Reviews have noted many themes in the previous books that are also explored in "Mockingjay". A review from The Baltimore Sun noted that "the themes of the series, including physical hardships, loyalty in extreme circumstances and traversing morally ambiguous terrain, are continued at an even larger scale." In the book, Katniss must deal with betrayal and violence against people. At the same time, while she was symbolically touching thousands of lives, she must also lead those people into war. Finally, Katniss realizes she cannot even trust President Coin, leader of District 13.
In an interview with Collins, it was noted that the series "tackles issues like severe poverty, starvation, oppression, and the effects of war." Collins replied that this inspiration was from her father, who, when going to war in Vietnam, made sure that his children understood the consequences and effects of war. Yvonne Zipp of The Christian Science Monitor noted that it was "the most brutal of the trilogy" and that "Collins doesn't take war lightly – her characters debate the morality involved in tactics used to try to overthrow the rotting, immoral government, and they pay a high cost for those tactics." Katie Roiphe of The New York Times wrote that "it is the perfect teenage story with its exquisitely refined rage against the cruel and arbitrary power of the adult world." In a review for USA Today, Bob Minzesheimer pointed out that the novel contained optimism: "Hope emerges from despair. Even in a dystopian future, there's a better future."
Minzesheimer also noted a central question of "Real or not real?" which was asked throughout the novel by Peeta. Susan Carpenter of the Los Angeles Times also pointed this out, writing, "Mockingjay takes readers into new territories and an even more brutal and confusing world: one where it's unclear what sides the characters are on, one where presumed loyalties are repeatedly stood on their head".