Your brain produces thousands of thoughts, but how many are actually true? A CBT therapist explores the thinking errors that fuel anxiety, depression and self-doubt, and explains how to stop allowing unreliable thoughts to control your life.

One of the most important lessons I try to teach my clients is something that sounds remarkably simple:

Just because you think something doesn’t mean it’s true.

Yet this is a principle that many of us struggle to put into practice.

Every day, our brains bombard us with thoughts, interpretations, predictions, judgements and assumptions. Some are useful, some are irrelevant, and others can be downright destructive.

The trouble is that we often accept these thoughts without questioning them.

We treat them as facts.

Imagine sending a message to a friend and receiving no reply.

Your brain immediately offers an explanation:

I’ve upset her.

She’s probably annoyed with me.

Maybe she doesn’t want to be friends anymore.

Within minutes, you might feel anxious, rejected or upset.

But what actually happened?

You sent a message. Your friend hasn’t replied.

That’s it.

Everything else is a story your brain has constructed.

She might be busy, driving, sleeping, distracted or simply intending to reply later.

Yet your emotional response can be just as powerful as if you had concrete evidence that she’d rejected you.

This is one of the most fascinating, and sometimes frustrating, aspects of human psychology.

We can make ourselves miserable by believing things that haven’t even happened.

As a cognitive behavioural therapist, I see this pattern repeatedly. People experience considerable emotional distress not only because of what’s happening in their lives, but because of how they’re interpreting those events.

The encouraging news is that we can learn to recognise these thinking errors, question their accuracy and respond more constructively.

1. Your brain is not an objective reporter

We like to believe that our thoughts provide an accurate representation of reality.

Unfortunately, the human brain doesn’t work quite like that.

Our perceptions are influenced by previous experiences, expectations, emotions, beliefs and the information we happen to notice.

Rather than passively recording everything around us, our brains constantly interpret incomplete information.

This is usually helpful. We couldn’t function effectively if we had to consciously analyse every detail of every situation.

However, these mental shortcuts can also produce errors.

Psychologists call some of these errors cognitive biases. In cognitive behavioural therapy, we often refer to recurring inaccurate or unhelpful interpretations as cognitive distortions.

For example, if you already believe you’re unlikeable, you may be particularly sensitive to signs of rejection.

Someone looks away during a conversation.

You interpret this as boredom.

Someone doesn’t invite you to an event.

You interpret this as evidence that nobody likes you.

Someone offers constructive feedback.

You interpret this as confirmation that you’re inadequate.

Over time, these interpretations can strengthen the original belief.

The brain begins selectively collecting evidence that supports its existing assumptions while overlooking information that contradicts them.

It’s a psychological feedback loop.

And the more often we repeat these interpretations, the more familiar and convincing they may become.

2. The negativity bias: Why bad experiences capture our attention

Have you ever received ten compliments and one criticism, only to spend the rest of the day thinking about the criticism?

Perhaps nine people praised your presentation, but one person looked unimpressed.

Which response do you remember?

For many people, it’s the negative one.

Psychologists refer to this general tendency as the negativity bias.

In an influential 2001 review, researchers Roy Baumeister and colleagues examined evidence suggesting that negative events, emotions and information often have a stronger psychological impact than comparable positive experiences.

Their paper, Bad Is Stronger Than Good, explored this tendency across areas including relationships, learning, emotion and social interaction.

Why might this happen?

One possible explanation is that paying attention to threats and unpleasant experiences has adaptive value.

Noticing potential danger can help us protect ourselves.

But a tendency to prioritise negative information can become problematic when applied to everyday social situations.

Your brain might devote considerable attention to one awkward conversation while barely registering five enjoyable ones.

Or it might repeatedly replay a minor mistake while overlooking everything you accomplished successfully.

This doesn’t mean our brains are programmed to be negative all the time.

It means that negative information can be particularly attention-grabbing, especially when we’re stressed or anxious.

The problem isn’t that your brain notices negative things. It’s that you may start treating them as more important, more meaningful and more representative than they really are.

3. Mind-reading: The imaginary conversations we have in our heads

Mind-reading is one of the most common thinking errors I encounter in therapy.

It involves assuming we know what another person is thinking, usually something negative about us, without sufficient evidence.

Consider these everyday examples.

At work: Your manager seems unusually quiet during a meeting.

Your brain tells you: She’s unhappy with my performance. I must have done something wrong.

