How to Stop Overthinking: A Neuroscientist Explains Why Your Brain Won't Quit

It’s 11 PM and you’re replaying a conversation from this morning. You said something at the meeting and now you’re dissecting it word by word, rehearsing what you should have said, imagining what everyone thought, constructing entire narratives about how that one sentence is going to derail your career.

You know this is pointless. You know replaying it won’t change what happened. And yet your brain won’t stop.

If someone told you to “just stop thinking about it,” you’ve probably noticed that advice is about as useful as telling someone with a cough to “just stop coughing.” The problem isn’t that you don’t want to stop. The problem is that your brain has learned to overthink the same way it learns any habit: through repetition and reward.

Overthinking is a habit loop. Not a personality trait. Not a sign that something is wrong with you. A habit. And once you see it as a habit, you can start working with your brain instead of fighting against it.

I’ve spent over twenty years studying how the brain forms and breaks habits, first in my neuroscience lab at Brown University and then in my anxiety clinic. What I’ve found is that overthinking runs on the exact same brain circuitry as any other habit, from nail biting to checking your phone. And the same approach that breaks those habits works for overthinking too.

Why Can’t I Stop Overthinking?

Overthinking is a category of repetitive negative thinking. It includes rumination (replaying the past), worry (rehearsing the future), and analysis paralysis (turning decisions over and over without resolving them). What they all share is this: your brain treats them like problem-solving.

Here’s how it works. Something uncertain happens. Maybe your boss sent a short email. Maybe a friend didn’t text back. Maybe you have a decision to make and you’re not sure of the right answer. Your brain registers uncertainty, and uncertainty feels uncomfortable. So your brain does what it has learned to do: it analyzes. It replays. It rehearses. It runs scenarios.

And for a moment, that feels productive. You feel like you’re doing something about the problem. That feeling of “at least I’m working on it” is the reward your brain was looking for.

But here’s what the research shows. Rumination doesn’t solve problems. A landmark review by Susan Nolen-Hoeksema found that rumination actually impairs problem-solving ability, increases negative thinking, and predicts depression and anxiety over time (Nolen-Hoeksema S et al., “Rethinking Rumination,” Perspectives on Psychological Science, 2008, DOI: 10.1111/j.1745-6924.2008.00088.x). Your brain thinks it’s helping. It isn’t. The reward is a mirage.

This is the definition of a habit loop. A trigger (uncertainty), a behavior (analyze, replay, rehearse), and a result that feels rewarding enough to keep the loop running, even though it’s actually making things worse.

The Overthinking Habit Loop

Let me map it out clearly, because seeing the loop is the first step to breaking it.

Trigger: Uncertainty, ambiguity, an unfinished conversation, lying in bed with nothing to distract you, or anything that makes your brain register “unresolved.”

Behavior: The mental churn. Replaying past conversations. Rehearsing future ones. Running worst-case scenarios. Asking “what if” questions that have no answers. Analyzing a situation from every conceivable angle.

Result: A brief feeling of control (“I’m being thorough”), a sense of productivity (“at least I’m thinking about it”), followed by exhaustion, more anxiety, and no resolution.

The tricky part is that your brain doesn’t register the exhaustion as the result. It registers the brief moment of feeling productive as the result. That’s why the loop persists even though you can clearly see it’s not helping. Your brain learned the wrong lesson.

And here’s why willpower doesn’t work: the part of your brain that would need to stop the overthinking (your prefrontal cortex) is the same part that’s doing the overthinking. You can’t use the tool that’s broken to fix the tool that’s broken. That’s like trying to stop a runaway car by pushing the accelerator harder.

This is the same dynamic behind worry. Worry is a specific form of overthinking focused on the future, and it runs on the same loop. If you find yourself doing both, that’s not two problems. It’s one loop with two expressions.

Michael’s Story

I had a patient I’ll call Michael. Smart guy, up-and-coming career. But Michael was completely tyrannized by his own thoughts. He would have a perfectly normal interaction with his boss, and then spend hours replaying it. Analyzing every word he said. Predicting how it would tank his career. Constructing elaborate failure scenarios from a three-minute conversation.

By the time he got home, he was too exhausted to be productive. The overthinking was eating his entire evening. And then he’d feel guilty about wasting the evening, which would trigger more overthinking about his work performance, and the loop would run again.

What we did was simple. First, Michael learned to notice when the overthinking started. Not to stop it. Just to notice it. Then he started labeling the voices: “That’s the judge.” “That’s the worrier.” “That’s the career catastrophizer.” Something shifted when he gave them names. He could watch the judge judging without being fused with it. He could notice the worrier worrying without believing every prediction.

He wasn’t trying to silence the committee in his head. He was updating his brain’s relationship with it. And that made all the difference.

How to Actually Stop Overthinking

The approach I teach is called Three Gears. It works with your brain’s reward-based learning system instead of against it.

