Young people with heroin dependence: Findings from the Australian Treatment Outcome Study (ATOS)

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1 Journal of Substance Abuse Treatment 27 (2004) Regular article Young people with heroin dependence: Findings from the Australian Treatment Outcome Study (ATOS) Katherine L. Mills, B.HlthSc. (Hons) a, *, Maree Teesson, Ph.D. a, Shane Darke, Ph.D. a, Joanne Ross, Ph.D. a, Michael Lynskey, Ph.D. b a National Drug and Alcohol Research Centre, University of New South Wales, Australia b Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA Received 29 December 2003; received in revised form 16 April 2004; accepted 2 May 2004 Abstract This paper examines the patterns and correlates of heroin use in a cohort of 210 young Australians aged between 18 and 24, who were participants in the Australian Treatment Outcome Study, a longitudinal study of treatment outcomes for heroin dependence. Of major importance were the high rates of psychiatric comorbidity found among this group (37% lifetime Post Traumatic Stress Disorder, 23% current Major Depression, 75% Anti-Social Personality Disorder, and 51% Borderline Personality Disorder). Seventeen percent had attempted suicide in the preceding year. Although both the young (aged years) heroin users and their older counterparts (aged years) initiated drug use at the same age, young heroin users progressed to heroin use, regular heroin use, and treatment for heroin use, twice as quickly as older heroin users. These findings suggest that there is a limited window of opportunity in which early interventions may be applied before young heroin users progress to problematic use. D 2004 Elsevier Inc. All rights reserved. Keywords: Youth; Heroin; Dependence; Treatment; ATOS 1. Introduction The increasing use of heroin among young adults is an important public health issue. A decline in the age of initiation into heroin use and increases in the prevalence of heroin use among young adults have been documented in the United States (Johnston, O Malley, & Bachman, 2001), the United Kingdom (Parker, Bury, & Eggington, 1998), and Australia (Darke, Topp, Kaye, & Hall, 2002, Degenhardt, Lynskey, & Hall, 2000). In Australia, 6% of the total disease burden for year olds is accounted for by the harmful use of heroin and heroin dependence (Mathers, Vos, & Stevenson, 1999). There has also been a concomitant increase in the number of young people seeking treatment for heroin dependence (Shand & Mattick, 2001; Torres, Mattick, Chen, & Baillie, 1995). Lynskey and Hall (1998) found the mean age of initiation into heroin use dropped from between years of age * Corresponding author. National Drug and Alcohol Research Centre, University of New South Wales, NSW, 2052, Australia. address: k.mills@unsw.edu.au (K.L. Mills). for those born between , to years of age for those born between This decline in the age of initiation of heroin and other drug use has been associated with an increased risk of many adverse outcomes including polydrug use (Darke & Hall, 1995; Lynskey & Hall, 1998; Plant & Plant, 1992), development of problematic drug use (Brook, Balka, & Whiteman, 1999; Fergusson & Horwood, 1997; Grant & Dawson, 1998), unintentional non-fatal overdose, earning money via criminal activity, spending more on illicit drugs (Lynskey & Hall, 1998), and completing fewer years of education (Lynskey & Hall, 2000). Young users may also be more susceptible to the adverse consequences of drug use (e.g., overdose) due to their lack of experience and maturity (Lynskey & Hall, 1998; Plant & Plant, 1992). Despite the increasing number of young people using heroin, and the harms associated with earlier initiation of use, very little is known about the characteristics, drug use, and associated harms experienced by young adults who use heroin. This information is necessary to determine any specific treatment needs and for the provision of appropriate services. A recent review by Hopfer, Kuri, Crowley, and Hooks (2002) found only five studies /04/$ see front matter D 2004 Elsevier Inc. All rights reserved. doi: /j.jsat

