Other medical conditions. Hoarding disorder is not diagnosed if the symptoms are judged to be a direct consequence of another medical condition (Criterion E), such as trau- matic brain injury, surgical resection for treatment of a tumor or seizure control, cerebro- vascular disease, infections of the central nervous system (e.g., herpes simplex encephalitis), or neurogenetic conditions such as Prader-Willi syndrome. Damage to the anterior ven- tromedial prefrontal and cingulate cortices has been particularly associated with the ex- cessive accumulation of objects. In these individuals, the hoarding behavior is not present prior to the onset of the brain damage and appears shortly after the brain damage occurs.
Some of these individuals appear to have little interest in the accumulated items and are able to discard them easily or do not care if others discard them, whereas others appear to be very reluctant to discard anything.
Neurodevelopmental disorders. Hoarding disorder is not diagnosed if the accumula- tion of objects is judged to be a direct consequence of a neurodevelopmental disorder, such as autism spectrum disorder or intellectual disability (intellectual developmental disorder).
Schizophrenia spectrum and other psychotic disorders. Hoarding disorder is not di— agnosed if the accumulation of objects is judged to be a direct consequence of delusions or negative symptoms in schizophrenia spectrum and other psychotic disorders.
Major depressive episode. Hoarding disorder is not diagnosed if the accumulation of objects is judged to be a direct consequence of psychomotor retardation, fatigue, or loss of energy during a major depressive episode.
Obsessive-compulsive disorder. Hoarding disorder is not diagnosed if the symptoms are judged to be a direct consequence of typical obsessions or compulsions, such as fears of contamination, harm, or feelings of incompleteness in obsessive-compulsive disorder (OCD). Feelings of incompleteness (e.g., losing one’s identity, or having to document and preserve all life experiences) are the most frequent OCD symptoms associated with this form of hoarding. The accumulation of objects can also be the result of persistently avoid- ing onerous rituals (e.g., not discarding objects in order to avoid endless washing or check- ing rituals). \
In OCD, the behavior is generally unwanted and highly distressing, and the individual ex- periences no pleasure or reward from it. Excessive acquisition is usually not present; if exces- sive acquisition is present, items are acquired because of a specific obsession (e.g., the need to buy items that have been accidentally touched in order to avoid contaminating other people), not because of a genuine desire to possess the items. Individuals who hoard in the context of
OCD are also more likely to accumulate bizarre items, such as trash, feces, urine, nails, hair, used diapers, or rotten food. Accumulation of such items is very unusual in hoarding disorder.
When severe hoarding appears concurrently with other typical symptoms of 0CD but is judged to be independent from these symptoms, both hoarding disorder and 0CD may be diagnosed.
Neurocognitive disorders. Hoarding disorder is not diagnosed if the accumulation of objects is judged to be a direct consequence of a degenerative disorder, such as neurocog- nitive disorder associated with frontotemporal lobar degeneration or Alzheimer’s disease.
Typically, onset of the accumulating behavior is gradual and follows onset of the neuro- cognitive disorder. The accumulating behavior may be accompanied by self—neglect and severe domestic squalor, alongside other neuropsychiatric symptoms, such as disinhibi- tion, gambling, rituals/stereotypies, tics, and self—injurious behaviors.
Approximately 75% of individuals with hoarding disorder have a comorbid mood or anx- iety disorder. The most common comorbid conditions are major depressive disorder (up to 50% of cases), social anxiety disorder (social phobia), and generalized anxiety disorder.