A PET imaging study conducted at the UCLA NeuropsychiatricInstitute indicates the neurobiology of America's estimated 1 millioncompulsive hoarders differs significantly from people with otherobsessive-compulsive disorder (OCD) symptoms. The findings indicate thatdifferent medications could improve treatment success.
Detailed in the June 4 edition of the peer-reviewed AmericanJournal of Psychiatry, the study is the first to examine the neurobiology ofpeople with compulsive hoarding and saving, one of several symptom clustersassociated with OCD.
The study identified lower brain activity in the anteriorcingulate gyrus of compulsive hoarders, compared with other OCD patients. Thisbrain structure helps govern decision-making, focused attention, motivation andproblem-solving, cognitive functions that are frequently impaired in compulsivehoarders. The study also found a correlation between severity of hoardingsymptoms and lower brain activity in the anterior cingulate gyrus across all ofthe study subjects with OCD.
In addition, the hoarding group showed decreased brainactivity in the posterior cingulate gyrus compared to healthy control subjectswho had no OCD symptoms. The posterior cingulate gyrus is involved in spatialorientation and memory. The decreased activity in hoarders may explain why theyhave difficulty with excessive clutter and fear of losing belongings.
The findings also demonstrate how neurobiological testingcould improve diagnosis and treatment of psychiatric disorders. Lower activityin the anterior and posterior cingulate areas may not only underlie compulsivehoarding symptoms, but also their poor response to standard treatments for OCD.The results suggest cognitive-enhancing medications commonly used in patientswith age-related dementia may be more effective at treating compulsive hoardingbehaviors than standard OCD medications such as serotonin reuptake inhibitors.
"Our work shows that hoarding and saving compulsions longassociated with OCD may spring from unique, previously unrecognizedneurobiological malfunctions that standard treatments do not necessarilyaddress," said Dr. Sanjaya Saxena, lead author and director of the UCLANeuropsychiatric Institute's OCD Research Program.
"In addition, the results emphasize the need to rethink howwe categorize psychiatric disorders. Diagnosis and treatment should be drivenby biology rather than symptoms. Our findings suggest that the compulsivehoarding syndrome may be a neurobiologically distinct variant of OCD," saidSaxena, an associate professor-in-residence of psychiatry and biobehavioralsciences at UCLA's David Geffen School of Medicine.
Hoarding and saving behaviors are associated with a numberof psychiatric disorders, including age-related dementia and cognitiveimpairment, but they are most commonly associated with OCD. An estimated 7million to 8 million people in the United States suffer from OCD, withcompulsive hoarding present in up to one-third. Compulsive hoarding is theprimary source of impairment in 10 percent to 20 percent of OCD patients.
Compulsive hoarding is one of several symptom clustersassociated with OCD. Others include contamination fears that lead to cleaningcompulsions, aggressive and harm-related obsessions that lead to doubt andchecking, and symmetry and order concerns. Each of these symptom clusters maybe associated with a distinct pattern of brain activity. Standard OCDtreatments, including serotonin reuptake inhibitor medications, typically areless effective in OCD patients with prominent compulsive hoarding behaviors.
The UCLA Neuropsychiatric Institute study involved 62adults: 12 with OCD who had prominent compulsive hoarding behaviors, 33 withOCD who had mild or no symptoms of hoarding, and 17 control subjects who had noOCD symptoms. The researchers used positron emission tomography (PET) tomeasure brain glucose metabolism, a marker of regional brain activity, in eachsubject and compared the results.
Upcoming studies at the UCLA Neuropsychiatric Institute willuse both PET and magnetic resonance imaging scanning to look for structural andfunctional abnormalities in the brains of subjects with compulsive hoarding andother types of OCD as the team seeks to further refine and understand thesedifferences. The research team also will examine the effectiveness of newermedications that better address the unique brain activity found in subjectswith compulsive hoarding behaviors.
More information about ongoing and future research at theOCD Research Program is available at (310) 794-7305.
Funding for the study was provided by grants and awards fromthe National Institute of Mental Health, the Obsessive-Compulsive Foundation,the National Alliance for Research in Schizophrenia and Depression, theDepartment of Energy, and a private donor.
Other members of the UCLA Neuropsychiatric Instituteresearch 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 NeuropsychiatricInstitute conducts research on functional brain imaging, medication treatment,cognitive-behavioral therapy, neuropsychological deficits, genetics, andfunctional outcome of OCD, major depressive disorder, and OCD SpectrumDisorders such as body dysmorphic disorder and Tourette's syndrome.
The UCLA Neuropsychiatric Institute is an interdisciplinaryresearch and education institute devoted to the understanding of complex humanbehavior, including the genetic, biological, behavioral and socioculturalunderpinnings of normal behavior, and the causes and consequences ofneuropsychiatric disorders.
UCLA Neuropsychiatric Institute: www.npi.ucla.edu
UCLA OCD Research Program: www.mentalhealth.ucla.edu/projects/anxiety/ocdresearch.htm
David Geffen School of Medicine at UCLA: www.medsch.ucla.edu