THE DRUG-AIDS HYPOTHESIS
Peter Duesberg and David Rasnick
3. The American/European drug epidemic
3.1. Chronology of the drug epidemic in America.
During and after the Vietnam war, in the 1970s, the number of illicit
recreational drug users in America soared from a negligible background
to currently about 20 million who use drugs chronically, or about 8% of
the total US population of 250 million. In addition, 75 million Americans
(30%) use such drugs occasionally (51-53). This sudden epidemic of drug
addiction followed a 40 year period (from World War II until the upsurge
in the 1970s) during which there was very little illicit recreational drug
Prior to World War I, heroine, cocaine, and nitrite inhalants were legal,
and widely prescribed as medicines and sold as recreational drugs (54-56).
Those who became addicted generated an early drug epidemic that lasted
about 35 years, from around the mid-1880s until the 1920s (52). The concurrent
diseases and social consequences soon led to anti-drug legislation, which
together with the political situation of the wars ended "the first
cocaine epidemic" (52, 55, 57). According to the Bureau of Justice
Cocaine abuse decreased substantially by the 1920ís, and then virtually
disappeared from the American scene until the 1970ís. During the 1930ís
drug interest dwindled due to concern with the events in Europe. During
WW II international trafficking was eliminated. As the 1950s ended, efforts
to treat, rehabilitate and care for drug addicts were made for the first
time since the turn of the century. (52).
As of 1964 the Bureau chronicles the appearance of the new American
rapid rise in marijuana use; amphetamines and barbiturates move from
homes to the streets; rise in heroin addicts leads to methadone maintenance
pilot programs (1964). By the late 1960s increases in cocaine, heroin and
marijuana use prompted concern about drugs... In the 1970s the Vietnam
war produces drug testing and dependence among returning veterans. And
by 1980 crack appears in American cities and AIDS first described in medical
literature. Athletes die from overdoses, showing the lethal implications
of crack/cocaine (1986) (52).
The director of NIDA wrote in 1985, "Over the past 10 years, cocaine
... has evolved from a relatively minor problem into a major public health
threat." (58). In 1986 scientists from the National Institute on Drug
Abuse (NIDA) published an epidemiological overview of drug use in the US
in Science. According to the NIDA scientists cocaine addiction spiraled
in the US from "negligible" numbers in 1973 to 9,946 non-fatal
and 580 fatal medical cases in 1985 (59). The new cocaine epidemic has
since increased more than 10-fold, raising the numbers of cocaine patients
to 80,355 cases in 1990, and 123,423 in 1993 and 142,878 in 1994 (26, 51,
59-62) (see Fig. 2 and Table
2). Cocaine emergencies hit a new record of 13,496 cases in California
in 1994, up from 3,688 in 1985 (63). Even popular writers have accurately
chronicled the rise of the new American drug epidemic, as for example Jill
Jonnes in Hep-cats, narcs, and pipe dreams (55).
In step with its medical consequences cocaine consumption escalated
to unprecedented records. By 1996 the number of regular cocaine users had
reached 3.6 million, with 28 million who had at least tried the drug once
in their lifetime (52, 62). To keep up with their demand cocaine imports
had to be increased 200-fold, from 2 tons in 1980 to 400 tons in 1990,
and have since been kept at this level (26, 53, 62) (Fig.
2). These data are based on cocaine seizures that increased from 500
kg in 1980 to 100 tons in 1990 and have since remained at this level (62,
64, 65) (see Fig 2). The Bureau of Justice Statistics
estimates that only 10-20% of the imported cocaine is confiscated, and
that American consumption is currently at least 400 tons per year (53,
66). This corresponds to about 110 g for each of the 3.6 million regular
users per year, which is rather close to the estimated daily consumption
of 1g per day per addict (67).
Heroin-related hospital emergencies doubled, from over 30,000 in 1990
to 63,232 in 1993 (51) (Table 2 and Fig.
2). Heroin deaths climbed from 2,260 in 1991 to 3,522 in 1994 according
to the Drug Abuse Warning Network (DAWN) (61) (Table
2). About 1,500 kg of heroin were confiscated annually between 1992
and 1995 (62). In view of these alarming statistics the popular press (51,
60, 68, 69) including the San Francisco Chronicle warned that "a
growing segment of the population [is] attracted by its [heroin] deadly
mystique and encouraged by its low prices..." (70).
