title: New insights into the neurobiological mechanisms of major depressive disorders.
abstract: OBJECTIVE
  To review the current evidence about the neurobiological mechanisms in major depressive disorders (MDD) and the key findings from studies using neuroimaging tools and animal models.
  
  
  METHODS
  This paper gives an overview of the role of genetic and environmental factors in the pathophysiology of MDD and describes the structural changes in brain structures of depressed individuals. A closer look is given at the molecular processes and neurotransmitters implicated in this mental disorder. Moreover, this paper discusses key findings from recent research using animal models and their relevance for clinical applications.
  
  
  RESULTS
  Although the exact cause of MDD is not known, there is enough evidence showing that genetic, psychological and environmental factors significantly increase the risk of developing this disease. Individuals affected by MDD exhibit a reduced volume of structures such as the amygdala, hippocampus and basal ganglia, as well as altered level of neurotransmitters in the brain.
  
  
  CONCLUSIONS
  The studies presented in this review show promising results that could shed light on the molecular mechanisms of MDD. However, more work needs to be done to better understand this psychiatric disorder and promote the development of new treatment strategies.
authors.affiliation: Department of Neuroscience, Faculty of Medicine, University of Montreal, Montreal, Quebec, H3C 3J7, Canada. Electronic address: marc.fakhoury@umontreal.ca.
authors.forename: Marc
authors.initials: M
authors.lastname: Fakhoury
mesh_terms: D000818:Animals; D003865:Major Depressive Disorder / Q000209:etiology / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans
keywords: Antidepressant drug; Major depressive disorder; Neurobiology; Neurotransmitter