However, the study of the previously described SNP rs6265-T (V66M) in the BDNF gene, associated with an increased risk of MDD in the Mexican American population (7) and paranoid schizophrenia in the Chinese population (47–49), revealed no significant difference between the studied groups and the group of healthy volunteers in total selection: for the “schizophrenia” group - p = 0.0641 (n = 102), and for the “depression” group - p = 0.7469 (n = 79). This evidence concerns the gene BDNF and depressive symptom measurement.