WHEN I was in third grade at the New Lincoln School in Manhattan, a clever sex education teacher showed my class a movie on drugs. In the style of classics like Reefer Madness, the film showed how different drugs were produced, how people could ingest them, and their extremely nasty side effects. Heroin was fashionable at the time, so glistening hypodermics and needle-tracked arms were prominently featured, along with short biographies of celebrities who had died of overdoses. Although the effect of such films on children today has probably been greatly diffused by constant exposure to drugs in all forms, it did the trick in '72. We felt nauseated and afraid. That year, everyone began checking their Halloween candy for needle-puncture marks.

Nobody ever found any. There were the usual stories of unfortunate children biting into apples and finding razor blades, but we had grown immune to these by then. Everyone knew that you didn't accept candy from strangers: everyone knew that New York's streets were dangerous, especially on October 31st, and that apples were boring anyway. As city kids, we were used to these things--they actually made the night more exciting.

So it seems strange--at least to one who put away her black cat costume about seven years ago--that there should be such a fuss this year over Halloween.

Of course, the recent Tylenol poisonings cast a shade of gloom over just about any drugstore purchase. These days we reach for the aspirin with a sinking feeling that this might be the last one we take. But candy and capsules are different things. Caution is always in order, but this year should have proved no more worrisome than any other.

Nevertheless, for weeks before this Halloween, parents groups mobilized either to ban the holiday altogether, or arrange substitute activities for disappointed lots. Aldermen and city councils all over the country debated their right to call a halt to trick-or-treating P. T. A. task forces patrolled neighborhood stores to watch for product contaminations. Local hospitals offered to X-ray the loot.

In the end, there were widely reported incidents of pin-laden chocolate and strange tasting fruit. A packet of hypodermics was found in a box of cereal in Danbury, Conn., and a Long Island man was injured when he bit into a candy bar containing a straight pin. At least 22 pieces of "Trick" candy appeared around New York City: Reese's Peanut Butter Cups, Cadbury Chocolates, apples, and even Coke contained dangerous and nasty surprises.

It is the quite possible that the collective hysteria that struck nation-wide last weekend indirectly caused these incidents to occur. With countless articles about the issue (prompted by countless meetings prompted by many over-reacting parents), newspapers and television spots put ideas into that many more sick heads. Just as paranoia builds on itself until the subject is immobilized, so the elaborate Halloween precautions may have spurred the very attacks they were meant to protect.

Back in fifth grade, I used to ride the subway to school every day. Sometimes I would be scared--there were some pretty unpleasant-looking people on the uptown IRT. "You can't go through life being scared of the subway," my father would tell me. "You can't live in a city and worry about crime all the time--it's completely futile." That's the same attitudes society in general has to take towards sporadic signs of sickess. Common sense is one thing, but over-concern over such things as Halloween candy can lead to unwarranted paralysis. If the sense of communal anxiety that overlook much of America last Sunday continues' to grow--who knows?--may be people will stop buying food altogether.