How does kava affect the brain?

Could you elaborate on the neurological impacts of kava? Specifically, I'm interested in understanding how it interacts with the brain's chemistry and potential effects on mood, anxiety levels, and cognitive functions. Are there any scientific studies that support its use as a natural remedy for stress or anxiety? Additionally, what are the potential side effects or risks associated with prolonged use of kava, and how should individuals monitor their intake to ensure safety? Your insights would be greatly appreciated.