Medicinal cannabis might not ease sleep problems in people with chronic pain over the long term, because frequent users might build up tolerance to its sleep-inducing effects, suggests preliminary research published online in BMJ Supportive & Palliative Care.
Chronic pain is thought to affect between 19% and 37% of adults in the developed world and is often accompanied by sleep problems, including difficulty getting to (latency) and staying asleep as well as waking up early.
The researchers wanted to find out what impact medicinal cannabis might have on sleep problems experienced by people over the age of 50 with chronic pain that had lasted at least a year.
They assessed the sleep quality and pain scores of 128 people who were being treated at a specialist pain clinic: 66 of them used medicinal cannabis to manage their sleep problems and 62 didn’t.
In all, around one in four (24%) said they always woke up early and weren’t able to get back to sleep; one in five (20%) reported always finding it difficult to fall asleep; and around one in five (27%) said they woke up during the night.
Medicinal cannabis users had used the drug for an average of 4 years, consuming around 31 g a month. Most (69%) smoked it, with around 20% either using cannabis oil or vapor.
After taking account of potentially influential factors, including average pain score, age, gender, use of other sleep aids or antidepressants, medicinal cannabis users were less likely to wake during the night than non-users.
But there were no differences between the two groups in the time taken to get to sleep or frequency of early awakening.
Further analysis of the sleep patterns of the medicinal cannabis users showed that frequency of use was associated with greater difficulty falling asleep and more frequent waking during the night.
“This may signal the development of tolerance,” suggest the researchers, although they acknowledge that more frequent users might be in more pain or be depressed/anxious, which may in turn be associated with more sleep problems.
This is an observational study, and as such, can’t establish cause, added to which the number of people involved was small and there were no details on the time of day people used cannabis.
But say the researchers: “These findings have large public health impacts considering the aging of the population, the relatively high prevalence of sleep problems in this population, along with the increasing use of medicinal cannabis.”