Toward a biopsychosocial model of hoarding disorder

The present paper aims to elaborate on the original cognitive-behavioral model of hoarding disorder (HD; Frost & Hartl, 1996) by incorporating the results of recent research on biological and psychological contributors to HD. According to the proposed model, HD is characterized by several vulnerability factors that are thought to increase the likelihood that HD will develop, including genetic predisposition, abnormalities of brain structure, environmental factors such as traumatic life experiences, neuroticism, and impairments of cognitive function. Superimposed on these vulnerability factors is a biphasic abnormality of central and peripheral nervous system activity; at rest, or when doing completing symptom-irrelevant tasks, individuals with HD show blunted activity in brain regions that make up the salience network, including anterior cingulate cortex and insula. This blunted reactivity is further demonstrated through diminished error-related negativity (ERN) and decreased physiological arousal during error trials. However, when individuals with HD make decisions about possessions, they show relative hyperactivation of the salience network (and other brain regions), with accompanying indecisiveness, negative affect, exaggerated ERN, increased physiological arousal, and activation of maladaptive beliefs about, and attachment to, possessions. These factors lead to acquiring and saving behaviors, which are subsequently reinforced through emotion modification.