The present research among injecting drug users (IDUs) focuses on injecting behavior with a risk of transmission of the human immunodeficiency virus (HIV). The first aim of this research is to study the relationship between participation in different (prevention) programs and injecting risk behavior; the second aim is to study determinants of this injecting risk behavior. Findings will be discussed in relation to approaches to primary prevention of HIV.
In this introduction, a brief general background will be provided, by outlining the history of opiate and cocaine use (1.1) and by discussing the relation between medical problems and illicit drug use within a policy context (1.2). The main routes of transmission of HIV among IDUs will be described, together with the principle measures aimed at prevention of injecting risk behavior (1.3). Section 1.4 focuses on the Amsterdam policy with respect to hard drug use and prevention of HIV. It describes the "low threshold" methadone program and the needle and syringe exchange program. Several potential determinants of injecting risk behavior have been considered. These will be introduced in section 1.5: severity and type of drug use, 1.6: psychopathology and 1.7: the motivation to protect oneself or others against HIV. Finally, section 1.8 presents the major hypotheses and questions to be addressed in this dissertation.
1.1 Opiate and cocaine use, a brief historical outline
Until the 19th century, opium and coca had been used for many centuries in their natural form, without many legal restrictions, and without irreversible physical damage to users1,2. In the 18th and 19th century, opium, and later morphine, the major alkaloid of opium, were increasingly used in the Western world as treatment for a wide variety of problems, while cocaine was introduced somewhat later, in the second half of the 19th century. Around 1850, the hypodermic syringe was perfected. Because pain could be controlled using less morphine when injected, physicians initially thought that injecting morphine was less likely to result in addiction than oral use 3. Purified cocaine became commercially available in 1884, followed shortly, around 1895, by heroin, which was produced commercially from morphine2 .3. Opium, and later morphine, were used as pain-killer and calming agent, heroin as cough suppressant and cocaine as stimulant, as cure for an opiate or alcohol habit and as local anaesthetic. As the use of these substances became more and more popular, so did the frequency of addiction and abuse. Around the turn of the century, a growing fear of addiction and of the casual social use of habit-forming substances developed among the public 3,4. Consequently, the use of opiates and cocaine was gradually declared illegal in the first quarter of the 20th century. As Platt & Labate note2, the attempt to solve the narcotic problem by legal control has resulted in a significant modification of what it means to be an addict or (ab)user. For example, criminal involvement, specific social and medical problems, paranoia, sociopathy, etc., may be more related to the illegality of drugs than to drug use itself2. During the 1920s and 1930s, opiate and cocaine use declined as a societal problem2 -4. The major epidemic of heroin use in the United States (U.S.) did not start until the early 1960s2, while in the Netherlands, the epidemic started when street heroin became available around 1972'. Similarly, although cocaine has been present in most European capitals for many years, a significant European market in illicit cocaine did not develop until the early 1970s 5. Many heroin users, both in Europe and in the U.S., use or abuse other drugs in addition to heroin: alcohol6, cocaine7, benzodiazepinese -8-10, and other substances like barbiturates and amphetamines".
1.2 Medical problems, drug use and policy
The acquired immunodeficiency syndrome (AIDS) was first reported as a distinct clinical entity in 1981' 2. In 1983, the risk groups had been identified, the routes of transmission of the etiologic agent (presumably a virus) were understood 13 and the etiologic agent, human immunodeficiency virus (HIV), was identified by Montagnier in France and Gallo in the U.S.14 HIV is transmitted mainly through sexual contact, through the use of contaminated injection equipment, through intrauterine or perinatal exposure and through blood(products). In the industrialized world, injecting drug users are, after homosexual men, the second largest group at risk of AIDS. In Europe, by December 31st 1991 (after adjustment for reporting delays), a cumulative total of 72.674 AIDS cases have been reported, of whom 42% were in the homo/bisexual transmission group, 34% were among injecting drug users, 9% a result of heterosexual transmission and 2% due to mother-to-child transmission's. HIV among injecting drug users is associated with a substantial spread of HIV to non-injecting heterosexual partners1 6-17 and from female injectors to their children's.
Before the onset of AIDS, mortality and morbidity rates among heroin addicts were already higher than in the general population's. This was the result of 1) the use of the drug itself (accidental overdosage, related to different degrees of purity of street heroin), 2) violence or accidents related to drug use and 3) the medical complications of unfavorable living conditions and of unhygienic injecting procedures (e.g. pulmonary infections like pneumonia and tuberculosis, endocarditis, septicemia, vasculitis, abscesses, viral hepatitis, tetanus and skin infections) 2,19. Stimson 20 points out that, before AIDS, despite the often severe medical problems associated with heroin use and injecting and the high mortality rate, the major concern of society in general and of scientific research was the problem of drug dependence itself, and not the associated infectious and contagious diseases. In other words, the major focus was the prevention or cure of illicit drug use, either by law enforcement, by medical/therapeutic treatment or both. Stimson argues that with AIDS, a new conceptual framework has developed in relation to illicit drug use, which he terms the "public health paradigm". A medical problem (HIV) associated with a specific drug use behavior (needle sharing) has become the focus of attention, rather than the problem of drug dependence. The major aim now appears to be prevention of the spread of HIV, and this is associated with several changes in emphasis. Firstly, at variance with earlier viewpoints, the drug user or injector is now seen as a rational actor, who cares about his or her health. Secondly, instead of curing the addiction, the first aim is now to educate drug users on HIV prevention, or, how to use drugs and remain healthy. Health promotion, "harm reduction" and risk reduction become important. These aims demand that drug users are reached out to. Thus, a third development is that services are no longer only available to the motivated; services have to be accessible to all and "user-friendly".
