The epidemiology of self-reported drug misuse in the United Kingdom

Sections

Summary
Introduction
The Surveys
THE RESULTS OF THE SURVEYS
1.Changes in the prevalence of misuse and the type of drug misused
2. . Community diagnosis - local differences in the prevalence of misuse
3. Individual risks
4. Operational research
5. Clinical picture and the natural history of misuse
6. Causes
Conclusion
Bibliography

Details

Author: Joy MOTT
Pages: 43 to 54
Creation Date: 1976/01/01

The epidemiology of self-reported drug misuse in the United Kingdom

Joy MOTT
Senior Research Officer, Home Office Research Unit, London

Summary

Self-report methods are, in general, the only feasible way of obtaining information on the prevalence of drug misuse, other than opiate misuse, in the population. The present review examines the results of surveys of self-reported drug misuse conducted in the United Kingdom between 1968 and 1972 and discusses the findings in terms of the uses of epidemiology. The evidence from the surveys suggests that, by 1972, a higher proportion of students in higher education, particularly those following courses in the social sciences, admitted to having ever misused controlled drugs compared with the general population of similar age. There were considerable local and regional variations in the prevalence of self-reported misuse. The majority of those who admitted to having ever misused drugs in the samples surveyed since 1970 said they had misused cannabis. The only individual characteristics that were found to be consistently associated with admitting to having ever misused drugs were favourable attitudes to drugs and slightly elevated neuroticism scores.

Introduction

Reviews of the results of epidemiological research into drug misuse 1in the United Kingdom has so far been limited to opiate misuse (Hawks, 1970; Hawks et al., 1970; de Alarcon, 1969, 1971) although the number of known users remains small. 2de Alarcon (1971) suggested that the emphasis on opiate misuse had occurred because the misuse of these drugs has the most serious medical consequences and is, therefore, of considerable public concern. Further, the opiate misuser is easily identifiable, a circumstance which facilitates the collection of data and thereby increases confidence in the estimates of the prevalence of misuse. 2

Information on the prevalence of other forms of drug misuse has not been as readily available. When, in the late 1960s, the Advisory Committee on Drug Dependence sought information on the prevalence of the misuse of cannabis, amphetamines and LSD, it was forced to rely on statistics of convictions for offences involving these drugs and on the guesses of witnesses (for example, see para. 36 "Cannabis" 1968).

1

Drug misuse is defined here as the non-medical use of drugs controlled by the Misuse of Drugs Act 1971.

2

As a consequence of the United Kingdom drug control legislation, the Home Office has, since 1920, been informed of persons having prescriptions dispensed for opiates, and since 1968 doctors have been required to notify the Home Office of their addict patients. These central records include some details of the social characteristics of the opiate misusers, for example, their age at coming to notice, their sex and the origin of their addiction. Estimates of the incidence and prevalence of opiate misuse using the notification statistics are regularly prepared by the Home Office Drugs Branch. These were 2,782 known opiate misusers during 1968 and 3,270 during 1974.

Criminologists have long been aware that recorded criminal statistics are at best crude estimates of the extent of crime. In attempts to make better estimates of the prevalence of crime a considerable body of research has been undertaken on hidden delinquency or "the dark figure of crime", that is, the number of persons who admit (to research workers) to having committed offences but who have not come to the attention of the police (see Hood and Sparks, 1970). Criminal statistics relating to drug offences are even less reliable estimates of the prevalence of drug misuse than they are of most other types of offence because the most common types of drug offence, under United Kingdom legislation at least, are the so-called victimless offences of the unauthorized possession or supply of controlled drugs; such offences are considerably less likely to come to the attention of the police than offences involving victims.

The self-report methods of data collection that have been developed for the study of hidden delinquency have been widely used in the study of the epidemiology of drug misuse (for example, Smart (1974) describing Canadian research). For the United Kingdom surveys of self-reported drug misuse, data have been collected in a variety of ways - individual interviews, anonymous postal or supervised self-completed questionnaires with and without follow-up interviews.

