders. An adapted version of the SMI could increase its relevance for a psychosis population and could facilitate the development of individualised case conceptualisations.