The epidemiology of drug dependence in the United Kingdom

Sections

Introduction
1. Historical
2. Community diagnosis
3. The individual's chances
4. Operational research
5. Completing the clinical picture and the identification of syndromes
6. Clues to causes
Conclusions

Details

Author: D. V. HAWKS
Pages: 15 to 24
Creation Date: 1970/01/01

The epidemiology of drug dependence in the United Kingdom *

Ph.D. D. V. HAWKS Addiction Research Unit, Institute of Psychiatry, London, England

Introduction

The literature relating to the epidemiology of drug dependence has now reached such proportions that any attempt to review it must adopt certain limitations. The present paper concerns itself only with the British scene and gives emphasis, undue emphasis it must be acknowledged, to the problem of narcotic dependence.

There are a number of considerations which suggest that the epidemiological method may be usefully applied to the study of drug dependence. The fact that drug dependence, particularly of the narcotic type, is rare even in the vulnerable age group, suggests that it should be possible to identify those factors associated with the development of the condition. The existence, even in the same city, of high and low prevalence areas offers similar advantages. The age and sex specificity of drug dependence further contributes to the identifiability of the relevant population. The social contagiousness of addiction and the importance of exposure in determining vulnerability are other features of the drug phenomenon which recommend the use of a method initially adapted to the study of epidemics. Of perhaps greatest persuasiveness however is the undoubted multifactoral causation of drug dependence. Neither an exclusively pharmacological explanation nor one couched wholly in sociological terms provides an adequate account of the causation of drug dependence. An investigation of the aetiology of drug dependence must necessarily consider the pharmacological, social, economic and personal factors involved.

While there is much to recommend the application of the epidemiological method to the problem of drug dependence there are a number of inherent difficulties. There is in the first instance "a relative shortage of apparatus which makes it difficult to provide schemes of analysis by which complicated problems are reduced to simple formulae" (Marshall 1963). Thus, whatever the acknowledged importance of social factors our ineptitude in measuring these factors must inevitably contrast unfavourably with the pharmacologist's more exact techniques. Another manifestation of the relatively primitive state of the social sciences is the lack of any coherent theoretical framework within which the many diverse factors involved can be accommodated.

This article is based on a paper read to the Royal Society of Medicine (Section: Psychiatry) on 13 January 1970

The problem of measurement, while characteristic of the social sciences, is particularly pertinent in the field of drug dependence where there exists no commonly accepted criteria of dependence and immense variation in the cases studied. That large numbers of those designated as drug addicts in England are poly-drug misusers renders their designation as narcotic dependent or barbiturate dependent somewhat arbitrary.

Factors such as these make the definition of the population to be studied extremely complex. Until recently, even reasonably complete statistics relating to those dependent on narcotics were lacking in the United Kingdom. Descriptions of addicts tended therefore to relate only to identifiable cases with no assurance that they were representative of the total. In the absence of such information attempts to ascertain the natural history of addiction or to test the efficacy of treatment must necessarily be biased.

The problem of measurement extends beyond the question of defining the population however it applies also to the instruments themselves. In the absence of biochemical tests which allow us to assess the exact quantity and quality of drugs ingested the determination of such information must necessarily rely on verbal report. Even if such tests were available their use would be limited to the immediate past and could tell us nothing about the addict's previous drug use. The fact that the non-therapeutic use of drugs is an illegal activity increases the unreliability of self report in any context Where it is felt that the information supplied may affect the addict's ability to obtain more drugs. Added to this is the fact that the effect of the drugs themselves on the accuracy of self report is largely unknown. Even so with few exceptions information as to the personal and social history of drug addicts has been based entirely on addicts self report. While criminal, medical and employment histories may be checked the reliability and validity of the more personal and probably more pertinent aspects of an individual's history are largely untested. The historical nature of many of the events enquired about adds further to their inaccessibility.

Even if the relevant factors were accessible their very multiplicity demands multi-variate methods of statistical analysis which allow the effect of different factors in combination to be examined.

One very important characteristic of the drug phenomenon has been its continually fluctuating quality. Studies which are mounted to investigate a particular phenomenon are likely, unless they are extremely flexible, to find that the phenomenon no longer exists or else that it has assumed some other form.

In reviewing those studies carried out in the United Kingdom Morris's (1957) seven uses of epidemiology have been adopted as a convenient, framework.