2 68 K.L. Mills et al. / Journal of Substance Abuse Treatment 27 (2004) reporting on the clinical characteristics of heroin using youth. These studies tend to describe young heroin users as polydrug users, with psychiatric comorbidity, who engage in anti-social behaviors. Similar findings were reported in a recent study of young adults undergoing heroin detoxification (Pugatch et al., 2001). However, much of this research on the characteristics of young heroin users is somewhat dated and confined to samples from the United States. In addition, although it is known that earlier initiation into substance use increases the risk of progressing to problematic use, it is not known whether young people today are progressing to problematic use more rapidly than in previous years. This may have implications for the amount of time available in which early interventions may be implemented. The Australian Treatment Outcome Study (ATOS) is the first large scale longitudinal study of treatment outcomes for heroin use to be conducted in Australia. The present study describes the characteristics, drug use, and psychopathology of young heroin users (aged years), and it examines the rate of progression from first episode of intoxication (on any substance either licit or illicit) to initial heroin use, from initial heroin use to regular heroin use, and from initial heroin use to first treatment episode, among the young heroin users compared with older heroin users (aged 25 56). 2. Method 2.1. Procedure The data presented in this report were collected between February 2001 and August 2002 as part of the New South Wales (NSW) component of ATOS (Ross et al., 2002), which is a longitudinal study of entrants to treatment for heroin dependence. Participants were recruited from 19 agencies treating heroin dependence in the greater Sydney region. Agencies were randomly selected from within treatment modality and stratified by regional health area. The agencies represent the major treatment modalities and comprised ten methadone/buprenorphine maintenance agencies (MT), four drug-free residential rehabilitation agencies (RR), and nine detoxification facilities (DTX). Four agencies provided both maintenance and detoxification services. Heroin users not currently in treatment (NT) were recruited from needle and syringe programs in the regional health areas from which treatment entrants were recruited. Ethical approval was granted by the Human Ethics Review Committees of all participating area health services and the University of New South Wales. Eligibility criteria were: (1) no treatment for heroin dependence in the preceding month; (2) no imprisonment in the preceding month; (3) aged 18 years or over; (4) agreed to give contact details for followup interviews; and (5) not having been previously enrolled in ATOS. The nontreatment group had one additional criterion: they could not be enrolled in treatment for their heroin dependence at the time of baseline interview. Of those entering treatment who were eligible to participate in ATOS (n = 694), 535 (77%) were enrolled in the study. The remainder refused to participate either directly (n = 62, 9%) or passively by repeatedly failing to attend the baseline interview (n = 97, 14%). The primary reason for exclusion from the study was having been in treatment (n = 534, 64%) or having been in prison (n = 118, 14%) in the preceding month. Similarly, of the 91 people who were eligible for inclusion in the NT group, 80 were enrolled in the study (88%). Eleven people (12%) refused to participate. The primary reason for exclusion from the study was being currently involved in treatment or having been in treatment in the preceding month (n = 175, 82%). The total sample consisted of 615 heroin users: 201 entering methadone maintenance, 201 entering detoxification, 133 entering residential rehabilitation, and 80 nontreatment subjects. Of these 210 were young heroin users and 405 belong to the older comparison group. All participants were paid A$20 for completing the baseline interview, which took approximately 1 hour to complete. Written consent was obtained from all participants. Participants in ATOS are re-interviewed at 3-month and 12-month posttreatment entrance Structured interview Participants were administered a structured interview. Sections addressed demographics, treatment history, drug use history, heroin overdose history, criminal activity, physical health and psychopathology. Drug use, needle risk-taking, injection related health problems and criminal behaviors over the month preceding interview were measured using the Opiate Treatment Index (OTI; Darke, Hall, Heather, Wodak, & Ward, 1992). Consistent with the Australian National Survey of Mental Health and Wellbeing; (Andrews, Hall, Teesson, & Henderson, 1999), DSM-IV diagnoses of current Major Depression (in the preceding month), lifetime Post Traumatic Stress Disorder (PTSD), Anti-Social Personality Disorder, and ICD-10 diagnoses of Borderline Personality Disorder (BPD) were obtained using the Composite International Diagnostic Instrument (CIDI; World Health Organization, 1993). General physical and mental health were measured using the Short Form-12 (SF-12). The SF-12 is a standardized, internationally used instrument that provides a general measure of health status. The 12 items on the SF-12 are summarized in two weighted summary scales, and generate a mental health and physical health score. Lower scores indicate poorer health (population M = 50, SD = 10; Ware, Kosinski, & Keller, 1996). Interviewers undertook accredited CIDI training and received extensive training in

