Is there a solution? A new survey for the BBC asked 2,000 teenagers about their biggest worries and hopes. Many fear their concerns will not be addressed.
Knife crime, online safety and mental health
Teenagers: Not recognised as a group until about 100 years ago, teenagers have serious concerns and have led major political protests in recent years. Glossary
Adolescent - People who are still growing up, especially teenagers.
Menacing - Threatening; suggesting the presence of danger.
Warring factions - Groups of people who are involved in a conflict or quarrel with each other.
Compelling - Very interesting, irresistible.
Enduring - Lasting.
Algorithms - Any set of rules followed by a computer. In the context of social media, “the algorithm” refers to the intelligent AI that learns the interests of the user and presents them with posts that it thinks will interest them.
Apathetic - Showing no interest.