Amphetamines
The amphetamines are central nervous system stimulants 'With sympathomimetic effects of which two main varieties are 'Widely used by illicit drug users: amphetamine and methylamphetarnine (also known as methamphetamine in the United States and in Australia). Although they differ structurally from cocaine the central stimulant and euphoric effects of amphetamines and cocaine are very similar. Indeed, experienced cocaine users are unable to distinguish between their effects when they are injected intravenously under double-blind conditions (Jaffe 1985),
The major characteristics which distinguish the drugs pharmacologically are the much longer half-life of amphetamine, and the local anaesthetic and vasoconstrictive properties of cocaine (see Chapter 2 ofthis book).
The problems associated with chronic, heavy use of amphetamines were reported with their first therapeutic uses as a treatment for narcolepsy, although they were not recognised as a specific effect of the drug until the late 1950s. There was anecdotal evidence of recreational use among students in the late 1930s and amphetamines were 'Widelyused by combatants from many countries in World War II to reduce fatigue and delay sleep under combat conditions. They were used for the same purpose in the Korean and Vietnam wars, and during the American space program (Grinspoon and Hedblorn 1975).
The problems caused by chronic heavy use ofamphetamines became apparent in the post-war period during a succession of epidemics of amphetamine use . The earliest and most dramatic occurred in post-war japan between 1945-1954 (Brill and Hirose 19(9) when large surplus stocks of injectable methamphetamine were dumped on the domestic market and heavily promoted by over-the-counter sales. At its peak 1.5 million persons in Japan were estimated to be injecting methamphetamine (Grinspoon and Hedblorn 1975).
The problem that brought the epidemic to official attention was the occurrence of psychiatric disorders among heavy users. The Japanese Government responded with severe restrictions on the availability of methamphetamine, the introduction of penal sanctions against use and a strong public propaganda campaign against the use of methamphetamine. This combination of actions enjoyed strong public support and so reduced the prevalence of methamphetamine use, concentrating it among minority groups and deviant inner-cityyouth (BrillandHirose 1969.Hemmi 1%9).Methamphetamine and inhalant use have continued to be problems among these groups, albeit .u a much lower level (Suwaki 1989).
Similar epidemics of amphetamine use occurred in Sweden in the 1940s, 1950s and 1960s (Bejerot 1969, Goldberg 1968a. b; Inghe 1969, Ray1978),in the US in the late 1960s (Cohen 1969) and early 1970s (Grinspoon and Hedblorn 1975), in the UK in the late 1950s (Connell 1959) and again in the late 1960s (Advisory Committee on Drug Dependence 1970, Hawks et al 1969). There are indications that there was a smaller epidemic of amphetamine use in Australia in the middle and late 1960s. During this time there was a large increase in the prescription of amphetamines by general practitioners (Baume 1977), increased use of amphetamines among young offenders and young adults attending psychiatric hospitals (Briscoe et al 1%8, Healy 1978), and an increase in the prevalence of persons diagnosed with amphetamine psychoses (Bell 1973).
In each of the early post-war epidemics amphetamine use was fuelled by a combination of ready availability, and perceived safety by users and the medical profession (Ellinwood 1974). The epidemics of the 1950s in Britain involved the use of inhalers containing large doses of amphetamine which were available over the counter. When the availability of inhalers was restricted and amphetamine was eventually replaced as the decongestant agent, the use of oral amphetamines increased. These preparations were freely available on prescription by medical practitioners as a treatment for lethargy, depression and obesity (Kiloh and Brandon 1962). In Sweden medically prescribed preludin (phenmetrazine) tablets were crushed and injected. In Britain in the late 1960s, some general practitioners prescribed injectable methamphetamine in the belief that these were safer drugs to inject than heroin or cocaine (Hawks et al 1969).
In many of these epidemics an indicator which first brought widespread amphetamine use to medical attention was an increase in paranoid psychoses among heavy users. A psychosis was observed in 1938 in a patient who was being treated for narcolepsy and other cases were observed in the 1940s. In the majority of cases, however, they were regarded as psychoses which amphetamines had precipitated in predisposed users. The English psychiatrist Connell (959) made a strong case for there being a direct connection between chronicheavyamphetamine use and the development ofa paranoid psychosis. He documented a large number of cases histories of paranoid psychoses that occurred among chronic amphetamine users, including persons without any evidence of a personal or family predisposition to develop a psychosis.