3 K.L. Mills et al. / Journal of Substance Abuse Treatment 27 (2004) the administration of the CIDI and other study measures prior to the commencement of the study Statistical analyses For continuous data, t-tests were used. Where distributions were highly skewed, medians are reported and Mann- Whitney U tests conducted. Linear regressions were used to analyze whether young heroin users progressed to problematic drug use more quickly than older heroin users. For dichotomous categorical variables, chi-square analyses were conducted and Odds Ratios (OR) with 95% Confidence Intervals (95% CI) reported. All analyses were conducted using SPSS (release 11.0; SPSS, 2001) Sample characteristics The mean age was 29.3 years (SD = 7.8, range 18 56), and 66% were male. The sample completed a mean of 10.0 years of secondary education (SD = 1.7, range 2 12), 29% had completed a trade/technical course, and 6% a university degree. Forty-one percent of the sample had a prison history. The main sources of income were: government allowances (46%), criminal activity (24%) and wage/salary (18%). Further details on the demographics of the sample may be found in Ross et al. (2002). 3. Results 3.1. Demographic characteristics Young heroin users (aged years) comprised 34% (n = 210) of the sample. The mean age of young heroin users was 21.5 (SD = 1.9) years, and the majority were male (60%). Young heroin users completed an average of 10.2 (SD = 1.4) years of education, with 26% having completed tertiary education (i.e., a trade/technical course, or degree). It is important to bear in mind that due to the age of the young heroin users in the present study, many have not had the opportunity to complete tertiary education, and may go on to do so. A large proportion of these young people lived with their parents (42%), and derived their main source of income from a government allowance (37%), criminal activity (28%), or employment (20%). Twenty-four percent had a history of incarceration. There were no significant differences between the demographic characteristics of male and female young heroin users (see Table 1), with the exception that males were twice as likely to be living with their parents (49% vs. 32%; OR 2.05; 95% CI: ) Treatment and drug use history A large proportion of young heroin users were enrolled in MT (37%), followed by DTX (31%), and RR (21%). Table 1 Demographic characteristics of young male and female heroin users Demographic characteristics Eleven percent were not in treatment. Young heroin users had previously attempted treatment a median of 4 times (range 0 77). Young heroin users first became intoxicated at age 13.5 (SD = 2.5) years, most commonly using cannabis (46%). Age of first injection was 17.4 (SD = 2.9) years, heroin being the most common drug of first injection (64%). Young heroin users had tried 8.7 (SD = 1.8) different drug classes (both licit and illicit) over their lifetime, and 6.5 (SD = 2.1) over the last 6 months. In the month prior to interview, females were using antidepressants (prescribed and/or discretionary use) more than once per week, while males were using once a week or less, as indicated by their mean OTI Q scores (0.13 vs. 0.44; t 208 = 2.081, p <.05). There were no other significant differences between males and females in drug use or treatment histories (see Table 2) Heroin use and dependence Young heroin users first used heroin at age 16.8 (SD = 2.4), first injected heroin at age 17.8 (SD = 2.7), and first used heroin at least monthly at age 17.2 (SD = 2.5). The mean length of heroin using career was 4.7 (SD = 2.3) years. They used heroin on a median of 166 days (range 2 180) over the preceding 6 months, and used daily over the last month, as indicated by their OTI Q score (median 2.0, range ). In the preceding month, 13% of young heroin users administered their heroin by non injecting methods. Almost all met DSM-IV criteria for heroin dependence (98%). Forty-one percent of young heroin users had overdosed in their lifetime, with 24% having done so in the preceding 12 months. There were no significant differences in males and females heroin use history (see Table 2) Physical health Males (n = 125) Females (n = 85) Mean age in years (SD) 21.7 (1.7) 21.3 (1.9) Mean no. of years of school completed (SD) 10.2 (1.4) 10.2 (1.6) Completed tertiary education (%) Living with parents (last month) (%)* Main source of income (%): Employment Crime Government allowance Prison history (%) Significant group differences exist. * p <.01. The mean SF-12 physical health score for young heroin users was 44.5 (SD = 9.3), half an SD (worse than) the

