Exposure to environmental factors increases connectivity between symptom domains in the psychopathology network

BACKGROUND We investigated to what degree environmental exposure (childhood trauma, urbanicity, cannabis use, and discrimination) impacts symptom connectivity using both continuous and categorical measures of psychopathology. METHODS Outcomes were continuous symptom dimensions of self-reported psychopathology using the Self-report Symptom Checklist-90-R in 3021 participants from The Early Developmental Stages of the Psychopathology (EDSP) study and binary DSM-III-R categories of mental disorders and a binary measure of psychotic symptoms in 7076 participants from The Netherlands Mental Health Survey and Incidence Study (NEMESIS-1). For each symptom dimension in the EDSP and mental disorder in the NEMESIS-1 as the dependent variable, regression analyses were carried out including each of the remaining symptom dimensions/mental disorders and its interaction with cumulative environmental risk load (the sum score of environmental exposures) as independent variables. RESULTS All symptom dimensions in the EDSP and related diagnostic categories in the NEMESIS-1 were strongly associated with each other, and environmental exposures increased the degree of symptom connectivity in the networks in both cohorts. CONCLUSIONS Our findings showing strong connectivity across symptom dimensions and related binary diagnostic constructs in two independent population cohorts provide further evidence for the conceptualization of psychopathology as a contextually sensitive network of mutually interacting symptoms.