A recent study has uncovered significant findings regarding the relationship between attention-deficit hyperactivity disorder (ADHD) and hoarding disorder. The study, published in the Journal of Psychiatric Research, found that individuals with ADHD have a markedly higher prevalence of hoarding symptoms compared to those with obsessive-compulsive disorder (OCD) and healthy individuals.
The motivation for this research stemmed from the complex and somewhat misunderstood nature of hoarding disorder. Traditionally considered a subtype of OCD, hoarding disorder has been recognized as a distinct psychiatric condition since 2013. It is characterized by an ongoing difficulty in discarding possessions, regardless of their actual value, leading to cluttered and unmanageable living spaces.
“While hoarding disorder is an underdiagnosed disorder in the general population, many patients with ADHD complain about their hoarding symptoms in clinical practice,” explained study author Giacomo Grassi, a psychiatrist at Brain Center Firenze in Italy.
“However, only a few studies investigated the presence of hoarding symptoms in ADHD subjects. Thus, the aim of the study was to assess the prevalence of hoarding disorder symptoms on adults with ADHD. The second aim was to compare the prevalence of hoarding disorder between patients with ADHD, patients with OCD and healthy controls.”
The study involved 157 adults: 57 with ADHD, 50 with OCD, and 50 controls, matched in age and gender. The diagnoses of ADHD and OCD were based on the criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).
The researchers used several validated tools to assess various aspects of these disorders. The Saving Inventory-Revised (SI-R) was utilized to evaluate hoarding symptoms, while the Barkley Adult ADHD Rating Scale-IV (BAARS-IV) assessed ADHD symptoms. Additionally, the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the Symptoms of Depression Questionnaire (SDQ) were used to measure OCD and mood/anxiety symptoms, respectively. The Barratt Impulsiveness Scale (BIS-11) provided insights into impulsivity traits.
The researchers found that adults with ADHD had a 32.1% prevalence of hoarding disorder comorbidity, significantly higher than the 8% in OCD patients and 4% in healthy controls. Even when criteria for hoarding disorder diagnosis were narrowed down (by focusing specifically on excessive clutter and difficulty discarding, while excluding compulsive acquisition), ADHD patients still exhibited higher prevalence rates.
In terms of specific hoarding symptoms, ADHD individuals scored significantly higher than both OCD patients and healthy controls. Interestingly, no significant difference was found in hoarding symptoms between medicated and non-medicated patients within the ADHD and OCD groups. Further, the study highlighted that in the ADHD group, those with hoarding disorder comorbidity exhibited more severe ADHD symptoms and higher impulsivity scores.
“In our study we found a high prevalence of significant hoarding symptoms in adults with ADHD,” Grassi told PsyPost. “Almost one third of ADHD patients have significant hoarding disorder symptoms.”
“The surprising discovery is that ADHD patients have higher hoarding disorder rates than patients with obsessive-compulsive disorder. This latter fact is important considering that, in the DSM-5, hoarding disorder is classified in the obsessive-compulsive and related disorder chapter and it has been historically considered a variant of OCD before its classification as a separate disorder.”
Despite its insightful findings, the study has certain limitations. For example, the small sample size might have restricted the depth of clinical differences identified. Going forward, the researchers suggest larger-scale studies to further explore the ADHD-HD relationship, particularly focusing on treatment implications.
“The clinical impact (e.g. on general functioning, quality of life) of hoarding symptoms in ADHD patients is still largely unknown,” Grassi said. “Also, while some case reports suggest some effect of anti-ADHD medications on patients with a primary diagnosis of hoarding disorder, no studies investigated the effects of anti-ADHD medications on hoarding symptoms in patients with ADHD.”
“The take home message of our study is that hoarding disorder seem to be common in adults with ADHD, therefore clinicians should pay attention to this comorbidity in the ADHD population,” he added.
The study, “Who really hoards? Hoarding symptoms in adults with attention-deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD) and healthy controls“, was authored by Giacomo Grassi, Corinna Moradei, Chiara Cecchelli, and Michael van Ameringen.
