Vagus nerve stimulation as a therapy for treatment resistant depression

Treball de fi de grau en Biologia HumanaTutor: Andrés Ozaita MinteguiThe major depressive disorder (MDD) is a prevalent chronic disease considered one of the most important causes of morbidity and mortality in the world. MDD is predicted to be the leading cause of disability by the year 2020. From all patients with MDD, at least 10% to 20% suffer treatment resistant depression (TDR) since they do not have satisfactory response to current available treatments. This paper summarizes the current pathophysiological hypothesis of depression including the alterations in monoaminergic transmission, the hypothalamic-pituitary-adrenal axis, neuroplasticity and inflammation, and their relation with an adjuvant therapeutic strategy, the vagus nerve stimulation (VNS). This recently accepted therapy consists in the stimulation through implanted electrodes of the left vagus nerve, which is known to be a direct connection between the nervous system and the periphery. This therapy has been accepted for the treatment of epilepsy and depression but is also under study for the treatment of chronic inflammatory disorders. In conclusion, although VNS is nowadays an invasive therapy, it has shown effectiveness in the treatment of mental and inflammatory disorders and promises to be an additional strategy in the treatment of a variety of diseased states