Nonlinear associations between reported childhood trauma and cognitive impairment in schizophrenia spectrum disorders

Cognitive impairment is a core feature of schizophrenia associated with childhood trauma, but the specific adversity factors underlying this relationship remain unclear. We hypothesized that physical neglect, rather than emotional neglect or abuse (emotional, physical, sexual), would be specifically related to general cognition and memory (verbal learning, working memory), even when controlling for co-occurring traumas, and explain most of the cognitive differences between cases and controls. Data visualization revealed several nonlinear relationships, which were examined through exploratory analyses.

215 individuals with schizophrenia and 213 controls were assessed using the Childhood Trauma Questionnaire and Screen for Cognitive Impairment in Psychiatry. Regression models examined relationships between adversity and cognition. Nonlinear associations were evaluated using segmented regressions. Specificity and proportion of variance explained were tested through sensitivity analyses.

In schizophrenia, general cognition was associated with all traumas, except sexual abuse. Verbal learning was related to emotional abuse and physical trauma, while working memory was associated with physical neglect and emotional trauma. Nonlinear relationships with cognition were detected for cumulative trauma, emotional neglect, and emotional abuse. Limited evidence was found for specificity. When compared with controls, cumulative trauma explained more cognitive impairment than any subtype.

We provide novel evidence for nonlinear associations between trauma and cognition, which may account for discrepancy among existing studies and suggest sensitivity of neural substrates of memory to particular levels of trauma. Our results also indicate that some of the cognitive deficits in schizophrenia may be attributed to the influence of early environmental factors.