Deolali

The word for losing it comes from a transit camp in Maharashtra.

British soldiers waiting at Deolali for passage home coined the phrase doolally tap for the state it induced. English kept the place and dropped the rest.

Soldiers lost their minds waiting for a troopship at a camp called Deolali.

Deolali, near Nashik in western India, held British troops between the end of their service and the next ship home, sometimes for months with nothing whatever to do; tap comes from an Indian word for fever. English kept the clipped form doolally long after the camp and the empire behind it had gone.