A 15-year-old child can be difficult to treat due to all the following reasons EXCEPT:

A 15-year-old child can be difficult to treat primarily due to their developmental stage, which often includes a desire for independence, heightened awareness of peer influence, and significant concern about body image. These factors can impact their willingness to cooperate with treatment and can complicate the responses to medical interventions.

Independence issues arise as adolescents strive for autonomy, which might lead them to resist authority or express reluctance to follow medical advice. Peer pressure plays a significant role in the lives of teenagers, influencing their choices, behaviors, and even their perception of health and illness. Cognizance of body image is critical during this stage, as teenagers are often very sensitive to changes in their appearance, which can affect their self-esteem and willingness to engage in treatment.

Contrastingly, stranger anxiety is not typically a concern for a 15-year-old. This form of anxiety is more commonly observed in younger children who may exhibit fear or discomfort around unfamiliar people. By the age of 15, most adolescents are developing social skills and interactions that enable them to manage new relationships with adults and healthcare providers without the same level of anxiety that younger children might exhibit. Therefore, this aspect does not significantly impact their treatment as it would for younger populations.