Short-Term Abstinence Reveals Hematological, Biochemical, and Gene–Protein Profile Changes in Methamphetamine and Ice Users

Addictive substances are a critical public health problem in Thailand and worldwide. Methamphetamine and ice (MI) are frequently used to enhance alertness and prolong working hours by directly affecting the central nervous system and other organs. This study aimed to identify biomarkers for current MI users (MIB) and individuals after 20 days of abstinence (MIA) Compared with healthy controls, MI use increased red blood cell (RBC) and platelet (PLT) counts, did not affect total white blood cell (WBC) numbers, but increased the proportion of neutrophils while decreasing lymphocytes, monocytes, eosinophils, and basophils. Short-term MI abstinence did not substantially alter hematological or biochemical parameters, except for an increase in alanine aminotransferase (ALT). MIB showed impaired neutrophil phagocytosis and reduced bactericidal activity via the respiratory burst. In MIA, respiratory burst activity was partially restored but remained lower than in healthy controls. Transcriptomic analysis identified CEACAM4, IFIT2, KCNJ2, FRAT2, and RNF139 as a candidate mRNA biomarker panel for MIA. Serum proteomic analysis revealed distinct protein profiles between methamphetamine-only users and MI users, indicating differential systemic effects between these groups. In conclusion, MI impairs hematological parameters and neutrophil function. Both mRNA and protein biomarkers may be useful for monitoring abstinence status during rehabilitation.