Overthinking: What It Is and What Drives It

What Overthinking Actually Is

Overthinking is not the same as thinking hard about something difficult. The distinction matters. When you are genuinely problem-solving, your mind moves through a process: you gather information, weigh options, reach a conclusion, and act. Overthinking does the opposite. It circles. The same question comes back in a slightly different form, then again, then again — and each pass through produces no new information and no decision. Psychologists call this pattern repetitive negative thinking (RNT) — in plain terms, thoughts that keep looping back to the same negative territory without ever settling anything. The key word is repetitive. It is not depth; it is recurrence.

The mechanism behind it involves a brain network called the default mode network (DMN) — a set of regions that switches on when you are not focused on an external task, roughly the mental equivalent of your phone running background apps you never closed. In most people, the DMN quietens down when attention is needed elsewhere. In people who overthink chronically, research suggests this network stays more active and is less effectively dialled down by the prefrontal regions responsible for goal-directed thinking. The result is a kind of cognitive background noise that intrudes on focus, distorts memory recall, and inflates the perceived significance of minor events. It feels like your mind is working on something important. Neurologically, it is idling with the engine running — using fuel, going nowhere.

What makes overthinking particularly difficult to recognise in yourself is that it tends to feel productive. You tell yourself you are being thorough, responsible, careful. But there is a reliable test: after a thinking session, do you feel clearer or more exhausted? Problem-solving produces clarity. Overthinking produces fatigue and, frequently, more doubt than you started with. Researchers sometimes use the term perseverative cognition — thinking that persists beyond its useful function — to describe the underlying mechanism. It is thinking that has come unstuck from purpose.

Why Some Brains Overthink More Than Others

Not everyone is equally susceptible to overthinking, and if you're one of the people who is, that is not a character failing on your part. There are neurological and psychological factors that raise the baseline. Anxiety is the most strongly associated condition: when the threat-detection systems in your brain are chronically sensitised, your mind generates more worst-case scenarios and places disproportionate weight on ambiguous information. This is your brain doing its job — scanning for danger — but in a context where most of your dangers are social and reputational rather than physical, the scanning loops without resolution.

ADHD introduces a different dynamic. People with ADHD often experience what clinicians describe as hyperactive inner speech — a mind that generates thoughts rapidly and struggles to inhibit ones that have become unhelpful. This is not the same as anxiety-driven rumination, but it can look similar from the outside and feel similarly exhausting from the inside. Perfectionism adds another layer: when your internal standard requires certainty before acting, and certainty is rarely available, your thinking continues by default. Research from the University of Exeter has shown that perfectionism is a robust predictor of rumination, meaning the more you demand a flawless outcome, the longer your mind stays stuck in pre-action loops.

Temperament also plays a role. Some people are naturally higher in what psychologists call neuroticism — a trait linked to stronger emotional responses to stress — and if that's you, you'll tend to generate more self-referential negative thoughts in ambiguous situations. This is not a permanent condition. It is a baseline, and baselines can be shifted with practice.

The Three Patterns Overthinkers Get Stuck In

Most overthinking takes one of three forms, and they are worth naming clearly because they call for different responses.

Rumination is backwards-facing. It involves replaying past events — a conversation that went badly, a decision that had consequences — and cycling through what you should have said or done differently. The emotional tone is usually shame or regret. Rumination does not extract lessons; it rehearses pain. Dr Ethan Kross at the University of Michigan has spent years studying how the self-referential nature of rumination amplifies negative emotion rather than processing it, and how creating psychological distance — speaking to yourself in the third person, imagining advice you would give a friend — reliably reduces its intensity.

Worry is forward-facing. It involves generating future scenarios, usually negative ones, and trying to mentally prepare for them. Some anticipatory thinking is useful. Worry crosses into overthinking when the scenarios become increasingly unlikely, when preparation tips into catastrophising, and when the thinking produces anxiety rather than readiness.

Analysis paralysis sits between the two. It happens when you need to make a decision but your mind keeps generating more considerations, edge cases, and variables rather than converging on a choice. The more options you have, the worse this tends to get — psychologist Barry Schwartz documented this phenomenon extensively in research on the paradox of choice, showing that more options reliably produce less satisfaction and more post-decision regret. Think of it like standing in a supermarket aisle with forty types of pasta sauce: more choice doesn't make you more confident, it just gives your mind more places to circle.

