Research Letter

CHANGES IN ILLICIT OPIOID USE ACROSS CANADA

Correspondence to: Dr. Benedikt Fischer, Centre for Addictions
Research of BC, University of Victoria, Rm. 124, Technology Enterprise
Facility, PO Box 1700 Stn CSC, Victoria BC V8W 2Y2; fax 250 472-5321;
bfischer@uvic.ca

For almost a century, heroin addiction has been a core element of the
illicit drug use problem in Canada.1,2 According to recent data, there
are an estimated 125 000 injection drug users in Canada, most of whom
use heroin and cocaine.3 Heroin addiction is associated with a variety
of harms, including death, morbidity and crime. There are many
examples of these harms: the number of overdose-related deaths in
British Columbia rose dramatically from 39 to 331 between 1988 and
1993;4 the majority of new cases of hepatitis C in Canada are related
to illicit drug use;5 and most heroin addicts are involved in regular
criminal activity.6 Considerable public resources are expended on
heroin addiction. Canadian law enforcement agencies direct substantial
expenditures to prevent heroin importation and distribution -- albeit
with limited success.7,8 On the health care side, the number of people
receiving methadone maintenance treatment (the primary treatment
response for heroin addiction) has increased 5 times since the
mid-1990s, to about 25 000 spaces across Canada.9-11 Furthermore,
alternative treatment options are in development, including
buprenorphine maintenance and medical heroin treatment.3,12,13 In the
past several years, there have been isolated reports of substantially
increased levels of prescription opioid abuse in Canada, the United
States and other jurisdictions.14-16 However, until now, its impact
on usage patterns among street drug users in Canada has been unclear
and not systematically documented.

The multisite OPICAN cohort (formed through community-supported
outreach and snowball recruitment methods and comprising regular
illicit opioid users who were not receiving treatment at the time of
recruitment) was established in 2001 with a baseline sample of 679
participants to assess current opioid use patterns and related social
and health indicators.17 The participants were recruited from 7
Canadian cities (Vancouver, Edmonton, Toronto, Montreal, Quebec,
Fredericton and St. John) and were assessed most recently in 2005. The
OPICAN study sites were chosen to produce a cross-section of existing
profiles of illicit opioid use in large and midsized cities across
Canada and were determined by local feasibility of the study protocol.
Between 2001 and the assessment in 2005, the longitudinal component of
the study had a follow-up rate of 58.6%. Participants who were lost to
follow-up were replaced with newly recruited participants to ensure
large enough samples for hypothesis testing. Local samples of
populations in Fredericton and St. John were added in 2005. All
assessments of participants throughout the study were conducted by
means of a standardized protocol, which included an interview, a
clinical assessment (e.g., for psychiatric symptoms) and biological
measures (e.g., saliva antibody tests for HIV and hepatitis C virus).
Ethics approval for each component of the study was obtained from
local institutions. The Research Ethics Board of the Centre for
Addiction and Mental Health provided the first approval in 2001. The
data reported here are based on a sample of 585 participants from the
2005 follow-up and exclude those who were involved in methadone
maintenance treatment before assessment (to eliminate treatment effects).

We obtained information on the following sociodemographic and drug-use
characteristics of the participants: age, sex, ethnic background,
housing situation (permanent or nonpermanent), sources of income (paid
work), illegal sources of income (sex work, drug dealing, other
criminal activities), injection drug use in the 30 days before
assessment, drug overdose and illicit use of opioids (Demerol,
Dilaudid, heroin, methadone from the street, morphine, OxyContin,
Percocet, Percodan and Tylenol 3 or 4) in the 30 days before
assessment. Categorical variables were analyzed with the use of
Pearson's 2 test; continuous variables were analyzed with the use of
independent sample t tests and analysis of variance. In the case of
unequal variances, the Kruskal-Wallis and median tests were also
performed on continuous data. All variables were considered
statistically significant if p was less than 0.05.

