Examining Differences in Fear Learning in Patients With Obsessive-Compulsive Disorder With Pupillometry, Startle Electromyography and Skin Conductance Responses.

Dorothee Pöhlchen,Deniz A Gürsel,Victor I Spoormaker,Florian P Binder,Götz Berberich,Marthe Priouret,Miriam S Kraft,Kathrin Koch

doi:10.3389/fpsyt.2021.730742

Abstract

Obsessive-compulsive disorder (OCD) is characterized by recurrent, persistent thoughts and repetitive behaviors causing stress and anxiety. In the associative learning model of OCD, mechanisms of fear extinction are supposed to partly underlie symptom development, maintenance and treatment of OCD, proposing that OCD patients suffer from rigid memory associations and inhibitory learning deficits. To test these assumptions, previous studies have used skin conductance and subjective ratings as readouts in fear conditioning paradigms, finding impaired fear extinction learning, impaired fear extinction recall or no differences between individuals with OCD and healthy controls. Against this heterogeneous background, we tested fear acquisition and extinction in 37 OCD patients and 56 healthy controls, employing skin conductance as well as pupillometry and startle electromyography. Extinction recall was also included in a subsample. We did not observe differences between groups in any of the task phases, except a trend toward higher startle amplitudes during extinction for OCD. Overall, sensitive readouts such as pupillometry and startle responses did not provide evidence for moderate-to-large inhibitory learning deficits using classical fear conditioning, challenging the assumption of generically impaired extinction learning and memory in OCD.

Highlights

Obsessive-compulsive disorder (OCD) is an anxiety related disorder characterized by persistent, intrusive and undesired thoughts that result in high anxiety and distress as well as compulsive behaviors [1]
The neutral stimulus becomes a conditioned stimulus (CS+). This stimulus elicits a physiological conditioned response (CR) that can be quantified as an increase in the skin conductance response (SCR), larger pupil dilations and a potentiated startle reflex compared to previous trials or control conditions
The first sample originally contained 24 healthy controls (HC) (12 females, aged 33.1 ± 11.2, M ± standard deviation (SD)) who were recruited through online advertisements and 28 treatment-seeking OCD patients (14 females, aged 34.4 ± 12.7, M ± SD) who were recruited from clinics specialized on OCD in the larger Munich area

Summary

Introduction

Obsessive-compulsive disorder (OCD) is an anxiety related disorder characterized by persistent, intrusive and undesired thoughts (obsessions) that result in high anxiety and distress as well as compulsive behaviors [1]. Fear and anxiety are core characteristics of OCD and key features of the symptomatology, typically preceding and accompanying obsessions and compulsions [2]. One experimental model to assess the creation and maintenance of such pathological associative memories is classical fear-conditioning. This paradigm is used to investigate the learned association between a neutral stimulus and an inherently aversive unconditioned stimulus (US). The neutral stimulus becomes a conditioned stimulus (CS+). A common experimental manipulation in fear conditioning studies is extinction - the creation of a new association between the CS and safety due to repeated presentations of the CS without the US. Fear extinction can be conceptualized as a conflict between two opposing knowledge states, comprising the original acquisition of an excitatory association between the CS and the US and the new, inhibitory learning, decreasing the CR to the CS [3]

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