Varese ( Liverpool) and colleagues addressed this question in their meta analysis of prospective cross sectional cohort studies.Child hood trauma is known to influence adult mental health.Different types of traumatic events linked to psychosis include 1. Child maltreatment 2. bullying 3. parental loss 4. separation
This study is the first quantitative analysis of the research so far in this area.
The team searched databases from 1906 up to 2011 and followed a comprehensive strategy to identify all potential studies.Since DSM 3 was published in 1980, studies after this period only was included. studies that used diagnostic as well as dimensional measures of psychosis were included. 41 studies were included in the final analysis.( it started with 27898 studies! ).
Trauma was significantly associated with an increased risk for psychosis with an OR = 2.78 (95% CI = 2.34–3.31). The effect of adversity on psychosis was largely comparable across different study designs (OR = 2.72 [95% CI = 1.90–3.88] for case-control studies; OR = 2.99 [95% CI = 2.12–4.20] for population-based cross-sectional studies; OR = 2.75 [95% CI = 2.17–3.47] for prospective studies).
With the exception of parental death, (although this association became significant after the exclusion of a potential outlier) statistically significant associations were observed between all types of childhood adversity and psychosis. They found no evidence for any specific type of trauma to be a stronger predictor of psychosis than any other. These findings suggest that other adversity-related variables such as age of exposure and multi-victimization might be more strongly related to psychosis risk than exposure type.
Population Attributable risk was calculated as 33%. i.e. if the adversities examined as risk factors were entirely removed from the population (with the assumption that the pattern of the other risk factors remained unchanged), and assuming causality, the number of people with psychosis would be reduced by 33%.
Some limitations to consider
1. Most studies have not tested for dose-response relationships.
2. Cross- sectional studies do not allow us to ascertain the direc- tion of causality . (prospective studies included provide evidence for temporal causality)
3. Self-reported retrospective measures of childhood experiences has problems. ( Associations with psychosis were also observed in studies which employed other methods to assess trauma exposure )
4. Substantial statistical heterogeneity for all outcomes and exposures of interest ( probably due to differences in assessment of childhood adverse experiences and assessment of psychosis outcomes)
5. Cannot rule out the effect of proximal and distal interactions of adversity with other factors (eg, cannabis use, genes, urbanicity) as most studies did not correct for these interactions or corrected for only a subset of these factors as possible moderators .
Clinical practice Implications:
1. Support the need for primary prevention interventions for psychosis.
2. Clinicians should routinely ask about adverse events in childhood to develop comprehensive formulations and treatment plans when working with patients with schizophrenia or similar diagnoses.
3. Psychosocial interventions which have been used for patients affected by trauma might be considered among the treatment options for patients with psychosis.
Varese F, Smeets F, Drukker M, Lieverse R, Lataster T, Viechtbauer W, Read J, van Os J, Bentall RP.
Schizophr Bull. 2012 Jun;38(4):661-71