How Does Obsessive-Compulsive Disorder Affect Behavior Inhibition?

What you need to know

• People with OCD show greater difficulty inhibiting automatic eye movements compared to those with generalized anxiety disorder and healthy controls
• OCD patients are especially sensitive to peripheral visual stimuli, struggling more to inhibit responses to stimuli farther from the center of vision
• The study suggests behavior inhibition difficulties may be a key mechanism underlying OCD symptoms

Background on OCD and behavior inhibition

Obsessive-compulsive disorder (OCD) is a mental health condition characterized by intrusive, unwanted thoughts (obsessions) and repetitive behaviors or mental acts (compulsions) that a person feels compelled to perform. While most people experience occasional unwanted thoughts or engage in repetitive behaviors at times, those with OCD experience these to such an extreme degree that it interferes significantly with their daily lives.

One theory about the underlying mechanisms of OCD is that people with the disorder have difficulty inhibiting or stopping automatic behaviors and responses. This is referred to as “behavior inhibition.” The ability to inhibit automatic responses allows us to override habitual or reflexive actions when they are not appropriate for a given situation. For people with OCD, a deficit in this ability could explain why they struggle to stop compulsive behaviors even when they recognize them as excessive or irrational.

Previous research has yielded mixed results on whether people with OCD truly have impaired behavior inhibition compared to those without the disorder. Some studies have found evidence of inhibition difficulties, while others have not. The authors of this study aimed to clarify this question using a novel approach - examining eye movements as a measure of behavior inhibition.

How eye movements reveal behavior inhibition

The researchers used a technique called eye tracking to measure participants’ ability to control their automatic eye movements. Specifically, they used two types of tasks:

1. Prosaccade task: Participants were instructed to look directly at a visual target that appeared on a screen. This measures the natural, automatic eye movement toward a stimulus.

2. Antisaccade task: Participants were instructed to look in the opposite direction from where a visual target appeared. This requires inhibiting the automatic eye movement toward the target and instead making a controlled movement away from it.

By comparing performance on these two tasks, the researchers could assess participants’ ability to override their automatic responses (behavior inhibition). They measured two key aspects of performance:

• Saccade latency: How long it took participants to initiate an eye movement after the target appeared
• Error rate: How often participants made eye movements in the wrong direction during the antisaccade task

The study included three groups of participants:

• 25 people diagnosed with OCD
• 25 people diagnosed with generalized anxiety disorder (GAD)
• 25 healthy control participants with no diagnosed mental health conditions

Including the GAD group allowed the researchers to determine if any observed differences were specific to OCD or were related to anxiety more broadly.

Key findings on behavior inhibition in OCD

The study revealed several important findings about behavior inhibition in people with OCD:

Greater difficulty with antisaccades

Participants with OCD showed significantly longer latencies (slower reaction times) and higher error rates on the antisaccade task compared to both the GAD and healthy control groups. This suggests they had more difficulty inhibiting the automatic eye movement toward the target and generating the controlled movement away from it.

Importantly, the OCD group did not show impaired performance on the prosaccade task. In fact, they were slightly faster than the other groups at making automatic eye movements toward targets. This indicates their difficulty was specific to inhibiting and overriding automatic responses, not a general problem with eye movements or visual processing.

Heightened sensitivity to peripheral stimuli

The researchers also varied the location where the visual targets appeared, presenting them either near the center of the screen or farther in the periphery. They found that participants with OCD struggled even more with peripheral targets compared to central ones.

Specifically, the OCD group showed:

• Longer latencies for antisaccades to peripheral vs. central targets
• Higher error rates for antisaccades to peripheral vs. central targets
• Shorter latencies for prosaccades to peripheral vs. central targets

This pattern suggests that people with OCD may be hypersensitive to stimuli in their peripheral vision, making it even harder for them to inhibit automatic responses to these stimuli.

Specific to OCD vs. general anxiety

The fact that participants with generalized anxiety disorder did not show the same pattern of impaired antisaccade performance indicates that these behavior inhibition difficulties are specific to OCD rather than a feature of anxiety disorders more broadly.

Implications for understanding and treating OCD

These findings have several important implications for our understanding of OCD and potential treatment approaches:

Behavior inhibition as a core mechanism

The study provides strong evidence that impaired behavior inhibition is a key feature of OCD. This aligns with the experiences many people with OCD report of feeling unable to stop compulsive behaviors even when they want to. It suggests that interventions aimed at improving inhibitory control could be beneficial for managing OCD symptoms.

Heightened sensitivity to peripheral stimuli

The finding that people with OCD struggle even more with inhibiting responses to peripheral visual stimuli is a novel contribution. It may help explain why people with OCD often report being hyperaware of potential “contaminants” or hazards in their environment, even those that others might not notice. Treatment approaches that help patients learn to better filter and selectively attend to visual information could be useful.

Distinguishing OCD from anxiety disorders

The results highlight that OCD involves distinct cognitive and neural processes compared to other anxiety disorders. This supports the recent reclassification of OCD as its own category of disorder rather than an anxiety disorder in diagnostic manuals. It suggests that while anxiety may be a component of OCD for many people, treatments need to address the specific inhibitory control deficits associated with the disorder.

Conclusions

• People with OCD show impaired ability to inhibit automatic eye movements, especially for stimuli in their peripheral vision
• These behavior inhibition difficulties appear to be specific to OCD rather than a general feature of anxiety disorders
• Impaired inhibitory control and heightened sensitivity to peripheral stimuli may be key mechanisms underlying OCD symptoms
• Treatments targeting these specific cognitive processes could be promising avenues for managing OCD