This Wikipedia article defines laughter in many terms, such as... "a visual expression of happiness, or an inward feeling of joy" and "a part of human behavior regulated by the brain, ...
Anger is an emotion generated by neural processes in the brain and is associated with elevated blood pressure. How can an emotion, which is totally related to brain, result in blood pressure changes?
It is tragic, but apparently Killer whales and Dolphins can commit suicide too (e.g. here)... This suggests they can become depressed. I wondered whether they were "clinically" depressed like many ...