1. Historical

The history of recent changes in the pattern of drug abuse in the United Kingdom has been charted in a number of sources. Bewley (1968) has pointed out that in the past ten years there has been a marked change in the incidence of drug dependence in the United Kingdom and in the characteristics of those known to be dependent. Before 1950 the number known to be dependent on narcotic drugs was relatively stable, varying between 400 and 600. Those involved tended to be middle aged and drawn disproportionately from the medical and paramedical professions. In most cases addiction had a therapeutic origin and the drug involved was usually morphine. Almost coincidental with the publication of the first report of the Inter Departmental Committee on Drug Addiction (The Brain Committee) there originated a series of changes which have continued in the same direction until the present day. There appeared both an increase in the number of people known to be dependent on narcotic drugs; and an increasing tendency for their addiction to have non-therapeutic origins. The persons concerned also tended to be younger and predominantly male. There was evidence that the drug of preference was heroin rather than morphine and indications that other drugs were being increasingly abused. Whereas the misuse of illicitly obtained drugs was originally confined to London the problem also spread to other parts of the country.

It needs to be emphasised that the figures on which these observations are based have never until recently been comprehensive. Prior to the introduction of the Dangerous Drugs (Notification of Addicts) Regulations 1968, it was not obligatory for doctors treating dependent patients to notify their dependence and the figures published by the Home Office were largely derived from the routine examination of pharmacists' records. The annual statistics published by the Home Office until 1968 showed only those addicts known to have been taking drugs during the previous year; they excluded those who were not known to be currently taking drugs; for example, those addicts in prison or abroad or those who obtained their drugs entirely from illicit sources. While the total number of addicts to opiates in the United Kingdom is still by international standards small-estimated by Bewley (1968) to be of the order of 4-8 per 100,000-the rate at which new cases have been notified leaves no cause for complacency. Ten times as many new cases were being recorded in 1968 as in the ten years previously.

Spear (1969) recently attempted to analyse the events of the 1950s which heralded the present epidemic. He observed that the first significant change in the situation occurred after the Second World War when there was an increase in the number of seizures of cannabis made by H. M. Customs and Excise. The first post-war annual report (1946) acknowledged that there was a small traffic in cannabis, largely confined to two negro groups with coloured seamen being the principle importers. A further "considerable increase" was noted in the following year and the same sources implicated. By 1950 it was clear that the traffic in cannabis was of greater importance than the traffic in opium and the total number of persons prosecuted for offences involving cannabis has shown a steady rise ever since. While the use of this drug continued to be linked mostly with the coloured population in 1950 it became apparent that cannabis was also being used by the indigenous population. A major case of drug trafficking occurred soon after when approximately 1,200 grains of morphine, mostly in tablet form and 14 oz of cocaine were stolen from a firm of wholesale chemists. While the drugs had been stolen by one of the firm's employees it transpired that the instigator was a person having contacts with drug addicts in the West End of London. However, the persons to whom he supplied drugs were already known addicts and there was no evidence that others were recruited to the habit by his activities. A further major case of trafficking occurred in 1951 when the dispensary of a hospital was broken into and considerable quantities of morphine, heroin and cocaine stolen. The person involved turned out to be a former employee of the hospital. Although the full extent of his activities cannot be charted it appears that a majority of those supplied drugs by him had no previous experience of heroin addiction. All of those who it could be ascertained had received their initial supplies from this source subsequently came to the notice of the Home Office as heroin addicts. While Spear does not attempt to explain the change in the pattern of drug abuse in the United Kingdom he does observe that the appearance of a pusher in the West End and the scarcity of cannabis following increased police activity appears to have played a significant part.

Bewley (1966) reports that until 1945 there was very little misuse of cannabis in the United Kingdom but between 1945 and 1960 there was a slow increase and between 1960 and 1965 a marked increase in the use of this drug. While it is difficult to estimate accurately the number of people who use cannabis, if one assumes as Bewley does that for every conviction there are possibly 10 or 20 people who are not convicted the number of regular cannabis users in the United Kingdom would be approximately 30 per 100,000 of the population. This figure would be doubled if occasional users were included.

Changes in the incidence of misuse of amphetamines were first observed by Connell (1958) who described a number of patients whose use of amphetamines led to psychotic episodes. Later there was evidence of an increase in the misuse of amphetamines taken in tablet form and obtained illegally (Linken 1963; Connell 1964, 1965a, b; Sharpley 1964). The principal drug involved was Drinamyl and misuse was confined to parts of the West End of London. While it is difficult to estimate the extent of illicit use of amphetamines, since the majority of people using them neither appear before the courts or develop symptoms necessitating medical consultation, urine screening of selected populations has confirmed an increase in the misuse of amphetamines. (Scott & Wilcox 1965; Crockett & Marks 1969). A survey conducted in Newcastle (Kiloh & Brandon 1962) showed that approximately 500 people in a population of 250,000 were psychologically dependent on amphetamines. The majority of these were middle aged women who had been originally prescribed amphetamines as treatment for depression or as appetite surpressants. Extrapolating from this figure gives a rate of 200 per 100,000 of the population. Similar studies carried out by Brandon and Smith (1952) and Wilson and Beacon (1964) have shown that of those patients receiving amphetamines or related drugs from general practitioners between 21 % and 58 % are psychologically dependent on them.