The public health paradigm, as outlined by Stimson, seems to be on firm ground in several European countries, like England and the Netherlands. In the U.S., law enforcement and medical approaches with respect to drug use have clashed since the start of the century^ Recently, the U.S. government declared the "war on drugs". With regard to HIV, the U.S. government appears to favor the standpoint that a law enforcement approach is the best way to prevent HIV infections among drug users. On the other hand, U.S. public health professionals widely support the view that HIV, as compared to drug dependence, is the more serious threat to public health or to people in general. Many voices are raised to acknowledge the failure of the moralistic and law enforcement approach in preventing drug use and in preventing HIV infections in drug users. For example, Mosher & Yanagisako 21 argue that illicit drug use should not be seen as a moral problem requiring a punitive approach within the criminal justice system. Instead, drug use should be seen as a public health problem, which ought to be taken care of by the public health system. An issue around which much doubt exists, especially in the U.S., is the question whether harm reduction as HIVprevention strategy is compatible with the aim of primary drug use prevention 22. Racial tensions make HIV prevention issues even more complicated. For example, the Black Leadership Commission on AIDS in New York sees bleach distribution by public health officials as a social policy "copout", or, in other words, as an inexpensive way to stop AIDS from spreading among users while the government fails to provide the millions of dollars needed to help black users get off drugs 23. A New York City needle and syringe exchange program was closed after black citizens accused the mayor of "genocide "24.
It needs to be noted that the public health paradigm, as described by Stimson, is not all that new; minimisation of harm from drug use was - in England - a policy objective since the 1920S 25. In the Netherlands, the "harmreduction" approach (although not indicated as such) was adopted in the middle of the 1970s 26-28. Rather than giving rise to a new approach, AIDS seems to have given political legitimacy and acceptability to earlier formulated goals of normalization and harmreduction 21.
1.3 HIV transmission routes among IDUs and prevention measures
The main route of transmission of human immunodeficiency virus (HIV) among drug injectors is through using each other's needles and syringes, generally termed "needle sharing " 29. Heterosexual transmission plays a minor role, as compared to transmission by injecting risk behavior 30-36. "Frontloading" is a method of sharing drugs by which contamination of one's equipment with HIV can occur 37. However, the HIV risk of this behavior appears to be low relative to needle sharing 38. In the U.S., cocaine has in recent years become more popular, both as primary drug of abuse as secondary to the use of opiates 39 ,4 0. Both injecting cocaine and smoking crack (cocaine base) have been found related to an increased HIV risk 41-44, through increased injecting risk behavior and increased sexual risk behavior, respectively.
As soon as information became available on the nature, prevalence and transmission of HIV around 1983, it was generally understood that major behavioral changes among IDUs were essential, especially with regard to injecting behavior. Individual behavioral change depends on knowledge of the threat and on the availability of material resources necessary to avoid the danger. A third necessary factor is the motivation to change, which, in the case of HIV, means the motivation to protect oneself against HIV infection, or, for HIV-positive persons, the motivation to protect others. At the start of the HIV epidemic, there was much doubt as to whether drug users would be willing and capable of changing their behavior; in other words, whether they would act in a healthconscious and rational rather than selfdestructive way. However, due to the urgency of the threat, it was commonly felt that there was no time to study the effectiveness of measures before implementing them, nor to study behavioral determinants which could help to target prevention measures. Initially, health education focused on improving knowledge by informing IDUs about AIDS and the transmission of HIV, both agency-based and through outreach work. Later, programs were developed aiming to improve the risk reduction skills of drug users and to stimulate self-organization and peer support. Attempts were made to increase the availability of non-infected injection equipment: in the U.S. chiefly by providing a disinfectant (i.e., bleach) 45-48; in Europe mainly by providing new needles and syringes through exchange programs. The Amsterdam needle and syringe exchange started in 1984 (see 1.4.2), while in 1986 similar programs started in Sweden and Australia and in 1987 in England and Scotland 49. Thus, the present research of determinants of injecting risk behavior is complicated by the fact that, since 1984, prevention activities aimed at IDUs have been increasing steadily. In other words, the behavior under study was subject to efforts from various institutions to change this same behavior.
1.4 The Amsterdam "harm reduction" approach
Since the 1980s, many drug users in Amsterdam have been in contact with the medical and social services for drug users. Buning50 estimates that, on a yearly basis, there are around 7000 hard drug users in Amsterdam (including 2500 current injectors) of whom 70% are in touch with the care system.
In 1968, methadone reduction schemes were introduced in Amsterdam for opium addicts, which attracted many foreign drug users 51. From 1972 on, Chinese opium became less available, and people started to become addicted to heroin. Methadone reduction schemes were gradually replaced by maintenance schemes51. In Amsterdam, the harm reduction approach (although not indicated as such) was initiated around 1977, in addition to the existing facilities for methadone treatment, drug-free treatment and resocialisation projects. Due to the epidemic of heroin use, the number of arrested addicts with withdrawal symptoms increased strongly. As a result of this, in 1977, the police requested the help of the Mental Health department of the Municipal Health Service. This department formed a special drug team which visited arrested addicts on a daily basis and provided medical help if required. If severe withdrawal symptoms were present, decreasing doses of methadone were prescribed52. Soon it became clear that many drug users were not reached by the existing programs. Therefore, much emphasis was put on contacting addicts. In that same year, a program was started to visit addicts in general hospitals25. Two years later, in 1979, doctors of the Municipal Health Service were available for consultation in a building squatted by mainly Surinamese drug users, and a mobile methadone clinic for drug users of Surinamese origin was initiated, the "methadone by bus" project26 , 5 3. The methadone program also organized, in cooperation with the Sexually Transmitted Diseases clinic, an evening consultation for addicted prostitutes, at which methadone and medical care was provided. Both projects were defined as "low threshold", as their first goal was to get in touch with as many drug users as possible, in order to collect medical and social information, and to give medical care if necessary. The rationale of the harm reduction approach" can be described as: "If it is not possible to cure drug users, one should at least try to minimize the harm that is being done both to them and the wider social environment" (p. 154). In addition to the low threshold methadone program for Surinamese drug users and for addicted prostitutes, more and more general practitioners started to prescribe methadone to addicts in general. Around 1980, 80% of the methadone in Amsterdam was prescribed by general practitioners, and the number of foreign addicts, especially German, rose. A lively black market in methadone developed: the price decreased from approximately Dfl. 5,- per pill to Dfl. 1,- in 1980 51. To put a stop to this undesired development, in 1981 a Central Methadone Registration was started. In that same year, the low threshold methadone program was made accessible to all drug users residing in Amsterdam53.
