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Subjective experience of withdrawal from cannabis: bush, hydro and synthetic

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Date Commenced:
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Project Members: 
image - 1314150283 John Howard
Dr John Howard
Conjoint Senior Lecturer
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Honorary Professor
Ph 02 9385 0231
image - 1314156454 Paul Dillon
Mr Paul Dillon
Project Main Description: 

Cannabis is the most widely used illicit drug in Australia. There are three forms of cannabis: ‘Bush’: cannabis grown in an outdoor environment and thought to contain less psychoactive ingredient – THC; ‘Hydro’: cannabis grown hydroponically and thought to have a higher THC content; and ‘Synthetic’: ‘Synthetic’ cannabis is not a ‘true’ cannabis but rather a cannabinomimetic, a synthetic substance derived to bind human cannabinoid receptors and thus mimic the effects of cannabis.

“Legal highs” first became available for purchase in the early 2000s. At first thought to be contain purely herb-products, the active ingredients were subsequently identified as synthetic agonists of the CB1 and sometimes CB2 receptors. In Australia as well as many other countries, possession and sale of cannabinomimetics has been outlawed over the last 1-2 years, however enforcement is problematic due to ever present variants that may not be captured by legislation. Despite this, the popularity of synthetic cannabis has increased. Currently, in Australia, synthetic cannabis is available for purchase online and ‘under the counter’, with brand names such as Kronic and many other ‘brands’. A recent study shows that the product labels are unreliable, and it is impossible to determine what cannabinomimetic compound each product contains from the name of the brand or blend. Often products will claim to sell newer ‘legal’ compounds but mass spectrometry reveals that they contain the same illegal compounds as before.

Project Collaborators: External: 

Bryan Tran, Faculty of Medicine, UNSW

Dr David Allsop, University of Sydney

Paul Dillon, Drug and Alcohol Research and Training Australia


While a quantifiable withdrawal syndrome for ‘natural’ cannabis has been identified, no such study has been conducted on withdrawal from synthetic cannabis in Australia or elsewhere. To date, isolated withdrawal phenomena have been published in European and American case studies only. Symptoms include drug craving, unrest, sleep disturbance, nightmares, profuse sweating, nausea and headache. Our hypotheses are that:

  1. A withdrawal syndrome for synthetic cannabis exists
  2. This syndrome of withdrawal will be symptomatically similar to that experienced by regular users of ‘natural’ cannabis
  3. Because of the higher synthetic THC potency, withdrawal from synthetic cannabis may be more severe.
Design and Method: 

It is proposed to survey regular users of cannabis about their use of cannabis and other drugs, and their subjective experience of withdrawal from cannabis. The survey includes questions pertaining to demographics, frequency and quantity of drug use and the cannabis withdrawal scale. The survey will be anonymous and will be conducted using an Internet survey, hosted at NCPIC. Participants will be recruited via posts on appropriate cannabis user sites and blogs

Data analyses completed. Papers and a NCPIC Bulletin in preparation. 

Presentation at APSAD in 2013.

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