Bewley (1968) summarizing evidence from a number of sources has observed that in the past ten years there has been a marked increase in the number of overdoses with barbiturates. The suicide rate from barbiturate poisoning has more than doubled, added to which there has been a threefold increase in the number of people treated in hospitals for poisoning. There has also been an increase in the estimated total amount of barbiturates prescribed (Kessel 1965; Bewley 1966; Glatt 1962; Brooke & Glatt 1964). A survey conducted by Adams et al (1966) on a group practice of 10,000 showed that 407 patients had been given barbiturates over a considerable period of time. Though most of them continued to receive the drug without obvious addiction there was evidence of increasing dosage in 47. Mitcheson et al (1970) in a recent study of sedative abuse among heroin addicts found that 95 % of those interviewed had used sedatives and that 72 % were currently using sedatives. They emphasize, as others have done, that heroin addicts almost invariably abuse other drugs in addition to heroin.

Bewley (1968) reports that there has recently been evidence of illicit use of LSD and occassional cases involving other hallucinogens. Short lived psychoses have been found in people taking LSD (Bewley 1967). Though the drug would not appear to be as widely used as is reported in the United States LSD has been added to the amphetamines as a drug controlled under the Drugs, Prevention of Misuse Act (1964). While any attempt to estimate the prevalence of use is extremely hazardous in the absence of representative information Bewley has estimated the use as a possible 1-5 per 100,000 of the population.

2. Community diagnosis

There have been two studies which have reported the prevalence and early detection of heroin abuse in circumscribed communities. The first of these was carried out at Crawley, a new town with a population of 62,000, of whom 41% are under 20 years of age (de Alarcon & Rathod 1968). The study covered the age group 15-20 and employed five screening methods for detecting otherwise unknown heroin use. The methods employed were (1) local probation officer reports, (2) local police reports, (3) the reports of known heroin users, (4) a survey of recent jaundiced in-patients aged 15-25 years, and (5) a survey of casualty department records relating to all patients aged between 15-25 years who had been admitted for overdose of hypnotics or stimulents in the previous twelve months.

Classifying all the names obtained by the five screening methods and by direct referral as (1) confirmed heroin users, (2) probable users, (3) suspects and (4) nonusers, revealed that there were 50 confirmed users, five probable users, 37 suspects and six non-users. What was of particular interest was that only eight of the 50 confirmed users had been referred through the normal channels, leaving 42 who were first identified through one of the screening methods.

Consideration of the comparative value of the various screening methods showed that the two most productive were the heroin users themselves and the jaundice survey. Heroin users provided first evidence of 46 individuals and the hepatitis survey of 20. These two methods also provided the greatest number of confirmed cases.

Even if the comparison is confined to confirmed cases only the 50 cases detected by de Alarcon and Rathod contrast with the 8 cases of heroin abuse in Crawley known to the Home Office. Had the official figures been used the rate for Crawley would have been l.4 per 1,000 instead of the 8.5 found.

In a more recent article de Alarcon (1969) has analysed the spread of heroin abuse in Crawley in greater detail.

By establishing the approximate date on which heroin users had their first injection of heroin and the identity of the person who had given them this injection de Alarcon was able to discern both yearly incidence and source of contagion. This information was obtained from 58 users aged between 15-20 from 1962-1967 inclusive. By plotting the yearly incidence during this period three stages in the spread of heroin in the town emerged. (1) During 1962-1965 a small number of Crawley young people were initiated in other towns, (2) in the first half of 1966 a nucleus of established heroin users initiated by the former developed in Crawley, (3) in the second semester of 1966 and first semester of 1967 heroin abuse spread explosively in Crawley. Two major transmission trees covering 48 cases were traced; one of these trees included 32 users who could be traced back to the original initiator; the other included 16 users. Of the total 58 initiations to heroin 46 were carried out by Crawley boys, seven were initiated in other towns and five would not disclose their initiator.

The second study concerned an unidentified provincial town described as being compact and long established with a population of approximately 100,000 (Kosviner et al 1968). An attempt was made to contact and gain information on all the heroin users living in the town whether or not they were known to the authorities. The initial approach was made through four known heroin users trough whom contact was established with a total of 37 users. While there could be no way of confirming that all heroin users in the town had been contacted the names obtained corresponded very closely with those from official sources. That the subjects were heroin users was confirmed in 22 cases by direct observation of self injection and in the other cases by hospital notes, general practitioners or associates.

