Final answer:
Identity confusion is the most common developmental problem in adolescence, where individuals work on forming their own identity and can struggle with questions of self and future if this process is not successful.
Step-by-step explanation:
The most common developmental problem of adolescence is identity confusion. During adolescence, an individual goes through significant psychosocial changes, including the crucial task of forming a personal identity, which answers questions like "Who am I?" and "Who do I want to be?" According to Erik Erikson's theory of psychosocial development, this stage is known as identity versus role confusion. Adolescents attempt to resolve this by testing various roles and integrating them to form a single identity. Those who fail to engage in this process might be left with a weak sense of self and experience role confusion, leading to uncertainty regarding their identity and future.