Simplify the following text for a Grade 10 native English-speaking person.
Original: He apparently spent some time in a mental hospital in Kislovodsk in July 1933 , ostensibly a result of depression born of his final acceptance that he would never be allowed to edit the Mexican footage , turned over by Sinclair to Hollywood editors , who would irreparably alter the negatives .
Simplified: He apparently spent some time in a mental hospital in Kislovodsk in July 1933 . This was possibly a result of depression because he realized that he would never be allowed to edit the Mexican footage which was turned over by Sinclair to Hollywood editors .