The Seven-Per-Cent Solution(1976)

The story is true...only the facts have been made up.

Concerned about his friend's cocaine use, Dr. Watson tricks Sherlock Holmes into travelling to Vienna, where Holmes enters the care of Sigmund Freud. Freud attempts to solve the mysteries of Holmes' subconscious, while Holmes devotes himself to solving a mystery involving the kidnapping of Lola Deveraux.