A potential objective marker in first-episode schizophrenia based on abnormal niacin response

Area of Science:

• Neuroscience
• Psychiatry
• Biomarkers

Background:

• Schizophrenia (SZ) diagnosis lacks objective markers, complicating clinical management.
• Current niacin skin flush abnormality (NFA) quantification has limited sensitivity (~30%) for SZ detection.
• Objective diagnostic tools are crucial for early intervention in psychosis.

Purpose of the Study:

• To develop and validate a modified NFA method for improved objective diagnosis of first-episode schizophrenia (FES).
• To enhance the sensitivity and specificity of NFA in distinguishing FES from healthy controls and psychotic bipolar disorder patients.
• To assess the potential of NFA as an early diagnostic marker for schizophrenia.

Main Methods:

• Laser Doppler flowmetry measured niacin skin-flushing response in 123 first-episode psychosis patients (FES, PBP) and 80 non-psychiatric comparisons (NPC).
• A novel method modified bivariate cut-offs using EC50 and overall trend area (OTA).
• Performance was compared against the existing bivariate cut-offs method.

Main Results:

• The modified NFA method achieved 57% sensitivity, 89% specificity, and 73% accuracy for predicting FES in NPCs, outperforming the old method (28% sensitivity, 91% specificity, 59% accuracy).
• The novel method distinguished FES from psychotic bipolar disorder (PBP) with 62% accuracy, compared to 45% with the old method.
• Sensitivity and specificity remained most stable with the modified method across adjusted thresholds.

Conclusions:

• Modified NFA using EC50 and OTA shows potential as an objective biomarker for identifying first-episode schizophrenia.
• The enhanced niacin skin test offers a feasible approach for the early diagnosis and treatment of schizophrenia.
• Further validation is warranted to establish NFA as a reliable diagnostic tool.