Category: Obsessive Compulsive and Related Disorders
Excoriation (skin-picking) disorder is characterized by distressing or impairing picking resulting in lesions, as well as failed attempts to stop picking (APA, 2013). It has been proposed that deficits in response inhibition (RI; the ability to stop a prepotent response) may play a role in dysfunctional control of motor processes (Grant & Odlaug, 2009). Compared to healthy controls, skin pickers have shown significantly impaired inhibitory control, but intact cognitive flexibility (Odlaug, Chamberlain, & Grant, 2010). However, further research is needed to examine whether RI deficits are positively associated with the severity of skin picking.
To this end, participants (N = 17) endorsing elevated skin-picking symptoms completed self-report (SPS-R; Snorrason, Ólafsson, Flessner, & Woods, 2012) and clinician-administered (NE-YBOCS; Arnold et al., 1999) measures of symptom severity, as well as two cognitive tasks designed to assess RI capabilities. A go/no-go task (Lee, Yost, & Telch, 2009) was used to assess the ability to inhibit a pre-potent response. Participants were instructed to respond by pressing a key when a target object appeared (i.e., go trials), but were instructed to refrain from responding to a distracter (i.e., no-go trials), with number of commission errors as the primary outcome index. Additionally, participants completed a stop-signal task (Chamberlain et al., 2006, 2007), which assessed their ability to inhibit an ongoing response. Participants were instructed to quickly respond to left- or right-oriented arrows with corresponding response keys, but refrain from responding when an auditory tone followed the arrow. Stop-signal reaction time (SSRT) is a latent variable measured by subtracting mean stop-signal delay from mean go reaction time, and serves as the primary outcome index for this task. It was hypothesized that both self-report and clinician ratings of skin-picking symptom severity would be positively correlated with magnitude of RI deficits.
Results showed scores on the SPS-R and NE-YBOCS were not significantly correlated with the magnitude of RI deficits (ps > .05). Further, the direction of the relationship between symptom severity and RI deficits showed a trend of negative associations. These results suggest that the conceptualization of the potential role of RI in skin-picking disorder may not be as straightforward as previously thought. Clinical and theoretical implications, as well as directions for future research, will be presented.
Ashleigh Harvey– Graduate Student, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin
Marie Yaroch– University of Wisconsin- Milwaukee
Aerielle Pendleton– University of Wisconsin- Milwaukee
Ashley Huggins– University of Wisconsin- Milwaukee
Tara Miskovich– University of Wisconsin- Milwaukee
Christine Larson– University of Wisconsin- Milwaukee
Hanjoo Lee– University of Wisconsin-Milwaukee
University of Wisconsin-Milwaukee