Of 47 suspected users 31 were confirmed, 10 were found not to be using heroin and six had left the town. As was the case in the Crawley study all the authorities approached had underestimated the extent of the problem-six users unknown to any of the authorities were identified by the survey.

3. The individual's chances

There have been a number of papers which document the morbidity and mortality associated with heroin dependence. Bewley, Ben-Arie and James (1968) report a survey of 1,272 heroin addicts first known to the Home Office between 1947 and 1966. Of the total number 890 (70%) were known to be taking opiates in 1966 and of those 293 not known to be taking opiates 189 or 64% were either in hospital, prison or some similar institution. There had been 89 deaths, giving a mortality rate among the non-therapeutic addicts 28 times in excess of the expected rate. The principal causes of death were sepsis, overdose and suicide. Bewley et al observe that there had been an increase in the number of deaths and a decrease in the mean age of death with the greater number of younger addicts at risk.

In a similar study of 100 consecutive male heroin addicts discharged from Tooting Bec Hospital between October 1964 and December 1966 Bewley and Ben-Arie (1968) found that in the 2 1/4 years over which patients were followed up there were a further 155 admissions including readmissions to Tooting Bec. In addition there were 148 admissions to other hospitals including 95 to other mental hospitals.

The status of all patients was checked in January 1968. Forty-four were found to be taking heroin and nine some other opiate. Two were in hospital and 12 in prison; five were out of the United Kingdom. Fifteen were not known to be taking opiates and 13 were dead. The main cause of death was overdose.

In a further study Bewley, Ben-Arie and Marks (1968) reviewed 121 cases of jaundice in heroin addicts. Extensive liver function tests carried out on a further 284 addicts showed that 60 % had evidence of hepatocellular damage. Fifty of the latter group were questioned and none were found to regularly employ aseptic injection techniques. Of the 121 cases in which jaundice occurred the condition was most often attributed to sharing someone else's needle.

Marks and Chapple (1967) found that empirical liver function tests carried out on an unselected group of 89 heroin and cocaine users attending psychiatric out-patients or in-patient units revealed some degree of abnormality in 80% of cases. Six of the patients were jaundiced. Serial determination showed that in some cases the cessation of intravenous heroin and cocaine injections led to rapid restoration of liver function. Conversely resumption of the habit was associated with large and rapid rises in serum transaminase levels. Evidence of liver damage was rare in patients whose abuse was confined to the use of amphetamines, barbiturates or cannabis.

In a study of 436 non-therapeutic addicts first known to the Home Office between 1955 and 1964 James (1967) found a male mortality rate of 27 per 1,000 per year or 20 times the expected mortality rate for the male population of similar age. The mortality rate among female addicts was considerably less (3.3%) but even so it was over five times the expected mortality rate for females of the same age. Five of the male addicts committed suicide and four others died in circumstances which indicated suicide, giving a suicide rate among the male heroin addicts which was 50 times the expected suicide rate for a normal population corrected for age.

4. Operational research

There have been very few papers published comparing the efficacy of different programmes of treatment or even assessing the effect of treatment. Chapple and Gray (1968) have reported on one year's work at a centre for the treatment of addicts which operates three major treatment programmes, (1) a general supportive programme which included the prescribing of heroin, (2) a methadone maintenance programme and (3) an "off narcotics" programme. The fact that the allocation of patients to programmes was made at the doctors' discretion, however, precludes their comparison.

Zacune, Mitcheson and Malone (1969) have followed up the heroin users identified in the survey reported by Kosviner et al (1968). Data were collected one year later on the 37 heroin users previously identified and 14 newly identified users of heroin. Six of the original sample of 37 were not using heroin at all on follow-up, 16 were daily users and 12 irregular users. Of the six subjects who were off heroin, four had been daily users in the original survey, three had been successfully withdrawn and treated in hospital and one treated as an out-patient. In contrast to the original findings the number of persons registered with local medical practitioners had increased markedly as a result of the establishment of a containment unit and a deliberate policy of local prescribing. Recourse to illegal supplies had as a consequence diminished considerably. Eleven of the 37 subjects had been admitted to hospital a total of 23 times in the past year for treatment of their addiction. Twelve of these admissions were followed by relapse within a week, five within a month, three within two months; three cases remained abstinent for at least three months and were still abstinent at the time of the survey.

The fourteen newly identified cases tended to come from working class backgrounds, to have spent less time in full-time education and to have been involved in more serious delinquency than those originally identified. They appeared to have had little contact with the original sample and until the containment unit became the main source of drugs there was little communication between the two groups. A deliberate policy of registering patients with local G.Ps resulted in an increase in the total amount of heroin used since users were no longer dependent on the fluctuations of the illicit market. There was no evidence, however, that legally prescribed heroin came onto the illicit market in any significant amount. When the containment unit became the only legal source of heroin and cocaine, some of the subjects who had been irregular users of heroin obtained regular supplies of methadone from their general practitioners.