Gear 1: Map your loop. The next time you catch yourself overthinking, don’t try to stop. Instead, get interested in the loop itself. What triggered it? What does the overthinking actually give you? Be honest. Most people discover it gives them about ten seconds of feeling like they’re doing something productive, followed by thirty minutes of anxiety and exhaustion. That’s a terrible trade, but your brain hasn’t noticed yet. Mapping makes the trade visible.

Gear 2: Get curious about what overthinking actually feels like. This is the step most people skip, and it’s the most important one. When you’re in the middle of overthinking, pause and ask: “What does this feel like in my body, right now?” Not what you’re thinking about. What the overthinking itself feels like.

You might notice tension in your shoulders. A tightness in your chest. A heaviness behind your eyes. Your jaw clenching. The key is to bring curious attention to the physical experience of overthinking, because that’s what updates the reward value.

Here’s why this works. My research team at Brown found that a curiosity-based approach reduced anxiety by 67% in a randomized controlled trial, compared to psychoeducation alone (Roy A, Hoge EA, et al., “Clinical Efficacy and Psychological Mechanisms of an App-Based Digital Therapeutic for Generalized Anxiety Disorder,” JMIR Mental Health, 2021, DOI: 10.2196/26987, PMID: 34860673). The approach doesn’t try to stop the anxiety or the overthinking. It uses curiosity to update the brain’s reward value for the behavior.

When you get genuinely curious about what overthinking feels like, your brain starts to notice what it’s actually getting from the habit: not control, not resolution, but tension and exhaustion. That noticing is what updates the loop.

Gear 3: Find a bigger, better offer. Once your brain starts to get disenchanted with overthinking (once it notices the real result, not the imaginary one), you need something to replace it. Not distraction. Distraction is just avoidance, and avoidance strengthens the loop.

The bigger, better offer is curiosity itself. Curiosity about the present moment. What’s actually happening right now, in this room, in this body? Not the story your brain is spinning about what might happen tomorrow, but what is actually here.

My colleague and I published a paper examining why awareness-based approaches work when willpower fails (Ludwig VU, Brown KW, Brewer JA, “Self-Regulation Without Force: Can Awareness Leverage Reward to Drive Behavior Change?,” Perspectives on Psychological Science, 2020, DOI: 10.1177/1745691620931460, PMID: 32539591). The core finding: when people pay attention to the actual results of their habits (rather than the imagined rewards), the brain naturally updates its preferences. No force required.

Why Common Advice Doesn’t Work

You’ve probably heard these before:

“Just stop thinking about it.” Thought suppression backfires. Daniel Wegner’s famous white bear experiments showed that trying not to think about something makes you think about it more. Telling yourself to stop overthinking is itself more overthinking.

“Journal about it.” Journaling can be valuable, but without direction, it can become another form of rumination. Writing the same anxious thoughts in a notebook is the same loop running on paper.

“Distract yourself.” Distraction works temporarily because it removes you from the trigger. But it doesn’t update the habit loop. The moment the distraction ends, the overthinking comes back because your brain still believes it’s rewarding.

“Challenge your thoughts with CBT.” Cognitive behavioral therapy helps many people, and I’m not dismissing it. But CBT relies on your prefrontal cortex to rationally evaluate and reframe thoughts. Under stress, that same prefrontal cortex goes offline. That’s why CBT techniques work in the therapist’s office but can fail during a real overthinking spiral. If you’ve tried CBT and it hasn’t fully worked, the habit loop approach addresses a different brain mechanism. You can read more about this in our article on why CBT doesn’t work for everyone with anxiety.

What makes the Three Gears approach different is that it works with your brain’s reward system. You’re not trying to override the loop with willpower. You’re updating the reward value so your brain loses interest in the habit. That’s lasting change.

Next Steps

Overthinking isn’t a character flaw. It’s a habit your brain learned because it produces a false sense of control. Every time you replay a conversation or rehearse a worst-case scenario, your brain briefly feels like it’s solving a problem. It isn’t, but it takes curious attention to see that clearly.

The Three Gears are something you can start practicing right now, today, the next time your brain starts spinning. Map the loop. Get curious about what overthinking feels like in your body. And offer your brain something more rewarding than the churn: present-moment curiosity.

If you want to go deeper with this approach, Going Beyond Anxiety is my step-by-step program for breaking anxiety-driven habit loops. It walks you through the Three Gears with guided daily practices, a supportive community, and direct access to me. You can try it with a 30-day money-back guarantee.

You can also explore more in our anxiety guide or read about the habit loop to understand the framework behind everything I’ve described here.

Related Articles

• Anxiety: The Habit You Didn’t Know You Had: The complete guide to understanding anxiety as a habit loop
• How to Stop Worrying: The Neuroscience of Breaking the Worry Loop: Why worry is a habit and how curiosity breaks it
• The Habit Loop Explained: Understanding the trigger-behavior-reward cycle behind every habit
• Why CBT Doesn’t Work for Everyone with Anxiety: The structural gap in cognitive approaches and what addresses it
• Worry vs. Anxiety: What’s Actually Happening in Your Brain: Understanding the difference changes how you treat both

---