Participants
Participants were 26 adults with a primary diagnosis of HD, 37 adults
with a primary diagnosis of a DSM-5 (American Psychiatric Association,
2013) anxiety disorder (ANX), and 28 adult healthy control participants
without psychiatric disorders (HC). Participants were recruited from the
regular patient flow at an anxiety disorders specialty clinic, through a
registry of individuals who had previously consented to be contacted
about research opportunities at the clinic, and through media
advertisements and flyers posted throughout the surrounding community.
All participants were required to be fluent in English, be right-handed,
and have no history of anoxic or traumatic brain injury with loss of
consciousness greater than five minutes and no history of neurocognitive
disorder that may interfere with the ability to understand the study
tasks and provide informed consent. Any history of psychotic disorder or
bipolar disorder, current substance use disorder, and serious suicide
risk were also exclusionary.
Inclusion criteria for the HD group were a primary diagnosis of HD of at
least moderate severity as indicated by a Clinical Global Impression
(CGI) (Guy, 1976) rating of 4 or greater. Inclusion criteria for the ANX
group were a primary diagnosis of a DSM-5 anxiety disorder of at least
moderate severity as indicated by a CGI rating of 4 or greater. For both
clinical groups, comorbid conditions were permitted as long as they were
secondary to the primary diagnosis. Antidepressants, stimulants, and
benzodiazepines were permitted at stable dosages for a minimum of eight
weeks. All other psychiatric medications were excluded. For participants
taking benzodiazepines and stimulants, a 24-hour “washout” of these
medications was required prior to the study with the prescriber’s
approval. Inclusion criteria for the HC group were no past or current
psychiatric disorders or mental health treatment.
As shown in Table 1, although we attempted to match the control groups
to the HD group for age and sex assigned at birth, we had significant
age differences. As such, we controlled for age in all study analyses.
We note that we assessed sex assigned at birth and not gender identity
to be consistent with the National Institute of Mental Health National
Data Archive (NDA), in order to facilitate data transfer to the NDA (a
requirement of the grant). As expected, the HD group scored
significantly higher than did the control groups on the Saving
Inventory-Revised (SI-R), a measure of hoarding severity.
Table 1