1.4.1 The "low threshold" methadone program
In 1981, the low threshold methadone program put in operation two mobile methadone buses, which visited six locations daily, and four out-patient methadone clinics. Nonresidents were prescribed methadone only when it was medically indicated or when it enabled the user to return to the city or country of origin. The idea was to contact drug users through the buses. For bus clients, illicit use was permitted; the aim was to regulate their addiction and to give them medical care. Because these drug users were in contact with the care system, it was expected that those who wanted to quit their habit could relatively easily be directed to middle or high threshold programs. In the middle threshold program (the out-patient methadone clinics), illicit use was not permitted. Bi-weekly urine samples were taken and counselling was available. High threshold programs consisted of drug-free treatment. "Regulated" drug users who did not want to quit their habit were referred to their general practitioner for methadone prescriptions. In 1987, general practitioners were the main methadone prescribers for approximately 30% of all drug users on methadone in Amsterdam 54. As Buning et al. 53 describe, the "graduation model" worked only for drug users who were genuinely motivated to quit their habit, and a considerable number of drug users showed no motivation to change at all. Furthermore, drug users started to move back and forth between the low and middle threshold programs, and this was not related to a motivation to quit drug use. On the buses, drug users had to attend seven days a week to drink their liquid methadone: there were no "take away" dosages. At the out-patient methadone clinics, clients could get methadone pills for the weekend and sometimes even for longer periods. Thus, it was more attractive to attend the "middle threshold" program, and a clever drug user could remain in it some time without getting caught using illicitly and being sent back to the bus. Also, illicit use by drug users attending the out-patient methadone clinics was often condoned when these drug users were showing their good intentions by cooperating with counselling or by improving their social situation. Thus, the division low versus middle threshold gradually lost its significance. Therefore, when using the term "low threshold" methadone program hereafter, both the methadone buses and the outpatient methadone clinics are meant. Some authors have argued that a low threshold methadone program may contribute to HIV prevention 55- 56, partly through the opportunity to provide health education to a large number of drug users, partly through syringe exchange facilities for participants and partly through the stabilizing effect of methadone on heroin addiction. Moreover, methadone itself is expected to help drug users to stop or reduce injecting28.
1.4.2 The needle and syringe exchange program
In the Netherlands, the possession of needles and syringes has never been illegal. In Amsterdam, needles and syringes could traditionally be obtained at pharmacies and certain shops, and this has not changed since the AIDS epidemic57-58. A needle and syringe exchange program was initiated in 1984 by the Amsterdam drug users organization, the "Junkiebond". Its initial aim was to prevent the spread of Hepatitis B. In 1985, 100.000 2cc needles and syringes were handed out50, and this number has gradually risen to approximately one million, both in 1990 and in 1991 (A.D. Verster, Municipal Health Service, personal communication). Thus, since 1984, the (free) availability of 2 cc needles and syringes has strongly increased. Participation in the program, which in 1991 operates in approximately 15 locations, does not require identification or registration. For this reason, no information is available on the number of participants or on their demographic characteristics. Some locations exchange a maximum of 30 or 100 needles and syringes at a time. In principle, needles and syringes are exchanged on a one-for-one basis, which has as its purpose the removing of used equipment from circulation. This is important from a public health point of view, as it diminishes the chance of needlestick accidents among the general public. In fact, the exchange percentage in 1991 was estimated at 86% (A.D. Verster, personal communication), which means that for each 100 new needles and syringes 86 used ones came back. It should be clear that even participants who obtain all their new needles and syringes at the program and who bring all used equipment back can engage in risky injecting behavior: giving away used needles and syringes to others, or, when they have run out of new needles and syringes, and none of their own are available, using a needle and syringe which has already been used by somebody else.
1.5 Severity and type of drug use
With AIDS, a new vocabulary came into use, consisting of relatively neutral terms like "drug user", "intravenous drug user" (IVDU) and "injecting drug user" (IDU), as compared to earlier terms like drug misuser, drug abuser and addict. These earlier terms proceed from a vast body of research, concerning different types and characteristics of (illicit) drug use. After exposure to a drug, initial experimentation can occur, and tolerance may develop, which means that repeated administration of a certain amount of a drug fails to provide the same effect as the initial dose'. Physical dependence is characterized by a predictable pattern of physiological responses (the abstinence syndrome or withdrawal ill ness) which appears when regular administration of a drug is discontinued, while psy chological dependence indicates the need to avoid aversive subjective effects associated with discontinuance of the use of a drug'. Drug dependence can be defined" as the continued use of a drug (in the absence of a medical indication), despite adverse social and medical consequences, while behaving as if the effect of the drug is needed for continued well-being. Symptoms of drug dependence include, but are not limited to, tolerance and withdrawal illness. The intensity of dependence may vary from a mild desire to a compulsion to use. In relation to the use of substances, like cocaine, which are not associated with physiological signs of withdrawal, substance abuse can be defined as: "a maladaptive pattern of substance use indicated by continued use despite knowledge of having a persistent or recurrent social, occupational, psychological, or physical problem that is caused or exacerbated by use of the substance or recurrent use in situations in which use is physically hazardous °59. Addiction denotes the compulsive end of the continuum of dependency or substance abuse. Alexander 60 defines it as "an overwhelming involvement with drugs and/ or other activities that are harmful to the person involved and to society". This definition purports to rule out casual, recreational and regular use, everyday dependencies and "positive addictions", signifying only serious, self-destructive involvement, either with drugs or with activities like gambling. It is important to realize that physical dependence should not be equated with drug dependence, substance abuse or addiction. Tolerance and withdrawal symptoms may be present without drug dependence (for example in hospital patients receiving opioids), and drug dependence or addiction can occur without physical depend ence1 9 .5 9.
An important issue is the continuity of drug use. Sporadic use of cocaine is well known, as the use of cocaine does not cause physical dependence. Heroin use, on the other hand, is often pictured as continuous (daily) use over a period of years. This is contradicted, for example, by findings of Robertson et al. 61, among heroin users not in treatment, which indicate the presence of periods of spontaneous abstinence of heroin use (and relapse), and the existence of episodes of dependent and nondependent use. However, study subjects had a relatively short duration of use (3.6 years). Studies on the natural history of intravenous drug use show tremendous variability in patterns of use, both intra- and interindividual 6 2.
