[Diogenes syndrome and Hoarding disorder: Same or different?]

In 2013, the American Psychiatric Association published the DSM-5. In this new version, new diagnoses were proposed including the Hoarding disorder. In the French semeiology, the Diogenes syndrome is described, among other symptoms, by a pathological tendency to accumulate objects called syllogomania which is very close to hoarding. This paper explores the similarities and differences between the two syndromes.

The Diogenes syndrome was first described in 1966 but was officially named for the ancient Greek philosopher in 1975 by Clark. Its frequency is around five for 100,000 persons. Many aetiologies have been known to be associated with the Diogenes syndrome: schizophrenia, dementia - especially frontotemporal type, anxiety disorders, mood disorders, and substance abuse - especially alcohol abuse. The diagnostic requires one major criterion, the inability to ask for medical or social help, and one of three minor criteria: a pathological relationship to the body, which leads to somatic illness; a pathological relationship to the society, which leads to a progressive exclusion from it; and finally, a pathological link with objects. This last criterion is very interesting because it is closely related to the Hoarding syndrome: indeed, patients with syllogamania, as also named, have a tendency to hoard every object they find. At the end, their homes are full of useless objects, and some living places can be unusable because they are cluttered and congested. This last point is similar to the definition given in the DSM-5 for the Hoarding disorder which describes a persistent difficulty parting with possessions; distress associated with discarding possessions; and accumulations that congest and clutter active living areas. The Hoarding disorder was first part of the Obsessive and compulsive disorders, but it has progressively appeared that it could be individualized with its own prevalence of 2.3% to 14% lifetime. Genetical studies have shown that at least 50% of patients suffering from excessive hoarding had a relative with a dimension of hoarding. Finally, Mattaix-Cols et al. decided to create a new syndrome in the DSM-5, and the Hoarding disorder was born.

The discussion begins with relationships between the Hoarding disorder and the Diogenes syndrome. A patient with hoarding, and a poor insight, could be very isolated, and could persist in a lack of calling for help, because of not being aware of his pathology. Thus, it could be diagnosed as a Hoarding syndrome with a poor insight, or as a Diogenes syndrome, with the first major criterion (lack of calling for help) and one of the three minor criteria, the syllogomania, or hoarding. Moreover, some authors have described old people living for many years with a tendency to hoard. Progressively, some of them had a congested and cluttered home, and a few were living in squalor, a description very close to the Diogenes syndrome. Finally, we discuss the comorbidity of Hoarding disorder and Diogenes syndrome. In particular, the first one is associated with Attention deficit and hyperactivity disorders; and some authors also described the links between ADHD, bipolar disorder and frontotemporal dementia which is one of the aetiologies of the Diogenes syndrome. A psychodynamic model in which ADHD, Hoarding disorder and Diogenes syndrome are linked can be imagined, and the last one could be an overlooked evolution of the two first syndromes.

In conclusion, we can imagine a dimensional model, based on two dimensions: hoarding and squalor. Hoarding disorder is the major expression of the first dimension, and Diogenes syndrome the major expression of the second. Both of them could be a different expression of one central aetiology. More studies are needed to complete this vision.