SUMMARY One of the crucial subjects, either for the clinical or scientific activity, is the dimensional or categorical character of depression and other mental diseases. Each approach is different from the theoretical and epistemological points of view. At presence, the categorical model for the definition and estimation of the presence of a disorder are reflected in the data on epidemiology, the results of investigations, instruments and the interventions. These elements are related to a system of thinking which results in a particular form of conceiving the psychopathology and intervention. Nevertheless, the strong influence of the categorical model in which the disorders are defined as a group of accomplished criteria has not prevented from development of a dimensional model. The latter postulates the existence of a continuum between the normality and pathology which correspond with dimensions, levels and severity related to the certain behaviours, traits or even symptoms. The interest in the dimensional approach to psychopathology, in general and in mood disorders, is caused by the observation in clinics which indicate, for example, that many patients do not improve with medicines and present residual symptoms during long periods of time. For these reasons, some personality factors which would explain the chronic symptoms of disorders have been proposed in Psychology and Psychiatry. Although the diagnostic manuals consider different types of mood disorders, many investigations have showed the possibility to consider depression as a continuum, where the least severe extreme would be the depressive personality and the most severe, major depression. According to the abovementioned proposal, it is possible that some people present certain vulnerability which would explain the different answers in case of depression. Cognitive factors, together with social and genetic factors increase the risk of chronic depressive symptoms. The catastrophic perception of self, the world and future, the dichotomous thinking and tunnel vision are the cognitive factors associated with the presence of the mood disorders symptoms. Additionally, some studies show the importance of gender, as women are more prone to develop depression and similar disorders which is related to traditional social roles. This can be caused by the need to sacrifice the professional career to dedicate time to housework, or to assume multiple roles. Concerning the genetic factors, the presence of first degree relatives with mood disorders increases the risk of development of depression or dysthymia. The consideration of depressive personality is based on the presence of symptoms which do not fulfil the criteria of severity and frequency of major depression but do affect the mood. The presence of these stable traits is related to major chronicity and worse prognosis. This condition has been described in manuals as dysthymia. Nevertheless, as it remains relatively stable in time it could be understood as a personality disorder. The disorder would be a continuum with the normality similar to this described as neuroticism in which some entities are qualitatively and quantitatively different which represent the categories.