"The question is not why people take drugs, but why they ever stop," says Dr. David Musto, professor of psychiatry and the history of medicine at Yale medical school. It is a question that for the last 18 years has fascinated Musto, 50, the country's leading researcher on the cyclical history of American drug epidemics. While the recent infatuation with drugs, especially cocaine, may seem to be unique in the nation's history, Musto points out that what we are seeing is actually a repeat performance.

Musto is the father of four, ages 15 to 23, and lives in New Haven with his wife, Jeanne, 49, a piano teacher. He spoke with correspondent Maria Wilhelm on the attraction to drugs, past and present:

How do you define a drug?

A drug is any substance that has some definite mental or physical effect, so penicillin is a drug and so is alcohol. The definition of a dangerous drug varies over time. When cocaine was first introduced in this country in the 1880s, it was considered a drug but not a dangerous one. In fact because it cheered people up, it was considered the ideal recreational drug, the all-American tonic.

What are the earliest examples of dangerous drugs?

Opium was available in Greece about 2000 B.C., and you read that the physician Hippocrates observed that people who used it had trouble stopping. Alcohol is one of the oldest drugs known to man. In Ecclesiasticus there is the warning that wine was created from the beginning to make men joyful and not to make them drunk. Tobacco, when it was first introduced in Britain from the New World in the 17th century, was personally attacked by the king, James I, as being a dangerous and filthy habit.

When was cocaine use first reported?

Residents of the Andean highlands in South America have been chewing coca leaves for several thousand years, well before the Spanish conquistadors arrived in the 1530s. The Spanish tried to ban use of the coca leaf, but they found they got more work out of the natives in the silver mines if they allowed its use.

How did interest in the coca leaf spread?

Coca wine, or the alcoholic extract of coca leaves, had been introduced in America and Europe in the 1860s. A certain Dr. G. Archie Stockwell wrote a glowing account of the drink in 1877 in the Boston Medical and Surgical Journal, claiming the extract was good for fighting depression, conserving energy and was not addictive. He also claimed it cheered you up and not infrequently caused "unequivocal aphrodesia."

When did Sigmund Freud's experimentation with the drug begin?

In 1884 cocaine became commercially available from Merck & Co. in Germany and from Parke, Davis in the United States. In America cocaine was being touted as a cure for opium addiction, a real problem in the U.S. in the 1880s, and even for alcoholism. Freud hoped to get a friend off morphine by substituting cocaine. He got some from Merck, took it himself and found that everything G. Archie Stockwell had written was true. Freud was so enthusiastic about it that he wrote Über Coca, a hymn of praise to the coca leaf. He enthusiastically recommended the drug for all types of people, including athletes and people who were depressed as well as those who had to get a lot of intellectual work done.

Did cocaine have other champions?

Yes. Thomas Edison was a great fan of Vin Mariani, a French wine laced with cocaine. Pope Leo XIII was very favorably inclined toward it. He and other clergymen were even offered a discount of 10 percent. President Ulysses S. Grant took cocaine to ease the pain of throat cancer while writing his memoirs.

When did cocaine use spread to the general public?

Cocaine use exploded in America in 1885. Interest was so great that Parke, Davis boasted there wasn't a second-rate drugstore in the U.S. that didn't have a supply of cocaine. The drug was sold by mail order and in catalogues. It was in crystal form for preparing solutions and as a fine powder for sniffing. In 1890 it cost $5 an ounce. There were 250,000 opium and opiate addicts. To equal that number today there would have to be 750,000 addicts. At the turn of the century 15 different forms of cocaine were on the market from coca cigarettes and coca cheroots (a small cigar) to cordials and salves. By 1887 it was made the official remedy by the Hay Fever Association.

Didn't the original Coca-Cola contain cocaine?

