TORONTO, April 17, 2012 /PRNewswire/ - People with an opioid addiction had the highest risk of death when compared with rates for alcohol and other drugs, according to a new study by the Centre for Addiction and Mental Health (CAMH).
For those dependent on opioids, the risk of death was 5.71 times higher
than healthy individuals in the population of the same age, gender and
race. Those with methamphetamine use disorders were next highest with a
4.67-fold risk, followed by those with addictions to cannabis (3.85),
alcohol (3.83) and cocaine (2.96). Alcohol dependence was related to
the highest number of deaths overall.
The study, available online in the journal Drug and Alcohol Dependence, is the largest North American study to compare mortality rates among
different drug users with the longest follow-up. It tracked records of
more than 800,000 individuals hospitalized with drug dependence between
1990 and 2005. Of this group, more than 188,000 died during this
The findings mean that if 10 individuals in the general population died,
then over the same period there would be 57 deaths among people
dependent on opioids, which includes prescription opioids as well as
"One reason for undertaking this study was to examine whether
methamphetamine posed a particular threat to drug users, as it has been
called 'America's most dangerous drug,'" says CAMH Scientist Dr. Russell Callaghan, who led the study. Globally, methamphetamine and similar stimulants
are the second most commonly used class of illicit drugs.
"The risk is high, but opioids are associated with a higher risk. We
also wanted to compare mortality risks among several major drugs of
abuse, as this comparison hasn't been done on this scale before."
Alcohol dependence affected the highest number of individuals, with
166,482 deaths and 582,771 hospitalizations over the study period. In
the methamphetamine group, there were 4,122 deaths out of 74,139
hospitalizations, and for opioids, 12,196 deaths out of 67,104
Specific causes of mortality were not examined in this study, so the
deaths may not be directly caused by drugs but due to related injuries,
infectious disease or unrelated reasons. The researchers are now
exploring mortality causes for each drug group, which may also point to
reasons why women had a higher risk of death for alcohol, cocaine and
opioids than males.
"These are not occasional, recreational drug users, but people who have
been hospitalized for drug dependence," notes co-author Dr. Stephen Kish, Senior Scientist at CAMH.
To calculate mortality rates, Dr. Callaghan and colleagues examined
hospital records of all California inpatients with a diagnosis of
methamphetamine, alcohol, opioid, cannabis or cocaine-related disorders
from 1990-2005. They excluded records with evidence of multiple drug
use disorders. The inpatient records were then matched to death records
from the California Vital Statistics Database. Rates were adjusted by
age, sex and race to the California population in 2000.
"One surprising finding was the high rate of death among cannabis
users," says Dr. Callaghan. "There could be many potential reasons,
including the fact that they may have other chronic illnesses such as
psychiatric illnesses or AIDS, which can also increase the risk of
The findings point to the importance of brief interventions for people
receiving medical care for drug dependence or other related risks such
as infectious diseases or injuries, says Dr. Callaghan.
The Centre for Addiction and Mental Health (CAMH) is Canada's largest
mental health and addiction teaching hospital, as well as one of the
world's leading research centres in the area of addiction and mental
health. CAMH combines clinical care, research, education, policy
development and health promotion to help transform the lives of people
affected by mental health and addiction issues.
CAMH is fully affiliated with the University of Toronto, and is a Pan
American Health Organization/World Health Organization Collaborating
SOURCE Centre for Addiction and Mental Health
CONTACT: Michael Torres, Media Relations, CAMH; (416) 595-6015