Wednesday, April 7, 2010

The Genetics of Compulsive Hoarding

By Jane Collingwood
People who compulsively acquire and hoard clutter to the extent that it impairs their daily activities are labeled “compulsive hoarders.” The condition is classed as a subtype of obsessive-compulsive disorder (OCD), present in 30 to 40 percent of individuals affected with OCD. It may damage relationships, cut the individual off from society, and even endanger lives.

Compulsive hoarding is distinct from bad planning and disorganization because it is believed to be a pathological brain disorder. It is often a symptom of other disorders, such as impulse control disorder or attention-deficit hyperactivity disorder. Bereavement or another significant life event can trigger excessive hoarding behavior.

Hoarding often runs in families, but it is uncertain whether DNA is involved. “People with this problem tend to have a first-degree relative who also does,” says Randy O. Frost, Ph.D., a psychologist at Smith College, Northampton, Massachusetts. “So it might be genetic, or it might be a modeling effect.”

Gene research suggests that a region on chromosome 14 may be linked with compulsive hoarding in families with OCD. The study, carried out by a team from Johns Hopkins University School of Medicine in March 2007, analyzed samples from 999 OCD patients in 219 families. Families with two or more hoarding relatives showed a unique pattern on chromosome 14, whereas the other families’ OCD was linked to chromosome 3.

This was the third study to find genetic markers specifically associated with compulsive hoarding, according to Sanjaya Saxena, M.D., director of the University of California, San Diego, Obsessive-Compulsive Disorders Program.

In a letter to the editor of the American Journal of Psychiatry, she writes, “Other studies have confirmed that compulsive hoarding is strongly familial.” This research “adds to the mounting evidence indicating that compulsive hoarding is an etiologically discrete phenotype,” she believes.

What’s more, brain imaging studies suggest that compulsive hoarding involves a specific type of brain activity. Patients have a different pattern of glucose metabolism in the brain than either healthy people or non-hoarding OCD patients..." More