Smells, especially unpleasant ones, are seldom viewed as clinical symptoms. They are associated with old medical practice. Modern medicine has relinquished the sense of smell as a tool for diagnosis. However, certain psychiatric disorders are characterized by modifications in body odour, as in Diogenes syndrome, depression, schizophrenia or alcoholism.

Various psychopathological and physiological hypotheses are given to explain this phenomenon. In the 60s, the hypothesis of a metabolic disorder in schizophrenics, leading to a specific odour, was put forward but not confirmed. More recently, a possible problem in the sense of smell has been suspected in severely depressed patients who might not properly perceive the sense of pleasure associated with good smells.

We will go also into psychological and psychodynamic aspects. For example, the misanthropy associated with bodily slovenliness, and hoarding (a real second skin), is consistent with repulsive bad smells noted during house calls to the sufferers of Diogenes syndrome. Bad smells tend to entail a self-excluding process, well-known in homeless people.

Faced with these smells, carers may encounter specific difficulties. Can smelling bad diminish a patient's access to treatment? This communication sets about reviewing this little-studied psychiatric matter, and giving examples, through our clinical experiences, of the problems that carers encounter.