A rationale for identification of cases of drug abuse


The epidemiological rationale for identification of cases of drug abuse
The finding of dependence-producing drugs
The location of case-finding activity at institutions
The location of case-finding activity at drug distribution sites
Training case-finding personnel
Participant observation techniques
The use of drugs abusers as case--finding agents
The screening of high-risk populations
Identification in interviews and questionnaire surveys
Special methodological and ethical issues
Safety of field staff and subjects and the need for confidentiality
Incentives for subject participation
Ethical considerations
Case-finding versus case-definition
Implication for planners
Case-finding-how intensive and for what purpose?
General conclusions


Pages: 1 to 15
Creation Date: 1982/01/01

A rationale for identification of cases of drug abuse

P. H. HUGHES Psychiatry Department, University of Chicago, Chicago, United States America
G. K. JARVIS Department of Sociology, University of Alberta, Edmonton, Canada
U. KHANT Rangoon Psychiatric Hospital, Rangoon, Burma
M. E. MEDINA-MORA Centro Mexicano de Estudios en Salud Mental, Mexico City, Mexico
V. NAVARATNAM Universiti Sains Malaysia, Minden, Penang, Malaysia .
V. POSHYACHINDA Health Research Institute, Chulalongkorn University, Bangkok, Thailand
K. A. WADUD Pakistan Narcotics Control Board, Islamabad, Pakistan


To overcome the blanket of secrecy developed by many drug-abusing populations special strategies have been used to generate more reliable and valid data on the extent and nature of the problem. The epidemiological rationale for eight strategies to identify cases of drug abuse are reviewed along with their limitations and examples of their application. The choice of strategies in any given setting will depend upon the drug-use patterns and legal framework of the particular society, the form of social organization developed by drug abusers and the types of contact they have with formal institutions such as law enforcement and treatment agencies.


While general population surveys (Johnston [ 1] ) can delineate the broad distribution of drug abuse in society, and reporting systems (Rootman and Hughes [ 2] ) such as case registers can identify those drug abusers in contact with police and treatment agencies, both approaches identify only the "tip of the iceberg" of the hard-core criminalized and heavy abusers of drugs. The planner accepts the findings of these two approaches with caution as he knows the efforts of criminalized drug abusers to maintain a blanket of secrecy over their activities and identity.

In a companion article (Hughes and others [ 3] ), the authors have examined the dynamics of secrecy patterns developed by drug abusers and the obstacles these create for the epidemiologist who studies them. Even when drug abusers are identified, they are often uncooperative and may not respond honestly. But the authors offer some reason for optimism in suggesting that drug abusers are not entirely hidden in the community, for they do have a number of clinical and ethnographic characteristics which can make them more "visible" to the epidemiologist.

In this article, we examine other characteristics of drug abusers which may offer an epidemiological rationale for improved case-finding 1strategies. A number of these strategies have been successfully employed in diverse parts of the world, several of which appear to be especially tailored to the unique epidemiological characteristics of drug abusing populations. The application of these strategies should increase the proportion of identified heavy drug abusers and enhance their co-operation. But their application is not straightforward as a number of ethical, financial and methodological issues are encountered in attempting to find and study individuals who wish to keep their activities secret. This article, therefore, reviews the epidemiological rationale for drug abuse case finding strategies as well as a number of issues to be encountered in their application.

The epidemiological rationale for identification of cases of drug abuse

Some health conditions are so disturbing (e.g. cholera) that the affected population immediately seeks medical attention. For such disorders, special case-finding strategies may not be required. But for conditions such as drug abuse, the individuals affected often do not seek help and therefore strategies must be developed to locate them. To do this the epidemiological characteristics of the condition are studied to find clues that point to an optimal case-finding strategy.

We have reviewed the relevant epidemiological characteristics of drug abuse and our findings are summarized in the table below. Eight general characteristics of drug abuse are listed, each of which suggests a specific strategy to identify cases of drug abuse. The first characteristic, for example, states that a necessary condition for drug abuse is the presence of a dependence-producing substance. Drug abuse, therefore, resembles some infectious disorders in which case-finding is based on the identification of the disease-producing agent. This epidemiological characteristic provides the basis for a frequently applied case-finding strategy-also listed in the table--that is to find dependence-producing drugs on a individual's person or in his or her body fluids. In similar fashion seven other epidemiological characteristics and corresponding case finding strategies are listed.