Dutch opiate users are often polysubstance dependent, i.e., they use at least three categories of psychoactive substances, while no single substance predominates59. Substances used next to heroin include cocaine, amphetamines (mainly in the 1970s), tranquilizers (especially benzodiazepines), sleeping pills, alcohol and cannabis'
The smoking of cocaine base developed in the U.S. in the 1970s 65, and was first reported in the Netherlands in 1981 66. For smoking cocaine, the cocaine hydrochloride acid is converted back into a base (in the U.S. often indicated as "crack") by processing it with sodium bicarbonate (=baking soda) or aqueous ammonia. In the Netherlands, the cocaine base is mainly processed by users themselves^. Around 1981, the cocaine base was often smoked in a water pipe filled with rum66, but this method appears to be rare among Amsterdam addicts nowadays. Both heroin and cocaine base are smoked (either together or apart) by heating a tin foil from underneath and inhaling the vapor of the heroin and/or the cocaine base. This mode of smoking heroin and/or cocaine ("chasing the dragon") is indicated in Dutch as "chinezen". Sniffing of heroin is rare, while sniffing of cocaine occurs mainly among non-deviant cocaine users67.
With regard to injecting, it is estimated that about 40% of the Dutch drug users in Amsterdam have injected drugs recently, as compared to 5% among drug users from Surinam, the Netherlands Antilles, Morocco, Turkey and 70% among other drug users of foreign origin (mainly German and South-European) 50. Most injecting in Amsterdam appears to be injecting into the veins (i.e. intravenous use). This method of drug use has the quickest and strongest effect compared to other methods of use. As injecting can be seen as an adaptation to the conditions of decreased drug availability68, and as drug-use behaviors are not consistent over time 61. 62, the prevalence of a history of injecting is higher than the prevalence of current injecting. Thus, among drug users entering an epidemiological study of HIV infection in Amsterdam 69, 81 % report a history of injecting, while 63% report injecting in the preceding six months.
1.6 Coping, psychopathology and drug use
A wide variety of theories exist which try to explain drug use, drug dependence, drug abuse or addiction at a physiological, psychological, social and societal level'°. The present research focuses on the psychological aspects of drug use. Wills & Shiffman71 provide a conceptual framework which relates drug use to coping theory. The model is mainly based on studies of smoking and alcohol use. However, studies of opiate addiction also suggest that opiate use may serve a coping or adaptive function by fulfilling psychological needs 6 0 ,72, 73.
Given a certain amount of stress, individuals will employ different coping skills, dependent on the perceived severity and changeability of the stressor, the difficulty of the coping response, the variety and quality of a person's coping repertoire and the available social network resources. A central postulate within Wills & Shiffman's framework is that substances may be used as a coping mechanism for two reasons: to reduce negative affect, when a person is anxious or overaroused, or to increase positive affect, when a person feels fatigued, depressed or underaroused.
In relation to substance use, Wills & Shiffman distinguish two broad categories of coping skills: a) temptation-coping skills and b) stresscoping skills. Temptation-coping skills, like self-control and social skills, are relevant for dealing with situations in which substance use, or temptation for substance use, is present. Stress-coping skills are necessary to cope with major life events and with enduring life strains. Coping with these kind of stressors can be defined as specific cognitive or behavioral activities undertaken by the individual to maintain a balance between environmental and internal demands and resources currently available to meet those demands74. Two functions of coping, frequently occurring simultaneously, can be distinguished: the alteration of the ongoing person-environment relationship (instrumental or problem oriented coping) and the control of stressful emotions (emotion regulation). However, coping responses differ with regard to effectiveness. Some ways of coping may lead to gradual adaptation of self and/or one's environment and eventual resolution of life changes, whereas others may lead to unresolved grief, depression and social alienation or to hostility, conflicts and characterological disturbances. Wills & Shiffman (p. 8) predict that substance use as a way to cope with stress will in general have non-productive consequences: "Although substances may provide short-term changes in affect, a reliance on this approach for dealing with environmental stressors reduces the probability of learning and practicing alternative coping responses; in the long run this would tend to reduce social competence and increase overall stress levels. Additionally, drug-abusing behavior may gradually alienate potential social supporters, leading to increasing social alienation and increased dependency on the use of substances to cope".
This view of drug use, as a gradually failing attempt to cope with stressors, coincides with a different theoretical line of approach: the relationship of psychopathology to drug use. Rates of current psychiatric disorders (apart from substance use diagnoses) have been found to be high among drug add icts75 .76. The causal relation can go both ways: among persons starting with illicit drug use, there are relatively many with psychological problems or psychopathology, while on the other hand, illicit drug use may cause or aggravate psychological problems or psychopathology. Hard drug use, psychopathology, ineffective coping and social isolation seem closely interrelated at many levels. However, it is important to realize that these interrelations occur in a society in which use of hard drugs is illegal; they may be quite different in a society in which hard drug use is not considered deviant. Furthermore, most of the studies cited below concern drug users in treatment, or entering treatment, and cannot be generalized to drug users in general.
