Review Article: Sleep, Pain and Cannabis

One of the most common reasons that patients report the use of cannabis for medical purposes is to reduce pain and improve sleep. Despite this repeated association, it is not clear whether the effects of cannabis use on pain are mediated by the effect of improved sleep, or vice versa. This distinction may have important therapeutic implications as different cannabis preparations have different pharmacokinetic properties; short acting cannabinoids may therefore initiate sleep but not maintain it, while longer acting cannabinoids may be better at sleep maintenance than initiation. Recent reviews have examined the quantitative outcomes of sleep measures in clinical trials of cannabinoids in a range of disorders but did not focus on pain; others focused exclusively on one cannabinoid preparation. Given the current interest in the potential therapeutic uses of cannabis, we have prepared a general review of sleep, pain and cannabis with a view to identifying gaps in our knowledge that could be addressed in further research.