In listing only eight epidemiological characteristics, we recognize that a number of others could have been listed. These include such characteristics as (a) drugabusers fear they might be punished if their condition is known; (b)violence is associated with certain drug-use states and with criminal elements in drug trafficking; (c)drug abuse is not a monolithic condition but rather encompasses a wide range of patterns of drug use, associated behavior and effects; and (d)there are no internationally agreed operational criteria for defining individuals as drug abusers. But characteristics (a)through (d)do not appear to suggest specific case-finding strategies. We prefer to see them as special issues in identifying cases of drug abuse and they are discussed in the final section of this paper. The eight case-finding strategies will now be further examined along with examples of their practical application in the community, and their respective advantages and limitations.

1 case-finding refers to identification of cases of drug abuse.

Epidemiological rationale for finding cases of criminalized and heavy drug abusers

Epidemiological characteristics

Case-finding strategies

1. A dependence-producing drug is a necessary condition for drug abuse
Find dependence-producing drugs on an individual's person or in his or her body fluids
2. Abusers are likely to have contact with treatment and law-enforcement agencies
Locate case-finding activity at institutions in contact with drug abusers
3. Abusers must periodically contact traffickers or other distributors to maintain their drug supply
Locate case-finding activity at drug distribution
4. Clinical signs and ethnographic characteristics are associated with specific patterns of drug abuse
Train case-finding personnel to recognize common clinical and ethnographic signs
5. Abusuers often form clandestine drug subcultures similar to delinquent and criminal groups.
Use participant observation techniques developed to study deviant groups
6. Drug abusers tend to associate with other abusers to enjoy the effects of drugs
Use drugs abusers as case-finding agents
7. Heavy abusesr usually represent a small proportion of the total population but tend to concentrate in high-groups.
Screen high-risk populations
8. Drug taking is usually a conscious act
Drug abusers can identify themselves in interviews and questionnaire surveys

The finding of dependence-producing drugs

Drug abuse resembles infectious diseases in that it is caused by a disorder-producing agent and one case-finding strategy is to identify the abused drugs in the body fluids or on the abuser's person. In practice, this is possibly the most common case-finding strategy, as each year police report hundreds of thousands of abusers for possession of illicit drugs. While possession of a dependence-producing drug is not equivalent to abuse of the drug, it is considered presumptive evidence. In some settings the possession of drug-use paraphernalia is also illicit. It is common then for law enforcement agencies to report as drug abusers individuals arrested for possession of drugs or paraphernalia. The higher levels of drug trafficking are frequently managed by non-drug users, so that individuals arrested for possession of large amounts of illicit drugs are often reported as traffickers rather than drug abusers.

The widespread availability in recent years of relatively inexpensive laboratory equipment has provided law enforcement agencies with a practical too for identification of the specific types of substances being abused. Similar laboratory equipment has become available to health agencies and drug-abuse epidemiologists for the testing of body fluids, especially urine, for the presence of drugs.

The most promising of modern laboratory screening methods is the urine test. Metabolites of opiates, barbiturates, amphetamines etc., can be detected by collecting urine either in the field or in institutional settings. Thin-layer chromatography is one of the most common and relatively inexpensive methods now in use, although a variety of newer and more sophisticated methods are available such as radio immuno-assay (WHO [ 4] ).

An ambitious application of urine screening for identification of cases of drug abuse was introduced by the United States Army in the 1970s. Urine testing was mandatory for military personnel in high-risk units and unannounced spot checks were made in other areas. Drug abusers identified in this way were referred for treatment and received follow-up urine tests when they returned to their units (Ruben [ 5] ).Although many cases were identified using this method, mass urine screening is not foolproof; some drug users learn to avoid detection by taping plastic bags of "clean urine" to their legs.

Urine testing has recently been used as a key programme element in Singapore in an effort to identify and rehabilitate all opiate users in the country (McGlothlin [ 6] ). In 1977, Operation Ferret was initiated, in which all suspects at heroin distribution sites were arrested and taken for urine testing. If the urine was heroin-positive, those arrested received compulsory rehabilitation. Careful attention was given to labelling the urine sample, which was divided into two specimens and placed in locked boxes. If the suspect challenged the urine test results, the second sample was available for study.

Urine tests were recently applied in the screening of villagers in opium-growing regions of Thailand (Suwanwela and others [ 7] ). To overcome the practical problems of transporting urine in a tropical climate, the specimens were placed onto absorbent paper and were later extracted in the laboratory. This was possible because of the small amount of urine required for the radio immuno-assay method. In fact, the method was sufficiently sensitive to identify a number of false positive urines attributed to environmental contamination. For example, small traces of opium were found in the urine of non-users who had eaten rice handled by opium users who had not washed their hands. Other false positives resulted from the use of opium poppy seed and seed oil in the diet. By sitting next to an opium smoker in a poorly ventilated room, traces of the drug in the urine could also be produced. These findings were of considerable importance in case-finding studies in rural opium-producing regions, but are unlikely to be major factors in urban areas where environmental contamination is a remote possibility.