You spend the afternoon feeling anxious and distracted.

In reality, your manager might be worrying about an approaching deadline, dealing with a personal problem or simply feeling tired.

In relationships: Your partner seems less affectionate than usual.

Your brain tells you: He’s losing interest. Maybe he doesn’t love me anymore.

You become upset, seek reassurance or withdraw emotionally.

Your partner notices your change in behaviour and becomes confused.

Suddenly, a relationship problem has developed from an assumption that may have been entirely incorrect.

In social situations: Someone looks at their phone while you’re speaking.

Your brain tells you: I’m boring them.

You become self-conscious, speak less and avoid future conversations.

But perhaps they’re expecting an important message.

The problem with mind-reading is that we frequently mistake our interpretations for evidence.

How to challenge mind-reading

Ask yourself:

• How do I actually know what this person is thinking?

• Have they told me, or am I making an assumption?

• What other explanations could there be?

• Could my own insecurities be influencing my interpretation?

A particularly useful CBT technique is to separate observations from interpretations.

Observation: “My friend hasn’t replied to my message.”

Interpretation: “She’s deliberately ignoring me because she doesn’t like me.”

These are not the same thing.

If we can learn to recognise the difference, we can prevent an enormous amount of unnecessary emotional distress.

4. Catastrophising: Turning a problem into a disaster

Catastrophising involves predicting an extremely negative outcome and often underestimating our ability to cope with it.

Imagine you’ve made a mistake at work.

Your brain immediately produces a chain of predictions:

My boss will find out.

I’ll get into trouble.

I’ll lose my job.

I won’t be able to pay my bills.

My entire life will fall apart.

Within minutes, you’ve mentally travelled from a relatively minor mistake to financial ruin.

And your body may respond as though the imagined disaster is already happening.

Your heart rate increases. Your stomach tightens. You struggle to concentrate.

But none of those predicted events has occurred.

This is where the relationship between thoughts, emotions and physical sensations becomes particularly important.

Our brains can generate genuine emotional and physiological responses to imagined situations.

The anxiety is real, even when the feared outcome is speculative.

Research on negative interpretations

A meta-analysis examining 45 studies involving 2,591 participants found that interventions designed to modify cognitive biases could change the way people processed information. The overall effect on anxiety and depression symptoms was much smaller than the effect on the biases themselves.

This supports the importance of how we interpret situations, while also reminding us that changing thinking patterns isn’t a magical cure for every emotional difficulty.

The CBT solution: Decatastrophising

When you notice yourself imagining the worst, ask:

1. What’s the worst realistic outcome?

2. What’s the best realistic outcome?

3. What’s the most likely outcome?

4. If the worst happened, what practical steps could I take?

The fourth question is particularly powerful.

Anxiety often convinces us that we won’t cope.

But when we begin identifying possible solutions, we remind ourselves that we have resources, skills and choices.

The aim isn’t to guarantee that nothing bad will happen. It’s to recognise that difficulties are often more manageable than our anxious brains predict.

5. Fortune-telling: Predicting a future that hasn’t happened

Fortune-telling is closely related to catastrophising.

It involves assuming that we already know how something will turn out.

I won’t get the job.

That person won’t be interested in me.

I’ll embarrass myself at the party.

There’s no point trying because it won’t work.

Notice something interesting about these statements.

They’re predictions presented as facts.

And because people believe them, they often change their behaviour accordingly.

Someone who assumes they won’t get a job may never apply.

Someone who expects rejection may avoid dating.

Someone who predicts embarrassment may decline social invitations.

The feared outcome is never tested.

This is one of the most damaging consequences of negative thinking.

Our thoughts don’t merely affect how we feel. They can determine which opportunities we allow ourselves to pursue.

Try a behavioural experiment

If you believe that nobody will want to speak to you at a social event, test the prediction.

Attend for a manageable amount of time.

Initiate a conversation.

Observe what actually happens.

You might be pleasantly surprised.

And even if the conversation doesn’t go particularly well, you’ve learned something important: an awkward interaction is uncomfortable, but it isn’t necessarily catastrophic.

6. Emotional reasoning: When feelings masquerade as evidence

Emotional reasoning occurs when we assume that because something feels true, it must be true.

For example:

I feel guilty, therefore I must have done something wrong.

I feel anxious, therefore something bad is going to happen.

I feel inadequate, therefore I must be inadequate.

