Inclusion Criteria for Individuals with Hoarding Disorder:

   1. Age 18 to 70 years

   2. Either gender and all ethno-racial groups

   3. Physically healthy male or non-pregnant female.

   4. Hoarding Disorder primary condition

   5. Willing and able to understand and complete consent and study procedures

   6. English speaking

Exclusion Criteria for Individuals with Hoarding Disorder:

   1. Current or past history of bipolar, psychotic or eating disorders, substance
   dependence, or substance abuse in the last year.

   2. Clinically at risk of suicide with Columbia Suicide Severity Rating Scale (C-SSRS)
   Suicidal Ideation Subscale of 4 or higher (i.e. suicidal intent without specific plan)

   3. Major medical or neurological conditions that increase the risk of participation or
   that would prevent completing assigned behavioral practice tasks.

   4. Unable or unwilling to allow study staff into home for home assessment

   5. Currently at high risk for eviction

   6. Animal hoarding or squalor

Inclusion Criteria for Healthy Controls:

   1. Age 18 to 70 years

   2. Either gender and all ethno-racial groups

   3. Physically healthy male or non-pregnant female.

   4. Willing and able to understand and complete consent and study procedures

   5. English speaking

Exclusion Criteria for Healthy Controls:

   1. any current or lifetime psychiatric diagnosis

   2. current or past use of psychotropic medication

   3. major medical or neurological problem (e.g., unstable hypertension, seizure disorder,
   head trauma)

   4. Metal in body or any other contraindication for MRI