Is there a relationship between trauma, PTSD and negative symptoms of psychosis?

Aim: Previous systematic reviews have addressed and synthesised the relationship between trauma, PTSD and the positive symptoms of psychosis. The relationship between trauma, PTSD and the negative symptoms of psychosis however has yet to be systematically reviewed. Gaining a greater psychological understanding of negative symptoms is a priority as they impair functioning and tend to be treatment resistant. This review therefore aims to review the evidence on the relationship between trauma, PTSD and negative symptoms, and to evaluate this evidence in relation to key quality factors: the assessment of trauma, PTSD, negative symptoms and depression, as well as the design and statistical analysis employed to assess the relationship. Method: Searches of electronic databases Pubmed and PsycINFO were conducted and 41 studies were identified after inclusion and exclusion criteria were applied. Findings: Included studies appeared to yield equivocal findings with limited variability in study quality, as most studies were low or medium in quality and demonstrated multiple key methodological issues. The synthesis suggests higher quality studies that formally assess both trauma and PTSD, whilst employing a symptom specific assessment of negative symptoms, indicate more complex differential relationships are likely to exist between PTSD clusters and individual negative symptoms. Conclusions: Recommendations are made to improve the methodological quality of future studies in order to reduce the level of equivocal findings reported and to encourage consistency in research aims and methods. It is a priority to employ higher quality studies to identify whether trauma and PTSD are associated with negative symptoms, and to establish the mechanisms accounting for this association as they may provide a promising new direction for developing innovative psychosocial interventions for people affected by these difficulties