Green’s Dictionary of Slang

1. (US) drunk.

1934		J.L. Kuethe ‘Prison Parlance’ in AS IX:1 26: gaged. Intoxicated.
1947		D. Burley N.Y. Amsterdam News 29 Nov. 21: The horn tooter and his old lady who was ‘gaged’.

2. (US drugs, also gage) intoxicated by a (narcotic) drug.

1952		Lannoy & Masterson ‘Teen-age Hophead Jargon’ AS XXVII:1 25: GAGE, 1. n. Marijuana. 2. adj. Under the influence of drugs.
1957		C. Himes Imabelle 151: Jodie was gaged on heroin and kept snapping that knife open and shut.
1992		Bentley & Corbett Prison Sl. 77: Blazed High on marijuana. (Archaic: gaged).