I feel rejected, therefore someone must have rejected me.

But emotions aren’t objective measurements of reality.

They’re responses influenced by our interpretations, memories, physical state and circumstances.

Consider someone who feels anxious before giving a presentation.

They might interpret their anxiety as evidence that they’re incapable of public speaking.

But anxiety doesn’t establish incompetence.

It simply indicates that the situation feels threatening or important.

A person can be anxious and competent simultaneously.

Similarly, feeling unattractive doesn’t mean you are unattractive.

Feeling like a failure doesn’t mean you have failed.

Feeling unloved doesn’t establish that nobody loves you.

A useful reminder

Feelings are valid experiences, but they aren’t always accurate conclusions.

You don’t need to dismiss your emotions.

You need to become curious about the thoughts contributing to them.

7. Personalisation: Assuming everything is about you

Personalisation involves taking excessive responsibility for events or interpreting other people’s behaviour as being caused by something you’ve done.

Your colleague is in a bad mood.

It must be something I said.

Your friend cancels dinner.

She obviously doesn’t want to spend time with me.

Your partner seems distracted.

I must be doing something wrong.

This thinking pattern can be exhausting because it encourages us to monitor other people’s moods and behaviour constantly.

We become hypervigilant, searching for evidence that we’ve upset someone.

But the reality is that other people have their own thoughts, emotions, responsibilities and difficulties.

Not everything is about us.

Sometimes a bad mood is simply a bad mood.

Sometimes a cancelled arrangement is genuinely about being tired.

Sometimes someone else’s behaviour reflects their circumstances rather than our worth.

The next time you find yourself taking something personally, ask:

“Am I assuming responsibility for something that might have nothing to do with me?”

8. All-or-nothing thinking: The perfectionism trap

All-or-nothing thinking involves viewing situations in extremes.

Something is either a complete success or a total failure.

You’re either good at something or hopeless.

Someone either likes you or dislikes you.

A relationship is either perfect or doomed.

Consider someone trying to improve their fitness.

They plan to exercise four times a week.

But they miss two sessions.

Their brain tells them:

I’ve completely failed. There’s no point continuing.

So they stop exercising altogether.

In reality, two exercise sessions are considerably better than none.

But their rigid thinking prevents them from recognising partial success.

This pattern frequently appears in perfectionism.

If people cannot achieve their ideal outcome, they may feel that anything less is unacceptable.

The solution is to practise flexible thinking.

Instead of asking whether something was perfect, ask:

“What went reasonably well?”

“What could I improve?”

“Was there some progress, even if it wasn’t everything I hoped for?”

Life rarely operates in absolutes.

And neither should our thinking.

9. Mental filtering: When your brain edits out the positives

Imagine receiving feedback after completing an important project.

Your manager says:

“You’ve done an excellent job overall. There are just a couple of areas we could improve.”

What do you focus on?

If you’re prone to negative mental filtering, you may spend the rest of the day thinking about those two areas for improvement.

The praise barely registers.

This is closely related to confirmation bias, our tendency to notice or interpret information in ways that support existing beliefs.

If you believe you’re incompetent, you may dismiss compliments as politeness while treating criticism as definitive proof of inadequacy.

Over time, this can create a distorted picture of yourself.

The positive data log

One technique I sometimes recommend is keeping a positive data log.

Each day, record evidence that challenges a negative belief.

For example, if you believe “I’m not good enough”, write down specific examples of competence, kindness, persistence or achievement.

These don’t have to be extraordinary.

Perhaps you completed a difficult task, helped a colleague or handled a stressful situation reasonably well.

The aim isn’t to manufacture positivity.

It’s to create a more balanced evidence base.

After all, if your brain automatically records everything that goes wrong, shouldn’t you also make an effort to notice what goes right?

10. Labelling: Turning one mistake into your entire identity

This is another particularly damaging thinking error.

You make a mistake and immediately conclude:

I’m stupid.

You struggle to finish a task:

I’m lazy.

Someone rejects you:

I’m unattractive.

You experience anxiety:

I’m weak.

Notice how quickly a specific event becomes a sweeping judgement about your entire personality.

There’s an enormous difference between saying “I made a mistake” and “I’m an idiot”.

The first describes a behaviour.

The second attacks your identity.

When we repeatedly label ourselves negatively, we risk strengthening beliefs that undermine our confidence and motivation.

As a therapist, I often encourage clients to become more precise in the language they use about themselves.

