Two psychologists named it in 1978. The women they studied had PhDs and still believed they had fooled everyone.
In 1978, psychologists Pauline Rose Clance and Suzanne Imes published a paper in Psychotherapy: Theory, Research and Practice titled "The Impostor Phenomenon in High Achieving Women." They described an internal experience of intellectual phoniness among people whose accomplishments should have made that feeling impossible.1
Clance and Imes studied over 150 women who held PhDs, were recognized professionals, or had earned high marks on standardized tests. Despite this objective evidence, the women persisted in believing they were not truly intelligent and had deceived anyone who thought otherwise.2 The researchers identified two family patterns: women whose sibling had been labeled "the smart one," and women whose families praised everything, leaving them unable to trust any evaluation.
Clance and Imes originally called it a phenomenon, not a syndrome, because it is not a clinical disorder. It does not appear in the DSM-5.3 A 2020 systematic review of 62 studies found prevalence rates ranging from 9 to 82 percent across populations, with no consistent gender difference.4
In 1985, Clance published a 20-item questionnaire that became the most widely used measure of the experience.5 A question the scale cannot answer is why a system that constantly evaluates, ranks, and sorts people would produce millions of professionals who do not believe their own credentials.