It might take just one puff of cannabis to quickly if temporarily dull depression, depending on the strain, suggests a new study published this month in the Journal of Affective Disorders. But smoking weed for too long might also make you sadder over time, the researchers found.
Cannabis. Photo: Ethan Miller (Getty Images)
Researchers at Washington State University looked at the responses of over 500 medical weed users who regularly logged onto an app called Strainprint.
Users of Strainprint, which is available in Canada, can record what strain and dose of cannabis they're smoking, as well as how their personal symptoms change after taking it. In total, they looked at over 11,000 recorded toking sessions that included symptoms of anxiety, depression and stress.
On average, they found, people's ratings (on a one to 10 scale) of their depression, anxiety and stress dropped by at least 50 per cent within four hours of inhaling cannabis.
"Existing research on the effects of cannabis on depression, anxiety, and stress are very rare and have almost exclusively been done with orally administered THC pills in a laboratory," said lead author Carrie Cuttler, clinical assistant professor of psychology at WSU, in a statement. "What is unique about our study is that we looked at actual inhaled cannabis by medical marijuana patients who were using it in the comfort of their own homes as opposed to a laboratory."
They also looked more in-depth at the type of pot smoked and how it correlated to specific improvements of the three symptoms. The biggest spike in reducing depression was seen after only one puff of pot that was low in THC, the psychoactive component of cannabis that causes its mind-altering high, and high in cannabidiol (CBD), the other main ingredient.
With anxiety, two puffs from any strain was enough for the effect to reach its peak. For stress, the largest reduction was seen after at least 10 puffs from a strain high in both THC and CBD.
Those findings in particular might upturn a common narrative about pot, the authors believe.
"A lot of consumers seem to be under the false assumption that more THC is always better," Cuttler said. "Our study shows that CBD is also a very important ingredient in cannabis and may augment some of the positive effects of THC."
Not everything they found was good news, though. Users' baseline ratings of their anxiety and stress didn't change the more sessions they logged in, but their ratings of depression did take a slight drop. And coupled with other research showing a similar effect, the findings suggest that "chronic use of cannabis to cope with symptoms of depression may increase susceptibility for depression by altering the endocannabinoid system," they wrote.
On the bright side, other research has shown that these chemical changes seem to reverse within two days of abstaining from weed.
Aside from giving users a more practical shorthand for knowing how much weed they should take to wind down, the authors also say their findings highlight that cannabis isn't a miracle fixer-upper either.
"Importantly, while acute cannabis intoxication temporarily alleviates perceived states of depression, anxiety, and stress, the repeated use of cannabis does not appear to lead to any longer-term reductions in these symptoms," they wrote.
Studies have estimated that over 50 per cent of medical cannabis users take it to help with anxiety and depression, yet relatively few of the 29 US states that now allow medical weed explicitly consider anxiety and depression to be qualifying conditions for its use, according to the researchers. In Australia, anxiety and depression are not currently qualifying conditions.