How Does Stress Affect Brain Responses in People with OCD?

What you need to know

• People with OCD often experience worsening symptoms during times of stress, but the brain mechanisms underlying this are not well understood.

• This study examined how stress affects brain activity in people with OCD when viewing emotional images related to their symptoms.

• The researchers found that stress reduced activity in a key brain region involved in emotional processing in people with OCD, while it increased activity in that region for people without OCD.

Background on OCD and stress

Obsessive-compulsive disorder (OCD) is a mental health condition characterized by intrusive, anxiety-provoking thoughts (obsessions) and repetitive behaviors or mental acts (compulsions) that a person feels compelled to perform to relieve anxiety. OCD affects about 2-3% of people at some point in their lives.

Many people with OCD report that their symptoms worsen during times of stress. However, the exact relationship between stress and OCD symptoms is complex. Stress may make people more likely to misinterpret normal intrusive thoughts as significant or dangerous. It may also make it harder for people to resist urges to perform compulsions.

Understanding how stress impacts the brains of people with OCD could provide insights into why symptoms worsen under stress and potentially lead to better treatments. This study aimed to examine that question using brain imaging.

How the study worked

The researchers recruited 23 people diagnosed with OCD and 23 people without OCD to participate in the study. All participants completed two experimental sessions - one where they underwent a stressful task, and one control session without stress.

For the stress condition, participants had to submerge their hand in ice cold water while being observed and evaluated by researchers. This is a commonly used method to induce mild psychological and physiological stress in laboratory settings.

About an hour after the stress or control task, participants had their brains scanned using functional magnetic resonance imaging (fMRI) while viewing different types of pictures:

1. OCD-related images tailored to each participant’s symptoms
2. Generally fear-inducing images
3. Neutral, non-emotional images

The researchers then compared brain activity patterns between the OCD and non-OCD groups and between the stress and non-stress conditions.

Key findings

The main findings of the study were:

1. As expected, the stress task increased blood pressure, heart rate, and feelings of anxiety in both groups compared to the control condition.

2. People with OCD showed a reduced cortisol (stress hormone) response to the stressor compared to the control group. This aligns with previous research showing blunted physiological stress responses in OCD.

3. A key brain region called the dorsal anterior cingulate cortex (dACC) showed different patterns of activity between groups:

   • In people without OCD, stress increased dACC activity when viewing emotional images.
   • In people with OCD, stress decreased dACC activity when viewing emotional images.

The dACC is involved in many aspects of cognition and emotion, including detecting salient or important information in the environment, regulating emotional responses, and guiding behavior. The different response patterns suggest stress may disrupt normal emotional processing in the brains of people with OCD.

Possible interpretations

The researchers suggest a few potential interpretations of these findings:

1. The reduced dACC activity in OCD patients under stress may reflect impaired emotion regulation. People with OCD may have more difficulty reappraising or managing their emotional responses to triggering stimuli when stressed.

2. It could indicate problems shifting attention and mental resources to deal with emotional stimuli appropriately when under stress.

3. The blunted stress hormone (cortisol) response in OCD patients may play a role. Cortisol typically helps restore balance after stress, so an impaired cortisol response could contribute to prolonged difficulty managing emotions.

However, the researchers emphasize these are speculative interpretations that require further research to confirm. The study design can’t definitively prove causal relationships.

Limitations to consider

Some key limitations of this study include:

• The relatively small sample size of 23 people per group. Larger studies are needed to confirm the findings.

• Many of the OCD patients were taking medication, which could have impacted the results.

• The brain scanning occurred over an hour after the stressful task. The effects may be different immediately after stress exposure.

• The study induced general stress rather than OCD-specific triggers, which may produce different effects.

• The OCD group was heterogeneous in terms of specific symptoms and gender. Different subtypes of OCD may show different patterns.

Conclusions

• This study provides initial evidence that stress may disrupt normal emotional processing in the brains of people with OCD in ways that differ from people without OCD.

• Specifically, a key brain region involved in detecting important information and regulating emotions (the dACC) shows reduced activity under stress in OCD.

• This could potentially help explain why OCD symptoms often worsen during stressful periods, though more research is needed.

• Understanding these brain mechanisms could eventually lead to better treatments targeting the effects of stress in OCD.

While this study doesn’t provide definitive answers, it offers new insights into the complex relationship between stress and OCD symptoms at the brain level. Further research building on these findings may help improve our understanding and treatment of OCD over time.