Pubdate: Wed, 16 Mar 2016
Source: Globe and Mail (Canada)
Column: Health Advisor
Copyright: 2016 The Globe and Mail Company
Contact:  http://www.theglobeandmail.com/
Details: http://www.mapinc.org/media/168
Author: Judith Davidson
Note: Dr. Judith Davidson is a clinical psychologist and sleep 
researcher. She works with the Kingston Family Health Team and 
Queen's University at Kingston. She is the author of Sink into Sleep: 
A Step by Step Workbook for Reversing Insomnia. You can follow her on 
Facebook and on Twitter at  L5

MARIJUANA'S EFFECT ON SLEEPING STILL UNCLEAR

At least once a week, I hear from patients that smoking marijuana 
helps them to relax and to sleep. I know that other clinicians hear 
the same thing because they ask me about it at insomnia workshops. 
Does cannabis really improve sleep?

Several studies done in the 1970s examined the effects of smoked 
marijuana on objective sleep patterns, measured using 
polysomnography. This method of overnight recording involves the 
tracking of brain waves, eye movements and muscle tone in order to 
distinguish the sleep stages and their pattern of occurrence 
throughout the night.

Contrary to popular belief, smoking marijuana did not necessarily 
make it easier to get to sleep. Participants in some studies fell 
asleep faster while those in other studies took somewhat longer to 
fall asleep. There were also inconsistent effects on the amount of 
slow wave sleep, or deep sleep. The most consistent finding across 
these studies was that marijuana was associated with a reduction in 
rapid eye movement ( REM) sleep, the stage in which most of our 
dreaming occurs.

The main active constituent of marijuana was isolated in 1964 as 
tetrahydrocannabinol ( THC). Since then, dozens of other constituents 
have been characterized, including cannabidiol ( CBD), an important 
component thought to have muscle relaxant, anti-inflammatory and 
analgesic effects.

Fast-forward to the 21st century: It is now possible to create 
cannabis-based medicines with certain doses and combinations of THC 
and CBD. By having control over the specific drug composition, better 
studies on the effects of cannabis on sleep are possible.

However, few researchers have explored this. Rather, the studies 
today are mainly looking for effects on symptoms such as pain, muscle 
spasms and appetite; sleep is sometimes asked about, but rarely 
measured with polysomnography.

What we take away from these newer studies is that participants 
report a positive effect on their sleep with these compounds and that 
the THC component of cannabis may be more responsible for this than 
the CBD. There are insufficient data to say anything about the effect 
on sleep stages.

What we do know is that sleep becomes very disrupted when people who 
are using cannabis on a regular basis start withdrawing from it. 
Sleep difficulty and strange dreams are prominent withdrawal effects. 
Polysomnographic data show that it takes longer for people to fall 
asleep, their sleep is disrupted, deep sleep is reduced and REM sleep 
is increased.

What seems like a simple question - "Does cannabis really improve 
sleep?" - does not have a simple answer. Well-designed studies with 
good measurement of sleep are lacking. What research has been done is 
complicated by variations in the dose and chemical composition of 
cannabis, method of use ( smoked, oral spray, capsule), time of use 
in relation to bedtime, the participants' pattern of prior exposure 
to cannabis, and their medical and sleep histories.

Although the general feeling among users is that cannabis helps their 
sleep, there is as yet no clear evidence of this from research. This 
does not mean that the effects are absent. The experience of sleep is 
a subjective and personal thing, and all the reports of people's 
improved sleep with cannabis cannot be discounted. It is likely that 
some positive effects are present but clouded by problems in research 
design and measurement.

What's clear is that when cannabis is stopped after regular use, poor 
sleep is likely to occur, including more stage REM accompanied by 
weird dreams. This we can all agree on and, in a backward sort of 
way, it speaks to the substantial effects of cannabis on sleep.
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MAP posted-by: Jay Bergstrom