A systematic review on mediators between adversity and psychosis: potential targets for treatment

Abstract

Various psychological and biological pathways have been proposed as mediators between childhood adversity (CA) and psychosis. A systematic review of the evidence in this domain is needed. Our aim is to systematically review the evidence on psychological and biological mediators between CA and psychosis across the psychosis spectrum. This review followed PRISMA guidelines. Articles published between 1979 and July 2019 were identified through a literature search in OVID (PsychINFO, Medline and Embase) and Cochrane Libraries. The evidence by each analysis and each study is presented by group of mediator categories found. The percentage of total effect mediated was calculated. Forty-eight studies were included, 21 in clinical samples and 27 in the general population (GP) with a total of 82 352 subjects from GP and 3189 from clinical studies. The quality of studies was judged as ‘fair’. Our results showed (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 post-traumatic stress disorder symptoms; and through an affective pathway in GP but not in subjects with disorder; (iii) lack of studies exploring biological mediators. We found evidence suggesting that various overlapping and not competing pathways involving post-traumatic and mood symptoms, as well as negative cognitions contribute partially to the link between CA and psychosis. Experiences of CA, along with relevant mediators should be routinely assessed in patients with psychosis. Evidence testing efficacy of interventions targeting such mediators through cognitive behavioural approaches and/or pharmacological means is needed in future.

Physical activity and childhood trauma experiences in patients with schizophrenia or bipolar disorders

“…We postulate that physical activity, in conjunction with regular treatment may reduce the physiological or subjective stress response, and potentially lessen some of the adverse longterm effects of childhood trauma in SZ and BD. Given the importance of childhood trauma in the prognosis and illness course of patients with SZ and BD (Nemeroff 2016;Teicher et al 2016;Pruessner et al 2017), evidence-based interventions addressing long-term effects of trauma experiences are needed (Alameda et al 2020). Although there was no difference in body mass index between groups in the current study, a history of childhood trauma has been associated with higher body mass index and C-reactive protein (CRP) (Aas et al 2017;Moraes et al 2017) and poorer physical health behaviour in general (Grigsby et al 2020) demonstrating the need to improve physical health in individuals with trauma experiences.…”

“…Although childhood trauma experiences are linked to the development of more severe clinical profile in schizophrenia (SZ) and in bipolar disorder (BD), treatment studies specifically focussing on childhood trauma experiences such as, for example, Eye Movement Desensitisation Reprogramming (EMDR) or trauma focussed Cognitive Behavioural Therapy (CBT) are still sparse (Alameda et al 2020). Physical activity promotes resilience and reduces stress levels (Deuster and Silverman 2013), including reducing negative emotions following a stress task (Childs and de Wit 2014) and protects against adverse behavioural and metabolic consequences of stressful events (Silverman and Deuster 2014).…”

Dissociation as a causal pathway from sexual abuse to positive symptoms in the spectrum of psychotic disorders

“…In recent decades, the long-term negative effects of childhood maltreatment on the social and cognitive functioning of psychotic patients have led to significant researches into the understanding of possible underlying psychological mechanisms [8][9][10][11][12][13]. In this regard, numerous psychological models have been proposed to explain the association between childhood maltreatment and psychosis.…”

“…In this regard, numerous psychological models have been proposed to explain the association between childhood maltreatment and psychosis. For instance, one of the most important of these models has shown that childhood maltreatment may result in psychosis via a pathway of posttraumatic stress disorder-related symptoms, including intrusive memories and dissociation [12,13]. In this conceptual model, "flash-backs could be interpreted as being externally generated, which leads to hallucinatory experiences and hampers reality testing" [12].…”

Kaleidoscope

“…Alameda et al systematically reviewed 48 studies that covered approximately 85 000 individuals. 2 They determined a solid evidence for negative cognitive schemas about the self, the world and others mediating this link; dissociation and post-traumatic stress disorder symptoms also play a role, particularly with hallucinations as an outcome. There was a lack of good data for any biological mediators, although this may well be a research bias rather than evidence of absence.…”