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Continued heroin use during methadone treatment: relationships between frequency of use and reasons reported for heroin use
Drug and Alcohol Dependence 53 (1999) 191 – 195
Continued heroin use during methadone treatment: relationships between frequency of use and reasons reported for heroin use David Best *, Michael Gossop, Duncan Stewart, John Marsden, Petra Lehmann, John Strang National Addiction Centre, 4 Windsor Walk, Denmark Hill, London SE5 8AF, UK Received 6 January 1998; received in revised form 14 April 1998; accepted 23 June 1998
Abstract Seventy-seven (71%) of a group of 109 attenders at an out-patient drug treatment service reported that they had used heroin in the 90 days before interview, of whom 24 (31%) had used every day. Daily users were more likely to explain their use in terms of needing to curb withdrawals than were occasional heroin users. The latter group were more likely to report availability as a reason for use. From a clinical perspective, it is likely that those who use opportunistically are less likely to change their use as a function of clinical responses (e.g. higher methadone dose) than are those whose use is motivated by the attempt to curb withdrawal symptoms. © 1999 Published by Elsevier Science Ireland Ltd. All rights reserved. Keywords: Withdrawal; Methadone dose; Illicit heroin; Frequency of use; Reasons for use
1. Introduction Methadone treatment has been found to be associated with reductions in illicit drug use. The TOPS study (Hubbard et al., 1989) showed that those who stayed in methadone maintenance treatment for at least 3 months decreased regular heroin use from 65 to 70% in the year before treatment to 25 – 30% during treatment. Similar findings for reduced illicit heroin use has also been reported in British (Gossop et al., 1997) and other American studies (Simpson and Sells, 1982; Ball and Ross, 1991). Heroin use is not completely prevented by the initiation of methadone substitution treatment (Bell et al., 1990). Howard, et al. (1995) found that 57% of addicts attending a methadone programme in Sydney had used heroin at least once in the month before interview, and that 30.6% had used in the previous week. Similarly, while Ball and Ross (1991) found a reduction in illicit * Corresponding author.
drug use among those entering methadone substitution treatment, 29% of their sample reported that they had used drugs intravenously in the month before interview. McLellan et al. (1993) found that addicts who receive ancillary services such as counselling and psychotherapy showed markedly greater improvements than those who received methadone alone. There has been debate about the appropriate dose of methadone to be provided to addicts. Although Newman and Des Jarlais (1991) failed to confirm the relationship between methadone dose and heroin use, others have argued that high doses of methadone are more effective in suppressing illicit drug use. Stitzer et al. (1986) found that an abrupt increase in dose (from 30 to 60 mg) of methadone daily reduced illicit heroin from 80 to 62% in the first 2 weeks. Ball and Ross (1991) reported that when addicts were given doses of between 5 and 50 ml of methadone, many supplemented their dose with illicit heroin. In contrast, only 6% of the addicts who received doses of 60–100 ml reported continuing to use illicit heroin (Ball
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and Ross, 1991). Finally, Caplehorn and Bell (1991) reported that methadone maintenance patients receiving 60 mg or less of daily methadone were 4 – 8 times as likely to leave treatment as those receiving the maximum daily dose of 80 mg. However, little attention has been paid to the question of why methadone patients continue to use heroin. The explanations given by patients for their continued use of heroin has been widely ignored in favour of deterministic models which explain relapse in terms of dosing issues (Ball and Ross, 1991) or in terms of the situations in which the drug episode occurs (Marlatt, 1985). The current investigation further examines the issues of illicit heroin use during methadone maintenance treatment. The study looks specifically at the relationship between methadone dose and illicit heroin use among addicts receiving methadone substitution treatment. This relationship is also considered in terms of the reasons given by respondents for continued use of heroin. The study assesses the extent to which self-reported reasons for continued heroin use mediate the relationship between methadone dose and frequency of heroin use during treatment. If different patterns of continued heroin use are associated with self-reported reasons, then risk factors for relapse can be understood in terms of intrapsychic explanations as well as contextual variables.
