Mad as a hatter and Round the bend

Round the bend and mad as a hatter are semantically related in mentally strange topic. In some cases you can use "Round the bend" instead an adjective phrase "Mad as a hatter".

Round the bend adjective - Informal or slang terms for mentally irregular.

Mad as a hatter and round the bend are semantically related in mad topic. You can use "Mad as a hatter" instead an adjective phrase "Round the bend", if it concerns topics such as mentally strange.