Green’s Dictionary of Slang

glued adj.³

also superglued

[SE have one’s head glued on]

(orig. US campus) stable, sane.

1989		P. Munro Sl. U. 93: I’d go crazy without you here to keep me glued.
1990		S. Morgan Homeboy 294: He had guessed Sunny Deelight wasn’t exactly superglued.