The problems of obtaining valid and reliable admissions of illegal acts by self-report methods are well known - the informants may conceal or exaggerate both the type and the frequency of the commission of the acts. Various methods of validating the admissions of drug misuse, usually involving assessments of the internal consistency of response, have been used. The use, in the community, of objective methods of assessing misuse, by the analysis of body fluids, has been found to be impractical (Fish and Wells, 1972) and, in any case, could only provide information of the very recent misuse of certain controlled drugs.

The present review examines the results of surveys of self-reported drug misuse conducted in the United Kingdom between 1968 and 1972 and, following Hawks (1970) and Smart (op. cit.), discusses the findings in terms of the uses of epidemiology as described by Morris (1964).

The Surveys

The results are available of nine surveys designed primarily to estimate the prevalence of drug misuse amongst variously selected sub-groups of the population in the age range 14 to 26 years. Information on the prevalence of misuse was collected incidentally in a further four studies.

The type of sample surveyed and the dates when the surveys 3were conducted are:

1. Nationally representative samples: OPCS 4in 1969, Midweek in 1973;

2. Students in higher or further education: Young and Crutchley in 1968-70 at Enfield Polytechnic, Kosviner et al. of three university colleges in southern England in 1969/71, Somekh of five London university colleges during 1971/72, McKay et al. of Glasgow University medical students between 1970 and 1972, Fish and Wells of higher education students in Glasgow during 1971/72;

3

The results of the surveys are referred to in the text by author and date of publication.

4

Office of Population Censuses and Surveys, Social Survey Division, formerly the Government Social Survey.

3. Local populations: Cardiff in 1970 (Evans et al.), Cheltenham in 1971 (Cheltenham Youth Trust), Tower Hamlets in 1972 (Institute of Community Studies);

4. School children: Wiener of the pupils attending nine schools in Greater London in 1968, Hindmarch of Leeds school children in 1969, Fish and Wells of 18 schools in Glasgow in 1972, Swift et al., of pupils from a national sample of 70 schools in 1972.

Misuse has been defined in all the self-report surveys as the taking of drugs which have not been prescribed by a doctor. Particular drugs have usually been specified by presenting the informants with a list invariably including four controlled drugs - amphetamines ("pep pills"), cannabis, LSD and heroin. Some surveys have also included tranquillizers, sedatives and hypnotics while others have included all these as well as proprietary cough mixtures, solvents and glues.

The estimates of the prevalence of misuse in the various sub-samples of the populations that have been surveyed have been based on the number of informants who admit to having "ever used" one or other or several of the drugs covered by the survey.

Some workers report the proportions of "regular" misusers although definitions of "regular" vary considerably. For example, Wiener (1970) defined "regular" misusers as "those who sometimes take this drug or drugs at weekends or parties, or take this drug or drugs at least 1 to 5 times a week". Somekh (1975) described a group of students who admitted to having misused a drug or drugs more than ten times and who were continuing to misuse at the time of the survey. Fish and Wells (1974) asked their Glasgow samples to assess their own drug misuse as "regular" or "occasional" while Swift et al. (1974) distinguished a group of school children who admitted to having misused a drug or drugs four or more times.

THE RESULTS OF THE SURVEYS

1.Changes in the prevalence of misuse and the type of drug misused

The OPCS (1973) survey in 1969 found that 5 per cent of a representative sample of the population of England and Wales aged between 16 and 65 admitted to having ever misused one or other of six controlled drugs; 4 per cent of the sample admitted to having ever misused "pep pills" (oral amphetamine preparations) and about 2 per cent admitted to having ever used cannabis. The Midweek survey in 1973, which cannot be regarded as particularly reliable because of a low response rate to a postal questionnaire, and because the sample was small, suggested that 39 per cent of people aged between 17.5 and 34 years who appeared on the electoral registers of 12 parliamentary constituencies in Great Britain admitted to having ever misused cannabis. Very much smaller, but unspecified, proportions admitted to having ever misused amphetamines or LSD or sleeping pills. This survey found the highest proportion of persons admitting to having ever misused cannabis in the three Inner London constituencies.

