The Potential of Hair Matrix for Biomarker Analysis in Schizophrenia.

Schizophrenia (SCZ) is a complex psychiatric disorder with positive, negative, and cognitive symptoms that cause long-term functional impairment. Despite available treatments, limitations in addressing cognitive and negative symptoms, medication side effects, and poor adherence highlight the need for novel biomarkers to support precision medicine. Hair has emerged as a promising, non-invasive biological matrix for biomarker research. Hair analysis has been explored to detect trace elements, abused drugs, antipsychotics, cortisol, neurotransmitters, and to assess gene expression, with results often consistent with blood, urine, and post-mortem tissues. Its advantages include ease of sampling and the ability to provide long-term information, while limitations involve individual variability and methodological inconsistencies. This review summarizes current evidence on hair-based biomarkers in SCZ, critically evaluating their potential and challenges. By integrating molecular, metabolic, and genetic findings, we highlight the value of hair as a complementary tool for advancing biomarker discovery and personalized approaches in SCZ.