You may be mixing together hallucination (thinking you see something that's not really there), delusion (a faulty belief), and illusion (tricking your senses to produce a twist in your perception). Any of those psychological states could be associated with drug use. Elucidation, however, means making something clearer, rather than muddier in your mind.
Does the word elucidation have something to do with drugs?
When your teacher elucidates the role of carrier protein in facilitated diffusion, she is explaining an important part of plant biology. Her elucidation can help you understand how plants get rid of inwardly diffused substances that they don't need or that are toxic.
From Harriett Beecher Stowe's Uncle Tom's Cabin:
There was something so piquant and original in these elucidations of humanity, that Mr. Shelby could not help laughing in company. Perhaps you laugh too, dear reader; but you know humanity comes out in a variety of strange forms now-a-days, and there is no end to the odd things that humane people will say and do.
In Moby-Dick, Herman Melville writes,
All these particulars are faithfully narrated here, as they will not fail to elucidate several most important, however intricate passages, in scenes hereafter to be painted.
And in Miguel de Cervantes's Don Quixote:
. . . for I establish and elucidate elegantly some things of great importance which Polydore omitted to mention. He forgot to tell us who was the first man in the world that had a cold in his head, and who was the first to try salivation for the French disease, but I give it accurately set forth . . .