I am curious about the impact of social media on mental health, especially among teenagers. Could you provide some insights on this topic? Your response should contain at least 4 sentences and at least 2 placeholders represented by square brackets, such as [study_name]. Highlight at least 2 sections in your answer with markdown, i.e., *highlighted section*. In your response, the word *impact* should appear at least 2 times.
user