Efficiency and Extent of Niacin-Induced Skin Flushing Patterns in Early Stages of Psychosis

Objective: Niacin-induced skin flushing response (NSFR) attenuation is a well documented biomarker for psychosis and has also been used in studies of bipolar affective disorder. It appears not only in later stages but also in first episodes and in clinical high-risk (CHR) stages.

Methods: NSFR tests were conducted on healthy controls (HC), CHR individuals, and first-episode psychosis (FEP) patients from January 2019 to March 2024. The tests involved applying niacin patches at different concentrations and recording skin responses at multiple time points. A newly introduced slope variable was used to evaluate response efficiency. CHR participants were followed for 3 years to assess the predictive value of NSFR efficiency and attenuation degree for psychosis onset.

Results: This study included 98 CHR individuals (mean age: 18.4 years, 42.9% male), 54 FEP patients (24.7 years, 50% male), and 61 HC (25.8 years, 54.1% male). Over the 3-year follow-up, 23 (23.5%) CHR individuals converted to psychosis. CHR individuals showed NSFR attenuation levels between those of FEP patients and HC. Lower response efficiency was associated with a higher risk of developing psychosis, specifically at 10^-4 M and 10^-2 M concentrations (P = .001 and P = .039, respectively). The area under the curve for predicting psychosis onset using slope values at 10^-2 M was 0.645 (P = .034). For discriminating CHR from HC, significant factors included slope at 10^-3 M concentration (P = .006), total scores at 5 minutes (P = .001) and 15 minutes (P = .005), and total scores at 10^-3 M (P = .002) and 10^-2 M (P = .001). For discriminating FEP from HC, significant factors were the slope at 10^-4 M concentration (P = .023), total score at 5 minutes (P = .003), and total score at 10^-3 M concentration (P = .040).

Conclusions: NSFR efficiency is a sensitive marker for early psychosis risk, highlighting the need for precise and comprehensive detection methods.