This 2004 study investigates the effects of kava extracts on brain function and emotional regulation and reactivity. It’s a double-blind, placebo controlled trial, which means research participants were assigned either the treatment group (with kava) or a non-treatment groups (placebo, or something that won’t have an effect). This is done without any order, and both participants and their doctors didn’t know which treatment they were getting.
What they did
Researchers enrolled 20 healthy people to participate in the study. They were between the ages of 18 and 53 and had never tried or used kava extracts before. Participants were given either kava extract or an identical looking placebo. They were asked to not smoke, drink caffeine or alcohol during the study.
How they did it
Participants got a single dose or either kava extract (two 150mg capsules) or placebo (2 identical capsules without kava root).
Researchers measured the effects of kava using a variety of scales and questionnaires. The main one being the State-trait-cheerfulness inventory (STCI). This measures three constructs; cheerfulness, seriousness and bad mood as both traits and states. Participants were also given two questionnaires to measure brain function; visual attention and short term memory. These scales were before treatment and 60 minutes after either kava or placebo was taken.
What they found
Baseline scores for mood and cognition were similar before treatment. However, the group that took kava reported feeling more cheerful than the placebo group. The effect was stronger in people who were naturally more cheerful to start with. When it came to brain function, the kava group performed better on visual attention and memory tasks.
Researchers also looked at how brain function and mood were connected. In the kava group, those who were more cheerful, made more mistakes on the visual attention tests. On the other hand, in the placebo group, those that reported a bad mood performed better.
What it means
This study suggests that taking kava extracts can boost both cheerfulness and mood, especially in already happy people. In visual attention, one may say that kava enhances the ability to pay specific attention to important cues or information. Kava may also support short-term memory and learning by slowing the rate at which short term memories decay and increase the rate that they are stored in long term memory.
Researchers further suggest that kava may be good for the brain’s neurotransmitters, or chemical messengers. Particularly, the dopamine system, which is linked to feelings of optimism and satisfaction and serotonin, which is important for mood and cognitive processes.
All in all, kava had more positive effect on mood and brain function compared to placebo
Link to original article
Thompson, R., Ruch, W., & Hasenöhrl, R. U. (2004). Enhanced cognitive performance and cheerful mood by standardized extracts of Piper methysticum (Kava‐kava). Human Psychopharmacology: Clinical and Experimental, 19(4), 243-250.