What is 'round The Bend?
UK. One who is mentally imbalanced, eccentric, crazy, etc. Sometimes expressed as "right 'round the bend." An eighties tune, during the second "British Invasion" of music in the U.S., had the lyric, "You send me right 'round, baby, 'right round, like a record baby."
Did you see him talking to that tree? 'Round the bend, he is.