Why do I overthink? Understanding the mechanisms and how to break the cycle

Thinking a lot is not the real problem

It is important to make a key distinction: the issue is not the number of thoughts, but the lack of mental closure.

The human brain is designed to:

• identify a problem,
• analyze a situation,
• make a decision,
• then release attention.

When this cycle functions properly, mental activity can be intense but remains temporary.

When a decision is blocked, however, cognitive activity stays open, with no clear stopping point.

The internal mechanisms at play

1. Unclosed cognitive loops

The brain pays particular attention to unfinished tasks or unresolved decisions.

This phenomenon, known as the Zeigarnik effect, explains why certain thoughts keep returning as long as no closure has been reached.

The more ambiguous, emotionally charged, or risky a decision feels, the more active the loop remains.

2. Hyperactivation of executive control

When stakes are high or uncertainty is perceived as threatening, the prefrontal cortex becomes highly activated.

It mobilizes so-called “executive functions”: analysis, planning, anticipation, and option comparison.

In the short term, this mechanism is useful.

In the long term, if it does not lead to a decision, it results in cognitive fatigue and increasing mental rigidity.

3. Intolerance of uncertainty

For some individuals, or during certain life phases, uncertainty becomes particularly difficult to tolerate.

The brain then attempts to reduce it through constant analysis.

The paradox is that the more we analyze in order to feel reassured, the more uncertainty grows, as no option ever feels sufficiently safe.

Why overthinking is exhausting?

Rumination is, first and foremost, a signal. However, continuous thinking consumes mental energy. When it becomes chronic, it no longer provides new information. It simply recycles the same scenarios without producing decisions or action.

Without decision or closure, the brain remains in a prolonged state of alert, leading to:

• a sense of mental saturation,
• difficulty prioritizing,
• reduced decision quality,
• fatigue that persists even during rest.

What exhausts us most is not intellectual effort itself, but effort without resolution.

How to break the cycle (without forcing the mind)?

The goal is not to “stop thinking,” which is neither realistic nor desirable.

The real challenge is to restore clear stopping points for the brain.

Some key principles:

• externalize certain decisions to reduce mental load,
• accept that a “good enough” decision is often better than a perfect one,
• reintroduce explicit time frames and priorities,
• distinguish what is a genuine choice from what is driven by underlying fear.

When the brain understands that an exit exists, it naturally releases pressure.

Sources :

Zeigarnik, B. (1927). Psychologische Forschung.
McEwen, B. S. (1998). New England Journal of Medicine.
Carleton, R. N. (2016). Journal of Anxiety Disorders.
Nolen-Hoeksema, S. (2000). Journal of Abnormal Psychology.
Baumeister, R. F., et al. (1998). Journal of Personality and Social Psychology.