[2] Victims may exhibit a range of behaviors, including self-isolation, suicidal thoughts, and substance abuse, and signs of physical injury or illness, such as bruises, broken bones, or chronic fatigue.

The condition is the basis for the battered woman legal defense that has been used in cases of physically and psychologically abused women who have killed their male partners.

The condition was first researched extensively by Lenore E. Walker, who used Martin Seligman's learned helplessness theory to explain why women stayed in relationships with abusive men.

[1][3] Although the diagnosis has mainly centered on women,[4] it has occasionally been applied to men when employing the term battered person syndrome, especially as part of a legal defense.

"[1] Walker stated, "As there are significant differences between the theory underlying the construct of BWS, and to date there are no empirically supported data, it has not yet been applied to men.

This learned depression and passivity makes it difficult for the abused partner to marshal the resources and support system needed to leave.

A legal defense using BWS seeks to obtain an acquittal, a mitigated sentence or a conviction of a lesser offense.

In a series of appeals against murder convictions, feminist groups (particularly Southall Black Sisters and Justice for Women) challenged the legal definition of provocation and secured the courts' recognition of battered woman syndrome.

[19][20][21][22][23] Until the mid-1990s, the legal definition of provocation in England had relied on Devlin J in R v Duffy [1949] 1 All ER 932: "Provocation is some act, or series of acts done (or words spoken) ... which would cause in any reasonable person and actually causes in the accused, a sudden and temporary loss of self-control, rendering the accused so subject to passion as to make him or her for the moment not master of his or her mind."

The courts have recognized that this evidence may support a variety of defenses to a charge of murder or to mitigate the sentence if convicted of lesser offenses.

Under the term battered person syndrome, the defense has occasionally been used by men in reference to their abusive spouses.

Despite changes in legal and popular conceptions of domestic violence, judges and juries continue to ignore or discount victims' testimony about the abuse.

The threats created a genuine fear for the safety of herself and more significantly, her daughter, and this caused the defendant to lose control and make the ferocious attack.

[32] In HM's AG for Jersey v Holley (2005) 3 AER 371, the Privy Council regarded the Court of Appeal precedent in Smith[33] as wrongly decided, interpreting the Act as setting a purely objective standard.

[37] In Australia, self-defence might be considered the most appropriate defence to a charge of murder for a woman who kills to protect her life or the lives of her children in a domestic violence context.

[38] But the lack of success in raising self-defence in Australia for battered women has meant that provocation has been the main focus of the courts.

Under the new laws, victims of family violence will be able to put evidence of their abuse before the court as part of their defence, and argue self-defence even in the absence of an immediate threat, and where the response of killing involved greater force than the threatened harm.

[43] Napolitano's supporters argued that the judge in the case had been wrong to throw out evidence of her long-standing abuse at Pietro's hands (including an incident five months before when he stabbed her nine times with a pocket knife).

Fate spoke no English and was isolated within a small close-knit Wellington community of 12 families, so she felt trapped in the abusive relationship.

[45] Similarly, The Queen v Epifania Suluape (2002) NZCA 6, deals with a wife who pleaded provocation after she killed her husband with an axe when he proposed to leave her for another woman.

On appeal, the court was very conscious of the Samoan culture in New Zealand in restricting the power of the wife to act independently of her husband and reduced her sentence for manslaughter to five years.

[48] In 1994, as part of the Violence Against Women Act, the United States Congress ordered an investigation into the role of battered woman syndrome expert testimony in the courts to determine its validity and usefulness.

In 1997, they published the report of their investigation, titled The Validity and Use of Evidence Concerning Battering and Its Effects in Criminal Trials.

"The federal report ultimately rejected all terminology related to the battered woman syndrome...noting that these terms were 'no longer useful or appropriate'" (Rothenberg, "Social Change", 782).

In this historic case, the state's Supreme Court granted Florida citizens the ability to rely upon battered spouse syndrome as a defense in killing their abuser.