Yes. Every bottle of Coca-Cola in 1900 contained roughly five milligrams of the drug, or about one-half to one-third of a line of coke. In 1903, when the Atlanta city council passed an ordinance prohibiting the sale of cocaine at soda fountains, cocaine was removed from Coca-Cola. Among other sodas with the coca extract were Cola Coke, Wise-Ola, and Rocco Cola. Atlanta's Rainbow Bottling Company produced the simplest of them all, my favorite, a drink called Dope.

When did the country's infatuation with cocaine wear off?

By the mid-1890s cocaine was no longer seen as a pure joy but as producing real problems. By 1900 cocaine was considered the most dangerous drug that had ever affected the nation. Over time cocaine creates a habit; it can cause the user's mental processes to deteriorate, and the addict can become increasingly paranoid or violent. It took years for people to agree that this is what happens with prolonged use.

What measures were taken to stem the spread of the drug?

In 1909 the U.S. called the Shanghai Opium Commission to control both opium and cocaine. In 1910, in a presidential report, cocaine was called the "new vice...a creator of criminals and violence." About two years later The Hague Opium Convention formulated the first international treaty on opium and cocaine, calling for domestic legislation to restrict the sale of the drugs. In this country the Harrison Narcotic Act in 1914 levied taxes on all transactions dealing with opium and coca leaves and their derivatives. As interpreted by the Supreme Court in 1919, the Harrison Act made it illegal to provide the drugs for nonmedical use.

Did cocaine use decline?

The demand for the drug declined so greatly from 1910 to 1930 that it was no longer a public problem. Popular songs reflected the changed antidrug stance. Cole Porter originally wrote: "Some get a kick from cocaine," in 1934's I Get a Kick Out of You. But by 1956 popular recordings made no mention of the drug. The public resistance to the drug was so great that there wasn't a big drug problem here until the 1960s.

How did the current epidemic of cocaine use get started?

The first stage occurred in the '60s. In some quarters there was the feeling that drugs were an aid for self-fulfillment, that you could be the most you could be with a little help from drugs. Interest in cocaine began with the affluent and gradually spread in the late 1970s. We forget that as recently as 1974, Dr. Peter Bourne, later Jimmy Carter's drug adviser, called cocaine "probably the most benign of illicit drugs." And he was not alone.

What accounts for the resurgence of interest in drugs in the '60s?

Short memories. When you don't have much of a drug problem anymore, it's hard to keep up a drumbeat against drug use. Prior to the 1930s every state required schools to teach the dangers of narcotics. But in the '30s and '40s there was so little drug use that public education programs ceased to exist. Then in the '60s there was a large influx of young people into the experimental drug stage and marijuana use was a membership card in that counterculture. All the terrible things that had been said about pot didn't live up to the truth. Marijuana didn't drive people to violence.

How does the present drug epidemic differ from the previous one?

There was nothing like the widespread use of crack during the previous epidemic. Normally, for the evidence to accumulate that a drug does not hold out the promise it had on first appearance is a long process, from 20 to 30 years. And only gradually is society permeated by the conviction that it would be better not to have the drug. Actually, since crack accentuates the effects of cocaine, it might speed up the negative reaction to the drug and shorten our experience with it. Another real difference is the highly organized nature of the dangerous drug industry and the technological advantages—better planes, better communications—on the side of people pushing drugs. And then drugs like LSD, PCP and the various designer drugs and the many varieties of sleeping pills didn't exist.

Is urine testing a welcome advance in identifying drug users?

Because it's cheap and because it appears capable of routing out drug users no matter what they say, urine testing seems to be infallible. But the reality is different. There's a degree of unreliability in the test itself. A botched laboratory procedure can produce a false positive. To throw someone out of a job for one dirty sample is a misunderstanding of the usefulness of the test.

Can we learn from the past?

There is a danger that if we lose the memory of past events, we will repeat our mistakes. We did have a terrible drug epidemic around the turn of the century, and it did go away. The people who are fighting the current drug epidemic can feel optimistic that they aren't battling futilely. It may be a long battle, but it's not a hopeless one.