Silva dos Santos, AmílcarSales, MiguelSebastião, Ana MGusmão, Ricardo2021-04-272021-04-272021Front Psychiatry. 2021 Apr 9;12:607339http://hdl.handle.net/10451/47559Copyright © 2021 Silva-dos-Santos, Sales, Sebastião and Gusmão. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.In this opinion article, we humbly propose a new viewpoint on the etiopathogenesis of depression. We base the model on our interpretation of selected recent neurophysiological findings, mainly regarding Deep Brain Stimulation (DBS) to treat Parkinson’s Disease and also DBS to treat Treatment-Resistant Depression (TRD). We coin the idea a mental kindling-like mechanism. However, future clinical research, possibly complemented with human laboratory research or animal experiments, will be needed to test the validity of our proposed model. On the current manuscript framework, following the first and introductory section, we will set the stage by presenting selected studies and insights mainly from DBS to treat TRD and PD, on the second and middle section. Finally, we will discuss the proposed viewpoint on the third and last section of the present work.engParkinson's diseaseDeep brain stimulationDepressionEtiopathogenesisMental kindling-like mechanismTreatment-resistant depressionjournal article10.3389/fpsyt.2021.6073391664-0640