Zacune et al point out that while the total number of daily heroin users had not increased since the original survey was carried out it is impossible to assess the change in the total pattern of drug use in the town. While the Dangerous Drugs Act of 1967 is primarily aimed at heroin abuse it would be unwise to measure the over-all success of a policy for stopping the spread of drug addiction by reference to heroin only.

Edwards (1969) has analysed the assumptions underlying the British approach to the treatment of heroin addiction. Without attempting to assess the efficacy of the British system Edwards set out the hypotheses underlying the system and deals with some of the difficulties which arise; difficulties which include the problem of patients who do not need heroin demanding registration, the difficulty of ascertaining the appropriate dose, the use of compulsion and the concept of the stabilized addict.

Clark (1962) has reported the follow-up of 65 patients admitted to the Crighton Royal Hospital between 1949 and 1960 all of whom were drawn from the medical or nursing professions. The duration of follow-up varied from two to twelve years, though almost 60 % were followed up for five years or more. Fifty-six per cent of the patients were addicted to drugs controlled by the Dangerous Drugs Acts and 44 % were addicted to other drugs. The three categories employed in assessing prognosis were (1) whether further consumption of drugs had taken place, (2) whether further hospitalization had occurred, (3) whether full working capacity had been resumed. Employing these criteria 28 % of the patients had overcome their addiction though only 14 % of those addicted to drugs under the Dangerous Drugs Acts remained drug free. Fifty-two per cent of the total group required further hospitalization. Of the total group 30 % had continued their profession since discharge, however, of those addicted to drugs controlled under the Dangerous Drugs Act only 18 % continued their medical practice. Twenty-six per cent of the total had no gainful employment after discharge. The largest group of patients was comprised of those who had resorted to drugs for varying periods of time and in varying dosages since being discharged. Included in this group were a few patients who had become stabilized on regular doses of drugs and who appeared otherwise to manage their lives relatively satisfactorily provided the drug was maintained.

Kraft (1969) has described the successful treatment of a case of chronic barbiturate addiction using the method of systematic desensitization. Relaxation was induced by intravenous injections of 2.5 per cent solution of methohexitone sodium following which a number of situations generating anxiety were presented in ascending order. A similar technique applied to narcotic addicts produced a less favourable outcome however (personal communication).

Rathod and Thomson (1968) have published a preliminary report of the efficacy of aversion treatment. The technique used involved injecting 30 mg Scoline so that paralysis was produced at approximately the same time as the patient injected himself after which he was submitted to forceful accounts of the dangers of using heroin. Treatment consisted of five such sessions carried out over successive days. Ten patients underwent treatment having a total of 49 sessions. None ever used the heroin left with them after each treatment session. Eight of the patients continued to be drug free while in hospital for an average period of 13 weeks. One patient was discharged immediately after the fifth treatment session and remained drug free in the community for a period of 23 weeks. One patient relapsed eight weeks after the fifth treatment session and was treated again after which he remained drug free for 17 weeks.

In addition to the ten patients who underwent treatment three abandoned treatment after one or two sessions, two absconded and relapsed immediately into regular use and the third relapsed onto oral morphine. While there was no control group there were nine patients who either did not complete the treatment or else were never offered it, who resembled the treated patients as regards their social background and intellectual abilities. The outcome of treatment of these patients was very different from that of the fully treated patients in that none of them had been discharged and only three had been drug free for any period while in hospital. The authors emphasize that the conditioning procedure described forms part of a total therapeutic programme which includes withdrawal under methadone, group and individual psychotherapy, occupational therapy, consultation with parents and group therapy support on discharge.

5. Completing the clinical picture and the identification of syndromes

Those studies which have added to the clinical description of drug dependence in the United Kingdom have been reviewed in earlier sections.

There have been few comprehensive accounts of particular syndromes published. Connell's (1958) description of amphetamine psychosis is a notable exception and is too well known to require elaboration. Suffice it to say that more recent studies (Kramer et al 1967; Hawks et al 1969; Smith 1969) have confirmed Connell's view that psychotic episodes are a frequent occurrance in people abusing amphetamines.

