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Is cannabis really getting stronger?

Posted on 1 August 2016

Cannabis is the world's favourite illicit drug but recent reports on increased potency have led to public health fears. How reliable is the evidence? And is cannabis really getting stronger?

In an article written for The Conversation website, Ian Hamilton, a lecturer in Mental Health in the Department of Health Sciences, addresses some of the long standing issues around cannabis and the harm posed to users. Ian points out the inconclusive nature of the available evidence, and discusses the arguments put forward on both sides of the debate. Ian also looks at the limiting factors on obtaining better evidence, such as the "massive data hole" caused by us not knowing if cannabis recovered from home seizures is a representative sample of the cannabis in circulation. In addition, the quality and sophistication of the cannabis testing procedures have improved over recent decades, but this means that seminal and widely quoted research is now out-of-date. 

Ian concludes by calling for a national survey of cannabis to not only provide information about the strength of the drug, but also how it is consumed in the population.