In addition to the use of urine screening as the primary case identification method, it might also be used to validate the drug-use status of individuals identified by other methods. One of the most frequent criticisms of urine testing, however, is the lack of concern in some laboratories for reliable and valid procedures. Great care must therefore be taken to monitor continuously the accuracy of urine-testing results. Additional technical information on the identification of dependence-producing drugs in body fluids can be found in a WHO review [ 4] , and the application of laboratory methods in epidemiological studies was recently examined at a WHO regional meeting [ 8] .

The location of case-finding activity at institutions

A standard procedure for establishing case registers or case-reporting systems for any disorder is to involve those institutions which are already collecting data on affected individuals. For drug abuse it is most often law enforcement, drug treatment and rehabilitation agencies. While drug abusers may have contact with other institutions, these contacts might not be for drug-related reasons, and this would require special procedures to be introduced for their identification as abusers.

The Hong Kong Narcotics Register and the Malaysia Integrated Data System for Drug Abuse serve as excellent examples of this strategy. In Hong Kong, the case register receives standard reporting forms on all individuals admitted to drug treatment or rehabilitation programmes, either arrested by police or admitted to a correctional rehabilitation facility. In Malaysia, standardized case reports are also received from police, treatment and rehabilitation agencies. In both systems, sufficient identifying information is collected to permit multiple reports on the same individual to be matched; an unduplicated count of cases can then be produced.

The advantage of using this strategy for case-finding is that data are already being collected on these subjects, so that little additional expense is involved. The individuals reported have also passed through some formal case-definition process so that one is considerably confident that they are indeed drug abusers; that is, they have been either formally arrested for drug possession or have sought treatment for drug abuse. The major limitation is that one has identified only the so-called tip of the iceberg and must conduct additional studies to determine what exists below the surface. For a more detailed discussion of drug-abuse reporting systems, the reader is referred to a recent WHO publication on this subject (Rootman and Hughes [ 2] ).

The location of case-finding activity at drug distribution sites

There are some practical implications to the rather simple notion that if users did not periodically replenish their drug supplies, they would no longer be drug abusers. It suggests that if epidemiologists could station themselves at all sites of drug availability, they would be able to identify the drug-using population. In practice, this is not a simple matter as different drugs have different patterns of distribution. For heroin users who are physically dependent tend to visit their drug-distribution sites once or more times per day to avoid withdrawal symptoms, while for cannabis, users may purchase at one time a sufficient supply to meet their needs for weeks or months.

In Chicago, Hughes and Jaffe [ 9] observed that heroin users met regularly at neighbourhood drug-distribution sites called "copping areas". They observed that when addicts began to develop withdrawal symptoms and had money to buy heroin, they had no time to search for the drug. They required a stable distribution site where they knew the drug was available, even though local police kept these locations under surveillance. The Chicago team stationed at these sites recruited former drug dealers who were either methadone patients or closely supervised drug-rehabilitation programme staff. They contacted and made a census of regular addict visitors before and after treatment-outreach experiments. The research staff made periodic visits for independent observations and validation of the field worker data. This case-finding approach was used in six different neighbourhoods of Chicago, which suggests it might be applicable in other settings.

Shick, Dorus and Hughes [ 10] extended this approach to multiple drug users. They enumerated and observed adolescent multiple drug users who congregated at specific locations in Chicago parks for purposes of drug distribution and use. The sites offered abusers a place away from families and other adults where they could enjoy their drugs. They were secluded places, which gave them secrecy from their non drug-using peers and the possibility of advance warning and escape should the police appear.

Westermeyer [ 11] used opium dens in Laos for the purposes of case-finding and other data collection. He observed that clients of such dens were bound to them as to a family surrogate. The dens served a function similar to the neighbourhood tavern or tea house in other societies, a place to socialize with friends, to get information about work and about other activities related to survival in a subsistence economy. They also provided human contact and acceptance for individuals stigmatized by others for their drug use.

