You've been stuck in a loop. The same worry, the same checking, the same dread — going round and round without resolution. You've tried reasoning with yourself. You've tried reassurance. You've tried pushing through. But no matter what you do, the problem keeps pulling you back in.

What if the reason nothing is working is that you've been solving the wrong problem?

This is the idea behind one of CBT's most elegant and powerful techniques: Theory A vs Theory B. It's a tool that doesn't ask you to stop worrying or to think positively. Instead, it invites you to step back and consider whether the problem you think you have is actually the problem you have — or whether there's a completely different explanation that fits the evidence better and points toward a more effective solution.

It's used widely in the treatment of health anxiety, OCD, and other anxiety disorders, but its logic applies far more broadly. Any time you're caught in a cycle of worry and checking that isn't resolving, Theory A vs Theory B can help you see the situation with fresh eyes.

Theory A vs Theory B works by setting up two competing explanations for what you're experiencing and then evaluating which one better fits the evidence.

Theory A is the explanation your anxiety gives you — the one that feels true in the moment, the one that drives the checking, the avoidance, and the distress.

Theory B is an alternative explanation — one that reframes the problem not as the thing you fear, but as an anxiety problem about the thing you fear.

Here's a simple example. Imagine someone who frequently worries they have a serious illness. Every headache becomes a potential brain tumour. Every stomach ache becomes a potential sign of cancer. They Google symptoms constantly, visit the doctor regularly, and feel temporary relief after each reassurance — but the worry always returns.

Theory A: "I have a serious undiagnosed illness, and I need to keep checking to catch it early."

Theory B: "I have health anxiety — a pattern of catastrophically interpreting normal body sensations, which drives me to check and seek reassurance, which temporarily reduces anxiety but keeps the cycle going."

Both theories can explain the symptoms — the worry, the checking, the physical sensations, the temporary relief from reassurance. But they lead to completely different courses of action.

If Theory A is correct, the solution is more checking, more doctor visits, more Googling — essentially, more of what you've been doing.

If Theory B is correct, the solution is to work on the anxiety itself — to reduce the checking, tolerate the uncertainty, and address the thinking patterns that are maintaining the cycle.

The question isn't which theory feels more true (anxiety will always make Theory A feel more convincing). The question is which theory better explains the overall pattern of your experience.

The genius of Theory A vs Theory B is that it sidesteps the impossible task of proving a negative. You can never prove with absolute certainty that you don't have an illness, that the door is locked, that you haven't offended someone, or that something bad won't happen. Anxiety exploits this gap — "but what if?" is a question that can never be definitively answered.

Theory A vs Theory B doesn't try to answer that question. Instead, it shifts the focus entirely. Rather than debating whether the feared outcome is real, it asks: what is the most useful and accurate way to understand the pattern of my experience?

This is liberating because it gives you something actionable. You can't resolve an infinite "what if" loop. But you can recognise that the loop itself is the problem and take steps to address it.

Social anxiety

Theory A: "People are judging me negatively and I need to monitor my performance carefully to avoid humiliation."

Theory B: "I have social anxiety that creates a distorted self-image, turns my attention inward, and makes me assume others are critical when they're mostly not paying attention."

Evidence for Theory B includes the fact that other people rarely give feedback matching your fears, that your post-event anxiety doesn't correlate with actual outcomes, and that safety behaviours haven't made social situations easier — they've made them more effortful.

Relationship anxiety

Theory A: "My partner doesn't really love me and this relationship is going to end."

Theory B: "I have relationship anxiety that makes me hypervigilant to signs of rejection, misinterpret neutral behaviour as evidence of problems, and seek constant reassurance that paradoxically undermines the closeness I want."

Evidence for Theory B includes a pattern of this anxiety across multiple relationships, reassurance providing only brief relief, and a disconnect between your partner's actual behaviour and your interpretation of it.

"But what if Theory A is right?"

This is the anxiety talking, and it's a predictable response. The technique doesn't ask you to prove Theory A is wrong — that's impossible with most anxiety concerns. It asks you to consider which theory better explains the overall pattern. If you've been worrying about having a brain tumour for three years and multiple scans have been clear, Theory B is simply a better fit for the data — regardless of the lingering "what if."

"Theory B feels less convincing"

Of course it does. Anxiety is persuasive — it's designed to be. Theory A feels urgent and real because your threat detection system is pumping adrenaline and screaming that something is wrong. Theory B is quieter and more rational. But feelings aren't evidence. Evaluate the theories based on the facts, not on which one produces the stronger emotional response.

"I understand this intellectually but I still feel anxious."

That's expected and okay. Theory A vs Theory B is a cognitive shift — it changes how you understand your problem, which in turn changes what you do about it. The emotional shift comes later, as you begin acting in accordance with Theory B (reducing checking, tolerating uncertainty, facing feared situations) and your brain accumulates new evidence that the anxiety was the problem all along.

"What if my problem is actually both?"

Sometimes there's a real element alongside the anxiety. You might have a genuine health condition and health anxiety. You might have a real relationship issue and relationship anxiety. The technique still helps — it allows you to separate the realistic concern (which can be addressed practically) from the anxiety-driven catastrophising (which needs to be addressed through CBT).

Theory A vs Theory B works because it creates psychological distance from the anxiety. When you're caught in an anxiety spiral, you're inside the experience — everything feels urgent, real, and overwhelming. This technique invites you to step outside the experience and look at the pattern from above, like a scientist examining data.

It also resolves the paralysis that comes from trying to disprove anxious thoughts. You don't need to prove you're not ill, not in danger, not going to be rejected. You just need to recognise that the anxiety itself is a better explanation for what you're experiencing than the catastrophic interpretation your mind is offering.

And once you've made that shift — once you genuinely see the problem as anxiety rather than as the thing you're anxious about — the path forward becomes clear. You stop feeding the anxiety through checking and avoidance, and you start treating it with the tools that actually work.