Frequently diagnosed psychiatric disorders among opiate addicts are major depressive disorder, alcoholism and antisocial personality 76, 77. Drug dependence has been described as the result of attempts at self-medication, in order to cope with psychological or social problems78. Psychopathology among opiate addicts appears to be associated with im paired social functioning. Depressed addicts had only mild to moderate depressive symp toms, but had more severe medical and psychosocial problems than non-depressed addicts7 5 . These associated psychosocial impairments suggest a failure to cope with everyday problems. Research on coping and affective disorders in general7 9 suggests that problem oriented coping (i.e. problem analysis, information seeking and problem solving behavior) is associated with less depression, while avoidance, which appears to be an ineffective coping strategy, is associated with more depression. Research among addicts entering a clinical detoxification center found a correlation between social functioning (i.e., conflicts with family and others) and psychiatric problems°. However, the authors note that this finding may be due to the fact that the sample consisted of treatment-seeking addicts. Follow-up interviews with opiate addicts, 2.5 years after treatment, found the most prevalent psychiatric disorders related to poor current functioning and poor psychosocial adjustment at follow-ups'. Van Limbeek82 found lower levels of social adequacy among addicts with depressive symptoms. Drug addicts with severe psychiatric problems showed virtually no improvement in drug treatment8 3. Psychopathology among substance abusers was found related to a small social network; a large network was related to adequate general coping skills". Abstinence of heroin appears to be facilitated by close social ties 85. Findings by Kranzler & Liebowitz86 suggest that anxiety and/or depressive symptoms may contribute to relapsing into drug or alcohol use once a period of abstinence has been achieved. This is confirmed by Rhoads" for female drug users: the occurrence of stressful events combined with low perceived availability of support appears to lead to depression and anxiety. In the absence of social support, female addicts appear to "self-medicate" with drugs in order to cope with stressors.
To summarize, drug users seeking treatment have high levels of psychopathology. Drug users with psychopathology, when compared to other drug users, appear to function less well socially, to have less social support, to have a smaller social network and to have less temptation-coping skills.
1.7 Protection motivation
Apart from knowledge about the threat and the availability of material resources for safe injecting, behavioral change among IDUs at an individual level requires the motivation to protect oneself against HIV. In view of the high HIV prevalence among IDUs in many areas of the world, the relatively easy trans mission of HIV through needle sharing and the fatal course of HIV infection, it can be assumed that HIV represents a severe stressor for health-conscious IDUs. Even if HIV is not experienced as a major stressor, health-con scious IDUs will have to cope with the temptation to inject in the absence of a "safe" needle and syringe (either a self-used one or a new one) or in the absence of bleach or boiling facilities. Temptation coping skills are then of relevance.
Several related models have focussed on preventive health behavior in general: the health belief model8 8,89, the dual process model90 ,91 and protection motivation theory92 -94. Protection motivation theory assumes two simultaneous and independent processes: an appraisal of the magnitude of the threat and an appraisal of possible ways of coping.The figure shows how information (both environmental, like verbal persuasion, and intrapersonal, like prior experience) about a health risk evokes two cognitive processes. According to this theory, a maladaptive response would be facilitated by the rewards of this behavior and inhibited by the perceived vulnerability to the threat and its perceived seriousness. Anxiety, according to the model, has no direct relation with behavioral intention or behavior. Anxiety is mediated by perceived vulnerability, which can be seen as a cognitive representation of anxiety. An adaptive response is, according to the model, facilitated by the conviction that this behavior reduces the health risk (response efficacy) and, secondly, by the conviction that one is able to perform this behavior consistently (self-efficacy). Costs connected to the adaptive behavior are seen as inhibitive of the adaptive response. The figure shows that facilitating and inhibiting factors together lead to protection motivation; the latter is expected to determine adaptive or maladaptive behavior. Although factors like social support and network size are not explicitly included in protection motivation theory, these factors are expected to affect threat and/or coping-appraisal indirectly. Assuming that drug users are concerned about their health, the question is whether they will be able to cope effectively with the HIV threat. The relations between drug use, psychopathology, ineffective coping and social isolation, discussed in section 1.6, suggest that effective coping may be rare. Furthermore, among active drug users, the threat appraisal process may be distorted, due to the sedative effect of opiates and tranquilizers or to the euphoric effect of psychostimulants.
So far, this section has discussed the motivation to protect oneself against HIV, as a potential determinant of safe behavior. For infected IDUs, who are aware of their serostatus, a reason for safe behavior may also be self-protection motivation: the belief that AIDS can be postponed by avoiding reor other infections. However, no evidence for this belief has been found. Another reason for safe behavior may be the desire to protect others from HIV: other-protection motivation.
The main focus of the present research is needle sharing among injecting drug users. Needle sharing includes two different behaviors: borrowing and lending. Borrowing is defined as injecting with needles and/ or syringes which have been used by somebody else, lending as letting someone else inject with a needle and/or syringe which a person has already used him- or herself. The actual HIV risk associated with these two behaviors depends of course on one's serostatus.
In current HIV-related terminology, the term "injecting drug user" indicates persons with a history of injecting illicit drugs or currently injecting drugs, regardless of the presence of dependence, abuse or addiction. According to the above given definitions, almost all injecting drug users participating in the present research are heroin addicts (with a history of injecting), many of whom are polysubstance dependent. Considerable individual differences exist with regard to the frequency of use, the duration of use and the number and kind of drugs used in addition to heroin.
The first study is described in chapter 2. In this study, in 1987, currently injecting drug users were interviewed at different locations, in order to study the impact of the exchange program on injecting risk behavior. Participants were asked to participate in a follow-up interview. Demographic and drug use characteristics of IDUs who used the exchange program more than 90% of the time ("exchangers") were compared to IDUs who never or irregularly used the exchange program ("non-exchangers").
The other six studies (chapter 3-8) were conducted as part of an epidemiological study of HIV infection among drug users in Amsterdam. The aims of this ongoing cohortstudy, which started in 1985, are to study a) the prevalence, incidence and natural history of HIV infection in drug users, b) risk factors for existing and new infections, c) behavioral changes and d) determinants of HIV risk behavior. The cohort-study involves voluntary, confidential HIV-antibody testing and counselling. Participants enter mainly through "low threshold" methadone programs or through the separate Sexually Transmitted Diseases clinic for addicted prostitutes. After informed consent is obtained, specially trained nurses take a blood sample and interview participants using a standard questionnaire. Since 1989, additional questionnaires on specific psychosocial or behavioral topics have been added to the standard questionnaire over regular periods of time, and at each visit, a medical examination is done. From 1985 until 31st March 1992, 951 drug users participated at least once, of whom 582 participated in the follow-up study. HIV seroprevalence among the 951 participants was 26%. The seroprevalence was 4% among 182 drug users who had never injected and 31% among the 769 drug users with a history of injecting. The subgroup of 591 drug users who had injected in the six months preceding intake had a prevalence of 34%. As the six studies described in chapter 3-8 were conducted within the larger epidemiological study, the serostatus of all subjects was known and many of the subjects were - at follow-up visits - aware of their serostatus. For this reason, it was possible to study behavioral determinants while differentiating between HIV-negative and HIV-positive drug users, and to take knowledge of serostatus into account.
