Enhanced avoidance habits in obsessive-compulsive disorder

Abstract

Background: Obsessive-compulsive disorder (OCD) is a psychiatric condition that typically manifests in compulsive urges to perform irrational or excessive avoidance behaviors. A recent account has suggested that compulsivity in OCD might arise from excessive stimulus-response habit formation, rendering behavior insensitive to goal value. We tested if OCD patients have a bias toward habits using a novel shock avoidance task. To explore how habits, as a putative model of compulsivity, might relate to obsessions and anxiety, we recorded measures of contingency knowledge, explicit fear, and physiological arousal.

Methods: Twenty-five OCD patients and 25 control subjects completed a shock avoidance task designed to induce habits through overtraining, which were identified using goal-devaluation. The relationship between habitual behavior, erroneous cognitions, and physiological arousal was assessed using behavior, questionnaires, subjective report, and skin conductance responses.

Results: A devaluation sensitivity test revealed that both groups could inhibit unnecessary behavioral responses before overtraining. Following overtraining, OCD patients showed greater avoidance habits than control subjects. Groups did not differ in conditioned arousal (skin conductance responses) at any stage. Additionally, groups did not differ in contingency knowledge or explicit ratings of shock expectancy following the habit test. Habit responses were associated with a subjective urge to respond.

Conclusions: These data indicate that OCD patients have a tendency to develop excessive avoidance habits, providing support for a habit account of OCD. Future research is needed to fully characterize the causal role of physiological arousal and explicit fear in habit formation in OCD.

Keywords: Avoidance; cognitive neuroscience; goal-directed learning; habit; obsessive-compulsive disorder; psychophysiology.

Figure. 1

Task design. (A) Warning stimuli. The blue stimulus predicts a right shock, the red stimulus a left shock. If the correct avoidance response (e.g., left pedal to avoid left shock) is produced on time, subjects avoid shock. (B) Devaluation procedure. The electrodes on one side are disconnected from their connector (devalued), and the electrodes on the other side are unchanged (valued).

Figure 2

Training accuracy and general devaluation sensitivity. Error bars denote SEM. (A, B) Discriminative avoidance learning from training sessions. There were no group differences in total avoidance performance or skin conductance responses (SCRs) to warning stimuli. (C, D) Rate of false alarm responses and SCRs to safe stimulus did not differ between groups. (E, F) Devaluation sensitivity test. There were no differences in behavioral or physiological (SCR) sensitivity to devaluation. CS, conditioned stimulus; OCD, obsessive-compulsive disorder.

Figure 3

Habits in obsessive-compulsive disorder (OCD) patients. Error bars denote SEM. (A) Habit test. Behavioral responses made to the valued stimulus did not differ, F<1, but OCD patients responded significantly more to the stimulus that explicitly no longer predicted shock (devalued) than control subjects. (B) Skin conductance response (SCR) of OCD patients and control subjects during critical habit test did not differ. (C) Obsessive-compulsive disorder patients reported a significantly stronger urge to make avoidance responses in spite of devaluation, F_1,48 = 7.016, p = .011. (D) No group difference in explicit shock expectancy in light of the devaluation procedure. *Significant at p < .05. CS, conditioned stimulus.