Gods and Monsters

The story opens in the 1950s, after the Korean War; it has been more than a decade since James Whale, director of Frankenstein and Bride of Frankenstein, has retired. He lives with his long-time housemaid, Hanna, who loyally cares for him but disapproves of his homosexuality. Whale has suffered a series of strokes that have left him fragile and tormented by memories: growing up as a poor outcast, his tragic World War I service, and the filming of The Bride of Frankenstein. Whale slips into his past, and indulges in his fantasies, reminiscing about gay pool parties and also sexually teasing an embarrassed, starstruck fan who comes to interview him. Whale battles depression, at times contemplating suicide, as he realizes his life, his attractiveness, and his health are slipping away.
Whale befriends his young, handsome gardener and former Marine, Clayton Boone and the two begin a sometimes uneasy friendship as Boone poses for Whale's sketches. The two men bond while discussing their lives and dealing with Whale's spells of disorientation and weakness from the strokes. Boone, impressed with Whale's fame, watches The Bride of Frankenstein on TV as his friends mock the movie, his friendship with Whale, and Whale's intentions.
Boone assures Whale that he is straight and receives assurance from Whale that there is no sexual interest, but Boone storms out when Whale graphically discusses his sexual history. Boone later returns with the agreement that no such "locker room" discussions occur again. Boone is invited to escort Whale to a party hosted by George Cukor for Princess Margaret. There, a photo op has been arranged for Whale with "his Monsters": Boris Karloff and Elsa Lanchester from "ancient" movie fame. This event exacerbates his depression. A sudden rain storm becomes an excuse to leave.
Back at Whale's home, Boone needs a dry change of clothes. Whale can only find a sweater, so Boone wears a towel wrapped around his waist. Whale decides to try to sketch Boone one more time. After some minutes, he shows his sketches to Boone, disclosing that he has lost his ability to draw. After Boone drops his towel to pose nude, Whale makes him wear a World War I gas mask and then uses the opportunity to make a sexual advance on Boone, kissing his shoulder. Boone becomes enraged and attacks Whale, who confesses that this had been his plan and begs Boone to kill him to relieve him of his suffering. Boone refuses, puts Whale to bed, then sleeps downstairs. The next morning, Hanna is alarmed when she can't find Whale, prompting a search by Boone and Hanna. Boone finds Whale floating dead in the pool, as a distraught Hanna runs out clutching a suicide note. Boone and Hanna agree that Boone should disappear from the scene to avoid a scandal.
The film closes roughly a decade later as Boone and his young son, Michael, watch The Bride of Frankenstein on television. The son is skeptical of his father's claim that he knew Whale, but Clayton produces a sketch of the Frankenstein monster drawn by Whale, and signed, "To Clayton. Friend?" "Friend?", being a plea from the original misfit, Frankenstein's monster, and disclosing Whale's true intentions.

Question: What illness does Whale battle?
Answer: depression