In the past, lower serum BDNF levels in patients suffering from a number of neurological conditions compared to HC have been reported (such as depression,31 schizophrenia,32, 33, 34, 35, 36, 37, 38 Alzheimer’s,39, 40 or Huntington’s disease.41, 42. The gene discussed is BDNF; the disease is depressive symptom measurement.