Cytokine levels in symptomatic patients undergoing anti-psychotic treatment for First Episode Psychosis: a cross-sectional study.

Background Cytokines in first-episode psychosis (FEP) appear to be activated as part of an Inflammatory Response System (IRS) or a Compensatory Inflammatory Response System (CIRS) and have been proposed as clinical (state and trait) markers of psychosis. Antipsychotic medication normalizes the IRS/CIRS ratio despite a predominant activation of the IRS. The current study examined blood levels of IRS/CIRS cytokines proposed as clinical markers in symptomatic medicated patients with FEP. We screened all co-diagnoses and immunomodulating factors that have been linked to cytokine changes to increase the accuracy of findings. Methods We compared cytokines (n = 16) levels in the blood serum of patients with FEP (n = 20) recruited from a specialized FEP clinical service with a matched (age, gender, body mass index) group of healthy control subjects (HC)( n = 20). We screened for tobacco smoking, cannabis use, medications, and the absence of fever. Best-fitting regression models were used to identify differences in FEP vs HCs per diagnosis and additional variables of age, gender, and BMI. We correlated cytokine levels to Positive and Negative Symptoms Scale (PANSS) scores and antipsychotic load, recorded as chlorpromazine equivalents. Results We found elevated levels of IRS (IL-2 and IL-6), and reduced levels of IRS (IL-1, IL-8, IL-12), and CIRS (IL-4) in FEP vs HC. No significant differences in the IRS/CIRS ratio or a correlation between cytokine levels and PANSS scores were found. Lower levels of IL-2, IL-6 and IL-8 correlated to higher amounts of antipsychotics. Conclusion Our study on well-controlled moderately symptomatic patients with FEP taking antipsychotic treatment found that the IRS/CIRS ratio was not altered, while some alterations in cytokine levels were found. IL-2 and IL-6 remain elevated despite the immune-modulatory action of the antipsychotic agents; we suggest they could be used as screening tools for either trait (IL-6) and/or state (IL-2) markers of psychosis, in combination with C-reactive protein, to identify people with FEP that could potentially benefit from an adjuvant anti-inflammatory therapy alongside antipsychotics. Clinical trial registration number: Not applicable