These things can lead to people feeling those certain feelings
Depression
Anxiety
Stress
Not enough nutrients
Sleep deprived
Enfermedad de Huntington.
B: situations, people, and events
Age: 1-3 13 grams per day
Age 4-8 19 grams per day
Age 9-13 34 grams per day
Age 14-18 46 grams for girls and 52 grams for boys
I hope this helps. :)