Compulsive hoarding
Synonyms and keywords:  Hoarding disorder; pathological hoarding; pack rat; packrat; syllogomania

# Overview
Compulsive hoarding (or pathological hoarding) is extreme hoarding behavior in humans. It involves the collection or failure to discard large numbers of objects even when their storage causes significant clutter and impairment to basic living activities such as moving around the house, cooking, cleaning, showering or sleeping. Hoarding rubbish may be referred to as syllogomania. A slang term for a compulsive hoarder is pack rat or packrat.

# Characteristics
While there is no definition of compulsive hoarding in accepted diagnostic criteria (such as the current DSM), Frost and Hartl (1996) provide the following defining features:
- the acquisition of, and failure to discard, a large number of possessions that appear to be useless or of limited value
- living spaces sufficiently cluttered so as to preclude activities for which those spaces were designed
- significant distress or impairment in functioning caused by the hoarding

# Case study
The following (edited) case study is taken from a published account of compulsive hoarding:

# Classification

## OCD
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). There may be an overlap with a condition known as impulse control disorder (ICD), particularly when compulsive hoarding is linked to compulsive buying or acquisition behaviour. However, some people displaying compulsive hoarding behaviour show no other signs of what is usually considered to be OCD, OCPD or ICD. Those diagnosed with attention-deficit hyperactivity disorder (ADHD) often have hoarding tendencies.

## Book hoarding
Bibliomania is an obsessive-compulsive disorder involving the collecting or hoarding of books to the point where social relations or health are damaged. One of several psychological disorders associated with books, bibliomania is characterized by the collecting of books which have no use to the collector nor any great intrinsic value to a genuine book collector. The purchase of multiple copies of the same book and edition and the accumulation of books beyond possible capacity of use or enjoyment are frequent symptoms of bibliomania.

## Animal hoarding
Animal hoarding involves keeping higher than usual numbers of animals as pets without having the ability to properly house or care for them, while at the same time denying this inability. Compulsive hoarding can be characterized as a symptom of obsessive-compulsive disorder rather than deliberate cruelty towards animals. Hoarders are deeply attached to their pets, and find it extremely difficult to let the pets go. They typically cannot comprehend that they are harming their pets by failing to provide them with proper care. Hoarders tend to believe that they provide the right amount of care for their pets. The American Society for the Prevention of Cruelty to Animals provides a "Hoarding Prevention Team", which works with hoarders to help them attain a manageable and healthy number of pets. Along with other compulsive hoarding behaviours, it is linked in the DSM-IV to obsessive-compulsive disorder and obsessive-compulsive personality disorder. Alternatively, animal hoarding could be related to addiction, dementia, or even focal delusion.
Animal hoarders display symptoms of delusional disorder in that they have a belief system out of touch with reality. Virtually all hoarders lack insight into the extent of deterioration in their habitations and on the health of their animals, refusing to acknowledge that anything is wrong. Delusional disorder is an effective model in that it offers an explanation of hoarders apparent blindness to the realities of their situations. Another model that has been suggested to explain animal hoarding is attachment disorder, which is primarily caused by poor parent-child relationships during childhood. As a result, those suffering from attachment disorder may turn to possessions, such as animals, to fill their need for a loving relationship. Interviews with animal hoarders have revealed that often hoarders experienced domestic trauma in childhood, providing evidence for this model. Perhaps the strongest psychological model put forward to explain animal hoarding is obsessive-compulsive disorder (OCD).

# Differential Diagnosis
- Major depressive episode
- Neuro cognitive disorders
- Neuro developmental disorders
- Autism spectrum disorder
- Intellectual disability (intellectual developmental disorder)
- Obsessive-compulsive disorder
- Other medical conditions
- Cerebrovascular disease
- Traumatic brain injury
- Seizure control
- Herpes simplex encephalitis
- Prader-Willi syndrome
- Schizophrenia spectrum and other psychotic disorders

# Epidemiology and Demographics

## Prevalence
The point prevalence of hoarding disorder is 2,000-6,000 per 100,000 (2%-6%) of the overall population

# Risk Factors
- Genetic predisposition
- Stress
- Trauma

# Diagnostic Criteria

## DSM-V Diagnostic Criteria for Hoarding Disorder

# Related conditions
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). There may be an overlap with a condition known as impulse control disorder (ICD), particularly when compulsive hoarding is linked to compulsive buying or acquisition behaviour. However, some people displaying compulsive hoarding behaviour show no other signs of what is usually considered to be OCD, OCPD or ICD. Those diagnosed with Attention-deficit hyperactivity disorder (ADHD) often have hoarding tendencies.

# Physiology and treatment
People who exhibit compulsive hoarding tend to absorb glucose into the brain differently than people who do not exhibit this behavior.  The difference in cerebral metabolism of glucose is greatest in the rear and central parts of the brain.
The antidepressant drug paroxetine (brand name Paxil) is indicated in treatment of compulsive hoarding.  This usage may have dangerous side effects; tests are in progress. A study of this usage of the drug was conducted by the University of California, San Diego.