Final answer:
Anna O. displayed symptoms of hysteria and Freud believed her condition was caused by repressed traumatic experiences, specifically sexual abuse in childhood.
Step-by-step explanation:
Anna O., a patient of Josef Breuer, displayed symptoms such as partial paralysis, headaches, blurred vision, amnesia, and hallucinations. These symptoms were referred to as hysteria in Freud's time. Based on Anna O.'s treatment and Breuer's description, Freud concluded that hysteria was caused by repressed traumatic experiences, specifically sexual abuse in childhood.
However, it is important to note that Freud's theories and interpretations have been subjected to criticism and are not universally accepted.