Sigmund Freud
Freud wrote an account of 'Anna O' (Bertha Pappenheim) which was false and "quite possibly based on deliberate deceit". In the few years after Breuer's treatment of her, she was back in hospital four times and diagnosed with hysteria. Therefore, she was definitely not cured, as Breuer and Freud had claimed. Freud must have known this because there is a letter of his (Freud) "which makes it clear that Breuer knew Anna O was still ill in 1883".