A PET imaging study conducted at the UCLA Neuropsychiatric Institute indicates the neurobiology of America's estimated 1 million compulsive hoarders differs significantly from people with other obsessive-compulsive disorder (OCD) symptoms. The findings indicate that different medications could improve treatment success.
The study is the first to examine the neurobiology of people with compulsive hoarding and saving, one of several symptom clusters associated with OCD.
The study identified lower brain activity in the anterior cingulate gyrus of compulsive hoarders, compared with other OCD patients. This brain structure helps govern decision-making, focused attention, motivation and problem-solving, cognitive functions that are frequently impaired in compulsive hoarders. The study also found a correlation between severity of hoarding symptoms and lower brain activity in the anterior cingulate gyrus across all of the study subjects with OCD.
In addition, the hoarding group showed decreased brain activity in the posterior cingulate gyrus compared to healthy control subjects who had no OCD symptoms. The posterior cingulate gyrus is involved in spatial orientation and memory. The decreased activity in hoarders may explain why they have difficulty with excessive clutter and fear of losing belongings.
The findings also demonstrate how neurobiological testing could improve diagnosis and treatment of psychiatric disorders. Lower activity in the anterior and posterior cingulate areas may not only underlie compulsive hoarding symptoms, but also their poor response to standard treatments for OCD. The results suggest cognitive-enhancing medications commonly used in patients with age-related dementia may be more effective at treating compulsive hoarding behaviors than standard OCD medications such as serotonin reuptake inhibitors.
"Our work shows that hoarding and saving compulsions long associated with OCD may spring from unique, previously unrecognized neurobiological malfunctions that standard treatments do not necessarily address," said Dr. Sanjaya Saxena, lead author and director of the UCLA Neuropsychiatric Institute's OCD Research Program.
"In addition, the results emphasize the need to rethink how we categorize psychiatric disorders. Diagnosis and treatment should be driven by biology rather than symptoms. Our findings suggest that the compulsive hoarding syndrome may be a neurobiologically distinct variant of OCD," said Saxena, an associate professor-in-residence of psychiatry and biobehavioral sciences at UCLA's David Geffen School of Medicine.
Hoarding and saving behaviors are associated with a number of psychiatric disorders, including age-related dementia and cognitive impairment, but they are most commonly associated with OCD. An estimated 7 million to 8 million people in the United States suffer from OCD, with compulsive hoarding present in up to one-third. Compulsive hoarding is the primary source of impairment in 10 percent to 20 percent of OCD patients.
Compulsive hoarding is one of several symptom clusters associated with OCD. Others include contamination fears that lead to cleaning compulsions, aggressive and harm-related obsessions that lead to doubt and checking, and symmetry and order concerns. Each of these symptom clusters may be associated with a distinct pattern of brain activity. Standard OCD treatments, including serotonin reuptake inhibitor medications, typically are less effective in OCD patients with prominent compulsive hoarding behaviors.
The UCLA Neuropsychiatric Institute study involved 62 adults: 12 with OCD who had prominent compulsive hoarding behaviors, 33 with OCD who had mild or no symptoms of hoarding, and 17 control subjects who had no OCD symptoms. The researchers used positron emission tomography (PET) to measure brain glucose metabolism, a marker of regional brain activity, in each subject and compared the results.
Upcoming studies at the UCLA Neuropsychiatric Institute will use both PET and magnetic resonance imaging scanning to look for structural and functional abnormalities in the brains of subjects with compulsive hoarding and other types of OCD as the team seeks to further refine and understand these differences. The research team also will examine the effectiveness of newer medications that better address the unique brain activity found in subjects with compulsive hoarding behaviors.
More information about ongoing and future research at the OCD Research Program is available at (310) 794-7305.
Funding for the study was provided by grants and awards from the National Institute of Mental Health, the Obsessive-Compulsive Foundation, the National Alliance for Research in Schizophrenia and Depression, the Department of Energy, and a private donor.
Other members of the UCLA Neuropsychiatric Institute research team included Dr. Arthur L. Brody, Karron M. Maidment, Erlyn C. Smith, Narineh Zohrabi, Elyse Katz, Stephanie K. Baker and Dr. Lewis R. Baxter Jr.
The OCD Research Program at the UCLA Neuropsychiatric Institute conducts research on functional brain imaging, medication treatment, cognitive-behavioral therapy, neuropsychological deficits, genetics, and functional outcome of OCD, major depressive disorder, and OCD Spectrum Disorders such as body dysmorphic disorder and Tourette's syndrome.
The UCLA Neuropsychiatric Institute is an interdisciplinary research and education institute devoted to the understanding of complex human behavior, including the genetic, biological, behavioral and sociocultural underpinnings of normal behavior, and the causes and consequences of neuropsychiatric disorders.