Abigail Hanna, 21 from Topsfield, Massachusetts, was arrested in a hospital on Friday after Lyndon Albers, a child she had previously babysat, was discovered naked on the side of a road, three hours after she was reported missing and eight miles from her home.
The two-year-old toddler had cigarette burns on her body and her head shaved to reveal a bruise the size of a softball.
The private-school educated Hanna balanced with the help of guards as she was escorted into the courtroom on Monday.
Her legal team entered a plea of not guilty before a judge held her without bail.
A doctor told the court she was experiencing psychotic symptoms and not fit to stand trial while her lawyers said she had a history of suicide attempts and hallucinations.
Hanna has been charged with kidnapping a child in the middle of the night, assault and battery on a child with injury, assault and battery with a dangerous weapon, and breaking and entering at night to commit a felony.
The medical professional added that their interview with Hanna was conducted while she sat on the floor.
Her attorney Susan H. McNeil wrote in a statement that was shown to the court: 'At this time Abigail is addressing serious and potentially life-threatening issues.
'These issues have clearly impacted her overall mental health. We are in the early stages of the process of trying to determine the facts of what occurred over the past several days.
'We have entered a plea of not guilty to further the process.'
Lyndon's family released a statement Monday morning asking for privacy while the family recovers from their 'horrific ordeal.'
They said: 'We have suffered a horrific ordeal. We are grateful to have our daughter back. We are extremely thankful for the incredible efforts to rescue our daughter by the Police and all emergency responders.
'We are extremely grateful to the kind couple who found our daughter. We are extremely thankful for having the best family, friends and community supporting us through this difficult time.'
We are asking for privacy out of respect for the young ages of our children, and out of an understanding that as parents we need to be able to restore a sense of calm, comfort, and normalcy for the well being of our children
Hanna was educated at an $18,000-a-year private Christian Preparatory school in Connecticut, a report suggests.
She grew up in a family home worth more than $1million, according to Zillow, before attending Gordon College - but a spokesman told the Boston Globe she left after just one semester.
According to Facebook, she got engaged to Nathan Wolters earlier this month. But he deleted his profile after her arrest.
An ex-classmate, who wanted to remain anonymous, told the Globe: 'When I first met her I thought she was really nice, pretty sweet. She was usually very insightful when we had conversations, or in class.'
She revealed that she was transferred to The Master's when she was a junior and started babysitting while she was in Connecticut.
The classmate said Hanna was struggling with depression and 'body image' issues, but nothing that would have predicted her alleged actions.