Reasons for heroin use were closed categories selected on the basis of pilot interviews and asked to what extent heroin had been used ‘for its pleasurable effects’, ‘to manage withdrawal effects’, or ‘for no other reason than that it was available at the time’. Finally, respondents were asked to complete a Severity of Dependence Scale (SDS) (Gossop et al. 1995). While a number of reasons were given for continued use, the independent judges considered these to be the most comprehensive classes of the reasons given. The interview focused on behaviours in the previous 90 days, with cue cards provided for easy calculation of frequencies (for example 5 days/week as 65 days). Methadone dose was self-reported in interview and confirmed by comparison with patient case notes. Clients were given assurances about confidentiality of information obtained. The mean age of subjects was 34.6 years (S.D. 6.5 years). 78 were men and 31 were women. Ninety seven (89%) had lived at home for the previous 90 days, five (4.6%) in bedsits, three in hostels, two in squats and two on the street. They had been, though not necessarily in the same treatment programme, receiving a methadone prescription for an average of 4.3 years (S.D. 4.9 years), with a mean dose of 61.8 mg (S.D. 19.4, range 10–160 mg). All methadone was prescribed in the form of oral linctus. They had been using heroin for an average of 10.5 years (S.D. 6.9 years).
2. Method
3. Results
Data were gathered on 109 addicts recruited as they attended an out-patient drug treatment service in South London. The treatment centre, Marina House, is a statutory NHS treatment facility which offers maintenance to abstinence services. Patients were approached as they entered the building and were interviewed either before or immediately after their clinical transaction. The brevity of the interview (average completion time was around 7 min) ensured that almost no attenders were ‘missed’. One hundred and thirteen consecutive attenders were approached, of whom four refused to participate, producing a sample of 109 opiate addicts in treatment. A structured interview examining reasons for use, patterns of substance activity, and treatment details was conducted by an independent researcher. The drug grid, examining quantities and frequencies of prescribed and illicit drug use, was taken from the Maudsley Addiction Profile (Marsden et al., in press) with the time period extended from 30 to 90 days, as were the demographic characteristics of the population. The decision to use a 90-day time period was to detect any recent heroin activity, and so the period was chosen, on the basis of pilot testing, to detect any recent use that could be accurately recalled.
Seventy-seven (70.6%) of the addicts had used heroin on one or more occasions in the 90-day period prior to interview. The mean number of days of heroin use for these 77 heroin-using patients was 38.7 (S.D. 36.6 days), with 24 (22.0%) reporting that they had used heroin on all 90 days in the 3-month period (Table 1). Frequency of heroin use forms the basis of categorisation of addicts into three groups—those who had not used heroin at all in the 90-day period, subsequently referred to as ‘non-users’ (n= 32, 29.4%), those who had used heroin every day (‘daily users’, n= 24, 22.0%) and those who had used heroin, but not on a daily basis (‘occasional users’, n= 53, 48.6%). Of the occasional users, 47 (88.7%) had used between 1 and 30 days in the Table 1 Frequency of heroin use in the last 90 days Days of heroin use in the last 3 months Number Percentage 0 1–30 31–60 61–89 90
32 47 6 0 24
29.4 43.1 5.5 — 22.0
D. Best et al. / Drug and Alcohol Dependence 53 (1999) 191–195
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Table 2 Frequency of heroin use by reason given among daily and occasional heroin users Reasons
Test
Occasional heroin users (n =53)
Daily heroin users (n = 24)
t-test/x2
P
For pleasure
Mean (t-test) Category (x)
2.3 (9 1.15) n = 36/53; 67.9%
2.0 (9 1.20) n =12/24; 50.0%
t =0.83 x2 =2.3
0.41 NS
To curb withdrawals
Mean Category (x)
2.7 (9 1.34) n= 34/53; 64.1%
3.5 (90.18) n = 22/24; 91.7%
t= 3.17 x2 =4.0
B0.01 B0.05
Availability
Mean Category (x)
1.5 (9 0.99) n =11/53; 20.8%
1.1 (90.41) n =1/24; 4.2%
t= 2.6 x2 =6.3
B0.05 B0.05
Reasons for heroin are scored on a 4-point scale from 0 (never) to 4 (always).
