Possible Genetic Causes
Perhaps one of the least understood hoarding causes is genetics. According to the Department of Psychology at the University of California, San Diego, close to 85% percent of compulsive hoarders have another family member who is a compulsive hoarder. Hoarding seems to run in families, so it may be that that genetics has an impact on whether a person will become a compulsive hoarder.
A study carried out by a team at Johns Hopkins University School of Medicine in March 2007 looked at 999 OCD patients to see whether hoarding tendencies that ran in families could be traced back to a specific gene. Families in which more than one relative had OCD had a unique genetic pattern on chromosome 14, and other OCD patients seemed to share a unique genetic pattern on chromosome 3. It is unknown how these DNA changes contribute to hoarding but the research added to a slowly building body of work that is picking up DNA differences between hoarders and non-hoarders.
Environmental Hoarding Causes
Another way of explaining the fact that hoarding behaviors seem to run in families is to emphasize the importance of family experiences on compulsive hoarding. In other words, being exposed to a family member who hoards may increase the likelihood of a person going on to hoard in the future. In addition, emotional stress that comes from the environment may play a role in the development of compulsive hoarding. In a family where there is more stress than usual, or in which perfectionism is emphasized more than usual, children may be more likely to become compulsive hoarders.
Physical or Intellectual Hoarding Causes
Research seems to support the fact that brain differences contribute to OCD, and possibly hoarding. For example, a team at the University of Cambridge's Department of Psychiatry carried out a study in 2008 that used fMRI to measure brain activity during a cognitive activity. They looked at the brain activity of fourteen people who had OCD, twelve of their immediate relatives, and fourteen people who had no family history of OCD. During the study, they showed subjects pictures and conducted a simple picture test that would provoke decision making. They found that subjects with OCD, as well as their immediate relatives, had less activity in the lateral orbitofrontal cortex (OFC) than the control group. The OFC is one of the parts of the brain responsible for decision making, which explains why people with OCD, as well as compulsive hoarders, may have problems making decisions.
This study may also explain how brain changes contribute to hoarding, which is closely related to OCD. For example, compulsive hoarding may occur after strokes, surgery, injuries, or brain-related infections. Compulsive hoarders may have abnormal brain development or brain lesions.
People with OCD may also have difficulties with information processing, resulting in difficulties in decision-making, categorization, or memory. For example, a compulsive hoarder may have difficulty with deciding what to do with specific possessions, categorizing possessions, or remembering where possessions are.
Emotional Hoarding Causes
Hoarding may also be caused by anxiety. In fact, the committee in charge of the DSM (Diagnostic and Statistical Manual of Mental Disorders) has been considering classifying compulsive hoarding under anxiety disorders rather than under OCD, where it is commonly located. Compulsive hoarders may feel overwhelmed by their possessions, and they may exhibit perfectionist tendencies when trying to decide what to do with a possession. This creates a lot of stress, which they react to by merely storing the item. Compulsive hoarders may also fear losing important information, wasting materials, or discarding something that triggers a memory. Treatments such as cognitive behavioral therapy can help hoarders deal with these thoughts and emotions.
These hoarding causes need to be researched further in order to understand how they all fit together. At the same time, they help to explain why hoarders respond to an influx of possessions in the way that they do.
Mayo Clinic. "Hoarding: Causes." https://www.mayoclinic.com/health/hoarding/DS00966/DSECTION=causes
Clark County Combined Health District. "General Information on Hoarding Behavior."https://www.ccchd.com/hoarding.htm
UCSD. "What is Compulsive Hoarding." https://psychiatry.ucsd.edu/OCD_hoarding.html
Hartford Hospital. "What Is Compulsive Hoarding?" https://www.harthosp.org/InstituteOfLiving/AnxietyDisordersCenter/CompulsiveHoarding/default.aspx
International OCD Foundation. "Course and Causes of Hoarding." https://www.ocfoundation.org/hoarding/causes.aspx
Psych Central. "The Genetics of Compulsive Hoarding." https://psychcentral.com/lib/2009/the-genetics-of-compulsive-hoarding/
Science Daily. "Obsessive Compulsive Disorder Linked to Brain Activity." https://www.sciencedaily.com/releases/2008/07/080717140456.htm