Green’s Dictionary of Slang

(orig. US) the Depression, the financial and industrial slump of 1929 and subseq. years.

1939		B. Appel Power-House 230: You and your ‘depresh.’ I’ll get a job.
1940		Cole Porter ‘Well, Did You Evah’ 🎵 It’s fun, it’s fresh, / It’s post-Depresh! / It’s Shangri-la. / It’s Harper’s Bazaar!
2002		(ref. to 1937) Joe Ongie ‘Downey Days’ 🌐 For a while we had a man come by to do some gardening who was Italian and spoke lugubriously about ‘the depresh’ meaning the depression and we got to referring to him as ‘old Depresh’.