Introduction: There is considerable variability in the response of individuals to adverse environmental conditions, while some develop psychiatric illnesses like depression, others seem very capable of dealing with it. It is in this observation that the concepts of vulnerability and resilience are rooted.
Methods: We conducted a review of the literature by inserting in PubMed the keywords resilience, vulnerability and depressive disorders.
Discussion and conclusions: Freud formerly used the so-called crystal-principle to describe the concept of vulnerability: according to this, the different psychopathologies would arise depending on the different psychological weaknesses, just like a crystal thrown to the ground shatters along its lines of cleavage intrinsic to it, albeit invisible. The term resilience has been borrowed from physics where it is used to describe the ability of a material to withstand impact without cracking. In psychology, the term resilience refers to a complex and dynamic multidimensional construct, which derives from the interaction of neurobiological, social and personal factors and indicates the ability to adaptively cope with stress and adversity, preserving a normal physical and psychological functioning. Resilience has proven to be a protective factor against the development of psychiatric disorders such as depression. Making a conceptual leap, the concepts of vulnerability and resilience can be related to the psychodynamic classification of depression postulated by Gaetano Benedetti, who distinguished four kinds of depression: the first due to the failure of the ego, the second to the perversion of the superego, the third to the inhibition of the Id and the fourth to the collapse of the ego ideal. It is possible to improve the resilience of depressed subjects through pharmacological and psychotherapeutic interventions.