Adolescents' identity formation can be an excellent topic for your thesis. To begin with, I would urge to take contact with, for example, the work on identity formation in adolescence by the USA psychologists Eric Erickson and James Marcia.

Digital media use in adolescence.

Non-desired loneliness

impact of digital technology and media use on health of adolescent

cyberbullying and gamification

Substance use and abuse

Loss of meaning in life

Addicted to different media platforms

Purchasing drug through SNS

Absence from school.

Bethany Donaghy, David Moore & Jane Green (2023) Co-Occurring Physical Health Challenges in Neurodivergent Children and Young People: A Topical Review and Recommendation, Child Care in Practice, 29:1, 3-21, DOI: 10.1080/13575279.2022.2149471