Instead of “I’m useless”, try:

“I found that particular task difficult.”

Instead of “I’m a failure”, try:

“Something I attempted didn’t work out.”

Instead of “I’m terrible at relationships”, try:

“I’ve experienced relationship difficulties, and there are things I can learn.”

This isn’t simply positive thinking.

It’s accurate thinking.

11. Should statements: The invisible rules that make us miserable

Have you ever noticed how often your brain tells you what you should be doing?

I should be more successful by now.

I should have a partner.

I should be thinner.

I should be earning more money.

I shouldn’t feel anxious.

I should be able to cope with everything.

These rigid expectations can generate guilt, shame, frustration and resentment.

They also encourage us to compare our lives with an imagined standard of how things ought to be.

The problem is that many of these rules are arbitrary.

Who decided that you should be married by a certain age?

Who decided that you must earn a particular salary to be successful?

Who decided that experiencing anxiety means you’re not coping?

Of course, some expectations are useful. We need responsibilities, goals and standards.

But there’s a difference between healthy aspirations and relentless self-imposed demands.

Try replacing “I should” with “I’d like to” or “It would be helpful if”.

For example:

“I should exercise every day” becomes “I’d like to exercise regularly because it benefits my health.”

The second statement is more flexible and motivating.

It encourages action without making your self-worth conditional on perfection.

12. How negative thoughts create a vicious cycle

One of the most important concepts in CBT is that thoughts, feelings, physical sensations and behaviours influence one another.

Let’s imagine you’re invited to a party where you won’t know many people.

The next time you’re invited somewhere, your brain reminds you how anxious you felt before.

You avoid again.

Gradually, your world becomes smaller.

But what if you challenged the original thought?

Instead of accepting “Nobody will talk to me”, you might consider:

“I don’t know whether I’ll enjoy myself, but some people might be friendly. I can stay for an hour and see what happens.”

You might still feel anxious.

But you’re now more likely to attend, creating an opportunity for a different experience.

Changing how we think can change how we feel, but it can also change what we’re willing to do.

13. What does research tell us about changing negative thinking?

The evidence is encouraging, although it’s important to distinguish between different psychological approaches.

Research suggests that people experiencing anxiety often interpret ambiguous situations more negatively than people without significant anxiety.

For example, an ambiguous facial expression or an unanswered message may be interpreted as evidence of rejection or danger.

Researchers Colin MacLeod and Andrew Mathews reviewed studies examining whether these interpretation and attention biases could be modified.

Their 2012 review found evidence that modifying certain cognitive biases could influence vulnerability to anxiety, although questions remained about how best to translate these findings into effective clinical treatments.

A separate meta-analysis of 45 studies involving 2,591 participants found:

There is also substantial clinical evidence supporting psychological therapies that help people examine unhelpful thoughts and change their behaviour.

For example, NHS Talking Therapies statistics for May 2025 reported that:

• 50.9% of eligible referrals completing treatment met the service’s definition of recovery.

• 48.0% met the stricter definition of reliable recovery.

  

  NHS England Digital

These figures cover NHS Talking Therapies services overall, not CBT alone, and outcomes vary depending on the person’s difficulties and circumstances.

Nevertheless, they demonstrate that psychological difficulties can improve with structured, evidence-based treatment.

14. Five practical ways to stop believing every negative thought

The good news is that you don’t need to analyse every thought your brain produces.

That would be exhausting.

Instead, learn to recognise when a thought is making you unnecessarily anxious, miserable or avoidant.

Technique 1: Name the thinking error

When you notice an upsetting thought, ask:

“Is this mind-reading?”

“Am I catastrophising?”

“Am I predicting the future?”

“Am I confusing my feelings with facts?”

Simply recognising the pattern can help you gain some psychological distance.

Technique 2: Look for evidence

Ask yourself:

“What actual evidence supports this thought?”

“What evidence contradicts it?”

“Am I overlooking information because it doesn’t fit my existing belief?”

Try to approach the thought as a scientist would approach a hypothesis.

You wouldn’t accept a scientific conclusion without examining the evidence.

Why should your automatic thoughts receive special treatment?

Technique 3: Generate alternative explanations

Suppose your boss sends an email saying:

“Can we have a chat tomorrow?”

Your brain immediately responds:

I’m in trouble.

Before accepting this conclusion, identify at least three alternatives.

