Allostatic load is associated with positive symptoms in schizophrenia and first-episode psychosis and decreases with antipsychotic therapy

Background: Current pathophysiological models of schizophrenia suggest that stress contributes to the etiology and trajectory of the disorder. We investigated whether cumulative exposure to stress, quantified by allostatic load (AL), an integrative index of immune, metabolic, and neuroendocrine dysregulation, is elevated in patients with schizophrenia (SCZ) and first-episode psychosis (FEP) and related to psychotic symptoms and social and occupational functioning and assessed the temporal dynamics of AL in response to treatment with second-generation antipsychotics. Methods: We assessed AL in a naturalistic study of unmedicated patients with SCZ (n = 28), FEP (n = 28), and healthy controls matched for age and gender (n = 53) at baseline and 6 and 12 weeks after commencement of antipsychotic therapy. Biomarkers for the AL index were selected based on (1) representation of several physiological systems including the cardiovascular, neuroendocrine, immune, and metabolic systems; (2) use in previous AL research; and (3) associations with disease risk. We adopted a scaled AL algorithm whereby each marker proportionally contributes to the overall AL index. Unadjusted and adjusted differences between patients with SCZ, FEP, and controls in AL were tested with ANCOVA, and partial correlations were used to test associations of AL with psychometric variables. Results: AL was higher in patients with SCZ compared to controls (4.91 ± 1.89 vs. 2.87 ± 1.62, P < .001), patients with FEP compared to controls (3.80 ± 1.66 vs. 2.87 ± 1.62, P = .020) but not different between patients with SCZ and patients with FEP (P = .302). Adjusting for age and smoking, we found that positive symptoms were positively correlated with AL across all patients with a psychotic disorder (adjusted R = .520, P < .001) and Global Assessment of Functioning (GAF) scores were negatively correlated with AL at trend level (adjusted R = −.251, P = .070). No significant associations were found for negative symptoms (P = .582). AL decreased after treatment with olanzapine, risperidone, or quetiapine was commenced in patients with SCZ and FEP between the baseline assessment and the 6- and 12-week follow-up. Conclusion: Our data provide evidence for cumulative physiological dysregulation in patients with SCZ and FEP that is linked to the experience of current positive psychotic symptoms. AL could be a useful model that takes stress, long-term adaptation, and its failures into account to further understand the pathophysiology of schizophrenia.

Schizophrenia Bulletin

Schizophrenia Bulletin

43

1745-1701

N/A

S1

2