Impulsivity across severe mental disorders: a cross-sectional study of immune markers and psychopharmacotherapy

Abstract

Background Impulsivity is a transdiagnostic feature linked to severe clinical expression and a potential target for psychopharmacological strategies. Biological underpinnings are largely unknown, but involvement of immune dysregulation has been indicated, and the efects of psychopharmacological agents vary. We investigated if impul‑ sivity was associated with circulating immune marker levels and with a range of psychopharmacological treatment regimens in severe mental disorders.<p> <p>Methods Impulsivity was assessed in a sample (N=657) of patients with schizophrenia or schizophreniform disorder (SCZ) (N=116) or bipolar disorder (BD) (N=159) and healthy participants (N=382) using the Barratt Impulsiveness Scale (BIS-11) questionnaire. Plasma levels of systemic immune markers (RANTES, IL-1RA, IL-18, IL-18BP, sTNFR-1) were measured by enzyme immunoassays. Patients underwent thorough clinical assessment, including evaluation of psy‑ chotropic medication. Associations were assessed using linear regressions. <p>Results Impulsivity was positively associated with SCZ (p<0.001) and BD (p<0.001) diagnosis and negatively associated with age (p<0.05), but not signifcantly associated with any of the circulating immune markers indepen‑ dently of diagnostic status. Among patients, impulsivity was negatively associated with lithium treatment (p=0.003) and positively associated with antidepressant treatment (p=0.011) after controlling for diagnosis, psychotropic comedications, manic symptoms, and depressive symptoms. <p>Conclusions We report elevated impulsivity across SCZ and BD but no associations to systemic immune dysregu‑ lation based on the current immune marker selection. The present study reveals associations between impulsivity in severe mental disorders and treatment with lithium and antidepressants, with opposite directions. Future studies are warranted to determine the causal directionality of the observed associations with psychopharmacotherapy