Green’s Dictionary of Slang

1. in a difficult situation, in trouble, e.g. arrested.

1926		J. Black You Can’t Win (2000) 45: The next time you get jammed up say something before you get thrown in.
1935		(con. 1920s) J.T. Farrell Judgement Day in Studs Lonigan (1936) 721: Why did all these things have to come when he was losing his health and all jammed up?
1949		R. Chandler Little Sister 17: He’s got himself all jammed up with some floozy.
1950		Goldin et al. DAUL 109/2: Jammed up. 1. Arrested; in serious trouble.
1958		‘Ed Lacy’ Room to Swing 148: Ted, I’m jammed up. I want you to do me two favors.
1962		Ragen & Finston World’s Toughest Prison 805: jammed up – In a difficulty or trouble.
1973		D. Goines Street Players 175: What she had always visualized was finally coming true – getting jammed up with a nut.
1985		N. Pileggi Wiseguy (2001) 216: He’d told Henry he would not help if Henry got jammed up.
1990		R. Campbell Sweet La-La Land (1999) 211: He’s not out [of jail] a week and he’s got hisself jammed up.
2006		(con. 1972) Jurgenson & Cea Circle of Six 47: If a cop is accused of any wrongdoing on or off the job or in cop-speak—if he or she gets jammed up— [etc].
2021		(con. 2016) in J. Fenton We Own This City 168: ‘Small shit will you get jammed up all the time, won’t it?’.

2. having taken an overdose of drugs.

1969

R.R. Lingeman Drugs from A to Z (1970).