How The Brain Responds To Threat When Experiencing Intrusive Thoughts

People with sexual obsessions in OCD struggle with painful, intrusive thoughts. As a result, their brains get confused, leaving them feeling uncertain about their moral values. 

For example, consider Dave, who experiences conflict when he gets paedophile-intrusive thoughts (POCD) and feels sudden movement down there. He’s instantly terrified he’s a threat to children. But he needn’t be. And that’s because the sensation is a reflex. His nervous system triggers an involuntary response after being subjected to internal or external stimuli, such as thinking about or being around kids.

Have you ever noticed twitching in some people with anxiety, like their cheek and eye twitching? It does this when a muscle, or group of muscles, moves without conscious thought or action. In that case, it’s automatic and not the person’s fault. So you can imagine how Dave experiences unconscious movement down there when he’s anxious.

Amygdala Activation

First, the brain’s amygdala is constantly alert, scanning for danger to protect us and others from threatening situations. So when it detects that Dave could be attracted to kids, it fires up. In other words, his amygdala forewarns him through feelings, not words, to be careful. Of course, it doesn’t pick up that intrusive thoughts and sensations are false alarms; it thinks they’re real, so Dave gets the urge to avoid triggering situations. It’s a compulsion associated with fight response and reduces his anxiety momentarily. Or he escapes the situation, which links to a flight response. He flees to prevent the thoughts from turning to reality, and again, to reduce anxiety. 

What can he do?

Even though his anxiety becomes high, Dave can learn to calm his amygdala and show that it does not need to arouse a fight or flight response. Deep breathing exercises are good for this because the amygdala responds to calming activities. Then, when it’s calmer, Dave’s cortex, the thinking area of his brain, can step in and help him reason rationally. Unfortunately, it can’t help him do this when the amygdala is going full force because it blocks rational signals. So when it’s quieter, the cortex gets the chance to signal that the POCD thoughts are false and not to worry.

Breaking The Connection

But it doesn’t end there. Dave’s therapist reinforces that he must do practical exercises to change the amygdala’s wiring. These actions are the opposite of compulsions. It means facing the thoughts that the amygdala got wrong and not avoiding or fleeing the feared situations. That way, he can break the connection that makes him think rituals prevent a terrible thing from happening. These exercises are known as exposure and response prevention (ERP), an evidence-based treatment for OCD.

The Freeze Response

Dave agrees that ERP could be helpful but worries about certain times when he feels immobilised. For example, he feels numb when certain children are around him and appears to stare at them. And so he thinks it must mean he’s secretly attracted to them. However, he learns that feeling immobilised is another fear reaction to fight and flight. This time it’s a freeze response.

Dave also learns that his amygdala will settle down by itself within 15-30 minutes and usually no longer than an hour. That being so, he figures he can tolerate the fight, flight or freeze response and wait for his cortex to free up and suggest rational ideas for managing his situation. In other words, he gets the opportunity to influence what happens next, for example, using response prevention in ERP.


And for the ERP method to work, the amygdala needs activating for the habituation process to kick in. For instance, Dave realises he must face his fears in graded steps, such as strolling through a play park. Next, he must allow anxiety to rise, resist avoidance and escape rituals and wait for anxiety to diminish. And with a freeze response, Dave knows to breathe, wait it out, and not analyse his thoughts (preventing a mental compulsion). As a result of ERP, he builds distress tolerance, becoming less sensitised to his irrational fears over time. Again, it’s because his amygdala gradually becomes less active in triggering situations. 

The good thing about ERP is that the amygdala doesn’t know the difference between facing a real fear or deliberate exposure to your obsessive fears noted earlier. It’s why challenging fearful situations in ERP fire it up, thus leading to habituation. Of course, Dave does visual exposures, too. But, again, his amygdala doesn’t know what he conjures up in his mind isn’t real, so it becomes activated, which is the idea. Remember, habituation can only work when you challenge the fear, anxiety increases and you resist the corresponding rituals.


In short, intrusive thoughts and sensations come from the brain automatically. As a result, the amygdala activates a fight, flight or freeze response. Then, we assign meaning to them and develop an obsession. Breathing exercises soothe the amygdala, and ERP helps the brain signal that no alarm is required. Consequently, it makes the amygdala less active overall and we experience habituation.

2 responses to “How The Brain Responds To Threat When Experiencing Intrusive Thoughts”

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: