Professor Wayne Hall, of The University of Queensland’s Centre for Clinical Research, and Professor Louisa Degenhardt from the Burnet Institute, Melbourne, conducted the study which focused on the global prevalence and health burden of illicit drug use.
Cannabis was far and away the most widely used illicit drug globally, but heroin and other opiates caused the most harm, followed by amphetamine-type stimulants and cocaine, Professor Hall said.
“Among the most common harms were drug dependence, overdose deaths, accidents, violence, HIV-AIDS and other blood-borne infections,” Professor Hall said.
The study found that of an estimated 155–250 million people who used an illicit drug worldwide in 2008, about 129–191 million were cannabis users; 16–38 million problem users of opioids, amphetamines, or cocaine; and 11–21 million people injected drugs.
Professor Hall said the study aimed to determine the extent of illicit drug use and dependence, and their contribution to the global burden of disease.
It examined what iillicit drugs are most commonly used, those causing the most harm, the types of harm, and research priorities for better understanding illicit drug use and drug-related harm globally.
“We summarised what we know about how many people in various parts of the world use various types of illicit drugs, namely, cannabis, amphetamines, cocaine and heroin and other opiates and how much and what types of harm these drugs cause,” he said.
Researchers concluded that intelligent policy responses were urgently needed to address drug problems globally – particularly in high-income countries where rates of illicit drug use is substantial, and in low and middle income countries close to illicit drug production areas.
However, before this could be achieved, better data was needed on the global prevalence of different types of illicit drug use and drug-related harm.
“We found that information was of varied quality and largely missing for some parts of the world, especially developing countries,” Professor Hall said.
• Cannabis is the most widely used illicit drug globally (129-191 million users in 2008)
• Drug use is consistently more common in males than in females
• Levels of illicit drug use seem to be highest in high-income countries
• Factors that increase risk during adolescence include; poor quality parent-child relationships, parental conflict, and parental and sibling drug use
• Individual risk factors include being male, sensation seeking behaviour, poor school performance, and early oppositional and defiant behaviour
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