last 90 days, 6 (11.3%) between 31 and 60 days and none between 61 and 89 days in the last 3 months. The groups did not differ in terms of their length of time in treatment, their sex, or their age (the only demographic characteristics on which data were collected). Those who used no heroin in the last 3 months (‘non-heroin users’) were receiving a higher mean daily dose of prescribed methadone (72.6 9 34.5 mg) than those who had used heroin at some point in the previous 3 months (mean= 56.8 9 27.1 mg; t= 2.29; PB 0.05). There was no difference in mean dose of prescribed methadone between ‘occasional users’ (mean= 56.2925.5 mg) and ‘daily users’ of heroin (mean =58.7932.7 mg).
3.1. Reasons for using heroin Examining the 77 patients who reported heroin use in the study window, each respondent was asked the frequency with which they used for each of the three reasons offered. Thirty-nine (50.6%) reported that they always used ‘to curb withdrawals’, 14 (22.1%) that they often used for this reason, three (3.9%) occasionally and 21 (27.3%) never used to curb withdrawals. Twenty-nine (37.7%) reported that they never used for ‘pleasure’, 19 (24.7%) that they occasionally did so, 13 (16.9%) that they often did so, and 16 (20.8%) that they always used for pleasure. Sixty-four (83.1%) said that they never used simply because the drug was available, three (3.9%) that they did so occasionally, five (6.5%) often and five (6.5%) always. The subjects who reported that they had used heroin in the previous month were also asked to indicate their main reasons for using heroin. The relationship between frequency of heroin use and reported reasons given among daily and occasional heroin users is given in Table 2. While there is no difference in the frequency with which either group of addicts use heroin for pleasure, differing responses were elicited with the other two prompted reasons. As shown in Table 2 daily heroin users were more likely to report heroin use to curb withdrawals than occasional heroin users (92 vs. 64%,
respectively) whilst occasional users were more likely to report that they used heroin simply because it was available than were the daily users (21 vs. 4%, respectively).
4. Discussion More than 70% of the addicts receiving treatment in this sample had used heroin while being prescribed methadone in the 3 months before interview. The most common reason given for heroin use was to curb withdrawals, although more than half of those who had used heroin in this period reported that they had done so at least occasionally for pleasure. The least common reason reported for use was availability, although this was a more common explanation among occasional heroin users than among those who had used heroin on each day in this period. In contrast, daily users were significantly more likely to explain their use in terms of curbing withdrawals than the occasional users. It is possible that those who reported less than daily use had spells of daily use within the period which may have influenced the results. However, as none of the occasional users had used for more than two-thirds of the days available in the 3-month target period, they can be conceptually differentiated from the group whose illicit use is continuous over such a prolonged treatment period. Almost all of the daily heroin users reported that the main reason for their use was to curb withdrawals. This finding may have implications for the dosing procedures used, as it suggests that they may not be receiving sufficient medication to suppress the emergence of withdrawal symptoms. However, the fact that almost twothirds of those who had used heroin reported doing so for pleasure at some point in the previous 3 months and more than one in six had used simply because heroin was available suggests a high level of hedonistic and/or opportunistic heroin use. It is perhaps appropriate to differentiate hedonistic heroin use from use for withdrawal relief since it is more likely to be associated with opportunity and so unrelated to the effectiveness of the
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methadone they receive, in particular the amount prescribed. Methadone patients who are daily heroin users are more likely to explain their heroin use in terms of managing withdrawals than methadone patients who use heroin only occasionally. The occasional users were more likely to report that they used heroin simply because it was available, than were the daily users. These results suggest that there may be different strategies underpinning heroin use among opiate addicts in treatment that are associated with the frequency of illicit use. This may suggest that the quest to suppress opioid abuse by changes in methadone dose (Stitzer et al., 1986; Nolimal and Crowley, 1990) will only succeed for a sub-sample of those patients in treatment who continue to use heroin — those who do so to suppress withdrawal discomfort. These findings also support the association between methadone dose level and