Résumé : In this doctoral work, we have demonstrated that in chronic insomnia and subtypes of major depression with objective insomnia, the hyperarousal is a fundamental pathophysiological mechanism promoting the occurrence of cardio-metabollc complications and alterations of neurotransmission during sleep. In these particular subpopulatlons, It therefore seems essential to put in place appropriate therapeutic strategies to block the phenomenon of hyperarousal throughout the night in order to allow a better cardio-metabolic prevention and a better clinical evolution both symptomatically and cognitively.