In Pakistan, several studies have been carried out using the drug-distribution system as the point of reference. Opium smoking was studied in the North West Frontier Province by the Pakistan Narcotics Control Board [ 12] with law enforcement officers in plain clothes visiting 43 opium dens and interviewing 618 smokers. Opium distribution vendors 2 were used by McGlothlin and others [ 13] to obtain cases for interview studies and to make preliminary estimates of the number of opium users in a Pakistan city. The Pakistan Narcotics Control Board [ 14] also studied psychotropic substance abusers by watching known drug pushers, peddlers and chemists who dispensed drugs illegally, and by approaching customers for interviews after they had made their purchases.

While the epidemiologist may have only recently discovered the drug-distribution site for field research, law enforcement agencies have traditionally organized their activities around the drug-distribution system. This strategy evolved from their interest in reducing illicit drug supplies and the need for a starting point to reach higher-level traffickers. In most communities, narcotics officers are, therefore, quite knowledgeable about the location of "copping areas" and drug-user meeting places. The urine screening of visitors to heroin distribution sites has also been a central element of the apparently successful strategy of the Government of Singapore in halting the spread of heroin abuse in that country (McGlothlin [ 6] ).

Training case-finding personnel

In epidemiological studies the physical signs of a health disorder are often used to make a diagnosis or to define a case. In keeping with this tradition, Bejerot [15, 16] has described the use of a standardized clinical sign in Stockholm. This is the appearance of fresh needlemarks, and of "tracks", i.e. the characteristic scars and discoloration that develop about the veins repeatedly used to inject drugs. Since 1965, trained nurses in Stockholm have systematically examined arrestees for the presence of such marks and a drug-use history is recorded for cases identified. There have been studies of its reliability and validity, which suggest it to be a simple and inexpensive method of identifying intravenous drug abusers.

A physician's diagnosis of drug dependence is sometimes used when an individual is legally registered as an addict, often for drug maintenance or treatment programmes. The physician's diagnosis has in this way been used to place drug users on the Home Office list of Drug Dependent Persons in the United Kingdom of Great Britain and Northern Ireland and on the Narcotics Register in Burma. The use of a physician's examination as a case-finding tool in field studies, however, has not become widespread because it is expensive and would draw trained personnel from other areas of need. It is for this reason as well as for safety that the "Nalline" test is not often used. It requires trained health personnel to inject Nallorphine and to examine the pupil responses of individuals suspected of opiate use.


In 1979,the Government of Pakistan closed the opium vends and began to institute an opium registration and maintenance system under medical Supervision.

Experienced narcotics officers can be highly skilled in identifying drug users in the community by observing ethnographic signs such as their dress, gait, and other drugrelated behaviour. Some are also skilled at recognizing speech patterns as well as signs of intoxication and withdrawal from the various drugs. They know the characteristic odour and visual appearance of the different abused substances. Generally, these observational skills evolve over many years of experience, but they can be learned, and the United Nations [ 17] has prepared a publication to help train police to identify drugs and drug users in the community. Such knowledge and skill could also be acquired by drug-abuse epidemiologists and these might be of considerable use in case-finding activities. In this respect, the authors (Hughes and others [ 3] ) have prepared a selected review of ethnographic characteristics of drug abusers which might be used for this purpose.

Participant observation techniques

To study deviant populations such as delinquents, social scientists have used participant observation techniques which permit a researcher to penetrate the world of deviant subcultures. The most common approach is for the researcher to identify a target population for study, then arrange introductions through a person who is trusted by the deviant population. The researcher reveals the wish to conduct a study but will respect the rules of confidentiality by not identifying individuals in the report or publication. Much time is spent with the study group, making observations and getting information informally: notes are generally not made in front of the study subjects. There are, of course, many variations in the specific techniques used by different investigators (Gold [ 18] ).

Much of the participant observation research on drug users has been conducted in North America. One of the earliest was Howard Becker's classic study [ 19] of how the marijuana user learns to smoke and enjoy the experience. Becker emphasized the importance of experienced smokers in teaching the new users the breath-holding technique for efficient smoking of the drug and to help them identify the effects.

Finestone [ 20] described the distinctive "cool cat" subculture of young black heroin addicts in Chicago, their colourful dress, "hip" language and the way they interacted with others. Mills, a journalist, used the participant observer method to write The Panic in Needle Park [ 21] , which described a sudden heroin shortage in the city of New York and how this affected the lives of two addicts.

Feldman [ 22] has contributed to the etiology of drug abuse in observing that drugs were not always taken for their pharmacological effects. Rather, they were just one of many daring behavior patterns which young people engaged in to achieve peer status. Heroin use conferred the highest status in his study group because it had the greatest risks associated with its use. Feldman never had problems of personal safety when he visited the hangouts of drug users as he was always accompanied by his large German shepherd dog.

