Green’s Dictionary of Slang

tripped-out adj.

[trip out v.1 ]

1. (drugs) under the influence of LSD or another hallucinogen.

[US]Arizona Dly Star (Tucson, AZ) 19 Jan. 5/2: Brody [...] made his decision to give away what he calls a $25 million inheritance while ‘I was tripped out on drugs’.
Anniston Star (AL) 10 Apr. 23/2: .
[UK]Guardian Guide 14–20 Aug. 12: Old guys doing switched-on, tripped-out tribal music.
Hattiesburg American (MS) 28 Feb. 43/1: The Tripped Out Hippie Chicks [...] stole the show.

2. disorientated, confused, upset.

[US]E.E. Landy Underground Dict. (1972).
[US]R.C. Cruz Straight Outta Compton 9: House niggers who weren’t even invited to sit on the stoop gave Flip, Billy’s tripped-out friend, an excuse to follow suit.
[UK]J.J. Connolly Layer Cake 174: I reckon I’d better eat cos otherwise I’m gonna get more light-headed, more and more tripped out.