Hayek suffered from poor health and severe depression from 1969, with some improvement after 1974. He had two heart attacks (one of them already in 1960) which were discovered only in retrospect and was later misdiagnosed and treated for diabetes which reduced his blood sugar level. He also took medication for depression. His hearing declined and that affected his social life and forced him to give up his enjoyment of theatre. His work also suffered, he spent years unable to do any demanding work, and was occasionally so unwell that he could not get out of bed. He would continue to work on "Law, Legislation and Liberty" in periods when he was feeling better.