"How can a 10 year old be depressed"
PLENTY OF FUCKIN REASONS! Bullying, loneliness, toxic/dysfuncional family, poor living situation/environment, exposure to cruel world events, loss of a loved one, lack of support/care, struggles with education, poor self esteem
No, there is no "Benadryl challenge."
Your kids are either trying to get high or are trying to kill themselves. Stop blaming the internet and start thinking about ways you can help your teenager not feel like the only escape is to hurt themself.