4 70 K.L. Mills et al. / Journal of Substance Abuse Treatment 27 (2004) Table 2 Drug use and heroin use history of young male and female heroin users Drug use population mean (M = 50, SD = 10). The proportion of young heroin users classified with severe physical disability was 7%. Females had a significantly lower (worse) mean SF-12 score (42.3 vs. 46.1), and were three times more likely to be classified with severe physical disability compared with males (12% vs. 4%; OR 3.20; 95% CI: ) Injection-related health The following analyses were conducted only on those who had injected drugs in the preceding month (n = 183). A third of young heroin users injected on average four or more times a day in the month preceding interview. Almost one in five (19%) had borrowed needles, and 35% had lent needles in the preceding month. They had a mean of 1.6 injection-related health problems in the preceding month. Females were twice as likely to have borrowed needles (30% vs. 16%; OR 2.3; 95% CI: ), and had significantly more injection related health problems (1.9 vs. 1.5; t 181 = 2.88, p <.01) Criminal activity Males (n = 125) Females (n = 85) Any substance Mean age first intoxicated (SD) 13.4 (2.7) 13.7 (2.2) Mean age first injected (any drug) (SD) 17.6 (2.9) 17.2 (2.8) Mean number of drug classes used (SD) Ever 8.6 (1.8) 8.9 (1.8) Last 6 months 6.5 (2.0) 6.4 (2.1) Heroin use Mean age first used (SD) 16.8 (2.4) 16.8 (2.5) Mean age first used at least monthly (SD) 17.3 (2.5) 17.1 (2.5) Mean age first injected (SD) 17.9 (2.7) 17.6 (2.7) Median days used last 6 months Mean OTI Q score (last month) (SD) 2.5 (2.2) 3.2 (8.3) Heroin overdose (%) Ever Last 12 months Over half (62%) of the young heroin users had engaged in criminal activity in the preceding month with the most common crime being property crime (46%), followed by drug dealing (34%), fraud (17%), and violent crime (12%). Males were more likely than females to have committed property crime (66% vs. 56%; OR 1.83; 95% CI: ). Among those who had engaged in criminal activity in the preceding month, property crime was most commonly perpetrated more than once per week but less than daily (47%), dealing most commonly occurred on a daily basis (48%), fraud and violent crime most commonly occurred less than weekly (51% & 65% respectively) Mental health Young heroin users had high levels of psychopathology in almost all areas (see Table 3). Their mean score on the SF-12 scale for mental health was 31.9 (SD = 10.6), two SDs below (worse than) the population mean (M = 50, SD = 10). Approximately half (49%) had SF-12 scores indicative of severe mental disability. There were no significant gender differences with regard to general mental health. Current Major Depression was identified in 23% of young heroin users; 32% had a lifetime history of attempted suicide, and 17% had attempted suicide in the preceding 12 months. Thirty-seven percent had a lifetime history of PTSD. Antisocial Personality Disorder (ASPD) and BPD were also common among young heroin users (75% and 51% respectively). Females were twice as likely to have current Major Depression (32% vs. 17%; OR 2.31, 95% CI: ), a lifetime history of attempted suicide (40% vs. 26%; OR 1.90, 95% CI: ), attempted suicide in the last 12 months (25% vs. 12%; OR 2.36, 95% CI: ) and be diagnosed with PTSD (47% vs. 30%; OR 2.11, 95% CI: ) Progression to heroin use, regular heroin use, and treatment In order to examine trends in rates of progression to problematic heroin use, young heroin users were compared with the older users from the ATOS sample, aged over 24 years (M = 33.3, range 25 56). There was no significant difference in the age of first intoxication for young and older heroin users (13.5 vs years). Young heroin users had used heroin (16.8 vs. 21.1; t 613 = 10.45, p <.001), injected heroin (17.8 vs. 21.6; t 573 = 8.33, p <.001), used heroin on a regular basis (at least once per month; 17.2 vs. 22.2; t 613 = 11.92, p <.001), and first entered treatment for their heroin use (19.3 vs. 26.2; t 601 = 19.2, p <.001) at significantly younger ages compared with older heroin users. An age-cohort analysis revealed that the time between first intoxication using any substance and first use of Table 3 Psychopathology of young male and female heroin users Psychopathology Males (n = 125) Females (n = 85) Mean SF-12 mental health score (SD) 33.1 (11.1) 30.1 (9.8) Current major depression (%)* Ever attempted suicide (%)* Suicide attempt in the last 12 months (%)* ASPD (%) BPD (%) PTSD (%)* Significant group differences exist. * p <.05.