heroin use reported in a number of previous studies (Caplehorn et al., 1976; Ball and Ross, 1991; Caplehorn and Bell, 1991; Strain et al., 1993). This effect has not previously been shown in research undertaken in the UK. A number of possible confounding factors can be identified as possibly having disguised this effect, including lack of power in smallsample studies, the possible distorting effect of the largely unsupervised dispensing of methadone in the UK (Strang, et al., 1996), as well as the association we have reported above of different frequencies and reasons for such heroin use. If it is correct that high doses are likely to curb heroin use in those whose main reason for use is to curb withdrawals, but less likely to affect the heroin use of methadone patients whose reasons for use are not related to withdrawal experiences. Therefore, addicts in treatment who use heroin simply because it is available (perhaps as a consequence of the use patterns of partners or peers) may be less likely to change the frequency of heroin use as a response to increased methadone dose. The assumption of a relationship between dose and frequency of heroin activity assumes that heroin use is motivated only by physiological factors that are amenable to pharmacological manipulation by clinicians. Previous research with a similar sample population (Best et al. 1997) indicated that there is a relationship between the time of consumption of methadone use and illicit heroin use by addicts in treatment. The pharmacokinetic argument raised in this paper is that, while the use of methadone early in the day may provide a protective effect, those who consume their methadone later in the day may increase the possibility of experiencing craving (based on withdrawals) in the early part of the day. The possibility that there may be a pharmacokinetic association between pattern of methadone use, drug cravings, and illicit heroin use should not be
discounted as a pharmacological sub-stratum for the experiential reporting of discomfort. On the other hand, if heroin use by methadone patients is portrayed in terms of arbitrary social factors, such as opportunity and social setting, different explanations such as hedonistic motives, peer pressure and simple availability gain currency. This group are not likely to be exclusively using heroin as a consequence of physiological factors and so this pattern of illicit substance activity is less readily amenable to manipulation by increased substitute prescribing. There are two implications that can be drawn. The first is that the failure to observe a consistent relationship between methadone dose and continued use of heroin may result from the fact that relief of withdrawal represents only a partial explanation of heroin use by opiate addicts in treatment. The second is that motives for heroin activity may vary from one addict to another or even, from one occasion to another for the same addict. As a consequence, it is important that future research investigates the nature of the relationship between methadone dose and continued heroin use and also examines the effects of different motives for continued heroin use whilst on methadone.
References Ball, J.C., Ross, A., 1991. The Effectiveness of Methadone Maintenance Treatment: Patients Programs, Services and Outcomes. Springer-Verlag, New York. Bell, J., Fernandes, D., Batey, R., 1990. Heroin users seeking methadone treatment. Med. J. Aust. 152, 361 – 364. Best, D., Gossop, M., Marsden, J., Farrell, M., Farrell, M., 1997. Time of day of methadone consumption and illicit heroin use. Drug Alcohol Depend. 49, 49 – 54. Caplehorn, J.R.M., Bell, J., 1991. Methadone dosage and retention in maintenance treatment. Med. J. Aust. 154, 195 – 199. Caplehorn, J.R.M., Bell, J., Kleinbaum, D.G., Gebski, V.J., 1976. Methadone dose and heroin use during maintenance treatment. Addiction 88, 119 – 124. Gossop, M., Darke, S., Griffiths, P., et al., 1995. The severity of dependence scale (SDS): psychometric properties of the SDS in English and Australian samples of heroin, cocaine and amphetamine users. Addiction 90, 607 – 614. Gossop, M., Marsden, J., Edwards, C., et al., 1997. The national treatment outcome research study in the United Kingdom: 6 month follow-up outcomes. Psychol. Addict. Behav. 11 (4). Howard, K., Bell, J., Christie, M.J., 1995. Measuring heroin use in methadone maintenance programmes. Drug Alcohol Rev. 14, 27 – 34. Hubbard, R.L., Rachal, J.V., Craddock, S.G., Cavanaugh, E.R., 1989. Treatment outcome prospective study (TOPS): client characteristics and behaviours before, during and after treatment. In: Timms, F.M., Ludford, J.P. (Eds.), Drug Abuse Treatment Evaluation: Strategies, Progress and Prospects. NIDA Research Monograph, 51. Marlatt, G.A., 1985. Relapse prevention: theoretical rationale and overview of the model. In: Marlatt, G.A., Gordon, J.R. (Eds.), Relapse Prevention: Maintenance Strategies in the Treatment of Addictive Behaviours. Guildford Press, New York, pp. 3–70.
