Obsessive–compulsive disorder
British poet, essayist and lexicographer Samuel Johnson (1709–1784) also had OCD. He had elaborate rituals for crossing the thresholds of doorways, and repeatedly walked up and down staircases counting the steps. He would touch every post on the street as he walked past, only step in the middles of paving stones, and repeatedly perform tasks as though they had not been done properly the first time.