There have been cases where writer's block has lasted for years or decades. The most notable example of this in modern literary history was Henry Roth's writer's obstruct which persisted for sixty years and was caused by a combination of depression, political problems, and an unwillingness to confront past problems. This kind of writer's block seems to be quite rare, and most writer's obstruct lasts between an hour and a week, occasionally over a month.[citation needed] Writer's obstruct has caused problems for writers using the serial form, such as Stephen King's The Green Mile or Bag of Bones.