Major themes of Extremely Loud & Incredibly Close include trauma, mourning, family, and the struggle between self-destruction and self-preservation. Sien Uytterschout and Kristiaan Versluys have examined the specific types of trauma and recuperative measures that Oskar's grandmother and grandfather go through after the Dresden bombings and that Oskar goes through after the loss of his father. They argue that Oskar has a simultaneous death wish and extreme need for self-preservation: This theme is echoed in Thomas Schell, Sr.'s pronounced survivor guilt and Oskar's grandmother's well-disguised inability to cope with her trauma. They also argue that though Oskar's journey to "find" his father does not help him get over his traumatic experience, it does allow him to grow closer to his mother. Foer provides a parallel between WWII and the 9/11 attacks to not only show the timelessness of trauma and tragedy – how it affects people unbiasedly, but also how coping with trauma also means to revisit the trauma.
It is also important to note the impact of the child narrator on the effectiveness of the theme of trauma. In the novel, Oskar never directly addresses through his narration the trauma he faced. Only through his journey through the city and through his grandparents' letters does he mimic the journey one must take when coping with trauma.