According to a 1994-survey of the NIDA "more than 5 percent (221,000)
of the 4 million women who give birth each year use illicit drugs during
their pregnancy" (51). Many of these mothers are among the AIDS patients
listed as intravenous drug users, and many of their babies are listed as
pediatric AIDS cases by the Centers for Disease Control (CDC) (3) (see
6.8. and 6.9).
Based on the amounts confiscated, 2 million doses in 1981 and 97 million
doses in 1989, amphetamine consumption has spiraled 50-fold in the 1980s
(65). Non-scientific reports describe new upsurges of amphetamine consumption
in the US and Europe among male homosexuals (71, 72) and others (73). According
to the US Department of HHS, "amphetamine-related emergency room episodes...
[presenting with] violent paranoid behavior as well as stroke, seizure
and death ... "(74) increased from 8,800 in 1990 to 17,665 in 1993
(51, 61) (see Table 2). In California amphetamine
or Ďspeedí hospitalizations rose even faster from 1,466 in 1984 to 10,167
in 1994 (73, 75). And the Drug Abuse Warning Network reports a three-fold
increase in amphetamine deaths from 252 in 1991 to 751 in 1994 (61) (Table
There are no American statistics from the Bureau of Justice on the consumption
of nitrite inhalants, even though nitrites have been banned for recreational
use in the US since 1988. Despite this ban they are sold legally as room
deodorizers (76-78). Before the ban about five million doses of amylnitrites
were consumed in the US in 1980, mainly by male homosexuals (56, 79, 80).
After the ban, in 1993, 4.2 million Americans, including 2.8 million men
and 1.4 million women, had used nitrites based on a survey from the National
Institute on Drug Abuse (81).
3.2. Chronology of the drug epidemic in Europe.
Europe was hit by a drug explosion ("Drogen-Explosion") at
the same time as America. Based on the amounts confiscated by the Bundeskriminalamt
(BKA), the German consumption of cocaine, heroin, amphetamines, LSD and
cannabis increased 1000 to 10,000 fold from the 1960ís to the 1990ís (Table
According to the Deutsche Hauptstelle fuer Suchtgefahren (Center for
drug addictions) in 1997, 19.3% or 3 million of the 18 to 59 year old former
West German males, and 9.9% or 1.5 million of the females have used illicit
drugs at some time (82). The majority of these had used haschisch
(cannabis), but 7.5%, or 1.1 million, males and 4%, or 0.6 million, females
had used hard drugs such as cocaine, heroin and amphetamines. Among the
80 million current Germans, 4 million are addicted to alcohol and 120,000
to heroin (10).
The German ĎRauschgiftbilanzí reported an 11.2% increase in the consumption
of illicit recreational drugs in 1994 compared to 1993 (83). And the number
of first time users reached 15,000 in 1995, up 5% from 1994 (10). Most
of these, 83%, were over 21 years old.
In 1993, 122,240 Germans were reported for drug offenses and 29,086
were convicted. There were 2125 deaths officially blamed on drug use in
Germany in 1991, and 1565 in 1995 (10). This represents a 10-fold increase
since the decade that started in 1975 with 195 drug deaths (Fig.
2a). As can be seen in Fig. 2a the rise
in German drug deaths paralleled the rise in AIDS cases. Like in America,
German males outnumbered females about 3 to 1 in the consumption of hard
recreational drugs (cocaine, heroin and amphetamines, use of nitrite inhalants
is not recorded in Germany) (82), and 9 to 1 in AIDS cases (84).
Drug consumption by the combined European Union almost matches, and
in the case of heroin, even exceeds the American epidemic based on the
amounts confiscated (Table 3). For example,
5.9 tons of heroin were confiscated in Europe in 1994 compared to 1.5 tons
in the US (see above). At the same time, 29 tons of cocaine, 1.9 tons of
amphetamines, 733 tons of cannabis and 61,000 doses of LSD and 1.25 million
doses of ecstasy were seized in the European Union in 1994 (10).
A report of the European recreational drug explosion by Springer
Verlag mentions just two health consequences: "heart arrest"
from cocaine, "itching" and "collapse of the immune system"
from ecstasy (10).
