Its levels are reduced in patients with several psychiatric disorders, but it is unclear if the response to psychotherapy can alter its concentration.<h4>Objective</h4>To carry out a systematic review evaluating the effects of individual psychotherapy in BDNF levels in patients with mental disorders.<h4>Methods</h4>The databases PubMed, EMBASE, PsycArticles, SciELO, Web of Science, and CENTRAL; the last search was performed on October 2019 for trials evaluating the effects of individual psychotherapy in BDNF levels in adults with mental disorders. Here, BDNF is linked to mental disorder.