State of the Science: Hoarding Disorder Overview and Treatment Strategies

Overview of Hoarding Disorder (HD)

• Definition: Hoarding Disorder is a relatively new diagnosis, first formalized in the DSM-5 (2013). It is characterized by persistent difficulty discarding or parting with possessions, regardless of their actual value, resulting in excessive clutter that congests and litters living areas, precluding their intended use.

• Evolution of Conceptualization:

  • DSM-IV (1994): Hoarding was initially listed as a symptom of Obsessive-Compulsive Personality Disorder (OCPD), related to Freudian concepts of anal retentiveness.

  • Factor Analytic Research: Demonstrates that OCPD traits (perfectionism, rigidity) are distinct from hoarding behavior (Riddle et al., 2016).

  • OCD Relationship: Hoarding was long viewed as a variant of Obsessive-Compulsive Disorder (OCD), but research shows most HD patients do not have OCD, and most OCD patients do not hoard (Frost et al., 2011; Fullana et al., 2010).

  • Distinct Syndrome: HD is now recognized as a unique syndrome with its own physiopathology (Grisham et al., 2005; Pertusa et al., 2010).

Epidemiology and Symptomatology

• Prevalence: Approximately $1.5\%$ of the population (Nordsletten et al., 2013), translating to nearly $5$ million Americans.

• Primary Criterion: Difficulty discarding objects (regardless of value). This distinguishes HD from clutter caused by other conditions like severe depression, where a lack of energy (rather than a desire to save) creates messiness.

• Urges and Distress: Difficulty discarding must be driven by strong urges to save or distress evoked by the act of discarding.

• Reasons for Saving: Individuals spesso report fears of losing information, sentimental or aesthetic attachment, and fears of wastefulness (Frost et al., 2015).

• Functionality and Health Risks:

  • Living Space Impediment: Kitchens and beds often become storage sites, preventing cooking or sleeping.

  • Safety Hazards: High risk of death by fire (Lucini et al., 2009), inhibited emergency egress, mold, pests, rotting food, and structural damage (Larkin et al., 2024).

  • Legal Consequences: Threatened or actual eviction is common (Woody et al., 2020).

• Acquisition Specifier: While not required for diagnosis, excessive acquisition (buying, gathering free items) is present in approximately $85\%$ of self-reports and $95\%$ of family reports (Frost et al., 2009).

Theoretical Models of Hoarding Disorder

• Developmental Course: Symptoms typically begin in childhood or adolescence and worsen every decade (Grisham et al., 2006; Cath et al., 2017).

• Cognitive-Behavioral Model (Frost & Hartl, 1996):

  • Information-Processing Deficits: Problems with decision-making, categorization, organization, and low memory confidence.

  • Emotional Attachment: Possessions provide a sense of friendship or security.

  • Avoidance: Saving behavior avoids the negative emotions associated with decision-making.

  • Maladaptive Beliefs: Exaggerated responsibility for possessions and a desire for control (Steketee et al., 2003).

• Biopsychosocial Model (Tolin, 2023):

  • Vulnerability Factors: Genetic predispositions, brain structure, neuropsychological impairment, and stressful life events (e.g., physical/sexual assault).

  • Biphasic Brain Abnormality: Focuses on the salience network (anterior cingulate and anterior insular cortex).

    • At Rest: Activity is blunted, potentially explaining low motivation and insight.

    • During Decision-Making: These regions become overengaged when deciding about personal possessions, suggesting emotion regulation problems.

  • Reinforcement: Behavior is maintained by positive reinforcement (upregulation of positive emotion) and negative reinforcement (downregulation of negative emotion).

• Attachment Model (Mathes et al., 2020):

  • Suggests individuals with HD have "thwarted interpersonal needs" and compensate by forming secure attachments with inanimate objects.

  • Involves high attachment anxiety (fear of abandonment) and attachment avoidance (desire to avoid human intimacy).

• Addiction Model (Pickering & Norberg, 2023):

  • Applies Griffiths’s Components Model of Addiction.

  • Strong evidence exists for salience, mood modification, and conflict.

  • Limited evidence exists for tolerance, withdrawal, and relapse.

  • Controversial: Griffiths (2023) argued reinforcement in HD is inconsistent compared to classic addictions.