5 K.L. Mills et al. / Journal of Substance Abuse Treatment 27 (2004) Years of age heroin was significantly shorter for young heroin users compared with older heroin users (3.3 vs. 7.3 years; t 613 = 12.58, p <.001). Young heroin users also progressed more quickly towards regular heroin use from their first heroin use episode (0.4 vs. 1.1 years; t 613 = 5.01, p <.001), and from their first use of heroin toward treatment for their heroin use (2.4 vs. 5.1 years; t 601 = 8.80, p <.001; see Fig. 1). These effects remained even after controlling for the influence of sex and treatment status using linear regressions. An increased rate of progression from initial heroin use to first treatment for heroin use was also independently associated with being female (h = 1.35, 95% CI: ). 4. Discussion 1st intoxication 1st heroin use 1st regular heroin use 1st treatment Progression Younger Older Fig. 1. Progression from initiation of drug use to first heroin use, regular heroin use, and treatment for heroin use. The demographic characteristics of young heroin users in ATOS were similar to those found in other studies in the United States (Hopfer et al., 2002; Pugatch et al., 2001). It should be noted however, that this sample is not necessarily representative of all young heroin users. Young heroin users presented across all treatment modalities, primarily methadone/buprenorphine maintenance and detoxification services. This finding is consistent with that of Shand and Mattick (2001) who found that young heroin users were more likely to receive treatment in non-residential settings. Many of the young heroin users in the sample had previously attempted a formally recognized treatment for their heroin dependence. Over one in ten young heroin users in ATOS were using heroin by non-injecting routes of administration. The high proportion of young non-injection heroin users is in keeping with a recent shift towards inhaling heroin in younger populations (Schwartz, 1998) reported in the United Kingdom (Strang, Griffiths, & Gossop, 1997; Strang, Griffiths, Powis, & Gossop, 1999), Europe (Perez-Jimenez & Robert, 1997; Smyth, O Brien, & Barry, 2000), and the United States (Carpenter, Chutuape, & Stitzer, 1998; Neaigus et al., 2001). The non-injection use of heroin in Australia was first reported in the 1990s and appears to have increased in prevalence since then (Swift, Maher, Sunjic, & Doan, 1999). Despite education and harm minimization campaigns, needle sharing continues to occur. Consistent with international studies young heroin users reported high rates of risk taking behaviors including the lending of needles after use (Lee, Hollinrake, & Ng, 1998; Stein, Charuvastra, & Anderson, 2002). The higher prevalence of borrowing needles among females is in keeping with the findings of Darke and Hall (1995). Such behaviors place users at much greater risk of blood borne viruses such as hepatitis and HIV/AIDS, and have the potential to increase the spread of infectious diseases. It also increases their risk of injection related health problems such as abscesses and infections. These findings highlight the need for campaigns targeting young heroin users, particularly females, to reduce the sharing of needles among this group. The physical health of young heroin users was generally poor with SF-12 physical health scores close to half of an SD below (worse than) the norm for the general population. It is clear that such a large difference is of both statistical and clinical significance. Although young heroin users were found to be in moderately good health, a small but significant proportion, particularly among females, experienced severe levels of physical disability. Of major clinical importance is the serious psychiatric morbidity found among young heroin users. This study used internationally recognized, detailed measures of psychiatric comorbidity. Levels of psychiatric comorbidity among young heroin users were high, particularly among females. Major depression, PTSD, and a history of suicide were common. Close to one in five young heroin users had attempted suicide in the preceding 12 months. Consistent with research among heroin using populations and general populations, females in the present study were more likely to be depressed (Brienza et al., 2000), to have attempted suicide (Darke & Ross, 2002), and to meet criteria for PTSD (Kessler, Sonnega, Bromet, & Nelson, 1995). It is not surprising, then, that females used antidepressants more frequently in the last month. Given the higher rates of recent attempted suicide, and other impulsive behaviors such as lending needles and engaging in criminal activity, it is not surprising that this group also had high rates of ASPD and BPD. It has been suggested, however, that rates of ASPD found among injecting drug users may be elevated, as it is difficult to distinguish between criminality and social deviance generated by dependence on illegal drugs and that which is due to the presence of a personality disorder (Gerstley, Alterman, McLellan, & Woody, 1990). While ASPD is a diagnosis based largely on behavioral criteria, a diagnosis of BPD is based on criteria that are predominantly psychological (American Psychiatric Association, 1994). As such, there is considerably less scope for diagnostic confusion resulting from behaviors driven by drug use, rather than by a personality disorder. A diagnosis of BPD

