Abstract
Background
Various psychological and biological pathways have been proposed as mediators between childhood adverse events (CA) and psychosis. A systematic review of the evidence in this domain is needed; open new venues for treatment interventions in traumatized patients with psychosis.
The aim of the current work is to systematically review the evidence on clinical and biological mediators between CA and psychosis across the psychosis spectrum.
Methods
This systematic review followed PRISMA guidelines. Articles published between 1979 and July 2019 were identified through a literature search in OVID (PsychINFO; Medline and Embase). The direction of the evidence by each analysis and each study was presented by group of mediator categories found in the review; the percentage of total effect mediated was calculated and whether the mediation was partial, total or null (if it was absent) was reported.
Results
47 studies were included, with a total of 72286 GP subjects and 2800 from clinical samples. The quality of studies was judges as “fair”. We found (i) solid evidence of mediation between CA and psychosis by negative cognitive schemas about the self, the world and others (NS); by dissociation and other PTSD symptoms; (ii) evidence of a partial mediation through an affective pathway (affective dysregulation, anxiety and depression) in GP; (iii) that feeling of loneliness appeared as an important mediator that should be further explored; (iv) lack of studies exploring biological mediators; (v) little evidence supporting the mediating role of dysfunctional attachment between CA and psychosis.
Discussion
Experiences of adversity, alongside with all relevant mediators such as PTSD and mood related symptoms and NS should be routinely assessed in patients with psychosis. Targeting such mediators through cognitive behavioural approaches such as trauma-focused therapy and/or pharmacological means could be a beneficial add on to the traditional treatment of positive symptoms.