Although this is a psychological thriller, although it is a novel that is essentially a whodunnit, and although it is another tale of a relationship that is unable to survive when it hits the first bump in the road, Sharp Objects is, more than anything, a novel about mental illness. Each of the main characters is profoundly affected by mental illness, in varying degrees, and the results of this are deadly. The novel adeptly shows the difference between mental illness that can be treated, and mental illness that cannot, but portraying each of the characters in the middle of their illness and showing its devastating effects.
The protagonist of the novel, Camille Preaker, is a perfectly nice, kind, friendly and hard working young woman who is working as a journalist and whose talent and worth ethic have managed to catch the eye of her editor. To look at her you would never know that she suffers from severe post traumatic stress disorder, but it is a condition that has caused her to self-harm. She hallucinates words at random carved on her body and feels compelled to carve them out herself, which has resulted in skin that is horrific to look at and that in times of stress she begins to cut again. Self mutilation, however, does not physically affect anyone other than Camille, and so the author, in her, presents an example of someone with a mental illness who is able to present an image to the world of there being nothing wrong whatsoever.
Camille's family also exhibits extreme mental illness; her mother, Adora, suffers from Munchausen's Syndrome by proxy. This is a condition whereby the sufferer wants to draw attention to themselves with a series of medical or health issues, but they do this by proxy, which means that they cause others to become sick so that they can receive adoration and attention from medical staff as the "concerned loved one". She causes her younger daughter, Marian, to become sick, so that she can take her to the hospital over and over again, and this ultimately results in Marian's death. Adora is also sociopathic, never bonding with Camille and freely admitting that she preferred Marian.
Amma, Camille's sister, is still a child herself, barely a teen, yet she is completely sociopathic and already capable of killing and feeling nothing. She is brutal in her killing, and also completely emotionally disconnected from the victim in that strangulation is actually a deeply personal crime; Amma finds it possible to stare into the eyes of a child as she strangles them and feeling no emotion or remorse whatsoever. She is also not suspected, partly because she is so gifted a manipulator, but also because it is rare for a child to be suspected of murder, and so any clues that pointed towards her were largely overlooked.
