The Question and Answer section for Middlesex is a great resource to ask questions, find answers, and discuss the novel.
I don't think Cal has a mental disorder. He is traumatized from his conflict over is sexual identity but he is articulate and understanding. At times, he might be depressed but this is understandable considering what he is going through.
I'm sorry, additional information is required for your question to be answered. Due to the length of the text, a chapter number is essential.