The first thing you <em>should</em> do is to report it to a trusted adult or authority figure whether that be their or your parents, or the school counselor/resource officer.
However, after you do that, you can try to care for them and comfort them as much as you can. It is recommended that you don't give them overbearing care as that can cause them to feel worse about themselves. If they do begin to hurt themselves, tell an adult.
Here is the National Suicide Prevention Lifeline: 1-800-273-8255
Answer:
A disease that has been wiped out of existence has undergone <u>eradication</u><u>.</u> A good example can be the disease smallpox that was eradicated almost a century ago.
The brain gets used to you taking the drug. Some drugs will affect your neurotransmitters, or messages that get sent to your brain that regulates how we think or feel. You will eventually become dependent on the drug so if you stop you might feel sick or go through "withdrawal". Which people dont want to go through so they will continue to take the drug.