Stressful life events linked to overall, schizophrenia-related negative health outcomes

Exposure to stressful life events during adulthood was linked to poorer health, especially among those with high environmental liability for schizophrenia, according to study results published in JAMA Psychiatry.

“Most people do not develop mental disorders after experiencing [a stressful life event],” Lotta-Katrin Pries, MSc, of the department of psychiatry and neuropsychology at Maastricht University Medical Center in the Netherlands, and colleagues wrote. “According to the diathesis-stress model, a possible explanation is that early life events increase the vulnerability to SLEs later in life. Converging evidence for the diathesis-stress model stems from epidemiological studies focusing on the influence of the environment on psychopathology during the life span.

“Early adverse events, such as childhood adversity, moderate the association between adulthood SLEs and a broad range of multidimensional psychopathology outcomes across the severity spectrum from depression to psychosis,” they added. “Furthermore, the influences of exposures on psychopathology appear to accumulate in a dose-response fashion: the more severe the exposure, the more severe the outcome.”

Results of prior studies suggested that an effect of SLEs is partially contingent on an individual’s genetic and environmental liability, with an earlier study conducted by Pries and colleagues supporting the pleiotropic effect of stress vulnerability.

In the current study, the investigators sought to determine whether recent SLEs interacted with environmental and genetic schizophrenia liability in mental and physical health models. They analyzed data 6,646 participants of the population-based prospective cohort study, the Netherlands Mental Health Survey and Incidence Study-2, which was designed to evaluate the incidence, course, prevalence and consequences of mental disorders among the general Dutch general population. Researchers enrolled participants between Nov. 5, 2007, and July 31, 2009, and followed them up with three assessments over 9 years. Exposures included recent SLEs assessed at each wave, as well as aggregate scores of environmental and genetic liability for schizophrenia. Main outcomes and measures included independent and interacting associations of SLEs with exposome score for schizophrenia (ES-SCZ) and polygenic risk score for schizophrenia (PRS-SCZ) on mental and physical health.

Results showed SLEs were linked to poorer mental (B = 3.68; 95% CI, 4.05 to 3.32) and physical (B = 3.22; 95% CI, 3.66 to 2.79) health. The researchers observed an association between genetic and environmental liability for schizophrenia and poorer mental health, and environmental liability was associated with poorer physical health. According to an interaction model, ES-SCZ moderated the association of SLEs with mental and physical health, but PRS-SCZ did not, and multiple sensitivity analyses confirmed these results.

“Our findings showing that the network of antecedent environmental liability increased the vulnerability to stressful events later in life provide further support to the diathesis-stress theory,” Pries and colleagues wrote. “From a clinical perspective, our results suggest that the integration of SLEs can increase the clinical utility of electronic health records. From a public health perspective, our findings underline the promise for investment in public health strategies that focus on modifiable environmental factors over the life span to improve population-based mental health outcomes.”