One of the themes found within Higurashi No Naku Koro Ni is domestic violence. In the manga for the Tatarigoroshi (Curse Killing) arc, a pair of siblings that go by the names of Satoko and Satoshi Hojo were taken in by their aunt and uncle due to their parent's death earlier in their lives. Once taken in, the siblings were verbally and physically abused by their aunt and uncle. As the sibling's mental states worsen, their home lives start to mold into a greater nightmare than what it already was. This gives input into later events that occur within the arc.
Another theme found within Higurashi No Naku Koro Ni is research ethics. Throughout the series, the village the story takes place in holds a disease known as Himanizawa syndrome. In hopes to find the cure for the disease, Dr. Tanako decided to test her treatments on Satoko. The role of the research ethics and medicine also give input into early and late events within the manga.