Derry, the main character in the novel, suffers from a complex known as inferiority complex.

What is an inferiority complex?
An inferiority complex is a psychological condition in which an individual feels inadequate, worthless, and inferior to others. This complex can arise from various factors, including childhood experiences, social comparisons, and societal expectations. People with an inferiority complex often have low self-esteem and struggle with feelings of insecurity and self-doubt.

Evidence from the novel
Throughout the story, it becomes evident that Derry suffers from an inferiority complex due to several reasons:

Bullying and social isolation:
Derry is constantly subjected to bullying and ridicule by his peers. He is often called names and made to feel small and insignificant. This continuous mistreatment from others reinforces Derry's belief that he is inferior to those around him.

Comparisons with his siblings:
Derry's siblings are academically successful and popular, which further exacerbates his feelings of inferiority. He constantly compares himself to them and feels inadequate in comparison. This comparison leads him to believe that he is the least accomplished and least liked among his siblings.

Parental neglect:
Derry's parents constantly favor his siblings and pay little attention to him. This neglect reinforces his belief that he is unworthy of love and attention. The lack of parental validation further contributes to his inferiority complex.

Impact on Derry's behavior and relationships:
Derry's inferiority complex significantly impacts his behavior and relationships. He often avoids social situations, fearing judgment and rejection. He struggles to assert himself and lacks confidence in his abilities. His low self-esteem affects his interactions with others, making it difficult for him to form genuine connections.

Conclusion
In conclusion, Derry's experiences of bullying, social isolation, comparisons with his siblings, and parental neglect contribute to the development of his inferiority complex. This complex manifests as feelings of inadequacy, low self-esteem, and a constant sense of inferiority. Understanding Derry's inferiority complex is crucial in analyzing his character and the challenges he faces throughout the novel.