Conspiracy theories about Western plots to undermine Turkey run so deep in the nation’s collective psyche that only the language of psychology is suitable to understanding them.

The phenomenon is known as the Sèvres Syndrome, harking back nearly 100 years to a treaty that was never carried out but that would have divided Anatolia, the Asian landmass that makes up the bulk of modern Turkey. The syndrome is named for the French city where Western powers, at the conclusion of World War I, signed a treaty that brought about the collapse of the Ottoman Empire.

Analysts have used the terms “phobia,” “trauma” and “syndrome” to describe the country’s mind-set, as if Turkey were a patient on a psychologist’s couch. Ever since Sèvres, they have said, Turkey as a nation has been suffering from post-traumatic stress disorder.

One way the syndrome is believed to have manifested itself is in Turkey’s denial of the Armenian genocide. More recently, Turks have blamed the United States and Western allies for huge street protests, a corruption scandal and this summer’s failed military coup.