Background: Referrals to clinical services of people living in severe domestic squalor are not uncommon. It is timely to review literature concerning and discussing such cases.

Method: Using Medline, Psychinfo, Embase, CINAHL and reference lists from relevant publications, literature referring to over 1100 cases was identified and then reviewed.

Results: Half of those described as living in severe squalor are elderly. Outcomes of intervention are often poor. People living in severe squalor are most commonly diagnosed as having dementia, alcoholism or schizophrenia, though personality problems are evident in a high proportion. There is evidence to suggest that neglect of hygiene and of attention to cleanliness of accommodation may be largely attributable to frontal lobe changes. The review also revealed a second body of literature, not often cited in papers focussed on unclean living conditions and published in psychiatric or medical journals, that concludes that hoarding is most commonly due to obsessive-compulsive disorder (OCD). Accumulation of rubbish is described in over half of the case reports on severe domestic squalor, but it is suggested that this should only be called hoarding if it results from purposeful collection of items. Lack of impulse control may contribute to collecting behavior, resulting in reduction in living space if there is also a failure to discard.

Conclusions: There is a need for further studies, using standardized ratings of living conditions, investigating and trying to understand the complex interplay of triggers and vulnerabilities, exploring how best to intervene and examining outcomes of interventions.