Diogenes syndrome (DS) is an acquired behavioural disturbance more often affecting elderly patients, but possible in all ages. It is characterised by social withdrawal, extreme self and house neglect, tendency to hoard any kind of objects/rubbish (syllogomania), and rejection against external help for lack of concern about one’s condition. It is considered infrequent, but with quite high mortality. DS might be divided into several forms including Active (the patient gathers objects outside and accumulates them inside his house), Passive (patient invaded by his own rubbish), “à deux” (DS sharing between two people), and “under-threshold” (DS “blocked” by precocious intervention). Four cases are here presented. In case 1 (passive DS) alcoholism and cognitive impairment could be trigger factors for DS, predisposed by a “personality alteration”. In case 2 (active, “à trois”) superimposed psychosis could be the trigger, borderline intelligence being the predisposing factor. In case 3 (active), fronto-parietal internal hyperostosis might support an organic aetiology. Finally, case 4 was an example of isolated syllogomania in patient with evolving Alzheimer’s dementia. Despite being heterogeneous, our casuistry suggest that DS can develop in both sexes, is prevalent in geriatric age and often associated with cognitive impairment/psychiatric disturbances, which are not specific, nor sufficient to justify DS. Isolated syllogomania only shares the characteristic hoarding with DS; although cognitive impairment might be present, the other DS typical aspects (social isolation, help refusal, characterial aspects, personal hygiene neglect) are absent.