The second study was conducted in 2011 in the United Kingdom and included adult cannabis users. 3 Participants’ creativity was tested on two different days: (1) when they were not intoxicated and (2) when they were intoxicated after using their own cannabis (THC levels varied). Participants were tested while not intoxicated and intoxicated to understand their baseline creativity (whether they had low or high creative personalities) and the effect of cannabis on their creativity. The researchers assessed creativity through divergent thinking tasks, specifically verbal fluency and category fluency. To test verbal fluency, participants were asked to list as many words they could think of that linked to a letter of the alphabet, for example “M”. Category fluency was tested by asking participants to list as many words they could think of that linked to a specific category, for example “fruits”. The study found that cannabis slightly improved verbal fluency for the short-term among people who had low baseline creative personalities, but it did not affect category fluency.
In addition, cannabis had no effect on people who were considered to have high creative personalities at baseline. 3 The results from both of these studies might seem confusing, but both studies suggest there is no clear link between cannabis and divergent thinking. 3,5 Both types of thinking are important for creativity and work together. Divergent thinking helps with generating ideas, but convergent thinking is needed to make meaningful connections and select which idea is best. 2, 3
Therefore, it is important to consider how cannabis may affect convergent thinking as well. Since cannabis acts as a stimulant, it causes a boost in other areas of the brain too. This includes an area of the brain that activates convergent thinking. Convergent thinking requires concentration, problem solving and decision-making, and the research suggests that THC can weaken this type of thinking. 3