Background: Recent studies have highlighted the clinical usefulness of near-infrared spectroscopy (NIRS) in psychiatry. However, the potential effects of psychotropics on NIRS signals remain unknown.
Methods: We conducted a systematic chart review of 40 depressed patients who underwent NIRS scans during a verbal fluency task to clarify the relationships between psychotropic dosage and NIRS signals. The dosage of psychotropic medications was calculated using defined daily dose (DDD). We investigated the associations between the DDD of psychotropic medications and oxygenated hemoglobin (oxy-Hb) in single channel levels.
Limitations: Retrospective study design and small sample size are the main limitations.
Results: Multiple regression analysis revealed that one channel in the right temporoparietal region had a significant association with antidepressant DDD controlling for age, sex, depression severity, and the DDD of antipsychotics and benzodiazepines. Moreover, high doses of antidepressants had significant effects on NIRS signals compared with low doses, in group comparisons.
Conclusions: The dose-dependent impact of antidepressants on NIRS signals should be taken into account when interpreting NIRS data.
Keywords: Anatomical Therapeutic Chemical, (ATC); Antidepressant; Bipolar disorder; Diagnostic and Statistical Manual of Mental Disorders, (DSM); Hamilton Rating Scale for Depression-17 item, (HRSD-17); International Classification of Diseases, (ICD); Major depressive disorder (MDD); Montgomery Asberg Depression Rating Scale, (MADRS); Near-infrared spectroscopy (NIRS); Schizophrenia; World Health Organization, (WHO); defined daily dose, (DDD); magnetic resonance imaging, (MRI); major depressive disorder, (MDD); near-infrared spectroscopy, (NIRS); oxy-hemoglobin, (oxy-Hb); positron emission tomography, (PET); regional cerebral blood volume, (rCBV); verbal fluency task, (VFT).