Is overthinking the same as anxiety?

Not always. Overthinking can happen on its own, especially during stressful times. It's also one of the most common ways anxiety shows up. If your overthinking comes with physical tension, trouble sleeping or avoiding things, it may be worth exploring anxiety with a therapist.

Can you stop overthinking completely?

Most people find the goal isn't to stop thinking, but to get unstuck more quickly. With practice, many people notice the loop sooner and find it easier to step out of it.

Do I need a diagnosis to start therapy for overthinking?

No. You don't need a diagnosis or a referral to see a psychotherapist. "My mind won't switch off and it's wearing me out" is a good enough reason to reach out.