It’s beginning to look a lot like my hand: Fake hand perceived to resemble own hand for people with body dysmorphic disorder but not controls.

BACKGROUND AND AIMS Body dysmorphic disorder (BDD) is characterised by misperception of one's own bodily features. This study aimed to investigate whether visual perceptual processes and own-body-related multisensory integration processes differ in people with BDD compared to controls, and the roles those processes play in BDD aetiology and symptomatology. METHODS We attempted to induce the rubber hand illusion (RHI) on 16 people with BDD and 15 controls, using the standard procedure (see Botvinick & Cohen, 1998), wherein a visible fake hand and the participant's hidden real hand are stroked either synchronously (experimental condition) or asynchronously (control condition). This was repeated on both hands. RESULTS Participants in the BDD group endorsed response items indicating that during the experiment, the fake hand began to visually resemble their own hand, for the right hand only, and irrespective of the synchronicity of the stroking (F(1,15)=6.74, p=.02). No such effect was observed for the control group. CONCLUSIONS For people with BDD, simply gazing at a body-related stimulus can affect the way it is perceived. These results support the idea that people with BDD may have a more malleable perceptual body image than others, which may predispose them to the disorder. Moreover, most BDD sufferers spend an inordinate amount of time mirror-gazing. These results support the notion that mirror-gazing may play a critical role in the development of BDD, and may emphasise the importance of encouraging restriction of such behaviour as part of a treatment protocol