"Bigger Than Life" (1956) starring James Mason and Barbara Rush. Just watched this movie and it is EXCELLENT.
→[More:]Mason plays a schoolteacher who is proscribed cortisone for a life-threatening illness, and the psychotic side effects
(caused when he starts overdosing) turn him into a monster. Their 1950s domestic home is filled with freaky shadows and incredibly tense silences. Mason's performance is one for the history books. Highly recommended.