The vulnerability model is prevalent in the current Theory of Psychiatry. Systematic reflection after reviewing the historical proposition of this model can enrich its contents.

Complete and deepen the meaning of the concept “vulnerability” in Psychiatry.

Review historical approaches to the concept of vulnerability in Psychopathology. The study starts with Zubin & Spring and reaches contemporary approaches especially in the writings of Giovanni Stanghellini.

Seek sources to deepen its meaning looking back to Karl Jaspers and Ludwig Binswanger's classical Psychiatry. They offer psychopathological notions that can be used to enrich a model of vulnerability.

This is research in the context of Theory of Psychiatry, its method implies a historical literature review and a systematic philosophical reflection.

Vulnerability is still revealed to be the best concept to organize a model of mental illness. This study proposes to avoid any simple identification of vulnerability with statistical or genetic risk. Vulnerability in psychopathology should always be confronted with the horizon of human subjectivity. To keep in view this horizon – a limit impossible to grasp – is indispensable for clinicians and researchers if they want to understand patients who suffer mental illness. This process is helpful to avoid any reductionism about the image of mental illness and about the human being who suffers that illness.

“Vulnerability” is shown as a concept that needs to be thought over thoroughly and to be present in psychopathology to overcome reductionism and to understand the very possibility of psychiatric illness.

The authors have not supplied their declaration of competing interest.