6 72 K.L. Mills et al. / Journal of Substance Abuse Treatment 27 (2004) is associated with a range of risks including major depression, suicide, higher levels of drug use, and overdose (Brodsky, Malone, Ellis, Dulit, & Mann, 1997; Gupta & Trzepacz, 1997; Inman, Bascue, & Skoloda, 1985; Zanarini et al., 1998). There has been enormous variation across studies in the reported rates of personality disorders among substance abusers. Trull et al. (2000) recently reviewed rates of BPD among substance dependent individuals, and reported rates ranging from 11 to 65%, with the highest level reported among opioid users. The finding that younger users first used heroin, injected heroin, used heroin regularly, and entered treatment for their heroin use at significantly younger ages compared with older users may be in part reflective of the increased availability of illicit drugs to younger people, and in part to changes in societal attitudes towards drug use (Australian Institute of Health and Welfare, 2002). These findings are also consistent with other studies showing a decline in the age of initiation of heroin use. Previous research has found earlier initiation into drug use to be associated with reduced levels of education, greater polydrug use, problematic drug use, overdose, and a number of other adverse outcomes (Darke & Hall, 1995; Lynskey & Hall, 1998; Plant & Plant, 1992). Adding to these findings, the present study observed that young heroin users moved to problematic drug use more quickly than did older heroin users. From the time of first intoxication, young heroin users started using heroin, progressed to using regularly, and entering treatment in half the amount of time seen among older users. Given this trajectory, one would also expect to see a decline in the average age of fatal overdose in the coming years. This accelerated progression may be due to a number of societal factors such as the increased availability of heroin and the increased availability of treatments for heroin use. Not surprisingly, being female also predicted earlier treatment entrance. The greater willingness of females to seek treatment and utilize health services has been well documented (Bijl & Ravelli, 2000; Bland, Newman, & Orn, 1997; Proudfoot & Teesson, 2002). Some caution must be taken when interpreting the findings on progression to problematic drug use. First, the results may be affected by right censoring of the sample (Lynskey & Hall, 1998). That is, because the younger users have not yet reached older ages, their reported drug use occurs at a lower mean age. Second, the trends observed may also be due to response bias. The retrospective reporting of age of events may be subject to error, particularly for older users. Longitudinal studies of adolescents aged years found that estimates of age of first use tend to increase upon repeated assessment but the rank ordering of estimates remained (Henry, Moffit, Caspi, Langley, & Silva, 1994; Labouvie, Bates, & Pandina, 1997). It is unlikely, however, that response bias completely accounts for the strong trends observed here. Third, it is also possible that the mortality rate among those in the older group who accelerated at rates comparable to that of the younger users is higher. However, this is unlikely to explain the large in differences in rates of progression, as the mortality rate would have to be significantly higher among this group. If this were the case however, it only adds to the urgency of the situation. These findings have important implications as they imply that there is a very limited window in which early interventions may be applied before young heroin users progress to problematic use. By targeting this group in their early stages of use before they meet diagnostic criteria for dependence, the number of future heroin dependent people may be reduced (Anthony, 2000). Given the problems experienced by young heroin users it is essential that early interventions are developed in order to prevent the development of more chronic dependence and associated problems (Hopfer et al., 2002). Although the treatment needs of young heroin users appear to be similar to those of treatment seekers of all ages, further research is needed to investigate whether services specifically catering to young adults are necessary. The longitudinal nature of ATOS will allow the monitoring of this cohort s progress over time. 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