What Overthinking Does to Your Body and Brain

The physical cost of chronic overthinking is underestimated. When your mind locks into a loop of negative or anxious thinking, your body interprets this as a threat response and elevates cortisol — the primary stress hormone. In short bursts, cortisol is useful. Sustained elevation, which chronic overthinking produces, disrupts your sleep architecture, suppresses immune function, impairs memory consolidation, and raises your baseline heart rate. It is not a metaphor to say that overthinking is physically wearing. The mechanism is concrete.

Sleep is particularly affected. Your brain processes and consolidates the day's experiences during sleep, but a mind that has been running hot with repetitive thinking tends to carry that activity into the hypnagogic state — the transition into sleep — where unresolved thoughts resurface and delay the onset of deep sleep. This creates a cycle: poor sleep impairs your prefrontal cortex's ability to regulate emotional responses the following day, which makes your brain more reactive, which generates more anxious thinking, which further disrupts sleep. Decision fatigue compounds this. Research has consistently shown that the quality of decisions deteriorates after extended mental effort, and overthinking is one of the most energy-intensive cognitive activities your brain performs — even when it produces nothing useful. Like leaving fifty tabs open on your phone: none of them are doing anything useful, but the battery still drains.

How to Interrupt the Overthinking Loop

The most common advice given to overthinkers — "just stop thinking about it" — is not only unhelpful but counterproductive. Research by Daniel Wegner on thought suppression demonstrated reliably that attempting to suppress a thought increases its frequency. Tell yourself not to think about something and you will think about it more. What works instead is redirection and externalisation.

Cognitive defusion is a technique from Acceptance and Commitment Therapy (ACT) that involves creating distance between yourself and your thoughts rather than trying to fight them. Instead of thinking "this is going to go wrong", you observe "my mind is producing the thought that this might go wrong." The content is the same; your relationship to it changes. This is a specific, learnable skill, not a vague instruction to be more positive. Writing your thoughts down — on paper, not a screen — serves a similar function. When you externalise a thought onto a page, your brain perceives it as less urgent. It has been acknowledged. The loop, which often runs partly because your mind is trying to make sure something is not forgotten, can slow.

Time-boxing worry is another evidence-supported approach: set aside a specific period each day — 15 to 20 minutes — as your designated time to think through concerns, and redirect intrusive thoughts to that window when they show up outside it. This sounds mechanical, but it works because it removes the implicit rule that every anxious thought needs your immediate attention. Structured planning tools that separate what needs to happen today from the wider mental load can support this significantly — not as a cure for overthinking but as a way of reducing the ambient uncertainty that feeds it. Browse the range of productivity tools at OCCO London if you are looking for something to anchor your thinking to the day in front of you, rather than the weeks of hypotheticals ahead.

When Overthinking Is a Symptom of Something Else

Persistent, intrusive overthinking that does not respond to standard strategies — and that meaningfully interferes with your sleep, work, or relationships — is sometimes a symptom of an underlying condition rather than a habit to be managed. Generalised anxiety disorder (GAD) is characterised in part by excessive, difficult-to-control worry that extends across multiple areas of your life. OCD (obsessive-compulsive disorder) can show up as intrusive thoughts that feel qualitatively different from ordinary worry — more distressing, more specific, often accompanied by an urgency to neutralise them through checking or reassurance-seeking.

ADHD, particularly in adults who were not diagnosed in childhood, frequently presents with what looks like overthinking but is more precisely described as difficulty filtering internal mental noise and regulating self-referential thinking. If your experience of overthinking is long-standing, severe, and resistant to the strategies in this article, speaking with your GP is a reasonable and sensible first step. Cognitive behavioural therapy (CBT) — a talking therapy focused on identifying and changing unhelpful thought patterns — has a strong evidence base for both anxiety-related and ADHD-related rumination, and NHS Talking Therapies (the service previously known as IAPT) is available in most parts of England without needing a referral from your GP.