Anti-druggism is to the early '80s what anti-communism was to the early '50s. Hollywood continues to crank out cautionary hysterics on the evils of drug use and abuse, but you don't have to be king of the cynics to regard these efforts, and the motives behind them, with some skepticism.

The CBS movie tonight at 9 on Channel 9, "Desperate Lives," tells the sad, sad tale of how drugs ravaged a high school until a courageous teacher bucked the system and exposed the scandal. The film ends with her raiding students' lockers (as they rehearse "Angels We Have Heard on High" for a Christmas pageant), piling the drugs she finds onto a cart, wheeling the cart into the auditorium and setting fire to the drugs, with students coming forward to toss additional dope into the smudge pot.

And this presumably will straighten heads out left and right, with no more emotional, social or parental relationship problems for the kids. Along the way to nirvana, we, of course, get to witness colorful catastrophes brought on by drug use, just as movie audiences of previous decades got their moral lessons from Cecil B. DeMille, generously prefaced with graphic examples of the sins in question.

"Lives" does benefit from a lead performance by Diana Scarwid, of "Mommie Dearest" and other films, as the dedicated teacher who arrives in the southern California school from Tennessee, shocked to find drugs widely taken by students while teachers look the other way. When she tries to kick up a little outrage, she is warned that "making waves" and exposing the drug problem to the community could cost her her job.

Among the victims of the drug scourge are Doug McKeon as Scott, a disgruntled, restless tyke, and Helen Hunt as his sister Sandy, who is coaxed into trying some PCP whipped up in a lab by her boyfriend and, after one snort, promptly goes whackers and jumps through a window. Scott, meanwhile, falls in with an amoral pusher (Sam Bottoms) who tools around in a blue 280ZX. One night Scotty takes two Quaaludes and winds up falling face first into his food at the dinner table, then later laces a joint with angel dust while he and girlfriend Susan (Tricia Cast) are out joy riding.

The car goes over a cliff, Susan is killed, and Scott's head is messed up real good. He is, mysteriously, not told that the girl died in the accident, and when he asks what happened, he is coldly informed, "When the time's right, your memory will tell you." Naturally, when his memory tells him, he goes stark-raving nuts and has to be carted off by an ambulance.

No one could doubt that drug abuse has taken a ruinous toll among the young, but films like this, which treat drugs like some fiendish beastie from outer space, merely exploit the suffering for the sake of feverish dramaturgy. Producer Lew Hunter's script doesn't offer any valuable perspective on the disillusion that leads to drug dependence, and director Robert Lewis wallows in ghastliness at each opportunity.

Scarwid is at her best when affecting a look of horror that was one of the few things in "Mommie Dearest" one couldn't quite hoot at; she brings much more to the role than it deserves, and dresses it up with credibly feigned outrage. McKeon, who was seen only last night on CBS as a lovestruck 14-year-old in "An Innocent Love," and who plays the instantly reformed youth in "On Golden Pond," oddly enough looks a bit like his costar--their faces have the same sort of friendly, off-center fleshiness. McKeon may be turning into a young (younger) Timothy Hutton, the perpetually troubled youth, but there's plenty going on in his performances.

In the film, marijuana use is seen as leading to harder drugs--a still debatable supposition--and the level of sophistication can be ascertained from the advice Scarwid is called upon to give McKeon when she learns he is over-reliant on grass: "Try a movie," she suggests. "Try a book. Remember bicycling? Try Susan." It sounds like the Boy Scout manual from 1915.