3.3. Epidemiology and age distribution of recreational drugs.
In contrast to infectious diseases, the epidemiological distribution
of recreational drug use is far from random. Instead it is highly differentiated
in the American and European populations (Table
4). About 70-80% of the American consumers of hard recreational drugs
such as cocaine, heroin and amphetamines are males over 18 years of age
based on information from the Bureau of Justice Statistics, the NIDA, The
White House and Public Health Services other than the CDC (Table
4). The National Drug Control Strategy: 1996 from the White
House reports that 78% of the drug users are males, and that 74% are 21-44
years old (53). Patients and deaths from drug diseases (see 3.3.) show
essentially the same sex and age distribution (Table
4). Almost all drug decedents are over 18 years of age, and most are
over 25 (61, 62, 85) (see Table 4). According
to a German study the median age of death of European intravenous users
of cocaine and heroin is 30 years (39). Their American counterparts die
between 25 and 44 years (41, 86).
The drug epidemiology is further differentiated based on sexual persuasion.
While cocaine and heroin are used independent of sexual preferences in
all major American and European cities, including New York (87-90), Baltimore
(91, 92) and Milan (93), nitrite inhalants are almost entirely, and amphetamines
are partially, monopolized by male homosexuals (see 3.3.). However, in
contrast to the hard illegal drugs used for psychoactive effects only (Table
4), those used specifically as sexual stimulants by male homosexuals
like nitrite inhalants are not recorded nationally, neither by the Department
of Justice nor by any of the many divisions of the Department of HHS. Therefore,
we have put together the pattern of drug use by homosexuals from non-scientific
reports and from sporadic reports in the scientific literature.
Numerous non-scientific reports confirm the popularity of the "gay
drug" (94) (nitrite inhalants) among male homosexuals in America and
Europe (7, 76-78, 94-98) (see Table 5). The
gay interest journal, aK, just surveyed the availability of poppers
which "seit Jahren von vielen Leuten vor allem Schwulen beim Sex zwecks
Verstärkung der Lust verwendet wird" [used as a gay drug for
years] (99). The journal points out the fierce competition among sex shops
for the gay market, particularly in view of the enormous profit margins
of over 1000%. Bottles containing poppers that cost less than 1 Sfr to
produce sell for up to 58 Sfr in Zurich, Lucerne, Bern, and Basel. According
to the journal the popper market has recently been upset because sales
have been banned in some Swiss states because amyl nitrites, but not other
nitrites, are listed as poisons by the Federal Public Health Office, BGA.
In agreement with the non-scientific literature, the AIDS epidemiologist
David Ostrow reported that nitrite inhalant use in a study of over 5000
male homosexuals from Chicago, Baltimore, Los Angeles and Pittsburgh, the
MAC cohort, showed a "consistent and strong cross-sectional association
with ... anal sex" (100). The San Francisco Department of Health and
the NIAID sponsored San Francisco Menís Health Study also report that 98%
of nitrite inhalant users are homosexuals (79, 80) (Table
4). Like male homosexuals from San Francisco (80, 101, 102) and Chicago/Baltimore/Los
Angeles/Pittsburgh (103, 104), those from Vancouver (102, 105), Sidney
(102), Amsterdam (102) and London (106, 107) also show a specific affinity
for nitrite inhalants, because of "their ability to briefly relax
the smooth muscles of the anal sphincter and thereby facilitate penetration"
(104) (see Table 5).
The current American use can be estimated from British sales statistics
because nitrites were legal in the UK until 1996, and because the drug
use habits of the homosexual communities in the US and UK are comparable.
For example, in 1984, 86% of British male homosexual AIDS patients from
St Maryís Hospital in London had inhaled nitrites compared to 86.4% from
clinics in New York, San Francisco and Atlanta (108). Since in 1995 at
least 1.5 million bottles (15 ml each) were sold for a profit of £8.5
million in the United Kingdom (76), it is likely that the current American
use is proportional to its British counterpart. This assumption is confirmed
by numerous epidemiological studies of cohorts of American male homosexuals
(see 3.2, Table 5). Even the NIDA and the CDC
announced informally at a nitrite-AIDS conference in 1994 (109), that "nitrite
use by gay men in Chicago and San Francisco" has increased in the
1990s after a decline in the late 1980s (110).
Recently amphetamines have gained popularity, compared to nitrites,
as sexual stimulants among American male homosexuals (71). Says the director
of an outpatient treatment center in Los Angeles, "Look at the demographics.