Preble and Casey [ 23] rented a room in the apartment above a bar used as a drug user meeting place in the city of New York, and employed the barmaid to schedule appointments with drug users for interview purposes. They challenged contemporary notions of addicts as passive retreatist individuals by describing their busy and challenging lives, which required them to steal or in other ways obtain sufficient money each day to support their drug habits.

Police also used the participant observer strategy in the role of the undercover agent. When narcotics officers worked as undercover agents and were assigned to communities where they were not known, they posed as drug users or dealers in order to obtain information and to arrange drug purchases from dealers who were then arrested in the act.

The real value of participant observation studies lies in their rich and vivid descriptions of drug subcultures. From such studies we have learned that drug users are not just amoral, disconnected persons who are rejected by the larger society and marginal to the culture. They are part of a network of social relations which exerts considerable influence over them, even after they have been withdrawn from pharmacological dependence. .

Among its limitations, participant observation requires much time to obtain information on a relatively limited number of often unrepresentative subjects, so generalization of the findings is often limited. It is not often used as a case-finding strategy; instead, field observation is seen as contributing primarily to the design of systematic case-finding studies. One can learn where drug users meet, the time of day they are available for interviews, how co-operation can be obtained for case-finding, and other epidemiological studies. Field observations can make data-gathering staff aware of the sensitivities and concerns of the populations to be studied.

The use of drugs abusers as case--finding agents

De Alarcon and Rathod [ 24] demonstrated the feasibility of this strategy in an English community where they compared several sources of case-finding data to determine which provided the most cases. The sources included probation services, police, heroin-using patients, general medical practices for diagnosis of jaundice, drugrelated emergency room admissions, and direct referrals from courts and general physicians. In the community studied it was found that police and courts contributed 7 of the 98 names detected, and physicians were generally consulted only after the drug user had already contacted other agencies. The two most productive sources of case finding were the heroin users themselves and the monitoring of jaundice cases. It is notable that neither of these two approaches is commonly applied in reporting systems for drug abuse.

Kosviner and others [ 25] also demonstrated the feasibility of this strategy in an English town. They initially contacted four heroin users at weekly discussion groups and from these they found others. The investigators rented two furnished rooms in the town as an informal meeting place where interviews could be held.

The use of one case to involve others is sometimes referred to as the snowball technique. The drug user case-finding agents may or may not be paid for the contacts they provide.

A variation of the snowball technique was applied by Medina-Mora and others [ 26] in Mexico City. In an intensive case-finding study, they assigned a male and a female psychologist to identify all drug abusers in a target neighbourhood. They contacted a wide variety of informants, including priests, school teachers, health workers, and shop owners, and were in this way able to identify 123 abusers.

When police use drug users to provide information, these individuals are called "informers". They are generally recruited from arrested addicts by the offer of reduced prison sentences. In addition to providing general intelligence information, they are asked to help arrest higher-level drug dealers when this is feasible. The drug-user informer does not conduct formal interviews or help other drug users to complete questionnaires as he might if he were employed by an epidemiologist or treatment agency.

Whenever one considers the recruitment of drug users or ex-users, one must also check on the reliability of the information they provide. In Chicago, where methadone maintained ex-heroin addicts were used extensively for field studies, they were carefully supervised. The reliability of their data was periodically checked by sending professional field researchers to the same communities to make independent observations, which could then be compared. It was also possible to check the reliability of field worker data by collecting similar information from study subjects, for example, at the time of treatment programme admission. These data would be collected by trained admission clerks and compared with data gathered by field workers.

The major advantage of involving drug abusers in case-finding is that they can take the epidemiologists to drug-user meeting places and place them in contact with active drug users who are not known to treatment or other institutions. When ex-drug users are hired, it is advisable to collect their urine specimens periodically in order to make a speedy detection of a relapse to drug abuse if this occurs.

The screening of high-risk populations

Cases of heavy and criminalized drug abuse almost always represents less than 1 per cent of the total population and in most countries less than 0.1 per cent (Hughes and others [ 27] ). It is not cost-efficient to screen the entire population in order to find a relatively small proportion of cases. However, the observation that drug abuse tends to affect some "high-risk" populations more than others, permits case-finding to proceed more cost-efficiently. The high-risk populations can be intensely screened with a high yield of cases.