Cognitive-Behavioral Therapy for Hoarding Disorder (CBT-HD)

• Efficacy: Currently the only treatment with conclusive evidence. It produces large effect sizes from pre- to posttreatment, but clinical results are overall modest.

• Performance Metrics:

  • Average reduction on the Saving Inventory–Revised (SI-R) is $15-25\%$.

  • Only $24-43\%$ of patients achieve clinically significant change (Tolin et al., 2015).

• Prognostic Factors: Better outcomes are linked to female gender, younger age, higher motivation, and homework completion (Ayers et al., 2020; Wootton et al., 2021).

• Barriers: Low insight (anosognosia), lack of access to specialized care, and treatment-interfering comorbidities (severe depression or dementia).

• Structural Formats:

  • Group Therapy: Recommended due to structure, destigmatization, and peer feedback.

  • Peer-Led Groups: Facilitated by individuals with lived experience; show similar gains to therapist-led groups (Mathews et al., 2018).

  • Telehealth: Effectiveness appears comparable to in-person care (Yap et al., 2022).

  • Dosage: Typically $16-26$ sessions.

Core Components of CBT-HD Treatment

• Exposure Therapy: Unlike general OCD, HD responds poorly to simple Exposure and Response Prevention (ERP). However, exposure to sorting and discarding remains core.

  • Mechanism: Works via disconfirmation of fearful expectations (e.g., "I will have a breakdown if I discard this").

  • Habituation: May occur slower in HD due to the ego-syntonic nature of beliefs and attentional difficulties (Ayers et al., 2019).

• Cognitive Challenging:

  • Targets overestimation of memory impairment and shame.

  • Development of "rules for discarding" (e.g., "discard if not used in a year").

• Targeting Acquisition (Stimulus Control):

  • Avoiding high-risk triggers like yard sales or online free-item boards.

  • Strategies include shopping delegation, using pre-identified lists, and "one in, two out" rules.

• Distress Tolerance: Borrowing from Acceptance and Commitment Therapy (ACT), patients practice "riding the wave" of unpleasant emotions like regret or guilt without behavioral avoidance.

• Executive Functioning Training: Focuses on planning, problem-solving models, and using calendars/schedules for formal sorting windows.

Novel and Adjunctive Treatment Directions

• Cognitive Rehabilitation (CREST): Developed by Ayers and colleagues. Combines CBT with cognitive elements like scheduling and problem solving. Shows improved outcomes for older adults ($38\%$ reduction on SI-R).

• Acceptance and Commitment Therapy (ACT): Small studies suggest it reduces symptoms, though ACT-specific constructs (psychological flexibility) don't always mediate the changes (Krafft et al., 2023).

• Social Cognition Interaction Training (SCIT): Aimed at addressing social cue misreading and isolation; showed a $16\%$ reduction in HD symptoms in a pilot study (Chen et al., 2023).

• Family-Based Interventions: Psychoeducation for caregivers improves caregiver quality of life, though direct impact on the hoarder's symptoms is less clear.

• Technology & Biological Interventions:

  • Virtual Reality (VR): Used for decluttering practice to ready participants for real-world exposures (Raila et al., 2023).

  • Pharmacotherapy: No randomized controlled trials (RCTs) have been published. SSRIs and ADHD medications (e.g., Atomoxetine) show some promise in small, uncontrolled studies (Grassi et al., 2016).

  • Somatic Interventions: Case studies involve Repetitive Transcranial Magnetic Stimulation (rTMS) or tDCS, but no clinical trials exist.

Cultural Considerations and Future Research

• Cultural Gaps: $90\%$ of participants in published HD studies are White and from Western nations (Fernandez de la Cruz et al., 2016).

• Ethnic Findings: Self-reported discarding difficulty was found higher in Native American participants and less common in Black, Asian, and Hispanic participants in one U.S. national sample (Rodriguez et al., 2013).

• Future Directions:

  1. Neural Mechanisms: Clarify mixed results regarding frontal region under-engagement vs. over-engagement during decision-making.

  2. Assessment: Move toward computational modeling and HD-specific tasks rather than traditional neuropsychological tests that fail to distinguish indecisiveness in HD from other disorders.

  3. Treatment Refining: The current efficacy is too low; research must follow the understanding of underlying biological and cognitive mechanisms (Comer, 2024).