TABLE 1

The results of surveys of students

 

Type of drug ever used by misusers a

Survey

Sample size

Response rate %

Ever used %

Regular users %

Poly users %

Pep pills %

Cannabis %

LSD %

Heroin %

Other %

Enfield Polytechnic, 1970 (Young and Crutchley)
206 68 44 21b
-
24 59 16 0.4 1
3 colleges south-east England, 1969/71 (Kosviner et al.)
1142 75 32 c 13c
-
-
100
-
-
-
5 London colleges, 1971/72 (Somekh)
1113 65 34 15 c 15 28 95 23 0.8 18
1970/71 (McKay, et al.) Glasgow University Medical,d
749 95
13-16
4 4
-
100 d
-
-
-
Glasgow, 1971/72 (Fish and Wells)
985
-
28 5
-
25 75 23 0.9 45

a The percentage admitting to the misuse of particular drugs is based on the total number in the sample admitting to having ever misused any of the specified drugs.

b Social science students using cannabis

c Cannabis only.

d Data were collected from two samples surveyed in successive academic years, but as there is considerable overlap between them only the results from the 1970/71 sample are discussed here. It was not possible to calculate the proportions misusing other types of drug.

TABLE 2

Increase in the proportion of students admitting to having ever used cannabis

Sample and date of survey

Ever used Cannabis %

Enfield 1st year social science
 
1968 15
1969 40
1970 50
3 south-east England colleges, all years, all faculties
 
1969 24
1970 27
1971 38
5 London colleges first year students only, all faculties
 
1971 29
1972  
Glasgow medical a students
 
1970/1971
13
1971/1972
16

a The samples overlap and no data were presented for the first year students in each academic year.

University students form the sub-group of the population that has been most intensively surveyed. Only one such survey was repeated at annual intervals between 1968 and 1970 (Young and Crutchley, 1971, 1972) although changes in the prevalence of the misuse of cannabis may be deduced from the results of three other student surveys (see table 2). Considered together, these results indicated an increase in the prevalence of cannabis misuse amongst students but the amount of the increase depended upon the location of the institution (see tables 1 and 2), the course of study (see table 3) and the year of study, with a high prevalence amongst third year students compared with those in their first year (Somekh, 1975).

TABLE 3

Faculty differences in the proportions of students in the southern English samples who admitted to having ever used cannabis

 

Enfield 1970 %

South-east England 1969/1971 %

Five London colleges 1971/1972 %

Faculty:
     
Social science
50 40 44
Business Studies
18
-
-
Engineering
12
-
-
Arts
-
38 30
Science
-
17 27
Medicine
-
-
31

TABLE 4

The results of surveys of local populations

 

Type of drug ever used by misusers a

Survey

Sample size

Response rate %

Ever used %

Regular users %

Poly users %

Pep pills %

Cannabis %

LSD %

Opiates %

Other %

Cardiff, 1970
1616 68 9 1.5 4.8
-
100
-
-
88b
Cheltenham, 1971
300 80
Students 28
-
7 19 89 6 2 35c
     
Other 15
             
Tower Hamlets, 1972
238 67 16 7 9 27 78 13 0 36d

a The percentage admitting to the misuse of particular drugs is based on the total number in the sample admitting to having ever misused any of the specified drugs.

b Types of drugs other than cannabis not specified.

c Includes mandrax, librium and barbiturates.

d Includes all the above cleaning fluids, solvents and glues.

TABLE 5

The results of surveys of school children

 

Type of drug ever used by misusers a

Survey

Sample size

Ever used %

Regular users %

Poly users %

Pep pills %

Cannabis %

LSD %

Heroin %

Other %

London, 1968 (Wiener)
1093 10b 1 2 69 59 20 8 2
Leeds, 1969 (Hindmarch)
1126 10 4 1 84 30 10 0 77
Glasgow, 1972 (Fish and Wells)
503 23 4
-
40 54 53 4 72
National 1972c (Swift et al.)
4480 9 4 5 17 76 22 3 43

a The percentage admitting to the misuse of particular drugs is based on the total number in the sample admitting to having ever misused any of the specified drugs.

b Estimated to take absentees into account.

c Although nationally distributed this sample was not representative of all types of school.