In Thailand, the hill tribe population is at high risk for opium dependence, as some tribes grow the poppy and others live along the drug transport routes. In an effort to identify all cases of opium dependence in six hill tribe villages selected for intervention programmes, Suwanwela and others [ 7] applied four different case-finding methods: an interview survey of all households, a health examination of all subjects over the age of 10 years, urine examination for opiates of all subjects receiving health examinations, and the identification of either known or suspected opium addicts by key informants. By using multiple case-finding methods, the investigators were able to provide with considerable confidence their estimates of opium dependence in these villages at the time of the study. They also planned a post-intervention survey at a later date to determine the impact of the planned prevention and treatment measures. It was hoped that this research effort would suggest economical and effective case-finding methods for screening such high-risk populations.

In recent years we have observed numerous questionnaire surveys of high-risk populations such as students, and earlier in this article we described the urine screening of United States military personnel during the early part of 1970 when they were considered at high risk for drug abuse.

In screening such populations, one must be careful not to generalize their high rates of drug abuse to the total population. Such studies are important, however, particularly when effective prevention and treatment programmes are provided for the cases identified.

Identification in interviews and questionnaire surveys

The taking of dependence-producing drugs is almost always a conscious act of behavior, so that the individuals affected can identify themselves. This is in contrast to many health disorders which require medical expertise for the diagnosis. The ability of drug abusers to identify themselves has led to the widespread use of interview and questionnaire surveys. They often rely entirely on the self-report of the subject, hoping that drug abusers will identify themselves and answer questions honestly. Such surveys are likely to gather useful information on occasional drug abusers and those who have abused drugs in the past as they have little to fear if they respond honestly.

In settings where drug law enforcement is active, such surveys are likely to under represent criminalized and heavy abusers. These individuals will often avoid participating in the study and when they do participate they are not likely to place themselves in jeopardy by answering questions honestly.

Self-administered surveys (Smart and others [ 28] ) which assure the anonymity of respondents, can be answered honestly by drug abusers with no danger to themselves. But the use of these surveys is generally limited to literate populations who can read and write in answer to questions and who can readily be assembled at one place and time for survey administration. While students and the military do meet these criteria, the self administered survey appears to work best when it is anonymous; it is thus self-defeating as a case-finding strategy because individual cases will not be identified in an anonymous survey.

When the self-report survey is of the interview type (Johnston [ 1] ) the subject's identity is known to the interviewer. One would, therefore, have greater confidence in the ability of such surveys to identify heavy drug users if urine specimens were collected for laboratory testing.

From the foregoing discussion, one should not conclude that self-administered and interview surveys are of no value, because they can provide useful descriptions of occasional, moderate and past drug abuse in the population studied. These survey approaches are limited, however, in assessing heavy drug abuse and particularly in case finding efforts to identify heavy drug abusers for treatment or other interventions.

Special methodological and ethical issues

Case-finding studies to identify heavy drug abusers encounter many of the usual problems of epidemiological research such as reliability, validity and adequacy of the sampling approach. These issues will not be discussed further as they are addressed earlier in the paper and elsewhere in the literature. The issues which are examined here are unique to case-finding studies of heavy drug abusers.

Safety of field staff and subjects and the need for confidentiality

Because of the widespread use of informers by narcotics police, any person seeking information from drug abusers is suspect. When arrests occur as a result of police undercover work, all recent visitors and contacts are reviewed by the arrested person in order to identify the informer. Thus a field worker or his interviewees could become the object of suspicion and misdirected violence. It is therefore important for epidemiological field staff to establish their credentials with the target group at the beginning of the study. They should identify their sponsoring institution and guarantee anonymity of research results. The completion of informed consent forms by the study subject on the street corner in full public view would be counter-productive, but this can be done discreetly at an opportune time such as when formal interviews are conducted.

For the safety of the field workers and their subjects it is advisable to omit from data collection information of obvious direct relevance to police, such as the names and addresses of drug dealers. Contacts between data-gathering staff and local police can increase the natural suspicions of the study population. On the higher levels of research administration, however, contacts with law enforcement administrators is a matter of routine and should create no difficulty.

But there are other risks for field staff who must visit high crime and violence areas in the community. They may become involved in drug use themselves, and their study subjects can be suspicious and even violent when intoxicated with certain drugs, including alcohol. Research administrators need to be aware of these risks so that adequate precautions can be taken, such as recruiting staff with street work experience or teaming professional field staff with ex-drug users or others who have established contacts in the communities to be studied.

Incentives for subject participation

Social researchers often pay a fee to drug users for interviews. Drug users often give police officers information when they want a friendly witness in court. Drug users may also wish to provide information to the epidemiologist in return for help in obtaining treatment, but medical ethics do not permit treatment to be withheld from those who refuse to participate in research. Nevertheless, the availability of treatment can be a useful facilitator to case-finding studies. Hughes [ 29] offered attractive and convenient treatment as a motivation to Chicago heroin users; and Suwanwela and others [ 7] offered a medical examination and treatment of disorders diagnosed in the course of the Thai village surveys for opium use.