Itís such a nasty drug, the way it destroys the body and the mind. Crystal
(amphetamine) is a gay personís drug and a gay community problem."
According to the CDC from before 1984 (111-113), and according to independent
observers to this date (26, 76, 77, 80, 94, 105, 107, 113-116), American
and European male homosexuals at risk for AIDS or with AIDS stand out not
only for the amounts, but also for the bewildering combinations of recreational
drugs used (see Table 5). For example, the biggest
American survey of about 5000 male homosexual men, the MAC study, reports
various combinations of 11 recreational drugs (103, 104) (see Table
5). The median age of these 5000 American homosexual men at risk for
AIDS and with AIDS is 32 years (117).
In an interview with the gay magazine The Advocate about a Morning
party to benefit the Gay Menís Health Crisis (GMHC) on Fire Island in New
York in August 1992 Larry Kramer, founder of GMHC and author of the novel
I loathed the Morning Party. The Morning Party sent me into a depression
I cannot begin to descibe. After twelve years of the plague, I should come
back and see the organisation that was started in my living room having
a party like that! ... There were 4,000 or 5,000 gorgeous young kids on
the beach who were drugged out of their minds at high noon, rushing in
and out of the Protosans to fuck, all in the name of GMHC.
Among the 685 respondents to "the biggest ever survey of gay menís
drug use" conducted in England in the summer of 1996 by Gay Times,
80% had used poppers (nitrite inhalants), 48% ecstasy (amphetamines), 57%
speed (amphetamines), 40% coke (cocaine), 48% acid (LSD), 25% heroin, 76%
cannabis, 58% cigarettes, 95% alcohol (107) (Table
5). A tricontinental epidemiological study confirms and extends the
bewildering pattern of recreational drugs consumed by male homosexuals
with AIDS or at risk for AIDS in the US and Europe and finds the same pattern
repeated in Australia (102). Remarkably not one of the many studies recording
drug use by homosexual men with AIDS or at risk for AIDS has ever identified
even one AIDS patient who was drug-free (see Table
3.4. Drug diseases.
The ultimate costs of the American/European drug epidemic are the staggering
numbers of drug diseases and drug deaths: in 1994, 8,541 Americans died
from illicit recreational drugs, and 518,521 were delivered to emergency
rooms for drug diseases (52) (see Table 2).
In Germany there were 2125 deaths officially blamed on drug use in 1991,
and 1565 in 1995 (10). Because of the high morbidity and mortality associated
with long-term intravenous and oral drug use, addicts typically die at
an average age of only 30 years (26, 39, 41, 86, 118).
The first scientific paper on drug diseases describes immunodeficiency
caused by morphine addiction in Paris, France, in 1909 (119). An early
American study by the pathologist Willis Butler first drew attention in
1921 "to the fact that most addicts suffered from a serious illness,
such as syphilis or tuberculosis" (54). Since then numerous scientific
studies, listed in Table 6, have documented
the drug diseases of long-term drug addicts and their babies. These diseases
include immunodeficiency, pneumonia, tuberculosis, dementia, candidiasis,
weight loss, diarrhea, fever, night sweats, congenital abnormalities, mouth
infections, impotence, epileptic seizures, paranoia, lymphadenopathy, hemorrhages,
hypertension and many others (26, 40, 71, 120-127).
Table 6 also records the many overlaps between
the well established drug diseases and the diseases embraced by the CDCís
newest AIDS definition of 1993 (see 2.). These overlaps were unintentionally
confirmed in August 1996 by a drug treatment specialist of the Federal
Bureau of Prisons from Greenville, IL, at a seminar in Kona, Hawaii. The
specialist reported that every one of the over 300 AIDS patients he treated
over the past 10 years had been a drug user outside and often even inside
the prison (128).
The pathogenicity of recreational drugs is the product of 1) direct
drug biochemistry, and 2) indirect factors affecting the lifestyle of those
addicted to illicit drugs.
1) Biochemistry of drug diseases. Cocaine, heroin and amphetamines
each function as a catalyst of neurotropic reactions. Cocaine and heroin
are natural compounds and amphetamines are synthetic adrenalins, used in
Germany during World War II to suppress fatigue and anxiety in pilots and
tank commanders (129). A typical daily dose of 1-2 g of cocaine (10, 67),
or heroin (126) or amphetamine (118) consists of about 1021
molecules, or 107 molecules for every one of the 1014
cells of the human body. At that concentration these catalysts are so active
that recipients forget to eat, to drink, to sleep and lose many of the
inhibitions that control undrugged life the reason for their popularity
and eventual pathogenicity.
