Why Can’t I Stop Overthinking? What Your Brain Is Actually Doing

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If you’ve ever asked yourself, “why do I overthink everything?” You’re far from alone. Many people describe their inner world as a constant stream of racing thoughts, almost always pointed at the future, and almost always exhausting. What starts as a worry quickly becomes a physical experience: your heart beats faster, your body tenses, and before long, the thoughts themselves feel like a threat.

What Is Overthinking, Really?

Overthinking is often confused with being thorough or careful. But there’s a meaningful difference between productive problem-solving and what researchers call rumination: the mental habit of replaying past events or rehearsing future ones in a loop that doesn’t lead anywhere useful (Nolen-Hoeksema et al., 2008).

A helpful way to think about it: worry is disproportionate to the situation at hand. If you’re worried about whether you can make rent, a higher level of stress is reasonable. If you’re spending hours anxious about whether someone misread a text you sent, the intensity of the worry has outpaced the actual risk.

Clinically, it is helpful to consider the general adaptation syndrome, a three-stage model describing how the body responds to prolonged stress. Stage one is alarm, when the threat feels immediate. Stage two is resistance, when the body tries to cope. Stage three is exhaustion and that’s where many students with overthinking anxiety land: depleted, not because of what they’ve done, but because of what they’ve been thinking (Selye, 1956).

Signs of Overthinking Students Often Miss

When people first start therapy, they say something like: “I don’t know why I can’t just get started.” Or: “I have all these goals and I never follow through.” Or simply: “I feel exhausted, and I don’t know why.”

The signs of overthinking are often disguised as something else — low motivation, perfectionism, or just feeling “off.” Here are some patterns worth recognizing:

• You feel mentally exhausted without doing much. When your mind has been running at full speed all day: worrying, planning, replaying — it consumes real energy, even if you’ve barely moved.
• You struggle to start or finish things. Overthinking and perfectionism are closely linked. The pressure to do something “right” can make starting feel impossible, and finishing feel unsafe.
• You replay conversations or anticipate future ones. Going over what you said, or pre-scripting what you’ll say next; This is a hallmark of rumination, not preparation.
• You’re hard on yourself. Shame and self-criticism often live alongside overwhelm and stress. If your inner monologue is harsh, that’s worth paying attention to.
• You avoid things without knowing why. Avoidance is often anxiety’s quietest symptom. If there’s a task or situation you keep sidestepping, there may be worry underneath it.
• You can’t seem to “switch off.” Difficulty relaxing, enjoying downtime, or being present with people around you can all point to a mind that hasn’t found a way to rest.

When Overthinking Spikes at Night

There’s a reason your brain seems louder at bedtime. When we keep ourselves busy throughout the day, we don’t give our minds space to process our emotions. Think of it this way: for most of human history, people had long stretches of unstructured idle time. That idle time was when the mind did its processing work.

When we fill every waking moment with stimulation, those unprocessed thoughts get bottled up. The moment your head hits the pillow and the distractions fall away, they arrive.

If nighttime overthinking is affecting your sleep, see our article on CBT for Insomnia.

Why Overthinking and Anxiety Feed Each Other

Overthinking anxiety is a cycle. Anxiety activates the brain’s threat-detection system, scanning for danger. Overthinking is the mind’s attempt to solve that perceived threat. Future-focused worry rarely produces concrete solutions. More anxiety means more overthinking. More overthinking means more anxiety.

It’s worth knowing that this pattern doesn’t always mean anxiety is the whole story. For some students, anxious overthinking is a symptom of undiagnosed ADHD, the brain struggles to filter and prioritize thoughts — or to depression, where rumination tends to be more past-focused and tinged with hopelessness. These distinctions matter for treatment, which is why a proper assessment is so valuable.

Wondering if ADHD might be a factor? See our page on ADHD Assessments for Adults and Students.

When Is Overthinking Something to Take Seriously?

Overthinking exists on a spectrum. Some amount of worry is a normal part of being human, especially during high-pressure periods like work deadlines, transitions, or major decisions. But when it becomes impairing, that’s a meaningful signal.