The study described in chapter 3 examines changes over time (1985-1989) in drug use among 386 IDUs, both with regard to the current route of intake (injecting versus smoking/inhaling) as to the kinds of drugs used (heroin, cocaine, tranquilizers etc.)
In the same sample, evidence was sought for the assumption that "low threshold" methadone programs have a function in controlling the spread of HIV among drug users. For this purpose, long term regular participants in these programs were compared to short term and/or irregular participants (see chapter 4).
The next three studies focus on determinants of needle sharing. Chapter 5 is directed at psychopathology and stress and will examine the hypothesis that drug users with coexisting psychopathology or stress have higher levels of injecting risk behavior than other drug users. Chapter 6 focuses on demographic, social and drug use characteristics of HIV-negative injectors who inject in a risky manner. Chapter 7 investigates whether it is meaningful to study "protection motivation" in the prediction of injecting risk behavior among HIV-negative IDUs aware of their serostatus. The studies described in chapter 6 and 7 also look at the impact of the exchange program on needle sharing.
While these last two studies concern HIVnegative injectors, at risk of acquiring HIVinfection, chapter 8 describes a study of risk behavior, beliefs, attitudes and intentions of HIV-seropositive IDUs, aware of their serostatus.
In the general discussion (chapter 9), the findings of these studies are related to other empirical findings and to the conceptual framework of coping, psychopathology and protection motivation, presented in this introduction.
1. Epen van JH. De drugs van de wereld de wereld van de drugs. Alphen aan den Rijn/Brussel, Samson Stafleu, 1988.
2. Platt JJ & Labate C. Heroin addiction, Theory, research and treatment. New York, John Wiley & Sons, 1976.
3. Musto DF. Opium, cocaine and marijuana in American history. Sci Am 1991;265: 20-7.
4. Musto DF. The American disease: Origins of narcotic controls. New Haven, Yale University Press, 1987.
5. Lewis R. European markets in cocaine. Contemporary Crises 1989;13:35-52.
6. Belenko S. Alcohol abuse by heroin addicts: Review of research findings and issues. Inter J Addict 1979;14:965-75.
7. Black JL, Dolan MP, Penk WE, Robinowitz R and Deford HA. The effect of increased cocaine use on drug treatment. Addict Behav 1987;12289-92.
8. Stitzer ML, Griffiths RR, McLellan AT, Grabowski J and Hawthorne JW. Diazepam use among methadone maintenance patients: Patterns and dosages. Drug Alcohol Depend 1981;8:189-99.
9. Perera KMH, Tulley M, Jenner FA. The use of benzodiazepines among drug addicts. Br J Addict 1987;82:511-15.
10. Korf DJ, Hoogenhout HPH. Slaap- en kalmeringsmiddelen op de Amsterdamse drugsmarkt. Pharmaceutisch Weekblad 1989;124:95-100.
11. Nurco DN, Kinlock TW, Hanlon TE and Ball JC. Nonnarcotic drug use over an addiction career - A study of heroin addicts in Baltimore and New York City. Comp Psychiatry 1988;29:450-9.
12. Centers for Disease Control: Kaposi's sarcoma and Pneumocystis pneumonia among homosexual men - New York City and California, MMWR 1981;30: 305-8.
13. Jaffe HW, Bregman DJ, Selik RM. Acquired immune deficiency syndrome in the United States: The first 1,000 cases. J Infect Dis 1983;148:339-45.
14.Gallo RC. The AIDS virus. Sci Am 1987;256:39-51.
15. Anonymous. AIDS surveillance in Europe, update at 31st december 1991. Quarterly report no. 32, Paris, WHO/EC Collaborating Centre on AIDS, 1991.
16. Des Jarlais DC, Friedman SR, Hopkins W. Risk reduction for the Acquired Immunodeficiency Syndrome among intravenous drug users. Ann Intern Med 1985;103:755-9.
17. Moss AR. AIDS and intravenous drug use: the real heterosexual epidemic. Br Med J 1987;294:389-90.
18. Selwyn PA. Injection drug use, mortality and the AIDS epidemic. Am J Public Health 1991;81:1247-9.
19. Jaffe JH. Drug addiction and drug abuse, pp. 522-573 in: Goodman Gilman A, Rall TW, Nies AS, Taylor P (Eds.) Goodman and Gilman's The pharmacological basis of therapeutics. New York, Pergamon Press, 1990.
20. Stimson GV. Revising policy and practice: new ideas about the drugs problem, pp. 121-31 in: J Strang & GV Stimson (Eds.). AIDS and drug misuse, the challenge for policy and practice in the 1990s. London, Routledge, 1990.
21. Mosher JF & Yanagisako KL. Public health, not social warfare: A public health approach to illegal drug policy. J Public Health Policy 1991;xx:278-323.
22. Brettle RP. HIV and harm reduction for injection drug users. AIDS 1991;5:12536.
23. Broadhead RS. Social constructions of bleach in combating AIDS among injection drug users. J Drug Issues 1991;21(4):713-37.
24. Anderson W. The New York needle trial: the politics of public health in the age of AIDS. Am J Public Health 1991;81:1506-17.
25. Berridge V. AIDS, drugs and history. Br J Addict 1992;87:363-70.
26. Brussel GHA van. Openbare gezondheidszorg en drugproblematiek. T Soc Gezondheidszorg 1986;64(25):817-9.
27. Engelsman EL. Dutch policy on the management of drug related problems. Br J Addict 1989;84:211-8.
28. Buning EC. The role of harm-reduction programmes in curbing the spread of HIV by drug injectors, pp. 153-61 in: J Strang & GV Stimson (Eds.) AIDS and drug misuse, The challenge for policy and practice in the 1990s. London, Routledge, 1990.
29. Friedland GH, Harris C, Butkus-Small C. Shine D, Moll B, Darrow W, Klein RS. Intravenous drug abusers and the Acquired Immunodeficiency Syndrome (AIDS). Arch Intern Med 1985;145: 1413-7.
