Green’s Dictionary of Slang

para adj.

paranoid.

1993		R. Shell Iced 112: I been hittin’ all night and I’m para-para-para.
1998		I. Welsh Filth 275: It’s fun to dish out the odd terse, serious nod which makes them para that there’s some internal investigation going on.
2000		N. Griffiths Grits 86: A suppose am jes bein a bit para with all-a speed an stuff like.
2001		(con. 1981) A. Wheatle East of Acre Lane 62: You’re too para, man.
2011		J.J. Connolly Viva La Madness 64: I start checking faces, getting para.
2016		A. Wheatle Crongton Knights 27: The feds were para about anyone looking like a hood-rat.
2020		G. Armstrong Young Team 4: If ye walked roon [...] yi wid feel a bit para.

In phrases

on a para (adj.)

feeling nervous, paranoid.

1992

in R. Graef Living Dangerously 73: Otherwise you’re just on a para’ all the time — just paranoid.