A number of studies, mainly unpublished, have described the student cannabis taker, estimated in a variety of sources (Sington 1965, Linken 1968a, Binhie 1969) as constituting about 10 % of the student population. In the few studies that have been carried out on English populations (Binnie 1969; Webb et al 1969) it has been consistently found that those students who have smoked cannabis have rarely used other drugs with the exception of amphetamines. The majority who have used cannabis tend to have done so on only a few occasions and if differentiated from non-smokers at all tend to be more radical and permissive in their political and social attitudes. Webb et al (1969) found that those who had smoked cannabis consulted a psychiatrist more often in their lives and saw their general practitioner more often during the previous year. They were also more likely to report that they were regarded as trouble-makers at school and had in fact committed more offences of any sort than non-users. Those students who had smoked cannabis tended to have been both earlier and heavier users of both tobacco and alcohol-the more often they reported being drunk the more likely they were to be experienced users of cannabis. Somewhat surprisingly there was no relationship between multiple drug use and continued cannabis use. There is very little objective data on the vexed question as to whether previous cannabis use predisposes toward subsequent drug dependence. While it is frequently attested that the majority of heroin users in the United Kingdom have smoked cannabis, estimates as to the number of cannabis users who become heroin addicts vary considerably, and in part reflect the particular group considered.

6. Clues to causes

Morris has pointed out that the prime objective of epidemiology is to suggest causes and it is particularly in this capacity that those studies which have been carried out are deficient. It is perhaps inevitable that investigations conducted in response to an urgent social problem be descriptive. Those that have been carried out have largely revealed the extent of the problem and the characteristics of those affected and have not been designed to allow comparisons calculated to demonstrate causal connexions. There are immense difficulties in ensuring the latter and at least some of the difficulties peculiar to the study of drug dependence have been alluded to in the introductory section of this paper. Because of the difficulties associated with retrospective studies it is unlikely that the causal factors involved in drug dependence are going to be illuminated until prospective studies are carried out. Prospective studies in the area of drug dependence are extremely uneconomical because of the rarity of the condition and any attempt to make them more economical by considering only "at risk" groups requires some preconception of vulnerability. In the absence of studies designed to enable causal significance to be attached to certain factors a large number of variables have been implicated. These include material deprivation, delinquency, parental separation and bereavement, truancy, school failure, work instability, neuroticism, risk taking and precocity. Many of these are effects as much as they are causes.

While any generalisation in this area is attended by numerous exceptions there is little evidence in England that drug dependence is closely associated with material deprivation, nor does it appear to be closely identified with delinquency though the tendency to see those two forms of deviance as independent is not supported by the finding that a sizable minority of drug dependent persons will have displayed delinquent tendencies before becoming drug dependent. It has been suggested by some that the disparity between the aspirations of parents and children may contribute to drug dependence in middle class children. Others have proposed that the tendency for heroin addicts to be of above average intelligence may create a discrepancy between their potential and the opportunities offered them. Many of these factors are implicated in virtually every study of deviance (including mental illness) and it is perhaps simple minded to imagine that the factors contributing to drug abuse are going to be different from those which contribute to other forms of personal and Social pathology. A number of the studies reviewed have pointed to the importance of exposure to drugs and the role played by associates in initiating drug use and it is perhaps to these factors that we must turn if we are to explain the selectiveness of drug dependence. While the tendency in America is for drug dependence to be associated with delinquency this same tendency is not found to the same degree in the United Kingdom where delinquency is more often an effect or a consequence of drug dependence than its precursor. A number of studies in the United Kingdom have on the other hand emphasized the prevalence of prior psychiatric disturbance in people who become heroin addicts.

Despite these limitations a number of studies suggest associations having possible causal significance.

Noble (1970) carried out a retrospective survey of 67 boys referred to a London Remand Home during the years 1965-1967 all of whom were known to have taken drugs. The boys were divided into a hard and a soft group according to whether there was evidence of their taking narcotic drugs. When the groups were compared the hard group showed a significantly greater incidence of abnormal personality, family history of psychiatric illness and disturbed relationships within the family. The two groups did not differ as regards the number of previous convictions. The tendency for the hard group to display more disturbance could not be attributed to the deleterious effects of narcotic taking as twice as many of the hard group showed prior personality abnormality. Twice as many of the hard group's siblings had either juvenile court convictions or were known to the authorities to be in need of care (44 % versus 20 %). Eighty-one per cent of the hard group and 55 % of the soft group had poor work records since leaving school. While none of the boys in the soft group were known to the Home Office to have taken narcotics at the time of the initial assessment, subsequent examination of the Home Office files showed that 19% had progressed to hard drugs by June 1969 While their small number precludes detailed statistical analysis those soft drug users who progressed to hard drugs tended to be worse off in terms of their degree of personality disturbance, the incidence of psychiatric morbidity within the families and their work records.

Crockett and Marks (1969) in a study of amphetamin taking in a remand population found an over-all incidence of 6.9 %. Personality assessment showed that drug takers tended to be more self critical, conflicting in feelings and attitudes, more honest in their responses and generally more neurotic than non-takers.