Subsequently, American investigators documented the association between paranoid psychoses and heavy chronic amphetamine use, especially by injection (Kramer et al 1967, Grinspoon and Hedblom 1975). Other researchers demonstrated that the psychosis could be reproduced by the injection of large doses in addicts (Bell 1973) and by the repeated administration of large doses to normal volunteers (Angrist et al 1974). There was weaker, suggestive evidence that violent crimes were more likely to be committed by heavy amphetamine users during such paranoid episodes (Asnis and Smith 1978, Ellinwood 1971).
Once the abuse potential of amphetamines was recognised (in the late 1940s in Sweden and in the late 1960s elsewhere), their availability on medical prescription was severely restricted. This had two main consequences' First, the existence of a large market of users provided the incentive for the illicit manufacture and distribution of amphetamines, with the result that many of the later epidemics were supplied by a black market. Second, the development of a black market in turn changed the characteristics of users. The proportion of amphetamine users who were middle class, middle-aged women who used oral prescribed amphetamine declined while the proportion of younger male users correspondingly increased. The latter were primarily recruited from the drug subculture, where injection, the most hazardous form of administration (Chesher 1991), was the preferred route of administration. In this way the changes in the patterns of amphetamine use, and in the characteristics of users, mirrored that which occurred earlier in the century with morphine and heroin use (Courtwright 19R2).
There seems to have been a periodic recurrence of epidemic amphetamine use about once a decade in the post-war period in Australia, Britain and the United States (Ellinwood 1974). It seems as though each new generation of illicit drug users rediscovers the euphoric effects of amphetamines in the absence of any subcultural memory of the hazards of their use. Amphetamines then enjoy a vogue among injecting drug users because they are cheaper and easy to produce locally. Oral amphetamines are also widely used by recreational users, many of whom use lower doses intermittently, without incurring any problems.
The epidemics often lasted several years before largely disappearing. The reasons for their disappearance are uncertain but at least two processes have often played a part. First, once an epidemic becomes apparent, usually some years after the increased prevalence of use, governments usually introduce restrictions on availability, making amphetamines scarce and driving up the price, thereby deterring the less committed users (De Alarcon 1972). Second, the decline of the epidemic is often accelerated by the rediscovery within the injecting drug culture of the adverse effects of chronic heavy amphetamine use, as seems to have occurred in San Francisco in the late 1960s (Cohen 1969, Chesher 1991).
Amphetamine use in Australia 1985-1990
Much less is known about amphetamine use than about cocaine use in Australia during the second half of the1980s.This is largely because the concern about a looming cocaine epidemic (eg, Pierce and Levy1986) distracted attention from an emerging home grown amphetamine epidemic. Klee (1992) has argued that a similar phenomenon has occurred in Britain. As a consequence, most of what is known about amphetamine use in Australia has been gathered en passant in the course of research on the use of cocaine (eg, Reilly and Homel1988, Homel et al 1990), or on the risks of HIV transmission among injecting drug users (eg, Hall et al 1992).
There are, nonetheless, sufficient indicators of an increase in the availabilityand use of the amphetamines in Australia. There have been increases in police seizures of amphetamines and in amphetamine-related offences, such as' possession and selling (Tebbutt et al 1990), which suggest that amphetamine arid methamphetamine are readily available in New South Wales, Victoria and South Australia. There appears to be a well organised system of illicit manufacture and distribution which has developed because amphetamines have been easy to manufacture in the absence until recently of controls on the supply of precursor chemicals (ie, the chemicals from which amphetamines are manufactured).
The prevalence of amphetamine use in the general population has remained low. In the NCADA surveys of 1985 and 1988, the prevalence of stimulant use was higher than for cocaine, but still only 8% of the general population had ever used them (Commonwealth Department of Community Services and Health 1991). The prevalence of ever having used psychostimulants was even lower among high school samples, typically too low to provide trustworthy estimates (Tebbutt et al 1990).
There is evidence, however, of substantial amphetamine use among recreational and injecting drug users. Amphetamine has been consistently identified as the most popularly used illicit drug after cannabis in surveys of recreational drug users (eg, Reilly and Hamel 1988, Hall et al 1992, Plant et al 1989, Mugford 'and Cohen 1989). A secondary analysis of data from the sample of recreational drug users studied by Homel et al (1990) indicated that amphetamine users were more likely to be male, were less well educated and had a lower median income than persons who had not used amphetamines. They were also more likely to have tried a variety of other illicit drugs, particularly those perceived to be "harder" and riskier, such as cocaine, heroin and designer drugs.
