BDNF and major depressive disorder: Numerous tools were used for the research evaluation: Montgomery-Asberg Depression Rating Scales (MADRS), Hospital Anxiety and Depression Scale (HADS), Global Assessment of Functioning (GAF), quality of life (RAND-36), Kimberley Indigenous Cognitive Assessment of Depression (KICA-dep), Toronto Alexithymia Scale–20 (TAS-20), Clinical Dementia Rating (CDR), Mini-Mental State Examination (MMSE), and Brain-Derived Neurotrophic Factor (BDNF).