The pathogenicity of cocaine and heroin is exhaustively documented in
numerous pre-AIDS publications and in rare AIDS publications that acknowledge
HIV-free AIDS (see Table 6). However, little
is in the professional literature about the pathogenicity of amphetamines
(118). Since amphetamines became popular only during the AIDS epidemic,
their toxicity, like that of many other new drugs, has been credited to
HIV. Nevertheless, drug treatment specialists have informally descibed
amphetamine diseases. Says one specialist from St. Vincentís Hospital in
New York: "We are just starting to see heavy usage types in our emergency
rooms in New York City. Whatís troubling about this drug isnít just the
way it destroys the body life expectancy for those intravenously injecting
crystal is two years but the bizarre psychotic symptoms that develop"
(71).Even an orthodox AIDS specialist from AIDS project Los Angeles, now
director of an AIDS foundation in France, acknowledges the pathogenicity
of amphetamines, although coded in HIV-jargon, "there is ample evidence
to suggest that crystal accelarates premature progession to full-blown
AIDS in people dealing with HIV infection. Studies have shown that crystal
eats T-cells for breakfast, lunch and dinner." (71).
The pathogenicity of nitrite inhalants is the result of non-physiological
chemical reactions. Nitrite inhalants react with all biological macromolecules,
mutating and inactivating DNA and RNA, diazotizing proteins, killing vitamins
and oxydizing hemoglobin to inactive methemoglobin (26). At the recreational
dose of 1 ml per day (26, 130, 131) the user introduces about 1021
molecules into the lungs, or 107 molecules for every cell in
the human body enough for abundant toxicity. Under these conditions nitrites
are cytotoxic and immunotoxic in animals and humans (130, 132). The cytotoxicity
of nitrites on the epithelial tissues of the lung are enhanced by the toxins
of cigarette smoke, which also suppresses the immune system (133). In addition
to their cytotoxic potential, nitrites are among the best established mutagens
and carcinogens (134-137).
The pathogenicity of nitrites has been recognized long before the AIDS
epidemic, and continues to be acknowledged even by orthodox HIV/AIDS researchers
if only as a co-factor of HIV, the hypothetical source of all evil. For
example, in view of the toxicity of nitrite inhalants, a prescription requirement
was instated by the US Food and Drug Administration (FDA) in 1969 (138).
The FDA also limits nitrites as food preservatives to less than 200 ppm
(parts per million), because of direct toxicity and because "they
have been implicated in an increased incidence of cancer" (134) and
because they are listed as carcinogens by the National Research Council
since 1982 (137). In 1988 the NIDA published a monograph entitled Health
Hazards of Nitrite Inhalants that warns about the AIDS risks, particularly
Kaposiís sarcoma risks of nitrite inhalants (56, 130). As a result of the
NIDA monograph, the US Congress banned the sale of nitrites in 1988 citing
an "AIDS link" (139), a decision which was followed by the Crime
Control Act in 1990 with a Public Law [100-690] (7, 26, 140).
Based on the results of the NIAID-sponsored MAC study, AIDS epidemiologists
David Ostrow et al. in 1993 expressed concern about the nitrite-AIDS
connection: "From the earliest case control studies conducted by the
Centers for Disease Controlís (CDC) Task Force on Kaposiís Sarcoma and
Opportunistic Infections (Jaffe et al., 1983) to recent studies
of predictors of human immunodeficiency virus-type 1 (HIV) infection (Penkower
et al., 1991), recreational psychoactive drug use has been associated
with HIV-related illness or infection among homosexual men." (104).
In 1995, the National Institutes of Environmental Health Sciences reconfirmed
the nitrite-AIDS hypothesis. Based on exposure of mice to isobutylnitrites
(IBN) (poppers) for 15 weeks the Institute published in 1995, "The
results suggest that, in the absence of impaired pulmonary host defenses,
IBN produces significant and partially reversible suppression of systemic
humoral immunity" (141). And in the summer of 1996 the Royal Pharmaceutical
Society first banned the sale of nitrites in the UK citing: "Our primary
concerns were the health risks associated with the drug, including the
suggestive links between poppers and Kaposiís sarcoma" (142).