Participants were, on average, 35 years of age; most were male and
white. Half were not stably housed, and about 2 in 5 had received
income from illicit sources in the 30 days before assessment (Table
1). Overall, one-third of the total sample reported using heroin
during the 30 days before assessment. However, heroin was the most
commonly used opioid in only 2 of the 7 study sites (Vancouver and
Montreal), reported by about half of the local participants. At 4 of
the sites, heroin use was virtually absent. For the majority of
participants in these cities, prescription opioids (e.g.,
hydromorphone, morphine, oxycodone) were the predominant opioids used,
in locally different patterns (Table 2). Moreover, the longitudinal
analysis suggested that heroin use had significantly decreased in all
sites since 2001 (overall effect -24.9%, p ( 0.001). Use of cocaine
and crack cocaine was also very common across the sites and also
decreased over time (-14.1% and -11.7% respectively, p ( 0.001).
Parallel to the above changes, key risk behaviours (e.g., drug
injection, needle sharing and overdosing) decreased. For example,
injection drug use reported during the 30 days before assessment
decreased significantly in the total sample between 2001 and 2005,
from 84.5% to 63.7% (p ( 0.001).

Our data provide evidence that suggests that heroin use has become an
increasingly marginal form of drug use among illicit opioid users in
Canada, particularly outside of Vancouver and Montreal (port cities
that are major heroin import points). Instead, the use of prescription
opioids in varying forms has become the predominant form of illicit
opioid use. Recent data from the United States have indicated similar
patterns, including evidence that the rate of prescription opioid
abuse has exceeded the rate of heroin use in American household survey
populations in recent years.14,15,18

Our findings highlight several crucial points. First, prescription
opioids used by street drug users originally come from the medical
system rather than from illicit production and distribution (as is the
case for heroin). Our data on this are limited, but they do indicate
that, although the vast majority of cohort participants reported
buying their heroin from drug dealers, a substantial proportion of
prescription opioids used were obtained directly or indirectly (e.g.,
through friends or partners) from sources in the medical system (data
not shown). The problem of illicitly obtained prescription opioids
from medical sources has been repeatedly documented and is currently
receiving increased attention in the United States and
Australia.15,19,20 We cannot determine at this time whether the
fundamental shift from heroin to prescription opioid abuse in Canada
is driven mainly by demand or supply. However, Canada is the world's
top per capita consumer of a number of opioids (e.g., hydromorphone),
which makes for an "opioid-rich" environment.21,22 Since prescription
opioid control measures are lax (especially when compared with
measures implemented in the United States) and inconsistent across
Canada (only a few provinces have prescription monitoring programs in
place), this approach needs to be reconsidered in the interest of
prevention.23-25 However, such measures should not undermine access
to adequate opioid-based pain treatment, which has taken a long time
to accomplish.23,26,27 Furthermore, a better understanding of illicit
opioid users' comorbidity profiles is needed. Many report their
prescription opioid abuse as being related to previous exposure to
pain treatment or report psychiatric symptoms that are undiagnosed or
untreated (e.g., depression), for which their continued drug use may
function as "self-medication."28-30

Finally, the documented changes in illicit opioid use may require
adjustments to opioid addiction treatment programs. Currently
available or proposed treatment interventions (e.g., methadone
maintenance, buprenorphine maintenance or medical heroin treatment)
principally target heroin addiction.11,31 The efficacy of these
interventions for the growing population of illicit prescription
opioid users seeking treatment needs to be validated, or alternative
treatment interventions identified.

FOOTNOTES

This article has been peer reviewed.

Contributors: Benedikt Fischer designed the
study, co-developed the analysis plan and data
interpretation and was the principal author.
Jurgen Rehm co-developed the analysis plan and
contributed to the data interpretation and
drafting of the manuscript. Jayadeep Patra
executed the data analysis plan and contributed
to the data interpretation and drafting of the
manuscript. Michelle Firestone contributed to the
data interpretation and drafting of the
manuscript. All of the authors approved the final version of the manuscript

Acknowledgement: This study was funded by a grant
from the Canadian Institutes of Health Research.

Competing interests: None declared.

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