Ethical considerations

Drug abuse case-finding activity is organized to identify, study and sometimes treat individuals who often have no wish for this intrusion into their privacy. In recent years even the general public resists participation in surveys of various types, as survey organizations have increased in number and activity. Balanced against these ethical concerns is the real potential of benefit from such studies, both for the drug user and for society in the reduction of drug-related problems. In the case of some communicable disorders, the right of an individual to privacy must be balanced against the right of the community to be protected from its spread. There is thus considerable variation in the policies of governments on this issue and the research worker must work within the national framework of such policies.

Case-finding versus case-definition

Some people may feel that an important distinction exists between case-finding (the approach used to locate drug abusers) and case-definition (the criteria used to decide whether an individual is or is not a case of drug abuse). The authors have not attempted to maintain a fine distinction between these terms because in practice the distinctions can become blurred. We may, for example, suggest as criteria for case-definition any of the following: arrest for drug possession, treatment for drug dependence, self-report of regular use of dependence-producing drugs, positive urine test for drugs or presence of clinical or ethnographic signs of drug intoxication or withdrawal. All of these have been used at one time or another as criteria to define individuals as drug abusers, but they have also been used to finddrug abusers while screening various populations for cases.

Perhaps the real issue in this semantic discussion is the lack of internationally agreed operational definitions for defining cases of drug abuse or drug dependence in field studies. This is a difficult task, as drug abuse is not a monolithic condition: it involves many different drugs, patterns of use and effects. Nevertheless, if epidemiologists had clear guidelines on- what is a case of drug abuse or dependence, they could more easily collaborate with one another and with other disciplines in their mutual efforts to improve data on the extent and nature of drug abuse.

Implication for planners

To identify heavy drug users in large populations, such as an entire country, the proportion of cases is generally too small to justify screening every individual. In such circumstances one observes two trends in the literature. One approach is a reporting system to pool records of drug users in contact with major institutions such as police and drug-treatment centres. The second approach is to use epidemiological field teams or police to seek out actively those drug users who do not have drug-related contact with formal institutions. These users generally combine visits to drug-distribution sites and meeting places of abusers with the snowball method, i.e., using one drug user to find others.

Because drug users take steps to avoid being identified, it is advised that multiple approaches be used to identify cases. Generally the planner will have greater confidence in the data if several sources of case-finding information present a rather consistent picture. A particularly welcome development is the increasing use of urine testing in combination with other case-finding approaches. Provided the laboratory procedures are carefully monitored for accuracy, the validity of case-finding results can be checked by this rather inexpensive method, even in rural settings.

It is observed that different case-finding strategies are suitable for the users of different types of drugs. Opiate users, for example, are pharmacologically bound to local drug-distribution systems. The users of other types of drugs, such as cannabis, are not often so bound to distribution sites, but heavier abusers can often be located at meeting places where they socialize with friends. In brief, the epidemiologist may not have available one standard approach for all drug users. Rather, it may be necessary to tailor case-finding strategies to the specific drug-use patterns and legal framework of the particular society, the specific form of social organization developed by the drug-using population, and the degree and type of contact that they have with formal institutions in the community. The choice of approach will, in part, also depend upon the type of agency responsible for case-finding, but even here the planner will note the striking similarity of approaches used by both epidemiologists and police in the foregoing review. This would suggest some universality of basic approach regardless of discipline, given the technology now available.

Case-finding-how intensive and for what purpose?

Periodic surveys of students and community populations, and some form of reporting system for drug abusers, arrested and treated, will provide planners with the broad trends of drug abuse in society including the so-called tip of the iceberg of the hard core drug population. Certainly, most planners would also like to know what lies under the tip of the iceberg. But curiosity alone will not justify the additional expense, difficulty and risks to the individuals who must work in the field. Something serous must result from such an ambitious undertaking.

