Green’s Dictionary of Slang

1. (US) drunk or intoxicated.

1844		Stirling Obs. 19 Sept. 3/3: [from US press] Drunkeness Defined — [...] high-corned, cocked, shaved, disguised, jammed, [...] smashed, [...] snubbed, [...] battered [...] soaked, [...] bruised.
a.1856		Burlington Sentinel in Hall (1856) 461: We give a list of a few of the various words and phrases which have been in use, at one time or another, to signify some stage of inebriation: [...] jammed.
1922		Ogden Standard Examiner 12 Apr. 6/5: Mother— ‘Shellacked! I don’t understand,’ Daughter— ‘Jammed, both of them’.
1922		Appleton Post-Crescent (WI) 6 May 11/1: Flapper Dictionary jammed – Intoxicated, pickled, shellacked, canned, out like a light, potted, shined, drunk.
1949		Monteleone Criminal Sl. (rev. edn).

2. in financial difficulties.

1875

Wagga Wagga Advertiser (NSW) 23 Oct. 4/2: . If the Honorable Charlie were hard-up [...] Bob was the accommodating friend [...] while, on the other hand, if Bob was—to borrow his own term — ‘jammed,’ the Honorable Charles was equally ready to perform the same kind office for him.

3. (US Und.) in trouble with the law, arrested.

1935		A.J. Pollock Und. Speaks.
1949		Monteleone Criminal Sl. (rev. edn).

4. (also jambed) subject to discipline.

1915

‘Bartimeus’ ‘The Seven-Bell Boat’ in A Tall Ship 74: ‘Aren’t you coming ashore?’ [...] The outlaw shook his head. ‘No, my leave’s jambed.’.

5. (US) troubled, upset.

1971		R. Woodley Dealer 109: I’d just rather not talk about it [i.e. the death of his mother]. It jammed me up. I’m still jammed because of that.
1997–2000		College Sl. Research Project (Cal. State Poly. Uni., Pomona) 🌐 Jammed (adj.) Upset, irritated.