What is overthinking?

Overthinking is thinking about something over and over without moving it forward. You replay a conversation, rehearse a worry, or weigh a decision for the tenth time, and at the end you're more tired but no clearer.

Psychologists often describe two main forms. Rumination looks backwards: going over what happened, what you said, what it meant. Worry looks forwards: imagining what might go wrong. Research suggests that repetitive, passive dwelling of this kind tends to keep low mood going and gets in the way of solving problems, rather than helping (Nolen-Hoeksema et al., 2008; Lyubomirsky and Nolen-Hoeksema, 1995).

Thinking things through is useful. Overthinking is different: it's the same loop, again and again, with no next step.

Why your mind won't switch off

One reason is that the mind keeps track of unfinished business. When something is still open, such as an unanswered email, an undecided choice or an unresolved worry, it tends to pop back into attention, often at the worst moments.

Encouragingly, research suggests you don't always have to finish a task to quiet it. In a series of experiments, simply making a specific plan for an unfinished goal reduced how much it intruded on people's thoughts (Masicampo and Baumeister, 2011). The loop calms down once your mind knows what will happen next.

This matters because a wandering, busy mind has a cost. In a large study using real-time reports, people's minds wandered a great deal of the time, and they tended to feel less happy when they were mind-wandering (Killingsworth and Gilbert, 2010). Overthinking isn't just tiring. It takes you away from what's in front of you.

How the four shelves help with overthinking

The Mental Closet turns that idea into a simple routine. Instead of carrying every thought in one heap, you give each one a place. Each shelf asks one question and gives the thought a clear next step.

• Action: things you can do something about. Do it, or give it a time.
• Decision: things waiting for a choice. Decide, or set when you'll decide.
• Acceptance: things outside your control. Prepare what you can, then stop rehearsing.
• Release: things no longer worth carrying. Let them go, on purpose.

The point isn't to stop thinking. It's to stop thinking the same thought for free, again and again, when it already has a place to go. You can try it with a few example thoughts in the exercise above.

How to stop overthinking: 6 practical steps

These steps work on their own, and they're the backbone of the book and its pathway.

1. Get it out of your head. Write down everything that's circling, without sorting it yet. Seeing it on paper often shrinks it.
2. Name the loop. Ask: "Is this rumination about the past, or worry about the future?" Naming it makes it easier to step out of.
3. Give it a next step. For anything you can act on, write the very next action and when you'll do it.
4. Set a decision time. If you're stuck on a choice, pick a time to decide and the information you need by then.
5. Book a worry window. Give worries a short, fixed time each day, and postpone them until then when they arrive.
6. Let go on purpose. For what you can't change, say it plainly: "This is outside my control," and bring your attention back to what you're doing.

The "worry window" idea comes from stimulus control training for worry, which showed promising early results for reducing worry and related sleep problems in a small trial (McGowan and Behar, 2013). It's a simple way to tell your mind: "Not now, but yes, later."

Overthinking at night

Night-time is when overthinking is often loudest. The day is quiet, there's nothing to distract you, and unfinished business rises to the surface.

One small, well-studied habit may help. In a sleep laboratory study, people who spent five minutes writing a specific to-do list before bed fell asleep faster than people who wrote about tasks they had already completed (Scullin et al., 2018). Putting tomorrow on paper seems to let your mind put it down for the night.

Try it tonight: five minutes, a short list of what's open, with a next step beside each item. In the language of the book, you're putting things on the Action shelf before you sleep.

Overthinking decisions

Some overthinking is really a decision in disguise. You keep thinking about the job, the move or the message because you haven't chosen yet.

Research on decision-making styles suggests that people who always try to find the very best option, sometimes called maximisers, tend to report more regret and less satisfaction than people who look for an option that is good enough for their needs (Schwartz et al., 2002). For most everyday choices, "good enough, decided" beats "perfect, still undecided".

When you notice a decision loop, write down what you're choosing between, what matters most, and a deadline. Then decide by the deadline, even if it feels a little uncomfortable. The overthinking usually fades once the choice is made.

Overthinking or problem-solving? A quick test

Not all repeated thinking is a problem. Sometimes you need to turn something over a few times before you understand it. The difference is whether the thinking is going anywhere.

A simple check is to stop and ask three questions. Have I learned anything new about this in the last ten minutes? Is there a next step I could take today? Would thinking about it for another hour change what I do? If the answer to all three is no, you're probably overthinking rather than solving.

That's the moment to pick a shelf. If there's a step, it goes on Action. If there's a choice, it goes on Decision with a date. If neither, it belongs on Acceptance or Release, and you can let your attention come back to the room you're in.

A five-minute daily reset

Habits are easier to keep when they're short and happen at the same time each day. A daily reset is one way to make the four shelves part of your routine without adding much to your day.

1. Empty. At a set time, such as after lunch or before you finish work, write down whatever is circling in your mind.
2. Sort. Put each item on one of the four shelves. Don't solve anything yet. Just choose where it belongs.
3. Schedule. Give each Action item a time, and each Decision item a date.
4. Close. Read the Acceptance and Release items once, then put the page away.

It won't feel natural at first, and some days you'll skip it. That's normal. What helps is coming back to it the next day, so the routine gets easier with repetition rather than willpower.

When overthinking is more than a habit

Everyday overthinking is common and very manageable. But sometimes constant worry or rumination is part of something that deserves proper care, such as an anxiety disorder or depression.

If worry is hard to control on most days, affects your sleep, work or relationships, or comes with low mood that won't lift, please talk to your doctor. The NHS has a clear overview of generalised anxiety disorder. The Mental Closet is a practical book about attention and everyday overthinking. It isn't a treatment, and it isn't a substitute for professional help.

For most people, though, overthinking is a habit, and habits can change. Small, repeated practice is how the shelves start to feel natural. That's why the book comes with a free pathway, and why the best time to start is today, with one thought on one shelf.