How can we apply psychoanalytic theory to The Great Gatsby? I need a professional answer.

If you would like a trained professional to address this question of a psychoanalytical reading, you might look at the Youtube video on shame and Gatsby by Jared Defife, a professor of psychiatry and behavioral science at Emory University. It's called "A Psychoanalysis of Jay Gatsby." In it, Defife argues that Gatsby is motivated by shame at his background. As lay readers, we certainly can tell that more than just Daisy herself motivates Gatsby's desire for her: to him, she represents security and what it would be like never to have known financial need. You might also try the following article, which is in pdf format on the web: http://www.cusd80.com/cms/lib6/AZ01001175/Centricity/Domain/963/Psychoanalytic%20Crit%20-%20Gatsby.pdf

This article discusses the fear of intimacy experienced by all the main characters in the novel, including Tom, Daisy, Nick and Jordan.