What it means
Used when someone seems to have gone a bit mad or started behaving wildly irrational, like they’ve taken a turn in their head and ended up somewhere daft. Often said with a laugh, but it can be a proper eye roll too when someone’s chatting nonsense or making bonkers decisions. Old-school, very British, and still gets plenty of mileage today.
Usage examples
"She’s gone round the bend, mate. Bought a £300 air fryer, banned carbs, and now she’s training for five marathons in five days down the rec with a Lucozade"
"These endless forms are driving me round the bend, I can't take much more."
Where it comes from
The bend may be a curve of road or river, but the likeliest root is the asylum: certain Victorian institutions sat at the end of a long bent, curving drive, kept well out of sight. To be sent round the bend was to be carted off there, and so to have lost your marbles.
Other ways to say it
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