When a criminal defendant's actions with respect to the charged offense are bizarre and perhaps uncharacteristic of the person's general personality, criminal defense counsel must at least explore the possibility of a defense of insanity. One type of situation in which the insanity defense has been used is in the area of parents or guardians killing infants or very young babies for no explainable reason. The defense will not generally apply to an incident of child abuse or similar felony charges under New York law. Instead, the defense may potentially apply only where there is extremely unusual or shocking behavior seemingly caused by delusionary thinking that affects the person's ability to distinguish right from wrong.
In one case where the mother has been charged with second degree murder of her infant child and then living with the corpse for months, the foregoing defense may potentially be relevant. The authorities arrested the 28-year-old woman from Batavia after the daughter's infant body was found in the woman's apartment. The police acted on a tip from someone who had been visiting the mother.
Police contend that the woman killed the baby after she gave birth to her around three months ago. They contend that she acted "intentionally" under the circumstances. However, an insanity defense would go to the mens rea aspect of the crime in that, although she may have acted intentionally, she was in a delusional state of mind where she did not appreciate the distinction between right and wrong.
A neighbor reportedly described the woman as "extremely pleasant" and "very cordial," which may be consistent with an abrupt personality change due to delusional interferences. In any event, it is a subject that defense counsel will investigate early in order to determine whether the defense will be applicable to the felony charges. The determination is usually made in conjunction with an examination by a forensic psychiatrist. Each state has an allegiance generally to one of the specific variations of the insanity defense, and counsel will prepare such a defense under the particular tenets of New York Law.
Source: People, "New York State Woman Arrested for Allegedly Killing Her Newborn Daughter and Living with Her Corpse for Months", Tara Fowler, Aug. 31, 2015