Scott and Willcox (1965) in their study of two London remand homes distinguish two categories of male amphetamine user. The malignant user invariably come, from a grossly unfavourable home background and demonstrates a basic lack of confidence in making personal relationships together with an overdependence on one parent, usually the mother. The use of amphetamines by this group, who Scott and Willcox claim always to manifest a serious personality disorder, serves a compensatory function.

The benign user by contrast confines his amphetamine use to the weekends and does not increase his dosage. His home background is less unsatisfactory and he shows a greater capacity to make personal relationships with both sexes. Scott and Willcox argue that the relationship between crime and delinquency in both groups is parallel rather than causative, though they do not discount the possibility that drugs may exacerbate a pre-existing criminal tendency.

Backhouse and James (1969) report a study in which they investigated the relationship and prevalence of smoking, drinking and drug taking in delinquent adolescent boys. Of the 290 adolescent boys (14-16 years old) interviewed at a detention centre, 83 % admitted smoking cigarettes (22 % smoked more than 20 cigarettes per day), 63 % drank alcohol (27 % regularly and 7 % excessively) and 31 (12 %) admitted taking drugs. It was established that there was a positive relationship between drinking, smoking and drug taking among those interviewed. A replication of the study in the following year (1968) provided substantially similar results. Some indication of the significance of these associations is given by the fact that of the non-smokers, 6 % had misused drugs and 18 % drank alcohol regularly or excessively. By contrast, of the heavy smokers (that is people who smoke 19 or more cigarettes a day) 21 % had misused drugs and 40 % drank alcohol regularly or excessively.

Linken (1965) in a study of 27 students seeking advice for emotional difficulties in which drug taking played a part reports that 48 % had suffered parental loss and 59 % complained of prolonged depressive symptoms which they saw as a reason for taking drugs. Sixty- seven per cent had abused drugs before entering university. In a study of drug taking among young patients attending a clinic for venereal diseases Linken (1968b) ascertained that 18 % used drugs. The respective percentages for males and females were 16 % and 23 %. Sixteen per cent reported that they had been under psychiatric treatment and 2% reported having been in trouble with the police.

Bewley and Ben-Arie (1968) found that 100 male heroin addicts discharged from Tooting Bec Hospital did not differ in their religion, marital status or educational background from those of the population except that there was some tendency for a greater number of the addicts to be Jewish. As a group the addicts were more likely to be smokers and those who smoked tended to be heavier smokers than the rest of the population. Fourteen per cent were assessed as being excessive drinkers before starting heroin. Bewley et al note that there was generally a history of deviant behaviour occurring prior to drug taking in this group. The authors add however that those patients seen at Tooting Bec are not representative of all heroin addicts in that there is a tendency to admit those who are already ill or have a history of complications. They were also a group in which there was a high rate of conviction prior to first admission.

Kosviner et al (1968) in their study of heroin use in a provincial town employed parents' occupation as the basis for assessing the socio-economic class of their subjects. They found a marked tendency for the parents to be professionally employed even when corrected for the particular occupational bias exhibited by the town. Twenty-four subjects had a sibling of similar age and of these eight had tried or were using drugs. In contrast to other samples the majority of subjects were living at home with their parents. Most had attended schools where they had relatively good chances of gaining academic qualifications and entrance to higher education. Despite these opportunities the mean age of leaving school was 16 years and only nine subjects remained at school after 16. Nineteen had gone on to some form of full-time further education of whom 13 failed to complete the course.

While no detailed clinical examination was carried out it was ascertained that prior to drug use four subjects had been in touch with psychiatric services, three had brief attendances at child guidance clinics and one had attended a psychiatric out-patient department. Twenty were known to have convictions. Of the ten people who had been convicted of non-drug offences three had committed these before using any drugs at all and seven between first taking drugs and trying heroin. Only one person was convicted of a non-drug offence after starting heroin and this person had already been convicted of such a crime before the onset of heroin use. The authors conclude that the group bore little resemblance to those studied elsewhere. Even so there was no characteristic common to all the users. The characteristics most widely shared by the users were their high social class background and failure to complete courses despite good educational opportunities. The authors suggest that middle-class adolescents subjected to academic pressures and high parental expectations may use heroin as a reaction to this stress. In other cases it would appear that heroin was used as a positive act of rebellion rather than a means of dropping out.