There is consistent evidence that by 1972 about a third of the students, about 15 per cent of the non-student samples of comparable age and 10 per cent of the school samples, admitted to having ever misused a controlled drug, with cannabis as the drug most commonly admitted to having ever been misused. It seems that the prevalence of oral amphetamine misuse declined during the period under consideration (see tables 1, 4 and 5). There is evidence from two studies of young offenders, both using objective methods of estimating recent amphetamines misuse, to suggest that this decline was apparent by 1967 (Scott and Buckell, 1969; Cockett, 1969).

There was considerable variability in the proportions in the various samples surveyed at different times and in different places admitting to having ever misused LSD (see tables 1, 4 and 5). Thus, it is impossible to estimate changes in the prevalence of the misuse of this drug or to distinguish between possible local outbreaks of misuse and the shortcomings of the self-report method of data collection. There is however, consistent evidence that the prevalence of self-reported opiate misuse was negligible.

To the writer's knowledge there have been no surveys of similar samples conducted since 1972 and no repeated surveys since then of the populations attending the same schools or universities as those studied in the surveys reviewed here.

2. . Community diagnosis - local differences in the prevalence of misuse

It can reasonably be argued that students attending particular universities or schools inhabit circumscribed communities and the differences between the proportions of students attending universities in different parts of the country and following different courses of study have already been noted. It seems obvious that drug misuse may or may not become institutionalized or fashionable in particular academic departments in particular universities at particular times. Comparison of the results of the survey of London medical students by Somekh (1975b) in 1971/72 and Glasgow University medical students by McKay et al. (1973) in 1970/71 suggested that twice as many London as Glasgow students admitted to having ever misused a controlled drug, 31 per cent and 15 per cent respectively. When the results of the two student surveys in Glasgow between 1970 and 1972 are compared the proportion of medical students admitting to having ever misused drugs was about half that in a large sample of students "drawn from a number of centres for higher education in the city" (Fish and Wells, 1974), 15 per cent and 28 per cent respectively.

There have been three surveys of local populations (Cardiff in 1970, Cheltenham and the London borough of Tower Hamlets in 1972) in the age range 14 to 24 years. The results of the Cardiff survey are not strictly comparable with the other two because the sampling frame was different, the data were collected by a postal questionnaire with a variable response rate from the sexes and from different age groups, and because the survey was mainly concerned with cannabis misuse (Evans et al., 1974).

It may, however, be tentatively concluded that at the times the surveys were conducted the prevalence of drug misuse amongst locally selected samples of young people of comparable age who were not students was about half that for the student samples, although for both types of sample cannabis was the drug most commonly reported to have ever been misused (see tables 1 and 4).

3. Individual risks

The self-report surveys have not provided information on morbidity and mortality associated with drug misuse. It may be that the situation is similar to that in Canada where, as Smart ( op. cit.) suggests, the great majority of misusers are not, or have not yet had enough time to be, exposed to the possible risks associated with chronic heavy drug misuse, particularly of cannabis.

4. Operational research

The study by Swift et al. (1974) attempting to evaluate the effects of five types of lesson on school children's attitudes to drug misuse may be mentioned here. Data were collected on the prevalence of self-reported misuse before the children were exposed to the lessons but the evaluation was limited to investigating subsequent short term attitudinal changes.

5. Clinical picture and the natural history of misuse

None of the self-report surveys sought information on the misusers' personal experience of the adverse effects of the drugs so that the results do not provide information on the clinical picture of misuse.

Only one survey of young male offenders remanded in custody attempted to collect information on the history and duration of self-reported misuse (Cockett, 1971). It may, however, be deduced within the limited age range covered by all but two of the surveys that the majority of self-reported misusers said that they had first misused drugs between the ages of 15 and 16 years or before attending university. Hindmarch (1972) suggested that the drug most misused by school children (in Leeds) was more likely to be oral amphetamines if they began drug misuse between the ages of 15 and 16 and cannabis if they began misuse a year later.

In the published accounts of some of the surveys the proportion of "regular" misusers was estimated but with such very different definitions of "regular" that valid comparisons of the results are difficult. However, the surveys of samples of students in south-east England suggested that, by 1972, between 15 per cent and 20 per cent had or were continuing to misuse cannabis "regularly" compared with 5 per cent of Glasgow students.

