Enhanced Avoidance Habits in Obsessive-Compulsive Disorder: Gillan et al. (2014)

Question 1

It has long been the question how a patient with OCD can be taken over by an overwhelming compulsion, despite knowing that it serves no real purpose (ego-dystonia).

Answer 1

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Question 2

study aim=

Answer 2

Existing research suggests that patients with OCD have a bias toward appetitive habit formation at the expense of goal-directed behavior. However, compulsions in OCD are avoidant rather than appetitive.

Thus, the current study aimed to test whether there is a bias toward avoidance habit formation in OCD.

-> Does compulsivity in OCD arise from excessive stimulus-response habit formation?

Question 3

shock avoidance task=

Answer 3

A task that is designed to induce habits through overtraining. OCD and control subjects are connected to a shock machine with both of their wrists. In the task, shocks can be avoided by responding to warning stimuli with the correct foot pedal:
* CS1+: predicts a shock to the left wrist and can be avoided by pressing the left foot pedal.
* CS2+: predicts a shock to the right wrist and can be avoided by pressing the right foot pedal.

Question 4

outcome-devaluation in this study

Answer 4

After extensive overtraining, 1 wrist is disconnected, and the subject is told that they can no longer be shocked at that wrist and that they should only avoid receiving the other shock. There are 2 outcomes:
* Goal-directed behavior: the subject no longer responds to the CS that predicts the devalued outcome but maintains responding to avoid the valued outcome (that still predicts a shock).
* Habitual behavior: the subject keeps responding to both CSs.

Question 5

control variables

Answer 5

Both groups of participants showed similar accuracy, sensitivity to devaluation (before training), contingency knowledge and shock expectancy following devaluation. Furthermore, there was no difference in skin conductance responses. Lastly, after short-term training, OCD patients were as able as controls to stop pressing to the devalued stimulus.

Question 6

main result

Answer 6

Even though both groups showed a strong devaluation effect following over training, OCD patients showed greater avoidance of the stimulus that was no longer predictive of shock (devalued): they still responded to avoid it.
Furthermore, these responses were associated with a greater subjective urge to respond to the devalued outcomes.

Question 7

conclusion

Answer 7

OCD patients have a bias toward developing avoidance habits, which are related to a subjective urge to respond. This latter result suggests that these habits are more than just action slips.

-> Excessive habit formation in patients with OCD may contribute to compulsive symptoms.