We are pleased to note several examples in the foregoing review of serous efforts to combine intensive case-finding with the offer of treatment to all members of high-risk groups. When these efforts are successful, they approach the much-sought-after goal of addiction control. These efforts have occurred recently in different parts of the world, and include the experience in Singapore, in which all suspected cases at heroin distribution sites are given urine tests; if the tests are positive they are treated and carefully followed up. A recent evaluation of the programme suggested considerable success (McGlothlin [ 6] ). We also refer to the pre- and post-intervention surveys of Thai hill tribes (Suwanwela and others [ 7] ). These studies will permit prevention and treatment approaches to be evaluated by their impact upon the number of opium users in control and intervention villages. The United States Army urine-testing and treatment programme in the 1970s is noteworthy, in which this high-risk population could be efficiently screened to identify and treat active cases in order to halt the spread of heroin abuse (Flaherty [ 30] ) as is, finally, the Chicago experiments (Hughes [ 29] ) to reduce the numbers of heroin users at neighbourhood drug-distribution sites. The strategy used intensive case-finding and treatment outreach, relying upon ex-addict field workers. Each of these efforts to combine intensive case-finding with treatment appear to have had measurable impact on the serous drug problems of their respective target populations. They require the determined effort of administrators and the persistence of field staff. They are more expensive than less ambitious approaches, but the results may well justify the additional effort.

General conclusions

  1. The use of multiple approaches appears to be preferable to a single strategy for finding cases of criminalized and heavy abusers of drugs;

  2. Few contemporary survey or reporting systems adequately identify the criminalized and heavy abusers of drugs. Improved methods for defining this population need to be tested;

  3. An appropriate international body should develop operational criteria for defining drug abusers in epidemiological studies;

  4. Clinical and ethnographic signs for identifying drug abusers in the community have been inadequately utilized. Training materials, including films, might be developed to make these case-finding aids more available;

  5. Intensive case-finding efforts should be combined with treatment intervention programmes in defined communities to test different frameworks for drug-abuse prevention and control.



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I. Rootman and P. H. Hughes, "Drug abuse reporting systems", World Health Organization Offset Publication No. 55(Geneva, 1980).


P. H. Hughes and others, "Ethnographic and secrecy patterns among drug abusers", Bulletin on Narcotics (United Nations publication),Vol. 34,No. 1 (1982),pp. 1-12.


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H. L. Ruben, "A review of the first year's experience in the U.S. Army alcohol and drug abuse Program", American Journal of Public Health, Vol. 64,No. 10 (1974),pp. 999-1001.


W. H. McGlothlin, "The Singapore heroin control programme", Bulletin on Narcotics (United Nations publication),Vol. 32,No. 1 (1980), pp. 1-14.


C. Suwanwela and others, "The hill tribes of Thailand, their opium use and addiction", Bulletin on Narcotic (United Nations publication),Vol. 30,No. 2 (1978),pp. 1-19.


World Health Organization, "Report of working Group on the Application of Laboratory Methods in the Surveillance Epidemiology of Drug Dependence", Manila, 28 November-4 December 1978 (Manila, Regional Office for the western Pacific, February 1979), unpublished.


P. H. Hughes and J. H. Jaffe, "The heroin copping area: a location for epidemiological study and intervention activity", Archives of General Psychiatry, Vol. 24,No. 5(1971), pp. 394-400.


J. F. E. Shick, W. Dorus and P. H. Hughes, Adolescent drug using groups in Chicago parks", Drug and Alcohol Dependence, No. 3, 1978,pp. 199-210.


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W. H. McGlothlin and others, "Opium use in two communities of Pakistan-a preliminary comparison of rural and urban patterns", Bulletin on Narcotics (United Nations publication), Vol. 30,No. 4(1978),pp. 1-15.


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H. Feldman, "Street status and drug users", Society,1973,pp. 32-38.


E. Preble and J. J. Casey, "Taking care of business-the heroin user's life on the street", International Journal of the Addictions, Vol. 4,No. 1 (1969), pp. 1-24.


R. de Alarcon and N. H. Rathod, "Prevalence and early detection of heroin abuse" British Medical Journal, Vol. 2, 1968, pp. 549-553.


A. Kosviner and others, "Heroin use in a provincial town", The Lancet, Vol. 1, 1968, pp. 1189-1192.


M. E. Medina-Mora and others, "Amethodology for intensive case-finding and monitoring of drug use in a Mexican community", Bulletin on Narcotics (United Nations publication), Vol. 32,No. 2 (1980), pp. 17-26.


P. H. Hughes and others, "An international review of the extent of drug abuse" (unpublished monograph, 1980).


R. Smart and others, "A methodology for student drug-use surveys", World Health Organization Offset Publication No. 50 (Geneva, 1980).


P. H. Hughes, Behind the Wall of Respect: Community Experiments in Heroin Addiction Control (Chicago, University of Chicago Press, 1977), pp. 1-162.


J. E. Flaherty, Army Drug Abuse Program: A Future Model (Washington, D.C., Drug Abuse Council, 1973),pp. 1-79.