By the Numbers26 Scientific American January 2001

says, “and literally creates a new state ofmind.”

Pettigrew, who has bipolar disorder,found that his own brain took 10 timeslonger than normal to switch between barsand stripes, an anomaly borne out by stud-

ies on his bipolar patients. A clinical trial isgearing up in Australia to test whether thismay offer the first simple physical diagnos-tic for manic depression. Meanwhile KeithD. White of the University of Florida hasdiscovered that many schizophrenics have

distinctly abnormal binocular rivalry. “It ismuch too early to say whether this mightserve as a diagnostic test,” White cautions.“But I wonder whether this isn’t the onlyperceptual difference that we can measurein schizophrenia.” —W. Wayt Gibbs

ROD

GER

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YLE

In 1999 illegal drug use resulted in 555,000 emergency roomvisits, of which 30 percent were for cocaine, 16 percent formarijuana or hashish, 15 percent for heroin or morphine,and 2 percent for amphetamines. Alcohol in combination

with other drugs accounted for 35 percent. This is not the firsttime that the U.S. has suffered a widespread health crisisbrought on by drug abuse. In the 1880s (legal) drug companiesbegan selling medications containing cocaine, which had onlyrecently been synthesized from the leaves of the coca plant.Furthermore, pure cocaine could be bought legally at retailstores. Soon there were accounts of addiction and sudden deathfrom cardiac arrest and stroke among users, as well as cocaine-related crime. Much of the blame for crime fell on blacks, al-though credible proof of the allegations never surfaced. Reportsof health and crime problems associated with the drug con-tributed to rising public pressure for reform, which led in timeto a ban on retail sales of cocaine under the Harrison NarcoticAct of 1914. This and later legislation contributed to the nearelimination of the drug in the 1920s.

Cocaine use revived in the 1970s, longafter its deleterious effects had faded frommemory. By the mid-1980s history repeat-ed itself as the U.S. rediscovered the dangersof the drug, including its new form, crack.Crack was cheap and could be smoked, amethod of delivery that intensified thepleasure and the risk. Media stories aboutits evils, sometimes exaggerated, were ap-parently the key element in turning publicsentiment strongly in favor of harsh sen-tences, even for possession. The result wasone of the most important federal laws ofrecent years, the Anti-Drug Abuse Act of1986. It was enacted hurriedly withoutbenefit of committee hearings, so great wasthe pressure to do something about theproblem. Because crack was seen as unique-ly addictive and destructive, the lawspecified that the penalty for possession offive grams would be the same as that forpossession of 500 grams of powder cocaine.

African-Americans were much morelikely than whites to use crack, and so, asin the first drug epidemic, they came un-der greater obloquy. Because of the powdercocaine/crack penalty differential and oth-

er inequities in the justice system, blacks were far more likely togo to prison for drug offenses than whites, even though use of il-licit drugs overall was about the same among both races. Blacksaccount for 13 percent of those who use illegal drugs but 74 per-cent of those sentenced to prison for possession. In fact, the 1986federal law and certain state laws led to a substantial rise in thenumber of people arrested for possession of illegal drugs, at a timewhen arrests for sale and manufacture had stabilized.

The data in the chart catch the declining phase of the U.S.drug epidemic that started in the 1960s with the growing popu-larity of marijuana and, later, cocaine. Use of illegal drugs in theU.S. has fallen substantially below the extraordinarily high levelsof the mid-1980s and now appears to have steadied, but hiddenin the overall figures is a worrisome trend in the number of newusers of illegal drugs in the past few years, such as an increase innew cocaine users from 500,000 in 1994 to 900,000 in 1998. In1999 an estimated 14.8 million Americans were current users ofillegal drugs, and of these 3.6 million were drug-dependent.

The decline in overall use occurred for several reasons, in-cluding the skittishness of affluent co-caine users, who were made wary by neg-ative media stories. The drop in the num-ber of people in the 18-to-25 age group, inwhich drug use is greatest, was probablyalso a factor, and prevention initiatives bythe Office of National Drug Control Poli-cy, headed by Gen. Barry McCaffrey, mayhave had some beneficial effect. The de-crease in illegal drug use in the 1980s andearly 1990s was part of a broad trendamong Americans to use less psychoactivesubstances of any kind, including alcoholand tobacco.

Even with the decline, the U.S. way ofdealing with illegal drugs is widely seen byexperts outside the government as unjust,far too punitive and having the potentialfor involving the country in risky foreigninterventions. The system has survivedfor so many years because the public sup-ports it and has not focused on the de-fects. Surveys show that most Americansfavor the system, despite calls by severalnational figures for drug legalization, andthere is little evidence that support is soft-ening. —Rodger Doyle (rdoyle2@aol.com)

Coke, Crack, Pot, Speed et al.S O C I O L O G Y _ D R U G A B U S E

HEROIN

1975 1980 1985Year

1990 1995 2000

10

8

6

4

2

0

32

24

16

CRACK

AMPHETAMINES

Nu

mb

er o

f Use

rs in

Pas

t Yea

rs (m

illio

ns,

age

12 a

nd

old

er)

CANNABIS

COCAINE 

SOURCE: National Household Survey on Drug Abuse, Department of Health and Human Services. Latest available data are from 1998.

Illegal Drug Use in U.S.

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Copyright 2000 Scientific American, Inc.