What was the research about?
People with hoarding disorder are unable to give or throw things away. They also often buy or collect items to excess. Clutter caused by hoarding can lead to unsafe living conditions and make it hard to function in daily life. Group cognitive behavioral therapy, or CBT, is one type of treatment for hoarding disorder. Patients meet in groups with others who have hoarding disorder and learn to change their patterns of thinking and behavior.
Some communities only have a few therapists trained in CBT. This lack of therapists can make it hard for people with hoarding disorder to get treatment. Peer-led group therapy is a type of treatment led by people who have or have had hoarding disorder and received training to help others. It gives people more opportunities to get treatment.
The research team wanted to see if peer-led group therapy worked as well as therapist-led CBT to treat hoarding disorder.
What were the results?
The study found that peer-led group therapy helped as many patients with hoarding disorder as therapist-led CBT did. One month after treatment ended, patients in both groups had fewer symptoms of hoarding disorder. They were also better able to do daily activities, such as preparing food or taking showers. Within one to two years after treatment, patients in both groups still had fewer symptoms of hoarding disorder but they did not maintain the improvements in daily activities.
Who was in the study?
The study included 323 patients with hoarding disorder in San Francisco, California. Of these patients, 75 percent were female. Sixty percent of patients were white, 11 percent were Asian, 8 percent were African American, and 20 percent were other or more than one race; 9 percent were Hispanic. The average age was 59.
What did the research team do?
The research team assigned patients by chance to one of two groups. One group took part in CBT led by therapists using a hoarding disorder therapy workbook as a guide. This group had 16 two-hour group sessions over 20 weeks. Patients in this group learned about hoarding symptoms. They also learned how to set goals and how to change their behavior and thinking.
The other group took part in peer-led therapy. Patients in this group had 15 two-hour sessions over 20 weeks. The group leaders had current or past hoarding disorder and received training to help others with hoarding disorder. They used a workbook that had similar activities to those of the CBT group.
The research team surveyed each patient about his or her hoarding disorder symptoms and daily activities. The team collected this information at the beginning of the study and within one month after the end of treatment. One to two years after treatment ended, the team followed up with patients in the study again.
What were the limits of the study?
About 30 percent of patients in the study didn’t finish treatment. The results may have been different if everyone completed the treatment. The findings from the study may not apply to patients with hoarding disorder who don’t want treatment or who are not aware of their hoarding disorder.
Future studies could look into improving both types of treatment and examine ways to encourage patients to complete the treatments.
How can people use the results?
It can be hard to find trained therapists to help with hoarding disorder. Peer-led group therapy was as effective as group CBT and may be a good option for making treatment available to more people.
To compare the effectiveness of group peer-facilitated therapy (PFT) with group therapist-led cognitive behavioral therapy (CBT) in reducing the severity of hoarding disorder symptoms
|Design||Randomized controlled trial|
|Population||323 adults with hoarding disorder|
Primary: hoarding symptom severity
Secondary: hoarding-related functional impairment, sustainability of improvements in hoarding symptom severity and functional impairment over time, individual factors associated with response to treatment
|Timeframe||Within 1–2 years after treatment completion for primary outcome|
This randomized controlled trial compared the effectiveness of therapist-led group CBT with peer-facilitated group PFT for reducing the severity of hoarding disorder symptoms. PFT may be more accessible in communities that lack access to therapists trained in CBT.
The study included 323 participants living with hoarding disorder in San Francisco, California. Of these participants, 75% were female, 60% were white, 11% were Asian, 8% were African American, and 20% reported either other or more than one race. In addition, 9% were Hispanic. The mean age was 59.
The research team randomly assigned participants to either the CBT or PFT treatment groups. The CBT group attended 16 two-hour group sessions over 20 weeks led by one or two psychology postdoctoral fellows using a CBT workbook. Sessions included information about hoarding symptoms, goal setting, behavior modification, cognitive restructuring, motivational enhancement, executive functioning skills training, and relapse prevention.
The PFT group included 15 two-hour group sessions over 20 weeks led by one to two trained peers with current or past hoarding disorder. This group used a treatment workbook that covered topics similar to those of the CBT group.
The research team assessed each patient’s hoarding symptom severity and daily functioning using surveys taken at baseline, within one month after treatment ended, and again within one to two years after the patients finished treatment. On average, the last assessment occurred about 14.4 months after treatment ended.
People who screened positive for hoarding disorder and professionals who treat the disorder contributed to the development and design of the study. The Mental Health Association of San Francisco helped identify these contributors.
At the end of treatment, the study found no significant difference between groups in the reduction in hoarding symptom severity. Patients in the CBT group had a 28% reduction in symptom severity, while patients in the PFT group had a 26% reduction. The team also found no significant difference in the reduction in impairment in daily function between the CBT group (11% reduction) and the PFT group (12% reduction). Within one to two years after treatment, patients in both groups maintained reductions in hoarding symptom severity, but not in daily functioning.
At baseline, patients with higher symptom severity were more likely to reduce symptom severity with treatment than patients with lower symptom severity. Those who attended more sessions and completed homework from the sessions also showed more reduction in symptom severity than those who attended less sessions or did not complete homework. Also, patients who had higher levels of anxiety and depression along with their hoarding symptoms had less improvement in daily functioning than those with lower levels of anxiety and depression.
About 30% of patients dropped out of treatment before completion. Results may have been different if all patients had completed treatment. Because patients voluntarily sought hoarding treatment, they may have had a higher awareness and understanding of their disorder than patients who did not seek treatment. Results may not be the same for people who do not recognize their disorder or do not see it as problematic.
Conclusions and Relevance
In this study, PFT performed as well as CBT in reducing the severity of hoarding symptoms. Having the option to use PFT may increase access to treatment in communities with a limited pool of therapists trained in CBT.
Future Research Needs
Future research could continue to examine how to improve treatment outcomes for both CBT and PFT.
Final Research Report
View this project's final research report.
Results of This Project
Related Journal Citations
Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also confirms that the research has followed PCORI’s Methodology Standards. During peer review, experts who were not members of the research team read a draft report of the research. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. Reviewers do not have conflicts of interest with the study.
The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve how the research team analyzed its results or reported its conclusions. Learn more about PCORI’s peer-review process here.
In response to peer review, the PI made changes, including
- Providing more detail about the analyses, particularly about how missing data were handled. Data were missing mostly because participants did not complete the follow-up assessment. The researchers did not believe it was appropriate to impute data for entire questionnaires so they did not account for missing data in their analyses of the primary outcomes. These analyses were conducted only for the 76 percent of randomized participants who provided follow-up, which raised concerns about how well the results reflect the study population as a whole.
- Describing sensitivity analyses where the researchers reanalyzed outcomes for only those participants who completed treatment, in response to reviewers’ concerns about the effect of the high dropout rate from the intervention program.
- Laying out the differences in the number and format of group sessions between the compared interventions. The researchers indicated in their response to reviewers that they did not believe there were material effects of these differences on the outcomes given their experience with these interventions in past studies.
- Explaining why longitudinal follow-up assessments were added late in the study rather than being part of the original study protocol. The researchers added information to the report indicating that they obtained additional funding late in the study to complete the longitudinal analyses.
Conflict of Interest Disclosures
Study Registration Information
*Carol A. Mathews, MD, who was at University of California, San Francisco when this project was awarded, is now at University of Florida.
- Has Results