'To go Doolally'

The transit camp in Devlali, near Mumbai in India, became infamous within the British Army for dealing with soldiers with mental health issues - quite possibly 'post traumatic' in nature - as they waited to come home after very intense tours of duty - the troops then corrupted the camp name to 'doolally' and the phrase was accepted as meaning someone had serious mental health issues and had 'flipped their lid ' - ( on writing this post now going to look up 'flipped their lid' - it just goes on and on !)