Brain-derived neurotrophic factor (BDNF) is the most studied and characterized neurotrophin in the central nervous system of mammals, due to its potential role in numerous pathologies and psychiatric disorders. It plays a significant role in the development and maintenance of normal brain function, as it promotes several brain functions such as growth, survival and neuronal differentiation, and is directly involved in synaptic plasticity and in cognitive function. This paper reviews the role of BDNF in the central nervous system and its implication in major depressive disorder (MDD), schizophrenia, and neurodegeneration. Finally, it evaluates the effects of antipsychotic and antidepressant treatments on BDNF levels and proposes this neurotrophin as a synaptic repair strategy in neurodegenerative diseases and also as a therapeutic target for the treatment of MDD and schizophrenia.