Hawks et al (1969) in a study of 74 regular users of methylamphetamine injections found that 41 % of the sample had some definite or tentative evidence of neurotic disturbance in childhood. Twenty-three per cent had been sentenced to detention centre, approved school or borstal training and 20 % had been sentenced to prison. Sixty-five per cent had been charged with offences of one sort or another and 24 % had been convicted of both drug and non-drug offences. The majority at best had been employed in semi-skilled occupations and a comparison of their best and present occupation showed that there had been some downward mobility. Sixty-five per cent had not taken any examinations while at school and of those who pursued further education the majority had discontinued this prematurely. Consistent truancy from secondary school was reported by one half of those interviewed. Of the total sample slightly less than half had suffered parental bereavement or separation before they were 16 years old. There was evidence that a significant number had been heavy drinkers in the past. The degree of family pathology was assessed in terms of the frequency with which drinking problems, criminality, drug abuse and psychiatric illness in the parents and siblings was mentioned. While the absence of appropriate normative data prevented any assessment of the significance of this data the frequency with which the factors were mentioned appeared excessive.

Mitcheson et al (1970) in a study of sedative abuse by heroin addicts collected information which allows a comparison with that reported by Hawkes et al. The 65 subjects interviewed attended one of three day centres open to heroin addicts. Fifty-two per cent had experienced separation from one or both parents for a period of at least two years before the age of 16. Thirty-two per cent had been separated from both parents. Less than half had completed any examination when leaving school. All but one of the subjects had used methylamphetamine injections and 80% had injected barbiturates. Sixty-nine per cent had been on prescription for barbiturates. The tendency for those interviewed to have taken a wide variety of drugs in the past and to resort to both legal and illegal sources for their current supply of drugs, reported in previous studies, was confirmed.

Willis (1969) has compared hospitalized addicts in the United Kingdom and United States. He ascertained that in both groups a "friend" appeared to have initiated the use of heroin. The principle reasons for using heroin were curiosity as to its effect and its influence on depressed mood. In a minority of cases there was substantial evidence of manifest mood disturbances prior to heroin addiction. U.S. subjects had been using heroin longer as a result of starting at an earlier age. Females in both countries tended to be exposed to heroin earlier. It is generally conceded that females who become heroin addicts display greater pathology than male addicts. In contrast to their U.S. counterparts the U.K. addicts tended more frequently to have taken amphetamines, marihuana, cocaine, LSD and other opiates. The U.K. addicts whether male or female also tended more often to show strong craving and personal involvement. Excessive drinking was also reported more frequently by the U.K. subjects.

Conclusions

What then might one conclude from this review are the priorities which should guide future research in this area ? What would seem to be called for is not more and more research but more systematically applied research. It is possible to observe a variety of things being done in the treatment of heroin addicts, but done in a way which rarely anticipates evaluation. What is required is some conscious deliberation to test the effects of specific programmes rather than multiply the number of post hoc and inevitably anecdotal accounts of r├ęgimes which have not incorporated explicit techniques or objectives.

There is no lack of studies suggesting hypotheses - what is lacking are investigations explicitly designed to test such hypotheses rather than generate more, equally ambiguous, hunches. It has already been argued that such studies are likely to be prospective, which because of the relative rarity of the condition, will involve large numbers or else concentrate on "at risk" segments of the population. Studies such as those carried out by Weiner (1968), Wright (1968) and Murphy et al (1969) involving non-dependent, occasional drug users suggest criteria for the selection of such populations.

Weiner found that his occasional drug users, the majority of whom had used drugs only once or twice, were differential from non-users in terms of their knowledge of drugs, their precocious social attitudes and behaviour and their perception of themselves as antiauthority. Murphy et al compared 59 regular drug users including 20 registered heroin addicts with a control group drawn from the same school leaving class lists. While the potential drug users were not differentiated from their controls in terms of their school leaving age, pursuance of further education or school performance they were more often thought by their teachers to be "heading for trouble". The significance of this finding, which is based on confidential reports submitted by class teachers to the Youth Employment Office, is all the more notable when it is considered that these reports pre-dated drug use and did not merely reflect the fact that potential drug users came from broken homes.

It is usually contested that prospective studies are too expensive and too time consuming; the alternative however would seem to be to support a host of unconnected investigations whose logical ambiguities render them even more uneconomical vehicles of research. It is at least arguable that an equally viable alternative to attempting to reconstruct the aetiology of drug dependence whether retrospectively or prospectively from addicts' reports is to investigate the treatment process. A consideration of those factors influencing treatment may provide as economical an approach to the understanding of the addictive process as the more traditional historical analysis.

It seems highly improbable that a singular answer to drug addiction will be found - its explanation almost certainly resides in the same conglomerate of factors which promotes and sustains other manifestations of social and personal maladjustment and inadequacy. If this is so our emphasis should perhaps be on applying what we already know rather than attempting to add to the already multitudinous factors contributing to social and personal malaise in the hope of achieving a unique solution.

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