D. Best et al. / Drug and Alcohol Dependence 53 (1999) 191–195 Marsden, J., Gossop, M., Stewart, D., et al., in press. The Maudsley addiction profile (MAP): a brief instrument for assessing treatment outcome. Addiction (in press). McLellan, A.T., Arndt, I.O., Metzger, D.S., Woody, G.E., O’Brien, C.P., 1993. The effects of psychosocial services in substance abuse treatment. J. Am. Med. Assoc. 269, 1953–1959. Newman, R., Des Jarlais, D., 1991. Criteria for judging methadone maintenance programs. J. Am. Med. Assoc. 265, 2190–2191. Nolimal, D., Crowley, T., 1990. Difficulties in a clinical application of methadone-dose contingency contracting. J. Subst Abuse Treat. 7, 219 – 224. Simpson, D.D., Sells, S.B., 1982. Effectiveness of treatment for drug
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abuse: an overview of the DARP research program. Adv. Alcohol Subst. Abuse 2, 7 – 29. Stitzer, M.L., Bickel, W.K., Bigelow, G.E., Liebson, I.A., 1986. Effect of methadone dose contingencies on urinalysis test results of polydrug-abusing methadone-maintenance patients. Drug Alcohol Depend. 18, 341 – 348. Strain, E., Stitzer, M., Liebson, I., Bigelow, G., 1993. Dose-response effects of methadone in the treatment of opioid dependence. Ann. Int. Med. 119, 23. Strang, J., Sheridan, J., Barber, N., 1996. Prescribing injectable and oral methadone to opiate addicts: results from the 1995 national postal survey of community pharmacies in England and Wales. Br. Med. J. 313, 270 – 272.
Continued heroin use during methadone treatment: relationships between frequency of use and reasons reported for heroin use David Best *, Michael Gossop, Duncan Stewart, John Marsden, Petra Lehmann, John Strang National Addiction Centre, 4 Windsor Walk, Denmark Hill, London SE5 8AF, UK Received 6 January 1998; received in revised form 14 April 1998; accepted 23 June 1998
Abstract Seventy-seven (71%) of a group of 109 attenders at an out-patient drug treatment service reported that they had used heroin in the 90 days before interview, of whom 24 (31%) had used every day. Daily users were more likely to explain their use in terms of needing to curb withdrawals than were occasional heroin users. The latter group were more likely to report availability as a reason for use. From a clinical perspective, it is likely that those who use opportunistically are less likely to change their use as a function of clinical responses (e.g. higher methadone dose) than are those whose use is motivated by the attempt to curb withdrawal symptoms. © 1999 Published by Elsevier Science Ireland Ltd. All rights reserved. Keywords: Withdrawal; Methadone dose; Illicit heroin; Frequency of use; Reasons for use
1. Introduction Methadone treatment has been found to be associated with reductions in illicit drug use. The TOPS study (Hubbard et al., 1989) showed that those who stayed in methadone maintenance treatment for at least 3 months decreased regular heroin use from 65 to 70% in the year before treatment to 25 – 30% during treatment. Similar findings for reduced illicit heroin use has also been reported in British (Gossop et al., 1997) and other American studies (Simpson and Sells, 1982; Ball and Ross, 1991). Heroin use is not completely prevented by the initiation of methadone substitution treatment (Bell et al., 1990). Howard, et al. (1995) found that 57% of addicts attending a methadone programme in Sydney had used heroin at least once in the month before interview, and that 30.6% had used in the previous week. Similarly, while Ball and Ross (1991) found a reduction in illicit * Corresponding author.
