Background: Depressive disorders are among four leading causes of burden among the most disabling medical illnesses and antidepressant drugs (AD) occupying leading positions in the worldwide pharmaceutical market. However, typical AD show prolonged delay, refractory and adverse side effects. Methodology: The review analyzes experimental data and theoretical models of possible antidepressant effect of benzopentathiepine, 8-(trifluoromethyl)-1,2,3,4,5 - benzopentathiepin-6- amine hydrochloride (TC-2153). The antidepressant effect of TC-2153 is based on its ability to inhibit striatal enriched protein tyrosine phosphatase (STEP)- an enzyme that plays a key role in the intraneuronal transduction of signals from receptors of classic neurotransmitters and the brain derived neurotrophic factor (BDNF). The mechanism underlying antidepressant effect of TC-2153 includes increase in production as well as intracellular effect of BDNF on neuronal survival and neurogenesis. Results and Conclusion: There is no visible mechanisms of delay, refractory and adverse side effects of TC-2153. Thus, TC-2153 is a promising drug of new generation of atypical AD.