Spooner et al (1992) repeated their earlier street intercept survey of adolescent drug users in Sydney, interviewing 581 young adults between the ages of 16and 21 years who had used at least one illicit drug other than cannabis. Amphetamines remained the most popular illicit drug after cannabis, with nearly nine out of 10 having been offered amphetamines, and 75% having used amphetamines at least once. Over a third (36%) had used amphetamines within the last month and 14% had used it within the last week. A third of amphetamine users had injected the drug at some time.
Amphetamine use was also prevalent among the ANAIDUS cohort of 1245 injecting drug users recruited in Sydney in 1989. A third of this sample had injected amphetamines in a typical month. Although opioid drugs were still the drug of preference for the majority of the sample, there was a smaller group who were primarily using amphetamines and 5% of-the total sample were primarily daily amphetamine injectors. This substantial minority who were injecting amphetamines on a daily basis placed themselves at considerable risk of developing a paranoid psychosis.
A comparison of risky behaviour among daily injectors of opioids and amphetamines indicated very few differences in high risk injecting behaviour (eg, needle-sharing) and unprotected sex with multiple partners (Hall et al 1992). Thus, there was no evidence in the ANAIDUS Sydney sample that amphetamine injectors engaged in more risk-taking behaviour than primary heroin users. Nonetheless, there remains cause for concern that approximately a half of both amphetamine and opioid users had shared injection equipment in the few months preceding interview.
The broad pattern of injecting amphetamine use in the ANAIDUS Sydney cohort was confirmed in a Sydney study of injecting drug users attending needle and syringe exchanges and pharmacies (MS]KeysYoung1989). A secondary analysis of data on 243 persons attending needle exchanges and 99 attending pharmacies confirmed that injecting drug users in Sydney preferred heroin (79%) to amphetamine (18%). A comparison of the heroin and amphetamine injectors in the sample also indicated that amphetamine injectors were more likely to be younger and male, and less likely to be daily users, or to have shared needles than heroin users.
Similar findings have been reported from the Melbourne ANAIDUS cohort of 356 injecting drug users (Lewis et al 1991). The average age and sex composition of the sample was similar to the Sydney cohort (mean age 27.1 years, 54% male), as was age of initiation of injecting drug use (18.6 years in Melbourne, 18.4 years in Sydney). The prevalence of ever having injected amphetamine was higher in Melbourne than Sydney (93% and 78% respectively), as was the proportion of daily amphetamine injectors in the sample (20% in Melbourne and 5% in Sydney). Nevertheless, the characteristics that distinguished between primary amphetamine and heroin users were the same in both cities: amphetamine users were younger and less likely to have had any treatment contact. In both cities, amphetamine users were no more likely than were heroin users to have engaged in behaviours that would put them at risk of contracting HIV, such as needle sharing and unsafe sex.
Loxley and Marsh (1990) examined the risk behaviour of a sample of 195 injecting drug users in the Perth ANAIDUS cohort. Respondents were drawn from both treatment and non-treatment sources. Analysis of this data was based on age rather than drug type as age seemed to be a more important variable in defining sub-groups within the injecting drug user population. The results showed that a higher proportion of younger than older users had used amphetamines and ecstasy. This differed from the use of every other drug type, where there were higher proportions of older than younger users. Amphetamines were more frequently injected by younger users. Younger users were also less likely to have been in treatment, to have started injecting at a younger age and were more likely to inject all or most oftheir drugs, to have more sexual partners and to share occasionally.
As was the case with cocaine use, data on the number of persons who may be experiencing problems as a consequence of their amphetamine use are sparse. What is available is limited but it suggests that, while problems are occurring at a low level, there has been an increase in their prevalence in recent years. The data from the national census of drug and alcohol treatment agencies, for example, showed that 4% of the 5583 clients seen on the census day presented for problems primarily caused by amphetamine use, 10 times more than the number of clients presenting with cocaine-related problems. Data on hospital separations in New South Wales between 1983 and 1989-1990 showed an increase in the number involving amphetamines from 34 in 1983 to 122 in 1988-1989 (Tebbutt et al 1990). More recently, a survey of key informants in the treatment and law enforcement fields by the National Drug Abuse Information Centre (1991) indicated that most States reported a small increase in both use and problems in 1990. Given the evidence of an increase in the prevalence of use, especially of hazardous patterns such as daily injection, the prevalence of amphetamine-related problems is clearly an area deserving of further research.
There are a number of indications from research studies and official statistics that amphetamine use is increasing among Australian drug users probably because of its wider availability and lower cost by comparison with heroin and cocaine. There are suggestions of an increase in problems from the injection of amphetamines and particular cause for concern about the prevalence of daily amphetamine injection among injecting drug users.
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