drug use among those entering methadone substitution treatment, 29% of their sample reported that they had used drugs intravenously in the month before interview. McLellan et al. (1993) found that addicts who receive ancillary services such as counselling and psychotherapy showed markedly greater improvements than those who received methadone alone. There has been debate about the appropriate dose of methadone to be provided to addicts. Although Newman and Des Jarlais (1991) failed to confirm the relationship between methadone dose and heroin use, others have argued that high doses of methadone are more effective in suppressing illicit drug use. Stitzer et al. (1986) found that an abrupt increase in dose (from 30 to 60 mg) of methadone daily reduced illicit heroin from 80 to 62% in the first 2 weeks. Ball and Ross (1991) reported that when addicts were given doses of between 5 and 50 ml of methadone, many supplemented their dose with illicit heroin. In contrast, only 6% of the addicts who received doses of 60–100 ml reported continuing to use illicit heroin (Ball
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and Ross, 1991). Finally, Caplehorn and Bell (1991) reported that methadone maintenance patients receiving 60 mg or less of daily methadone were 4 – 8 times as likely to leave treatment as those receiving the maximum daily dose of 80 mg. However, little attention has been paid to the question of why methadone patients continue to use heroin. The explanations given by patients for their continued use of heroin has been widely ignored in favour of deterministic models which explain relapse in terms of dosing issues (Ball and Ross, 1991) or in terms of the situations in which the drug episode occurs (Marlatt, 1985). The current investigation further examines the issues of illicit heroin use during methadone maintenance treatment. The study looks specifically at the relationship between methadone dose and illicit heroin use among addicts receiving methadone substitution treatment. This relationship is also considered in terms of the reasons given by respondents for continued use of heroin. The study assesses the extent to which self-reported reasons for continued heroin use mediate the relationship between methadone dose and frequency of heroin use during treatment. If different patterns of continued heroin use are associated with self-reported reasons, then risk factors for relapse can be understood in terms of intrapsychic explanations as well as contextual variables.
Reasons for heroin use were closed categories selected on the basis of pilot interviews and asked to what extent heroin had been used ‘for its pleasurable effects’, ‘to manage withdrawal effects’, or ‘for no other reason than that it was available at the time’. Finally, respondents were asked to complete a Severity of Dependence Scale (SDS) (Gossop et al. 1995). While a number of reasons were given for continued use, the independent judges considered these to be the most comprehensive classes of the reasons given. The interview focused on behaviours in the previous 90 days, with cue cards provided for easy calculation of frequencies (for example 5 days/week as 65 days). Methadone dose was self-reported in interview and confirmed by comparison with patient case notes. Clients were given assurances about confidentiality of information obtained. The mean age of subjects was 34.6 years (S.D. 6.5 years). 78 were men and 31 were women. Ninety seven (89%) had lived at home for the previous 90 days, five (4.6%) in bedsits, three in hostels, two in squats and two on the street. They had been, though not necessarily in the same treatment programme, receiving a methadone prescription for an average of 4.3 years (S.D. 4.9 years), with a mean dose of 61.8 mg (S.D. 19.4, range 10–160 mg). All methadone was prescribed in the form of oral linctus. They had been using heroin for an average of 10.5 years (S.D. 6.9 years).
2. Method
3. Results
Data were gathered on 109 addicts recruited as they attended an out-patient drug treatment service in South London. The treatment centre, Marina House, is a statutory NHS treatment facility which offers maintenance to abstinence services. Patients were approached as they entered the building and were interviewed either before or immediately after their clinical transaction. The brevity of the interview (average completion time was around 7 min) ensured that almost no attenders were ‘missed’. One hundred and thirteen consecutive attenders were approached, of whom four refused to participate, producing a sample of 109 opiate addicts in treatment. A structured interview examining reasons for use, patterns of substance activity, and treatment details was conducted by an independent researcher. The drug grid, examining quantities and frequencies of prescribed and illicit drug use, was taken from the Maudsley Addiction Profile (Marsden et al., in press) with the time period extended from 30 to 90 days, as were the demographic characteristics of the population. The decision to use a 90-day time period was to detect any recent heroin activity, and so the period was chosen, on the basis of pilot testing, to detect any recent use that could be accurately recalled.
