Themes are the fundamental and often universal ideas explored in a literary work. 

Loneliness  

Darius often focuses on the ways in which he is different from everyone around him, which leaves him feeling lonely and isolated. His feelings of being different are exacerbated by society’s negative stereotypes about Persian people and by his own mental health struggles. One thing Darius learns over the course of the book is that feeling different from everyone else is, ironically, a universal human struggle. While Darius hates that the white kids at school stereotype him, he can’t stop even himself from stereotyping Iran and the people in it. When he’s surprised, for example, that there are no camels in Iran, he remembers a bully calling him a camel jockey.

Darius is jealous of his newfound friend Sohrab for being a so-called true Persian, but on his trip, he also learns that Sohrab feels different in Iran because of his Baha’i faith. During the holiday Nowruz, Darius’s father Stephen tells him he’s lucky to have such a big family, pointing out that in Iran, while Stephen is completely out of his element, Darius is connected to everyone around him by blood, culture, and history. While Darius acutely feels the sting of being called names like “terrorist” by peers in the U.S., by the end of the novel, he is proud of his heritage as a “fractional Persian.” 

Cultural Influences on Mental Health  

Darius Kellner, like his father Stephen, takes medication for depression, something not typical in Iran. Despite the support of his parents, Darius struggles to accept his mental health issues, and is even more ashamed by the critical comments his Persian family makes about his depression. When Darius’s new friend Sohrab comes to the Bahrami house one morning, Darius hides to take his depression meds. When his Uncle Soheil reaches out and touches Darius’s belly and suggests his excess weight is caused by meds, Darius feels judged. To Soheil and Babou, medication for depression—and depression itself—seem pointless. And yet, as much as Darius dislikes the questions and comments he receives from his family, his visit to Yazd gives his Iranian relatives reasons to rethink their preconceptions about depression. As much as Babou tries to toughen up Darius, it's Babou who ends up learning how to process his anger and sadness about his dying cultural traditions. As triggered as Darius can be when people judge him and his use of medication, his therapist, Dr. Howell, has given him a strong understanding of his feelings and of how to cope with them. In comparison, Sohrab deals poorly with his anger over his father’s death, lashing out at his close friend Darius, revealing the perils of being raised in a climate that is largely dismissive of mental health care. 

The Complexity of Parent-Child Relationships  

A central focus of the novel is the relationship between Darius and Stephen, as father and son work through their depression to stay connected with each other. At the novel’s onset, while Stephen desires Darius’s mental and emotional wellbeing, he doesn’t communicate this desire clearly and, as a result, the two are disconnected. The novel explores the relationship between Shirin and her parents as well. Whereas Darius is just starting to become more independent of his parents’ influence and control, Shirin is finally returning home after spending the past 17 years in the United States. Just as Darius and Stephen butt heads, Shirin must overrule Babou when he tries to haggle at Persepolis and again when she insists that he is not fit to drive. She must also confront the fact that her kids have missed out on many meaningful cultural experiences and Persian family traditions because she has not returned home for so long. The act of coming home is the beginning of a long process of healing relationships. For Shirin, this healing comes from being with her parents as an adult, while for Darius and Stephen, it comes from sharing vulnerability and learning to communicate more openly.