By Philip Elmer-DeWitt

The scene is South Central Los Angeles, but it could as easily be Detroit, Grand Rapids or Kansas City. A young white male driving a 1989 Thunderbird slowly circles one of the worst blocks in the city. He nods toward a group of blacks hanging out at a corner. As his smartly dressed date whirs up her electric window, a clamoring pack of drug dealers surrounds the car. Money is hastily exchanged for a tiny cellophane bag of off-white crystals. The car peels away, fleeing the inner city, headed toward suburban safety. But the driver of the Thunderbird, his supply exhausted, will be back in only three hours, slowly circling the block.

This is not the picture of the crack epidemic portrayed by the nightly news. On TV, crack addicts are almost invariably blacks and Hispanics from the ghetto. In real life, the problem is much broader: the number of white middle- and upper-class crack users may equal -- or even exceed -- the total from poor minority communities. No government studies break down crack use by economic status, but William Hopkins, a leading narcotics expert working for the state of New York, estimates that 70% of New York City's drug users are affluent. Across the U.S., drug counselors report rising numbers of professionals -- doctors, nurses, accountants, professors -- trying to kick crack habits gone out of control. "We've got Wall Street executives who buy crack in the middle of the day and smoke it in the office," says Alan Horowitz, program director at A.C.I., a treatment center in New York City. "We had one air- traffic controller at J.F.K. airport who was smoking crack on his breaks."

Crack, a smokable form of cocaine, is a drug that might have been designed for use on the job. It is easy to conceal, since it burns with virtually no odor, and the gratification is swift: an intense, almost sexual euphoria that lasts only about five minutes and is not accompanied by such telltale side effects as alcohol's slurred speech and heroin's drowsiness.

The problem of crack abuse among the affluent is especially disturbing because it comes at a time when the middle class seemed to be weaning itself from recreational drugs. Between 1985 and 1988, the number of casual drug users in the U.S. dropped from 23 million to 14.5 million, according to the National Institute on Drug Abuse. But according to another federal study, the number of Americans using crack cocaine at least once a week increased by one- third during that period, from under 650,000 to more than 860,000. "The poor people in the ghetto aren't buying all that cocaine," says William Smith, clinical director of California's Phoenix House. "This is a plague that knows no class or racial boundaries."

Psychologists say upwardly mobile Americans who turn to crack share personality traits that may make them vulnerable to the drug's siren call. Dr. Jeffrey Rosecan, director of the Cocaine Abuse Treatment Program at Manhattan's Columbia-Presbyterian Medical Center, sketches a profile of the typical crack user: a man in his 30s or 40s, single or divorced, with a high- pressure job, little inner peace and a history of moderate drug use and heavy drinking. "They're extremists, hard drivers, workaholics," says Rosecan. "With an all-or-nothing personality and a history of drug experimentation, you've got a formula for disaster when this person tries crack."

Crack is not for men only. One of the most striking developments of the past five years is the increase of crack abuse among middle-class women. The American Association for Clinical Chemistry, the organization whose members perform 80% of the drug tests in the U.S., reports that among people who test positive for drugs, the percentage of women jumped from 25% in 1972 to 40% in 1988. Many of them first used cocaine to help lose weight.

The rich have special problems procuring crack. They often have to make their buys in unfamiliar (and unsavory) neighborhoods, where they are prey to all kinds of rip-offs. Street crack is contaminated with an astonishing variety of chemicals, from amphetamines and meat tenderizers to pesticides. To make sure they are not being poisoned, some users are going back to a process popular years ago. They buy cocaine and convert it into a purer form of crack at home. This dangerous process, called free-basing, involves combining cocaine with baking soda and cooking the mixture. The latest trend among well- to-do users is to prepare their free base in microwave ovens.

Initially, a crack addict can continue to function at work. But that first euphoric kick can be followed by depression and paranoia, which the user suppresses by getting high again. So begins a cycle of compulsive binging known as "chasing the high." Five-dollar "nickels" give way to $40 "doves." Soon crack addicts are spending $200 and more every night.

The poor have a built-in defense against runaway crack abuse: they run out of money. The rich have the same limit; it just takes longer to get there. Stories abound of well-heeled users smoking their way through trust funds, savings accounts and charge-card credit lines. Some take out second mortgages and go on to sell jewelry and household items like TVs, VCRs and answering machines.

Having bought their way into addiction, affluent users often try to buy their way out. They can pick and choose from a long menu of treatments, from acupuncture to cocaine-blocking medications like imipramine and desipramine, but there are no quick fixes. In the end, all crack addicts, rich or poor, must put themselves back on their own feet -- a slow process that calls for professional counseling, steady support from family and friends, fearless self-examination and not a little pain.

With reporting by Jonathan Beaty/Los Angeles and Georgia Harbison/New York