Seventy-seven (70.6%) of the addicts had used heroin on one or more occasions in the 90-day period prior to interview. The mean number of days of heroin use for these 77 heroin-using patients was 38.7 (S.D. 36.6 days), with 24 (22.0%) reporting that they had used heroin on all 90 days in the 3-month period (Table 1). Frequency of heroin use forms the basis of categorisation of addicts into three groups—those who had not used heroin at all in the 90-day period, subsequently referred to as ‘non-users’ (n= 32, 29.4%), those who had used heroin every day (‘daily users’, n= 24, 22.0%) and those who had used heroin, but not on a daily basis (‘occasional users’, n= 53, 48.6%). Of the occasional users, 47 (88.7%) had used between 1 and 30 days in the Table 1 Frequency of heroin use in the last 90 days Days of heroin use in the last 3 months Number Percentage 0 1–30 31–60 61–89 90
32 47 6 0 24
29.4 43.1 5.5 — 22.0
D. Best et al. / Drug and Alcohol Dependence 53 (1999) 191–195
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Table 2 Frequency of heroin use by reason given among daily and occasional heroin users Reasons
Test
Occasional heroin users (n =53)
Daily heroin users (n = 24)
t-test/x2
P
For pleasure
Mean (t-test) Category (x)
2.3 (9 1.15) n = 36/53; 67.9%
2.0 (9 1.20) n =12/24; 50.0%
t =0.83 x2 =2.3
0.41 NS
To curb withdrawals
Mean Category (x)
2.7 (9 1.34) n= 34/53; 64.1%
3.5 (90.18) n = 22/24; 91.7%
t= 3.17 x2 =4.0
B0.01 B0.05
Availability
Mean Category (x)
1.5 (9 0.99) n =11/53; 20.8%
1.1 (90.41) n =1/24; 4.2%
t= 2.6 x2 =6.3
B0.05 B0.05
Reasons for heroin are scored on a 4-point scale from 0 (never) to 4 (always).
last 90 days, 6 (11.3%) between 31 and 60 days and none between 61 and 89 days in the last 3 months. The groups did not differ in terms of their length of time in treatment, their sex, or their age (the only demographic characteristics on which data were collected). Those who used no heroin in the last 3 months (‘non-heroin users’) were receiving a higher mean daily dose of prescribed methadone (72.6 9 34.5 mg) than those who had used heroin at some point in the previous 3 months (mean= 56.8 9 27.1 mg; t= 2.29; PB 0.05). There was no difference in mean dose of prescribed methadone between ‘occasional users’ (mean= 56.2925.5 mg) and ‘daily users’ of heroin (mean =58.7932.7 mg).
3.1. Reasons for using heroin Examining the 77 patients who reported heroin use in the study window, each respondent was asked the frequency with which they used for each of the three reasons offered. Thirty-nine (50.6%) reported that they always used ‘to curb withdrawals’, 14 (22.1%) that they often used for this reason, three (3.9%) occasionally and 21 (27.3%) never used to curb withdrawals. Twenty-nine (37.7%) reported that they never used for ‘pleasure’, 19 (24.7%) that they occasionally did so, 13 (16.9%) that they often did so, and 16 (20.8%) that they always used for pleasure. Sixty-four (83.1%) said that they never used simply because the drug was available, three (3.9%) that they did so occasionally, five (6.5%) often and five (6.5%) always. The subjects who reported that they had used heroin in the previous month were also asked to indicate their main reasons for using heroin. The relationship between frequency of heroin use and reported reasons given among daily and occasional heroin users is given in Table 2. While there is no difference in the frequency with which either group of addicts use heroin for pleasure, differing responses were elicited with the other two prompted reasons. As shown in Table 2 daily heroin users were more likely to report heroin use to curb withdrawals than occasional heroin users (92 vs. 64%,
respectively) whilst occasional users were more likely to report that they used heroin simply because it was available than were the daily users (21 vs. 4%, respectively).