30. Des Jarlais DC, Wish E, Friedman SR, Stoneburner R, Yancovitz SR, Mildvan D, EI-Sadr W, Brady E, Cuadrado M. Intravenous drug use and the heterosexual transmission of the Human Immunodeficiency Virus, Current trends in New York City. NY State J Med 1987;87:283-6.
31. Chaisson RE, Moss AR, Onishi R, Osmond D, Carlson JR. Human Immunodeficiency Virus infection in heterosexual intravenous drug users in San Francisco. Am 1 Public Health 1987;77:169-72.
32. Hoek van den JAR, Coutinho RA, Haastrecht van HJA, Zadelhoff van AW, Goudsmit J. Prevalence and risk factors of HIV infections among drug users and drug using prostitutes in Amsterdam. AIDS 1988;2:55-60.
33. Schoenbaum EE, Hartel D, Selwyn PA, Klein RS, Davenny K, Rogers M, Feiner C, Friedland G. Risk factors for Human Immunodeficiency Virus infection in intravenous drug users. N Engl J Med 1989;321:8749.
34. Battjes RJ, Pickens RW, Amsel Z, Brown LS. Heterosexual transmission of Human Immunodeficiency Virus among intravenous drug users. J Infect Dis 1990;162:1007-11.
35. Nelson KE, Vlahov D, Cohn S, Odunmbaku M, Lindsay A, Anthony JC, Hook EW. Sexually transmitted diseases in a population of intravenous drug users: association with seropositivity to the Human Immunodeficiency Virus (HIV). J Infect Dis 1991;164:457-63.
36. Ameijden EJC van, Hoek JAR van den, Haastrecht HJA van, Coutinho RA. The harm reduction approach and risk factors for HIV seroconversion in injecting drug users, Amsterdam. Am J Epidemiol July 1992;in press.
37. Grund JPC, Kaplan CD, Adriaans NFP, Blanken P. Drug sharing and HIV transmission risks: The practice of frontloading in the Dutch injecting drug user population. J Psychoactive Drugs 1991;23:1-10.
38. Samuels JF, Vlahov D Anthony JC, Solomon L, Celentano DD. The practice of 'frontloading' among intravenous drug users: association with HIV-antibody. AIDS 1991;5:343.
39. Kozel N, Adams EH. Epidemiology of drug abuse: An overview. Science 1986;234:970-4.
40. Kozel N, Adams EH. (eds.) Cocaine use in America: Epidemiologic and clinical perspectives. Natl Inst Drug Abuse Res Monogr Ser, no. 61.
41. Chiasson MA, Stoneburner RL, Hildebrandt DS, Ewing WE, Telzak EE, Jaffe HW. Heterosexual transmission of HIV-1 associated with the use of smokable freebase cocaine (crack). AIDS 1991;5:1121-6.
42. Sterk C. Cocaine and HIV seropositivity. The Lancet 1988:1052-3.
43. Chaisson RE, Bacchetti P, Osmond D, Brodie B, Sande MA, Moss AR. Cocaine use and HIV infection in intravenous drug users in San Francisco. JAMA 1989;261:561-5.
44. Weiss SH. Links between cocaine and retroviral infection. JAMA 1989;261: 607-8.
45. Wiebel W, Chene D, Johnson W. Adoption of bleach disinfection techniques among street intravenous drug users in Chicago. Presented at the VI International Conference on AIDS, San Francisco, June 1990.
46. Neaigus A, Sufian M, Friedman SR, Goldsmith DS, Stepherson B, Mota P, Pascal J, Des Jarlais DC. Effects of outreach intervention on risk reduction among intravenous drug users. AIDS education and prevention 1990;2:253-71.
47. Chaisson RE, Osmond D, Moss AR, Feldman HW, Biernacki P. HIV; bleach and needle sharing. Lancet 1987;1430.
48. Watters JK, Cheng Y, Segal M, Lorvick J, Case P, Carlson J. Epidemiology and prevention of HIV in intravenous drug users in San Francisco, 1986-1989. Presented at the VI International Conference on AIDS, San Francisco, June 1990.
49. Stimson GV. Syringe-exchange programmes for injecting drug users, AIDS 1989;3:253-60.
50. Buning EC. De GG&GD en het drugprobleem in cijfers IV. Amsterdam, GG&GD, 1990.
51. Geerlings PJ. Methadonverstrekking: Hoe en waarom. Pharmaceutisch Weekblad 1982;117:507-13.
52. Brussel GHA van, Roij-Motshagen AJ de. Medische hulpverlening aan verslaafden op de politiebureaus in Amsterdam 1977-1979. MC 1980;35:1476-8.
53. Buning EC, Brussel GHA van, Santen G van. The 'methadone by bus' project in Amsterdam. Br J Addict 1990;85: 1247-50.
54. Plomp HN & Reijneveld SA. Methadonverstrekking aan drugge-bruikers in Amsterdam, Analyse van gegevens van de Central Methadon Registratie over de jaren 1984 tot en met 1987. Amsterdam, VU uitgeverij 1991.
55. Buning EC, Coutinho RA, Brussel GHA van, Santen G van, Zadelhoff AW. Preventing AIDS in drug addicts in Amsterdam. Lancet 1986;1:1435. Letter to the editor.
56. Buning EC. AIDS related interventions among drug users in the Netherlands. Presented at the European Symposium on AIDS and Drug Abuse, Stockholm, September, 1989.
57. Hartgers C, Buning EC, Santen GW van, Verster Ad, Coutinho RA. Intraveneus druggebruik en het spuitomruilprogramma in Amsterdam. T Sociale Gezondheidsz 1988;66:207-10.
58. Santen GW van. Spuitverkoop aan druggebruikers in Amsterdamse apotheken. Amsterdam, GG&GD, 1990.
59. American Psychiatric Association. Diagnostic and statistical manual of mental disorders, Third edition, Revised. Washington, D.C, American Psychiatric Association, 1987.
