The footage of the oncoming train was used again in other RKO films including The Clay Pigeon (1949), Cry Danger (1951) and The Narrow Margin (1952).
Set largely around the Manhattan Museum, Lt. Cochrane warns Steele he's "liable to wind up in Bellevue!" This is a reference to another Manhattan institution, the Bellevue Hospital Center (the oldest public hospital in the U.S., founded in 1736), known for its mental health ward, where other city hospitals sent patients with mental-health problems.
Two of the most notable film noir titles, Laura (1944) and Scarlet Street (1945), also make central use of painting and art, and all three films use the subject to create mysterious and even sinister atmospheres. In the case of Crack-Up (1946), the presence of Claire Trevor lends an additional noir feel, since she was just coming off Murder, My Sweet (1944) and Johnny Angel (1945) and was still to appear in Born to Kill (1947), Key Largo (1948) and Raw Deal (1948), all of which are key noir titles. Trevor was a true icon of film noir and played both heroines and femme fatales, an unusual distinction.
Leading man Pat O'Brien and director Irving Reis, on the other hand, are something of anomalies in the world of film noir, though O'Brien would later appear in The People Against O'Hara (1951). Crack-Up (1946) was the only noir that Reis directed, but it's perhaps his best film, if not his best known. That distinction belongs to the picture he did next, The Bachelor and the Bobby-Soxer (1947), a romantic comedy which starred Cary Grant, Myrna Loy and Shirley Temple and which was a complete turnaround from Crack-Up. Reis is also remembered for directing many "Falcon" movies of the early 1940s including The Falcon Takes Over (1942).
In the post-World War II era, the technique of NARCOSYNTHESIS (as it was later called) was developed by psychiatrists as a means of treating patients who suffered from post-traumatic stress disorder. Narcosynthesis-also called sodium amytal interview, amobarbital interview, or amytal interview-uses a technique of free association as well as dream and transference material during the session as a basis for uncovering relevant topics for later therapeutic discussion. However, the accuracy of the therapy's results is debated.