Perhaps your boss wants to discuss a new project.

Perhaps they need your advice.

Perhaps it’s simply a routine catch-up.

You don’t have to believe the most positive explanation.

You simply need to recognise that several explanations are possible.

Technique 4: Ask whether the thought is helpful

Some thoughts may contain an element of truth but still be expressed in an unnecessarily destructive way.

For example:

“I’m terrible at public speaking.”

Perhaps you genuinely struggle with presentations.

But repeating that statement doesn’t help you improve.

A more constructive response would be:

“Public speaking is something I find difficult, but I can practise and develop my skills.”

The aim is to move from judgement towards problem-solving.

Technique 5: Take action rather than endlessly analysing

Sometimes the most effective way to challenge a thought is through behaviour.

If you believe you’re incapable of doing something, try a manageable version of it.

If you believe people will reject you, practise initiating conversations.

If you believe you cannot cope with uncertainty, deliberately tolerate small amounts of it.

These behavioural experiments provide real-world evidence.

And real-world evidence is often more persuasive than endlessly debating a thought in your head.

15. Try this CBT thought-challenging exercise

Think about something that’s been upsetting or worrying you recently.

Use the following exercise to examine the thought more objectively.

The more frequently you practise questioning unhelpful interpretations, the easier it may become to recognise them before they dominate your mood.

16. You don’t need to replace every negative thought with a positive one

I want to emphasise something important.

CBT isn’t about pretending that everything is wonderful.

Life contains genuine problems.

People sometimes reject us.

We make mistakes.

Relationships end.

We lose jobs, experience disappointment and encounter situations that are genuinely difficult.

The aim isn’t to deny reality.

It’s to respond to reality rather than to an exaggerated or imagined version of it.

If someone has treated you badly, you don’t need to convince yourself that they’re wonderful.

If you’re unhappy at work, you don’t need to tell yourself that your job is perfect.

If you’re experiencing financial difficulties, you don’t need to pretend everything is fine.

Instead, ask:

“What is actually happening?”

“What is within my control?”

“What can I do to improve the situation?”

Sometimes the healthiest response is to change your thinking.

Sometimes it’s to change your behaviour.

And sometimes it’s to change your circumstances.

Healthy thinking isn’t always positive. It’s realistic, flexible and constructive.

Final thoughts: Your brain is a storyteller, not a fortune-teller

One of the most liberating things we can learn is that we don’t have to believe everything our brains tell us.

Your brain might tell you that you’re not good enough.

That people don’t like you.

That something terrible is about to happen.

That you’ll never succeed.

That you won’t cope.

But these are thoughts.

They aren’t necessarily facts.

They’re interpretations produced by a brain influenced by past experiences, emotional states, learned beliefs and expectations.

You have the ability to question them.

You can ask for evidence.

You can consider alternative explanations.

You can recognise when you’re catastrophising, mind-reading or predicting the future.

And most importantly, you can choose how to respond.

I often remind my clients that you cannot always control the first thought that enters your mind, but you can learn to influence what happens next.

You don’t have to follow every thought down its particular rabbit hole.

You don’t have to argue with every negative prediction.

And you certainly don’t have to organise your life around assumptions that have never been tested.

The next time your brain tells you something upsetting, try responding with a little curiosity:

That’s an interesting thought. But is it actually true?

That small moment of questioning can be the beginning of a very different relationship with your own mind.

And sometimes, the difference between a miserable afternoon and a perfectly pleasant one is simply recognising that the story your brain has been telling you isn’t necessarily the truth.

Research and references

1. Baumeister, R. F., Bratslavsky, E., Finkenauer, C., & Vohs, K. D. (2001). Bad Is Stronger Than Good. Review of General Psychology, 5(4), 323–370. Read research.

2. Hallion, L. S., & Ruscio, A. M. (2011). A Meta-Analysis of the Effect of Cognitive Bias Modification on Anxiety and Depression. Psychological Bulletin, 137(6), 940–958. Read research.

3. MacLeod, C., & Mathews, A. (2012). Cognitive Bias Modification Approaches to Anxiety. Annual Review of Clinical Psychology, 8, 189–217. Read research.

4. NHS England Digital (2025). NHS Talking Therapies Monthly Statistics: May 2025 Outcomes. View statistics.

5. Beck, J. S. (2020). Cognitive Behavior Therapy: Basics and Beyond, 3rd edition. Guilford Press.