Inflammation, substance use, psychopathology, and cognition in phase 1 of the clinical antipsychotic trials of intervention effectiveness study

Introduction: Schizophrenia has been associated with aberrant blood levels of inflammatory markers. However, patients with comorbid illicit drug use have been inadequately studied with respect to immune function. Furthermore, associations between inflammatory markers, psychopathology, and cognition have been inconsistently considered. We investigated relationships between inflammatory markers, comorbid marijuana and cocaine use, and psychopathology and cognition in patients with schizophrenia. Method: For subjects with available fasting data from the baseline visit of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) schizophrenia trial, inflammatory markers were investigated as predictors of psychopathology and cognition in patients with and without comorbid marijuana or cocaine use, using linear regression models controlling for potential confounding factors. Results: Compared to subjects with a negative urine drug screen (UDS), marijuana use was a predictor of higher lymphocytes and E-selectin, and lower leptin (p ≤ 0.04 for each); cocaine use was a predictor of higher adiponectin (p = 0.04). In subjects with marijuana use, lower WBC and higher IL-6 were predictors of higher PANSS total score (p < 0.05 for each). In subjects with cocaine use, lower total and differential WBC were predictors of higher PANSS total score (p < 0.04 for each). In younger, non-obese subjects with a negative UDS, higher monocytes and IL-6 were predictors of PANSS total score (p < 0.04 for each). Conclusions: Our findings provide additional evidence that inflammation may be associated with psychopathology and cognition in some patients with schizophrenia. Furthermore, there is preliminary evidence for differential effects of comorbid marijuana and cocaine use on these relationships.