Consider reaching out to a mental health professional if your overthinking is:

• Regularly disrupting your sleep
• Making it hard to concentrate or complete home, school, or work tasks
• Pulling you away from relationships or things you used to enjoy
• Coming with intrusive thoughts that feel distressing or hard to control
• Tied to physical symptoms like tension, headaches, or a racing heart that don’t seem to ease

Intrusive thoughts in particular, a common feature of student mental health concerns, can feel frightening and isolating. They are more common than most people realize, and they are treatable (Clark & Beck, 2010).

What Actually Helps — And What Doesn’t

Let’s be honest about the most common coping strategy first: numbing. Scrolling, streaming, gaming, or using cannabis to quiet a busy mind. These aren’t moral failures, they make sense as short-term relief. But they don’t address the underlying issue. Imagine you had a cut that needed tending, numbing the pain doesn’t close the wound. The moment the numbing wears off, the pain returns.

Evidence-based approaches, like CBT,  help you change your relationship with your thoughts, rather than escape them. A few directions worth knowing about:

• Learn to tolerate uncomfortable feelings. One of the most meaningful shifts in therapy is recognizing that negative emotions are not emergencies to be fixed, they’re experiences to be moved through. Life involves both negative and positive emotions, and building tolerance for discomfort is a foundational skill.
• Try thought-tracking as a starting point. When a worry surfaces, write it down. Over time, notice patterns. Is it always about the same theme? Parenting, health, the future? Approaching your own thoughts like a researcher analyzing data can create just enough distance to reduce their power.
• Move your body and connect with people. Exercise and social connection are among the most consistently supported tools for managing anxiety and overwhelm. They’re not a cure, but they’re a meaningful foundation.
• Consider CBT. Cognitive Behavioural Therapy has strong evidence for addressing the thought patterns that drive overthinking, anxiety, and rumination (Hofmann et al., 2012). A therapist can help you identify and restructure the specific patterns keeping you stuck.

Learn more about how CBT for Anxiety works at our clinic.

You Don’t Have to Think Your Way Out of Overthinking

If your mind feels like it won’t slow down, that’s not a sign that something is deeply wrong with you. It’s a sign that your brain has learned a pattern and that it’s working very hard to keep you safe, even when the threat isn’t real.

You don’t have to figure this out alone, and you don’t have to out-think overthinking. What tends to help is professional support along with a genuine understanding of what’s happening in your mind and body.

Disclaimer: This article is for educational purposes and is not a substitute for professional mental health assessment or treatment.‍

If overthinking is getting in the way of your work, sleep, or daily life, our team offers CBT and mental health assessments in British Columbia and Ontario — including for those individuals without a family doctor or psychiatrist. → Free Discovery Session | Cognito Health 

References

Clark, D. A., & Beck, A. T. (2010). Cognitive therapy of anxiety disorders: Science and practice. Guilford Press.

Hofmann, S. G., Asnaani, A., Vonk, I. J. J., Sawyer, A. T., & Fang, A. (2012). The efficacy of cognitive behavioral therapy: A review of meta-analyses. Cognitive Therapy and Research, 36(5), 427–440. https://doi.org/10.1007/s10608-012-9476-1

Nolen-Hoeksema, S., Wisco, B. E., & Lyubomirsky, S. (2008). Rethinking rumination. Perspectives on Psychological Science, 3(5), 400–424. https://doi.org/10.1111/j.1745-6924.2008.00088.x

Rumination: A cycle of negative thinking. Psychiatry.org - Rumination: A Cycle of Negative Thinking. (2020, March 5). https://www.psychiatry.org/news-room/apa-blogs/rumination-a-cycle-of-negative-thinking 

Selye, H. (1956). The stress of life. McGraw-Hill.

Wiens, K., Bhattarai, A., Dores, A., Pedram, P., Williams, J. V. A., Bulloch, A. G. M., & Patten, S. B. (2020, January). Mental Health among Canadian postsecondary students: A mental health crisis?. Canadian journal of psychiatry. Revue canadienne de psychiatrie. https://pmc.ncbi.nlm.nih.gov/articles/PMC6966257/

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