This article from Nov 2020 describes a recent INECO Neuropsychology study that has produced results associating yerba mate with happiness. There is a release of dopamine released while drinking your mate. Drink mate, be happy.
"The reason for this lies in that drink mate in the morning , increases the release of a neurotransmitter called dopamine , which stimulates the centers of brain reward generating a feeling of pleasure and positive feelings , " said Dr. Teresa Torralva , director of the Department of INECO Neuropsychology. (Fuente www.perfil.com).