Was this Sentence Appropriate?

Okla. Woman Guilty of Harming Daughter - New York Times: "A woman who experts said has a rare mental disorder has been sentenced to more than 15 years in prison after admitting she injected fecal matter into her infant daughter. Sarena Sherrard, 31, pleaded guilty Tuesday to child abuse charges. Two mental health care providers, who have cared for Sherrard since her arrest, testified she could not resist the urge to harm her daughter. They blamed a disorder known as Munchausen syndrome by proxy, in which parents create or exaggerate injury to a child to bring attention to themselves. The cause is unknown. Sherrard was arrested in August 2005 after surveillance video showed her injecting a foreign substance into her daughter's catheter at Children's Hospital in Oklahoma City. Police had put the girl's room under surveillance because doctors suspected someone was harming her, according to court papers."