Le déni est un phénomène de refus de prendre en compte une part de réalité externe inacceptable, c'est-à-dire, non métabolisable sur le plan psychique. Ce terme initialement apparu au XIII^e siècle, au sens général de refuser quelque chose à quelqu'un, est utilisé en droit dès le XIV^e siècle. La langue moderne a gardé le terme avec des emplois restreints, et surtout en termes de jurisprudence. En psychiatrie, il représente une modalité défensive permettant parfois la coexistence de représentations isolées. La clinique nous confronte régulièrement à différentes formes de déni, relevant d'élaborations psychopathologiques multiples. Lorsque le déni n'est pas structurel, comme dans le cas de la perversion mais conjoncturel, il apparaît réversible et accessible aux soins. Après avoir tenté de définir le déni, nous décrivons plusieurs situations cliniques marquées par de multiples formes de déni, et les possibilités thérapeutiques de travailler avec ce déni ou autour du déni.

In case of disease and trauma some patients draw back upon denial to endure a reality that is unacceptable, i.e. that cannot be assimilated in the psychic sphere. The denial is a phenomenon of the patient refusing to recognise parts of reality. But what is denial? A symptom? A defensive psychotic mechanism? In clinical cases we are regularly confronted with different forms of “denial”, emanating from multiple psychopathologic elaborations. What psychiatric situations lead us to talk about “denial”? Is it always the same regardless of the circumstances of the situation? After defining denial, we have tried to approach its function in different cases of schizophrenia, personality disorder, pregnancy and somatic diseases with the help of clinical cases. According to E. Lancon, the verb “denier” appears in the French language about 1160 in the form of “denier” derived from the latin “denegare”. In modern French, “denier” expresses the fact: i) of refusing to admit or to recognise a fact or an assertion as true or as one's own, or, expressed differently to refuse to recognise the relation with someone else; ii) of refusing to give somebody an IOU. Appearing in the 13th century with the general meaning of “an action to refuse something to somebody”, the obligatory). After the 17th century, it means to deny a fact. In modern language, it is used in a more restricted sense and mainly in legal expressions. “Dénégation” from the Latin “denegatio” is a late 14th century loan of a legal expression that means rejection. In the first place, it describes a situation when a person maintains that a fact reported by another one is not true. At the end of the 18th century, it is the refusal to recognise a fact. Nowadays, the expression is defined by the fact of negation or denial. In French literature, denegation is used more frequently than denial. In psychiatry, denial represents a reactive, defensive and unconscious mechanism used by a subject confronted with an invasion of anxiety as a reaction to trauma or disease. It is present in certain paradoxical situations where a normal personality is overtaxed by a major traumatic event that generates cracks and discontinuities in the tissue of this psychic reality. Otherwise, in the structures of more pathological personalities such as sexual perverts or borderline personalities, denial is associated with “cleavage” (split). In this case, denial does not affect the global perception of reality. Thus we can say that denial is a psychodynamic mechanism that may appear in any patient to allow him to maintain his integrity and his somatopsychic homeostasis as long as reality or parts of reality cannot be accepted. In psychosis, denial concerns large areas of reality allowing persons not to confront the anguish of annihilation. Denial appears in the silence and the lack of relation with the others. Denial is massive in paranoiac or schizophrenia pathologies. In this way, denial presents a scale of distinctive graded denials. Each degree of denial finds its corresponding level in a determined psychopathological organisation. This organisation is graduated from psychosis to perversion. The expression “denial” is used very frequently in psychiatry, sometimes in the description of clinical cases, or otherwise to show the difficulties of institutional treatment. It is used as rag-bag expression that underlines the inability of the care giver to deal with a patient who does not allow any communication.