60. Alexander BK. The empirical and theoretical bases for an adaptive model of addiction. J Drug Issues 1990;20:37-65.
61. Robertson JR, Bucknall ABV, Skidmore CA, Roberts JJK, Smith JH.Remission and relapse in heroin users and implications for management: Treatment control or risk reduction. Intern 1 Addict 1989;24:229-47.
62. Samuels JF, Vlahov D, Anthony JC, Chaisson RE. Measurement of HIV risk behaviors among intravenous drug users. Br J Addict 1992;87:41.
63. Brussel GHA van, Zadelhoff AW van, Sluys TA. Polydruggebruik - een nieuw verschijnsel? T Alc Drugs 1987;13:198203.
64. Grund JPC, Adriaans NFP, Kaplan CD. Changing cocaine smoking rituals in the Dutch heroin addict population. Br J Addict 1991;86:439-48.
65. Siegel RK. Cocaine smoking. J Psychactive drugs 1982;14:271-359.
66. Boetje J. Free-basen: Een nieuwe methode van cocainegebruik. Ned Tijdschr Geneesk 1984;128:2237-8.
67. Cohen P. Cocaine use in Amsterdam in non-deviant subcultures. Amsterdam, Universiteit van Amsterdam, Instituut voor Sociale Geografie, 1989.
68. Grund JPC, Kaplan CD, Adriaans NFP. Needle sharing in the Netherlands: An ethnographic analysis. Am J Public Health 1991;81:1602-7.
69. Hoek van den JAR, Coutinho RA, Haastrecht van HJA, Zadelhoff van AW, Goudsmit J. Prevalence and risk factors of HIV infections among drug users and drug using prostitutes in Amsterdam. AIDS 1988;2:55-60.
70. Lettieri DJ, Sayers M, Wallenstein Pearson H. Theories on drug abuse, selected contemporary perspectives. Nat Inst drug Abuse Res Monogr Ser no. 30, 1980.
71. Wills TA, Shiffman S. Coping and substance abuse: a conceptual framework, pp. 3-23 in: S. Shiffman & T.A. Wills (eds.), Coping and substance abuse. Orlando, Academic Press, 1985.
72. Alexander BK, Hadaway PF. Opiate addiction: The case for an adaptive orientation. Psych Bull 1982;92:367-81.
73. Alexander BK. The disease and adaptive models of addiction: A framework analysis. J Drug Issues 1987;17:47-66.
74. Coyne JC, Lazarus RS. Cognitive style, stress perception and coping, pp. 144158 in: I.L. Kutash & L.B. Schlesinger (eds.) Handbook on stress and anxiety: Contemporary knowledge, theory and treatment. San Francisco, Jossey-Bass, 1980.
75. Kosten TR, Rounsaville BJ. Psychopathology in opioid addicts. Psychiatric Clin North America 1986;9:515-32.
76. Limbeek J van, Wouters L, Kaplan CD, Geerlings PJ, Alem V van. Prevalence of psychopathology in drug-addicted Dutch. J Substance Abuse Treatment 1992;9:43-52.
77. Rounsaville BJ, Weissman MM, Kleber H, Wilber C. Heterogenity of psychiatric diagnosis in treated opiate addicts. Arch Gen Psychiatry 1982;39:161-6.
78. Khantzian EJ. The self-medication hypothesis of addictive disorders: Focus on heroin and cocaine dependence. Am J Psychiatry 1985;142:1259-64.
79. Jaspers JPC, Asma MJO van, Bosch RJ van den. Coping en psychopathologie: Een overzicht van theorie en onderzoek. T Psychiatrie 1989;31:587-99.
80. Hendriks VM, Kaplan CD, Limbeek J van, Geerlings P. The addiction severity index: Reliability and validity in a Dutch addict population. J Substance Abuse Treatment 1989;6:133-41.
81. Rounsaville BJ, Kosten TR, Weissman MM, Kleber HD. Prognostic significance of psychopathology in treated opiate addicts. Arch Gen Psychiatry 1986;43: 739-45.
82. Limbeek J van, Schalken HFA, Geerlings PJ, Wouters L, Groot, PA de, Sijlbing G, Beelen W. Het gebruik van het Diagnostisch Interview Schema (DIS) bij het vaststellen van psychopathologie bij alcohol- en drugsverslaafden. T Psychiatrie 1986;28:459-74.
83. McLellan AT, Luborsky L, Woody GE, O'Brien CP, Druley KA. Predicting response to alcohol and drug abuse treatments. Arch Gen Psychiatry 1983;40: 620-5.
84. Westermeyer J, Neider J. Social Networks and psychopathology among substance abusers. Am J Psychiatry 1988;145: 1265-9.
85. Swierstra K. Heroineverslaving: levenslang of gaat het vanzelf over? T Alc Drugs 1987;13:78-92.
86. Kranzler HR, Liebowitz NR. Anxiety and depression in substance abuse: Clinical implications. Med Clin North America 1988;72:867-85.
87. Rhoads DL. A longitudinal study of life stress and social support among drug abusers. Intern J Addict 1983;18: 195-222.
88. Becker MH. The health belief model and personal health behavior. ThoroFare, CBS, 1974.
89. Janz NK, Becker MH. The Health Belief Model: A decade later. Health Education Quarterly 1984;11:1-47.
90. Leventhal H, Meyer D, Nerenz D. The common sense representation of illness danger, pp. 7-30 in: S. Rachman (Ed.) Contributions to medical psychology (vol. 2), New York, Pergamon Press, 1980.
91. Leventhal H, Safer MA, Panagis DM. The impact on the self-regulation of health beliefs, decisions and behavior. Health Education Quarterly 1983;10:3-31.
92. Rogers RW. A protection motivation theory of fear appeals and attitude change. J Psychology 1975;91:93-114.
93. Rogers W. Cognitive and psychological processes in fear appeals and attitude change: A revised theory of protectionmotivation, pp. 153-176 in: 1.T. Cacioppo & R. E. Petty (eds.), Social psychophysiology, a sourcebook. New York/London, The Guilford Press, 1983.
94. Rippetoe PA, Rogers RW. Effects of components of protection-motivation theory on adaptive and maladaptive coping with a health threat. J Personality and Social Psychology 1987;52:596-604.