Emotional Interference of Response Inhibition in Obsessive-Compulsive Disorder

Researchers have hypothesized that failures of inh ibition are partially responsible for habitual and perseverative symptoms that are unique to Obsessive-Compulsive Disorder (OCD). It is also well known that sequelae of emotional pr ocesses are also implicated in the etiology and maintenance of obsessions and compulsions. However, littl research has tested how emotional processes moderate inhibitory functions in OCD. In the present study, high contamination phobic (HCP, n = 17) and low contamination phobic (LCP, n = 30) participants completed an emotional go/no-go task, which measured the interfering effec ts contamination-threat processing on action restraint. The present study had a two level betwee n-subjects-quasi-independent factor (Group: LCP vs. HCP), and a two level within-subjects-exper im ntal-factor (Threat: Contamination vs. Neutral). The proportion of errors of commission (f ailures of action restraint) was the primary dependent variable. There were three predictions: 1 ) for the main effect of Threat, it was predicted that the visual processing of contaminati o images would significantly interfere with action restraint (Contamination errors of commissio n > Neutral errors of commission); 2) for the main effect of Group, it was predicted that HCP par ticipants would show poorer action restraint when compared to LCP participants (HCP errors of co mmission > LCP errors of commission); 3) for the Group x Threat interaction, it was predi cted that the visual processing of contamination images would interfere more with action restraint a mong HCP than LCP participants (Contamination errors of commission among HCP parti cipants > Neutral errors of commission among HCP participants, Neutral errors of commissio n among LCP participants, and Contamination errors of commission among LCP partic ipants). Predictions 1 and 3 were supported by results while results failed to suppor t the second prediction. These data suggest that the processing of emotionally arousing imagery inte rfer s with action restraint and the magnitude of this effect is greater among an analogue OCD sam ple reporting contamination symptoms. These findings are clinically relevant and signific antly extend etiological models of OCD by integrating basic neurocognitive and affective mech anisms. The unique and complimentary roles of emotional, attentional, and inhibitory processes in the etiology and maintenance of obsessions and compulsions are explored and updates to models f OCD are discussed. ACKNOWLEDGMENTS I have to start by thanking my dissertation commit tee for their patience and flexibility on this and all other research projects I have dragoon ed them into over the last five years. I have to send a special thank you to Dr. Lohr. His tutelage has influenced my personal and professional growth in innumerable ways. It is worth noting that the latter two sentences occupied less than one and a half lines and contained only one punctua tion mark. Also, thanks to my lab mates, particularly Dr. Joshua Cisler and Dr. Robert Brady , who played instrumental roles in my academic development and the formulation of this pr oject idea. Finally, I would like to thank Alex Fessler and Chelsea Golden for their assistanc e with data collection, Dr. Jan De Houwer for providing the programming script for his version of the emotional go/no-go task, and Tom Armstrong for sharing his experimental stimuli. Wit hout their help I would have most certainly been unable to complete this project in such a brie f amount of time. TABLE OF CONTENTS