Between 1 per cent and 15 per cent of the samples of students, school children and informants in the local samples admitted to having ever misused more than one type of controlled drug (poly drug users). It is not known whether such misusers tended to restrict themselves to the misuse of any particular type of drug for any length of time before changing to another or whether they tended to misuse whichever type of drug was currently available to them. Amongst the student samples it seems clear that the majority of "regular" misusers restricted themselves to cannabis.

There is evidence from surveys of school children (Wiener, 1970), students (Somekh, 1975a) and young male offenders (Backhouse and James, 1969) that self-reported drug misusers were also likely to report that they more often smoked and drank alcohol than those who did not report misuse.

Because the informants in almost all the samples surveyed were assured of their anonymity and the confidentiality of their responses to the researchers there has been no possibility of follow-up studies of the same individuals to collect information on their history of drug misuse after the initial survey. This limitation has meant that next to nothing, other than anecdotal impressions, is known about the natural history of non-opiate drug misuse among representative samples of the population.

6. Causes

The results of the self-report surveys suggest that between 1969 and 1972 male students, and particularly those taking courses in the social sciences at universities or polytechnics in south-east England, were the sub-group of the population most at risk of misusing controlled drugs, most usually cannabis. Young and Crutchley (1972) argue from the results of their 1968 to 1970 study of students attending one polytechnic in south-east England that the emergence of a bohemian sub-culture, especially amongst social science students, was associated with the misuse of cannabis as "an aid to pleasure and expressivity". How far these propositions applied to students attending other institutions at the time, or are currently applicable, is not known.

The other individual characteristics which the surveys have shown to be associated with admitting to having ever misused controlled drugs are favourable attitudes to the drugs (particularly those misused by the informant), contacts with other misusers, slightly elevated neuroticism scores (usually from one or other of the Eysenck personality inventories), left wing political attitudes and, for a minority in some samples, the admission of delinquent acts not concerned with drugs.

The sex ratio for misusers, in the five surveys where it was quoted, showed a preponderance of males to females of about 1.5:1, although there were some local differences, notably in the Cardiff sample (Evans et al., op. cit.). There is some suggestion of a greater prevalence of misuse among the higher social classes. However, it seems more likely that misuse, particularly of cannabis, is more closely associated with being a university student than with social class alone. Smart ( op. cit.) has produced evidence, including some from the United Kingdom, to suggest that the very small numbers of pathological drug misusers cannot be reduced unless the average consumption of drugs (including medically prescribed psycho-tropics) by the general population is reduced. Taken together, the present evidence suggests that the major cause of drug misuse is the availability of drugs and the social support provided by peer groups or particular sub-cultures, rather than the presence of pathologically predisposed individuals in the population at risk.

Conclusion

This review has shown that some of the uses of epidemiology have been less well served than others by the surveys of self-reported drug misuse so far conducted in the United Kingdom. The results of the surveys have produced a patchwork of information, which is not always strictly comparable, on the prevalence of misuse (usually defined as admitting to having ever misused a controlled drug) at one point in time between 1968 and 1972 in selected sub-groups of the population. The evidence suggests that by 1972 the majority of those who admitted to having ever misused controlled drugs said they had misused cannabis.

In the United Kingdom, and elsewhere, the debate about the removal of the legal restrictions on the possession of small amounts of cannabis for personal use centres round ( a) the allegedly high prevalence of misuse and the inability of the law enforcement agencies to reduce it, and ( b) the lack of evidence of long-term harmful effects caused by the drug. It is therefore surprising that there have been no recent follow-up surveys of the prevalence of self-reported drug misuse.

The use of epidemiology which might contribute most to the debate, and which has been among the most neglected in the surveys reviewed here, is the description of the clinical picture and the natural history of drug misuse. The collection of information by anonymous self-completed questionnaires is not appropriate for natural history studies, as the data would have to be collected by interviewing representative samples of misusers, and Robins (1969, 1972) has developed methods of concurrent follow-up which can greatly reduce their duration.

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