Also in 1996 a Swiss court convicted a sex offender for popper use because
poppers cause "headache, arrhythmia, vertigo, fainting, paralysis,
and unconsciousness". During the same year an official of the Swiss
Public Health Office, BGA, stated to the gay interest journal aK
that it was not possible yet to predict the health effects of popper use
("noch keine Risikoabschätzung des Poppers-Gebrauchs möglich"),
although he acknowledged that a man had just died after inhaling two grams
of amyl nitrite (99).
2) Lifestyle factors contributing to drug pathogenicity. Many
drug diseases are consequences not only of direct drug toxicity, but also
of frequent drug-induced suppression of appetite causing malnutrition and
sleep depravation, (126) both of which are the worldís leading causes of
immune suppression (143). These health risks are compounded by poverty
due to the enormous costs of illicit drugs. For example, an average cocaine
habit of 1g per day costs $800 per week (67).
One of the first to ring the alarm about drug diseases among male homosexual
drug users was the American writer John Lauritsen, author of Death rush,
poppers and AIDS (144) and The AIDS War (97). In The AIDS
War Lauritsen descibed in 1993 the explosion of drug use in the gay
scene in London:
Every Saturday night an estimated 2,000 gay men attend a dance club
where drug consumption is the main activity. According to London sources,
virtually 100 per cent of the men are on drugs, from 3.0 in the morning,
when the club opens, until it closes many hours later. Especially popular
is a variety of Ecstasy (amphetamines), whose ingredients are claimed to
include heroin. Poppers are sold legally in London. No one seems to think
they even count as drugs, as gay physicians, writing in the gay press,
have said that poppers are harmless.
None of the major AIDS organisations have properly warned about the
dangers of drugs. At most, their risk-reduction literature has urged people
to use alcohol and drugs in moderation, so as not to affect the Ďjudgementí.
Drugs are portrayed as risky only to the extent that they might facilitate
a lapse into Ďunsafe sexí. Poppers which cause genes to mutate, which cause
severe anemia, which can kill through heart attacks, which suppress the
immune system are depicted as bad only if they cause someone to forget
But recently even the established gay press appears to show some concern
that recreational drugs may do more than facilitate HIV infection. For
example, the British magazine Gay Times cited in its survey of the
bewildering drug use of male homosexuals in 1996 (Table
5) the concerns of a first aid officer from a London gay club:
I see some faces in the same dire state every week for years and I personally
think thereís gonna be an awful lot of very ill people in a few years time.
Taking all these substances on such a regular basis cannot be good for
you. Medically it canít. Sooner or later, somethingís got to give. (107).
And an article in 1996 in the American gay magazine The Advocate
with the title "A deal with the devil" asked philosophically:
So why is it that in the gay world, where almost half the urban male
population is dead or sick from an epidemic closely associated with substance
use, there is such ambivalence about drugs that AIDS organizations profess
to see nothing wrong with raising money from events that glamorize drug
use? Why, despite the bitter legacy of AIDS, do we continue assuring ourselves
that being gay means we have to be totally non-judgmental about the very
things that have wiped us out? (72)
The chronology and epidemiology of the American and European drug epidemics,
which affects primarily 25-54 year old males, coincide exactly with the
AIDS epidemic. Moreover, a comparison of the long-established list of drug
diseases with the CDCs long catalog of AIDS-defining diseases proves that
drugs alone could be responsible for the AIDS epidemic (see Table
6). It is for this reason that throughout the epidemic drug-aware AIDS
researchers found it difficult to distinguish between the drug and AIDS
epidemics as the following titles of their articles indicate:
1) 1987: AIDS and intravenous drug use: the real heterosexual epidemic
2) 1989: Cocaine abuse and acquired immunodeficiency syndrome: tale
of two epidemics (121).
3) 1991: The Twin Epidemics of Substance Use and HIV (21).
4) 1991: AIDS, drugs of abuse and the immune system: a complex immunotoxicological
5) 1993: Entangled epidemics: cocaine use and HIV disease (123).
6) 1995: New picture of who will get AIDS is dominated by addicts (146).
7) 1996: Clinical features of drug use and drug use related to HIV (40).