Marijuana, Sleep, and Dreams

The indica vs. sativa debate, continued. 

[First published July 13, 2015.]

Anyone who has smoked marijuana more than a couple of times knows that cannabis can alter how you sleep. The effect of cannabis on sleep is even part of the never-ending debate over Cannabis indica vs. Cannabis sativa, the two major species of the marijuana plant. Indica smokers typically report a marijuana high that is body-intensive and often soporific, sometimes leading to the condition aptly known as “couch lock.” Whereas sativa smokers, according to marijuana lore, experience a more cerebral, energetic “head high,” with fewer somatic effects. Not surprisingly, hybrid strains incorporating the alleged characteristics of both indica and sativa strains are popular in the medical marijuana community.

Although there is no official sanction for it in the medical community, marijuana is often dispensed medically for sleep problems. One piece of common wisdom holds that the higher the THC content of marijuana, the more helpful it will be in promoting sleep and improving poor sleep. The stronger the better, in other words. Similarly, indica strains are assumed to promote sleep more than sativa strains.

In an effort to clear the air, so to speak, a group of researchers, writing in Addictive Behaviors, sought to “document naturalistic choice of particular medical cannabis types among individuals who self-report using cannabis for the treatment of sleep problems…. Little research has documented species or cannabinoid concentration preferences among individuals who use medical cannabis for particular conditions…. We also evaluated the interaction between the type of cannabis used and diagnosis of cannabis use disorder among study participants.”

The researchers recruited participants from a medical cannabis dispensary in California under procedures approved by the VA and Stanford University review boards. 163 people with a mean age of 40, who used cannabis twice a day on average, provided self-reported information on their cannabis use for the study. 81 participants reported using cannabis for the management of insomnia, and another 14 reported using cannabis to reduce nightmares. (Frequent smokers insist they dream less. THC does appear to decrease the density of REM cycles, leading to more restful, dream-free sleep, according to some studies.)

So what did they find?

—“Individuals who reported using cannabis for nightmares, compared to those who did not, preferred sativa to indica.” (Small effect.)

Indica, considered the “heavier” high, might have seemed the likely choice here.

—"Individuals who self-report using cannabis to treat symptoms of insomnia and those with greater self-reported sleep latency reported using cannabis with significantly higher concentrations of CBD.” (Large effect.)

Again, a somewhat counterintuitive finding, since it is widely believed that CBD conduces toward a more wakeful state than THC alone.

—“Individuals who used sleep medication less than once/week used cannabis with higher THC concentrations than those who used sleep medication at least once a week.” (Large effect.) “There were no differences in THC concentration as a function of self-reported sleep quality, or use for insomnia or nightmares.”

Pretty straightforward finding: THC makes you sleepy. It is not clear, however, that above a certain threshold, more THC makes you even sleepier. In fact, some researchers would consider this finding unexpected, given that high THC concentrations have been shown to have a stimulating effect.

—“Older individuals were less likely to have cannabis use disorder compared to those younger….

No surprise about the older folks, since prior studies show a decrease in the prevalence of cannabis use disorders with age.

—“Individuals who preferred sativa or primary sativa hybrid strains were less likely to have cannabis use disorder compared to those who preferred indica or primary indica hybrid strains.” (Small effect.)

If replicated, this finding could have significant implications; both in strengthening programs to reduce marijuana smoking among the very young, and it warning consumers that some evidence suggests indica strains may be more addictive than sativa strains in plants with similar THC/CBD levels and ratios.

—“Neither concentration of THC nor CBD were associated with cannabis use disorder.”

Common sense, but useful to remember. In other addictive behaviors, such as heroin and alcohol abuse, the relative strength of the drug is not the primary determinant of its addictive potential.

Caveats and design limitations: The survey relied on retrospective reports of sleep quality and pot preferences. Also lacking is an examination of additional variables such as PTSD and co-occurring substance abuse.