There are a number of factors contribute to it: High expectations and pressure to succeed—teenagers can feel pressure to succeed in ways previous generations did not. Parents can knowingly or unknowingly mount pressure on their teenager children, all this contribute to anxiety in teens.
Social media—These days, everyone is constantly connected to social media. It’s not surprising that their self-esteem―and worldview ―becomes connected to responses to social media posts. It’s hard for teens not to compare their life and social connections to what they see others posting on social media.
There are also some children who have unexpected reactions to normal developmental experiences like going to school, going to a party, doing a sleepover or going to camp; children who worry excessively about everyday life activities. This often starts in the years right before puberty.