4. Discussion More than 70% of the addicts receiving treatment in this sample had used heroin while being prescribed methadone in the 3 months before interview. The most common reason given for heroin use was to curb withdrawals, although more than half of those who had used heroin in this period reported that they had done so at least occasionally for pleasure. The least common reason reported for use was availability, although this was a more common explanation among occasional heroin users than among those who had used heroin on each day in this period. In contrast, daily users were significantly more likely to explain their use in terms of curbing withdrawals than the occasional users. It is possible that those who reported less than daily use had spells of daily use within the period which may have influenced the results. However, as none of the occasional users had used for more than two-thirds of the days available in the 3-month target period, they can be conceptually differentiated from the group whose illicit use is continuous over such a prolonged treatment period. Almost all of the daily heroin users reported that the main reason for their use was to curb withdrawals. This finding may have implications for the dosing procedures used, as it suggests that they may not be receiving sufficient medication to suppress the emergence of withdrawal symptoms. However, the fact that almost twothirds of those who had used heroin reported doing so for pleasure at some point in the previous 3 months and more than one in six had used simply because heroin was available suggests a high level of hedonistic and/or opportunistic heroin use. It is perhaps appropriate to differentiate hedonistic heroin use from use for withdrawal relief since it is more likely to be associated with opportunity and so unrelated to the effectiveness of the
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methadone they receive, in particular the amount prescribed. Methadone patients who are daily heroin users are more likely to explain their heroin use in terms of managing withdrawals than methadone patients who use heroin only occasionally. The occasional users were more likely to report that they used heroin simply because it was available, than were the daily users. These results suggest that there may be different strategies underpinning heroin use among opiate addicts in treatment that are associated with the frequency of illicit use. This may suggest that the quest to suppress opioid abuse by changes in methadone dose (Stitzer et al., 1986; Nolimal and Crowley, 1990) will only succeed for a sub-sample of those patients in treatment who continue to use heroin — those who do so to suppress withdrawal discomfort. These findings also support the association between methadone dose level and heroin use reported in a number of previous studies (Caplehorn et al., 1976; Ball and Ross, 1991; Caplehorn and Bell, 1991; Strain et al., 1993). This effect has not previously been shown in research undertaken in the UK. A number of possible confounding factors can be identified as possibly having disguised this effect, including lack of power in smallsample studies, the possible distorting effect of the largely unsupervised dispensing of methadone in the UK (Strang, et al., 1996), as well as the association we have reported above of different frequencies and reasons for such heroin use. If it is correct that high doses are likely to curb heroin use in those whose main reason for use is to curb withdrawals, but less likely to affect the heroin use of methadone patients whose reasons for use are not related to withdrawal experiences. Therefore, addicts in treatment who use heroin simply because it is available (perhaps as a consequence of the use patterns of partners or peers) may be less likely to change the frequency of heroin use as a response to increased methadone dose. The assumption of a relationship between dose and frequency of heroin activity assumes that heroin use is motivated only by physiological factors that are amenable to pharmacological manipulation by clinicians. Previous research with a similar sample population (Best et al. 1997) indicated that there is a relationship between the time of consumption of methadone use and illicit heroin use by addicts in treatment. The pharmacokinetic argument raised in this paper is that, while the use of methadone early in the day may provide a protective effect, those who consume their methadone later in the day may increase the possibility of experiencing craving (based on withdrawals) in the early part of the day. The possibility that there may be a pharmacokinetic association between pattern of methadone use, drug cravings, and illicit heroin use should not be
discounted as a pharmacological sub-stratum for the experiential reporting of discomfort. On the other hand, if heroin use by methadone patients is portrayed in terms of arbitrary social factors, such as opportunity and social setting, different explanations such as hedonistic motives, peer pressure and simple availability gain currency. This group are not likely to be exclusively using heroin as a consequence of physiological factors and so this pattern of illicit substance activity is less readily amenable to manipulation by increased substitute prescribing. There are two implications that can be drawn. The first is that the failure to observe a consistent relationship between methadone dose and continued use of heroin may result from the fact that relief of withdrawal represents only a partial explanation of heroin use by opiate addicts in treatment. The second is that motives for heroin activity may vary from one addict to another or even, from one occasion to another for the same addict. As a consequence, it is important that future research investigates the nature of the relationship between methadone dose and continued heroin use and also examines the effects of different motives for continued heroin use whilst on methadone.
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