A Neural Basis for Collecting, Hoarding, and Related Disorders
Central to Stephen Blumberg’s exploits is his seemingly uncontrollable urge to collect objects, especially books, antiques, and ephemera. The collecting of objects is standard human behavior, with the majority of young children and at least a third of adults reporting doing so (Mataix-Cols and Nordsletten, 2012). Although collecting and hoarding-adjacent behaviors are common, there is still much to be learned regarding the neural mechanisms that underlie these practices. In non-human animals, damage to brain areas such as the ventral tegmental area, lateral hypothalamus, nucleus accumbens, hippocampus, amygdala, and thalamus reduces the biological urge to collect (Anderson et. al, 2005). In humans, this desire to collect is a bit more complicated. Alongside biological conditions, humans are also driven and shaped by social and environmental factors. This means that the more anterior regions of the brain involved in decision-making are also utilized in hoarding tendencies.
Neurological Basics
To understand the neurological basis of hoarding disorders, it can help to know which brain areas are involved.
The brain areas primarily associated with hoarding and collecting behaviors are the cingulate cortex and the ventromedial prefrontal cortex (VMPC). These areas are known to manage impulse control and moral judgment (Knuttson, 2014). Similar disorders such as impulse control disorder show abnormalities in adjacent regions of the brain. Poor impulse control is linked to two different but intertwined systems of the brain: the impulse system and the reflective system. The impulse system consists of the amygdala, which is responsible for managing feelings of distress and pleasure.
As seen in hoarding and collecting behaviors, the reflective system consists of the VMPC, which is in control of considering the short and long-term consequences of one’s actions. An imbalance between these two systems disrupts one’s ability to manage their impulses. Several studies demonstrated an association between hypoactivity or damage to the VMPC and an increase in impulsivity and/or insensitivity toward future outcomes (see: 10.1093/brain/123.11.2189; 10.1093/bmb/ldm03; https://doi.org/10.1186/1471-2377-11-151). Impairment to the VMPC is also closely related to emotional deficits such as weakened moral judgment and behavior.
Exploring VMPC Damage
Despite these known behavioral effects, people with damage to their VMPC maintain normal functioning in terms of memory and intelligence. This phenomenon was first observed in a man named Phineas Gage, who suffered a traumatic brain injury in 1848 when his skull was impaled by a rod following an explosion at his workplace. Following the accident, Gage developed a deep fascination with memorabilia and also displayed difficulty regulating his emotions. Modern Gage-like patients with mesial prefrontal damage demonstrate collecting tendencies that were not present prior to brain damage (Damasio, 1994 as cited in Anderson et. al, 2005).
The Department of Neurology at the University of Iowa College of Medicine conducted a study that further defined the role of the VMPC in collecting, hoarding, and related disorders. In order to identify a neuroanatomical correlate of abnormal collecting behavior, participants were given focal lesions at different regions of their cerebral hemispheres, then these lesions were analyzed using MRI imaging. Following the imaging procedure, investigators conducted interviews with the participant and a close relative about changes in behavior and personality following the onset of their focal lesion. Questions aimed to define abnormal collecting behavior, with 5 criteria used to standardize results: (1) the extent of accumulated items, (2) the content having little to no value, (3) interference with normal daily functioning, (4) the onset of collecting behavior following focal damage to the brain, and (5) resistance to change. Results support the hypothesis that collecting behavior can result from damage to mesial prefrontal regions, with the right mesial prefrontal region being most prominently involved. For more information regarding this study, see: doi:10.1093/brain/awh329.
As suggested by studies using a rodent model, collecting behavior is likely driven by predispositions originating from subcortical structures including the ventral tegmental area, lateral hypothalamus, nucleus accumbens, hippocampus, amygdala, and thalamus (Anderson et. al, 2005). This impulse is then modulated by cortical structures that take into account factors such as learning history, social norms, and consequences. Damage to cortical regions like the VMPC disrupts communication between cortical and subcortical structures, thus limiting one’s ability to control impulses or consider the potential negative outcomes of their actions.
Blumberg
Like Blumberg, people with problems related to hoarding exhibit difficulty restraining their desires to collect even at the expense of their own well-being. Consider Blumberg’s living conditions and all that he sacrificed in order to accrue his collection. Despite coming from a well-off family, he was described by onlookers as a “dirty” man who rarely showered, wore old clothes, and lived out of his car at points (Weiss, 1994). Even as a young boy, he was withdrawn, preferring the company of the elderly and old things. Despite issues with moral judgment and impulse control, people diagnosed with hoarding disorder maintain standard memory and intellect functioning (Boes et al., 2011). With all of his hoarding behaviors, Blumberg was also still able to think and plan critically to successfully steal more than twenty thousand rare books (Weiss, 1994). Although these behaviors are closely correlated with hoarding and collecting disorders, we cannot know for certain what his diagnosis would be.