Random Harvest.

"John Smith" (Ronald Colman) is a British officer who was gassed and became shell shocked in the trenches during the First World War. He is confined to an asylum as an unidentified inmate because he has lost his memory and has trouble speaking. When he regains consciousness, his past memory is restored, but his life with Paula is now forgotten. "Smithy", as Paula calls him, discovers a literary talent and tries writing to earn a living.