When is a little knowledge dangerous?: Circumstances of recent heroin overdose and links to knowledge of overdose risk factors
Introduction
Heroin overdose is a serious public health issue (Darke et al., 1996b). The risk factors for heroin overdose are well-known and include the demographics of heroin users, the concomitant use of other drugs, changes in tolerance, the amount of heroin used and injection as the route of administration (Darke and Hall, 2003, Dietze et al., 2005). This information suggests that there is potential for effective intervention and a variety of initiatives have been developed to prevent heroin overdose.
Some of the most common heroin overdose prevention initiatives have been described in a recent review and these range from modifying the heroin-using environment, such as supervised injecting facilities, to increasing the availability of maintenance pharmacotherapy treatment, as well as resuscitation using naloxone (Darke and Hall, 2003). One key and very common intervention is the dissemination of educative messages about overdose risk (Darke and Hall, 2003, Dietze et al., 2001a, McGregor et al., 2001). These target behaviour change linked to the risk factors for overdose by encouraging heroin users to: avoid concurrent use of CNS depressant drugs, monitor their tolerance, avoid using alone and sample their heroin for strength prior to using the desired amount (McGregor et al., 2001, Moore, 2004). Additional messages target responses to overdose by encouraging people to contact emergency health services or provide basic resuscitation (Darke and Hall, 2003).
There is growing evidence about the effectiveness of various intervention strategies including maintenance pharmacotherapy treatment (Darke and Hall, 2003), bystander resuscitation (Dietze et al., 2002a), supervised injecting facilities (MSIC Evaluation Committee, 2003) and the provision of naloxone for peer administration (Chicago Recovery Alliance, 2002). However, the effectiveness of education programs designed to increase knowledge about overdose risk has not yet been demonstrated.
Such education programs have been widely undertaken as a component of many harm reduction activities for heroin users (Moore, 2004). These programs are typically based on a social marketing approach with targeted campaigns oriented towards heroin users at the time when they come into contact with service providers. While the effectiveness of these programs in producing behaviour change has not been demonstrated (Darke and Hall, 2003), they have been shown to increase knowledge about overdose risk factors, as well as appropriate responses to overdose such as resuscitation techniques (McGregor et al., 2001).
In a recent critique of overdose prevention, Moore (2004) cites some of the social and contextual factors that militate against the effectiveness of heroin overdose prevention education. In particular, he argues that features of the drug use and social environments of heroin users and the desire for heavy intoxication and withdrawal avoidance work to undermine expectations of ‘rationality’ (i.e. choice of health promoting behaviour in preference over harmful behaviour) that underpin typical messages. This tension between individualistic (e.g. health belief models) and social models (e.g. situated rationality) of risk perception, knowledge and behaviour has been debated more generally in the health field (Bloor, 1995), with some arguing that a major strategic weakness is the lack of understanding of the interconnection between attitudes, knowledge and risk behaviour (Williams et al., 1995).
It is beyond the scope of this paper to engage fully with this debate, however, evidence suggests that a range of factors in addition to risk knowledge influence risk behaviour choices. Review studies show that knowledge about health risks does not necessarily produce corresponding reductions in risk behaviours, particularly in relation to blood-borne virus transmission (Aloisi et al., 1995, Ferron et al., 1993, Gibson et al., 1993, Tapia-Aguirre et al., 2004). With overdose risk it is possible therefore that overdose prevention approaches based on education about putative risk behaviours may alone have limited effectiveness for heroin users who have different priorities to the avoidance of overdose. For example, assumptions that individuals will choose health-promoting behaviour may be unrealistic in the context of ambivalent attitudes towards death (Bennett and Higgins, 1999, Miller, 2002). Further, where purchase and injection of heroin in public settings is the norm, the desire to avoid detection by police or other users may preclude careful drug preparation or injection (Aitken et al., 2002). Finally, known risk behaviours may even be valued for the user-defined benefits they produce (Bloor, 1995). In this way the applied value of ‘situated rationality’ concepts of risk behaviour which include social context as an influencing factor on behavioural choices is that they introduce the possibility of ‘functional risk’, where understandings of overdose prevention messages may actually lead to increases in risk behaviours. For example, some heroin users may interpret messages to mean that intoxication effects can be increased by using other CNS depressant drugs or some users may have an inflated (and inaccurate) evaluation of their own drug using competence.
This paper has two aims. First, we examine the extent or market penetration of overdose prevention messages in Melbourne. Second, we seek to examine whether knowledge of overdose risk reduction strategies is associated with a reduction in risk behaviours, as would be expected on the basis of a simple educational approach to heroin overdose prevention. As such, our study provides an indirect evaluation of the effectiveness of the overdose risk reduction education strategies described above. These aims are explored in the context of the circumstances of overdose in terms of known risk factors among a sample of recent heroin overdose survivors. This aspect is important as much research on heroin overdose is plagued by definitional difficulties and pays little regard to overdose recency.
Section snippets
Methods
We conducted a cross-sectional survey of recent non-fatal heroin overdose survivors recruited through their contact with the Melbourne Metropolitan Ambulance Service. Melbourne is the capital of the Australian state of Victoria.
Sample characteristics
Fig. 1 shows the characteristics of the sample and their experience of overdose.
Experience of overdose
The large majority (75%) had experienced an additional overdose, half in the 6 months prior to interview (Fig. 1). Most of these overdoses resulted in the administration of naloxone. The experience of overdose was unrelated to any of the participant characteristics listed in Fig. 1 with the exception of incarceration and age. Participants who reported ever being incarcerated were around three times as likely to
Overdose prevention education
Overdose prevention education is a key component of harm reduction work in Melbourne (Dietze et al., 2001a, Moore, 2004) and has been delivered in various forms, ranging from leaflet distribution within agencies to classroom-based overdose prevention workshops run by the Victorian Drug User Group since the late 1990s (VIVAIDS, S. Lord, personal communication, November 2005). Despite this, the ‘market penetration’ of these overdose prevention messages appears relatively low, with less than half
Conclusions
Overdose is common among heroin users and its prevention is, and should be, a key strategy in the reduction of drug related harm. In relation to overdose education we found that knowledge of overdose risk reduction strategies was associated with the paradoxical effect of increasing the prevalence of the target risk behaviours. These findings have implications for overdose prevention strategies targeted at individualised risk behaviour change, where it is generally presumed that increasing
Acknowledgments
This study was supported by grants from the National Health & Medical Research Council and the Victorian Health Promotion Foundation. The first author is the recipient of a VicHealth Public Health Research Fellowship. All authors were independent of these research funding sources and there were no competing interests for any of the authors. Mr. Greg Cooper (Metropolitan Ambulance Service, Melbourne) facilitated data collection and Mr. Stephen Burgess (Monash University) and Dr. Greg Rumbold
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