Compulsive hoaring (or pathological hoarding) is the acquisition of, and failure to discard such a large number of seemingly useless possessions that that it causes significant clutter and impairment to basic living activities such as moving around the house, cooking, cleaning, showering or sleeping. It is not clear whether compulsive hoarding is a condition in itself, or simply a symptom of other related conditions. Several studies have reported a correlation between hoarding and the presence and / or severity of obsessive-compulsive disorder (OCD). Hoarding behaviour is also related to obsessive-compulsive personality disorder (OCPD). Hoarding rubbish may be referred to as syllogomania or disposophobia, and the slang term for a compulsive hoarder is a pack rat.