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After the turn of the 20th century, the U.S. government began to heed the growing public concern about drug and alcohol abuse. Congress passed the Pure Food and Drug Act of 1906, which required that warning labels be added to prescription medications containing substances known to be habit-forming. The importation of smokable opium was banned in 1909, and restrictions on prescription drugs tightened with the passage of the Harrison Act in 1914. This act severely limited the sale of narcotics and required physicians and pharmacists to maintain records of drugs dispensed and prescribed, so that the government could monitor the distribution of narcotics. Additional laws prohibited the importation of these drugs, which resulted in the creation of a narcotics underground.
By 1919 the temperance movement had gained enough popular support to force passage of the 18th Amendment to the U.S. Constitution. Rather than curtail excessive drinking, however, the era of Prohibition merely effected a change in drinking behavior from socially and legally accepted patterns to illegal and covert use. But by 1933, after fourteen years, the experiment with Prohibition ended. Ironically in the following year, Alcoholics Anonymous was formed.
Marijuana use spread in the first half of this century. Tincture of cannabis was available by prescription as an analgesic and hypnotic. Although marijuana was not widely smoked except by certain ethnic groups and others who, during Prohibition, found it easier to obtain than alcohol, it became the subject of journalistic sensationalism. Marijuana was described as the first step to heroin and as leading to insanity and murder. Such reports aroused the public and resulted in the enactment in 1937 of the Marihuana Tax Act. This legislation levied a token tax with harsh penalties for failure to pay on all who prescribed or possessed it, and established marijuana as a dangerous drug.
The first half of the twentieth century brought many developments in medicinal chemistry--and many new substances with abuse potential. Naturally occurring stimulants and hallucinogens were isolated and purified, and other psychoactive drugs were synthesized. Barbital was introduced in 1903, spawning the synthesis of many other barbiturates, and in the 1920s various naturally occurring and synthetic stimulants were introduced. About the same time, scientists became interested in the psychoactive properties of peyote cactus and mushrooms that had been used for centuries by natives of the Southwestern United States and Mexico. Following Albert Hoffman's discovery in 1943 of the psychedelic effects of LSD, clinical interest was sparked by the belief that such drug effects might be related to the biochemistry of mental illness, and thus help to create effective therapeutics.
With advances in drug isolation, purification, and synthesis came the development of techniques to detect and quantify drugs in urine and other biologic specimens. The oldest technique for detecting drugs or their metabolites in urine is solvent extraction. Solvent extraction was employed to extract selectively acidic and basic drugs by adjusting the acidity of the solvent. Various chromatographic methods were developed to separate compounds and identify components based on their unique abilities to interact with fixed (immobile) substances (adsorption). Lederer ( 1989) cited Goppelsroeder 1904 book Studien uber die Anwendung der Capillaranalyse as marking the introduction of chromatography in the medical sciences. Subsequent refinements in the choice of solvents and adsorbents made the techniques more powerful. Paper chromatography, available in 1944, enabled the successful diagnostic differentiation of a number of metabolic diseases through urinalysis. Additional methods that depend upon substances' unique abilities to absorb and emit light were developed and used to detect specific drugs such as heroin, morphine, and cocaine.
The first drug-screening program was introduced in the early 1920s, but it was not based on urinalysis. It was established to detect alcohol intoxication. Because alcohol is quickly metabolized and excreted primarily through the lungs, determination of alcohol ingestion must be made by analyzing blood or breath. During Prohibition, blood samples from motorists charged with driving while intoxicated were submitted for crude biochemical analysis. Within ten years the noninvasive breath analyzers replaced blood-testing kits (Montagne, Pugh, & Fink, 1988) . . .
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