Providing monitoring and support to patients suffering from Major Depression plays a significant role in preventing reoccurrence and relapse of this disease which are very common characteristic of it. In this work the conceptual design of a Major Depression Remote Intelligent Monitor, called MADRIM is presented. The main goal of MADRIM is to follow the evolution of the patient during his/her recovery in order to understand its behavior and to support preventing the reoccurrence of depression. In this paper one of MADRIM's main modules, i.e. the Patient Evolution Model (PEM), is described in detail. The PEM, based on qualitative reasoning, studies the tendency in the depression level change of each patient. MADRIM is based on different input sources such are clinical data, life events and patient's mood as well as physiological data collected from sensors. As output the system provides three different levels of patient's enhancement information, i.e. progress information, alerts and alarms, to the different actors involved in the treatment, i.e. patients, primary care physicians, psychiatrists and virtual assistants.