Appellant was charged with first degree murder with the use of a deadly weapon. She asserted self-defense and claimed that she suffered from battered woman syndrome. An expert testified concerning the effects of the syndrome on a battered woman's beliefs, behavior, and perceptions. The jury returned a guilty verdict of involuntary manslaughter with the use of a deadly weapon. Appellant was sentenced to the Nevada Department of Prisons for a minimum term of nineteen (19) months and a maximum term of forty-eight (48) months. FACTS Appellant X and the victim, X were involved in a non-marital relationship for seven years and cohabited for six years. The couple constantly argued with resulting instances of verbal and physical abuse. X testified that X would beat her and "there were times when they sic were beatings . . . he always hit me, but there were times that were worse than others." She also testified that she knew, by X's expressions, when the argument would become violent. X' testimony was corroborated by other witnesses who testified regarding the violent nature of X' relationship with X. X was a general manager of the Sagebrush Ranch, a licensed brothel, where X was a custodian. The relationship between the parties deteriorated, X requested an early paycheck and was preparing to leave. The couple argued about financial issues for several hours. One witness testified that he observed X in a corner of her office with her hands raised to protect her face while X was standing over her with his hand raised as if to slap her. X appeared to be in a rage. X testified that she began loading a .357 revolver. When X walked toward her, the gun discharged. X was hit above his left eyebrow and was fatally wounded. X stated that the gun accidentally discharged while she was trying to load it. Evidence was presented that due to the model of the revolver, in order to load the gun and close the cylinder, the gun would have to be pointing down toward the floor. Although X told the police and testified that the shooting was accidental, due to the physical evidence, an accidental discharge was considered unlikely by both the defense and prosecution experts. for this reason, accidental discharge was not the focus of the defense. Instead, counsel for X argued that X shot X in self-defense and her insistence in describing the incident as an accident was a product of battered woman syndrome. Evidence was presented that women who suffer from battered woman syndrome often claim they accidentally killed their batterer. The jury convicted X of involuntary manslaughter with the use of a deadly weapon. The trial judge sentenced X to the Nevada State Prison for a minimum of nineteen (19) months and a maximum term of forty-eight (48) months without any enhancement. DISCUSSION X offered the following jury instruction: Evidence of battered womens sic syndrome can be considered by you, the jury, for the following purposes: (1) to determine whether the defendant actually believed that she needed to use deadly force. (2) to determine whether, due to battered womens sic syndrome, her belief was reasonable, and (3) to assist in determining the credibility of the defendant's testimony. The district court declined to give this instruction, finding that there were other instructions, specifically Instruction 34, that adequately advised the jury on the effects of domestic violence to a claim of self-defense pursuant to NRS 48.061 and 200.200. X claims that the failure to give the instruction deprived her of a fair trial. "A defendant in a criminal case is entitled, upon request, to a jury instruction on his or her theory of the case, so long as there is some evidence, no matter how weak or incredible, to support it." Williams v. State, 99 Nev. 530, 531, 665 P.2d 260, 261 (1983). X asserts that the offered instruction was necessary to eliminate confusion created by other instructions. X argues that Instruction 34 did not make it clear to the jury that evidence regarding battered woman syndrome could be considered in evaluating whether a reasonable person under the circumstances (i.e., suffering from battered woman syndrome) would believe that she was in imminent fear of her life or great bodily injury. X also contends that Instruction 34 did not address the effect of the syndrome on her state of mind at the time of the shooting and her claim that the shooting was accidental despite physical evidence to the contrary. We agree. Dr. Lenore E. A. Walker testified as an expert witness for X. "Dr. Walker has defined a battered woman as 'one who is repeatedly subjected to any forceful physical or psychological behavior by a man in order to coerce her to do something he wants her to do without any concern for her rights.'" Ann-Marie Montgomery, Note, State v. Riker, Battered Women under duress: the concept the Washington Supreme Court could not grasp, 19 Seattle U. L. Rev. 385, 391 (1996) (quoting Lenore E. Walker, the Battered Woman 15 (1980)). Dr. Walker testified that the abuse must occur twice before a woman can be considered a battered woman. the district court allowed her great latitude in describing aspects of the battered woman syndrome including the interaction between the "learned helplessness" and a process called the "three phases of violence" (the cycle theory). Dr. Walker's three phases of violence theory has been described as follows: three distinct phases to a battering relationship. In phase one, the tension building phase, the batterer indulges in psychological torture of the woman. This torture is followed by phase two, an "acute battering incident," in which the inevitable tension that has built up results in an uncontrollable discharge of violence. In phase three, the batterer expresses "loving contrition" by apologizing profusely and showing kindness and remorse. It is this third phase that is the most troublesome because the batterer's behavior provides the woman with positive reinforcement for staying in the relationship. This positive reinforcement leads battered women to experience a sense of learned helplessness. the theory of learned helplessness explains the counter-intuitive nature of the battered woman's responses to the incessant abuse she suffers . . . . When a woman realizes that her behavior bears no relationship to the violence she receives, she develops "survival or coping skills that keep her alive with minimal injuries." for example, many battered women become passive after an abusive incident. These coping skills are developed at the expense of escaping skills, which may include anger and active behavior, skills that would enable the battered woman to leave the relationship. The synergistic effects of the cycles of violence and learned helplessness are profound. a symptom of these effects is hypervigilance, a symptom that all battered women share. Battered women are hypervigilant to cues of potential danger and are acutely aware of their surroundings. to a battered woman, otherwise insignificant behaviors such as an eye twitch, a particular tone of voice, or a certain movement are all things that may signal an impending attack by a male. Montgomery, supra, at 392-94 (footnotes omitted) (quoting Lenore E. A. Walker, Battered Women Syndrome and Self-Defense, 6 Notre Dame J.L. Ethics and Pub. Pol'y 321, 326 (1992) & Lenore E. Walker, the Battered Woman Syndrome (1984)). The district court gave a number of instructions to the jury that dealt with the concept of self-defense. Of the twelve instructions involving issues of self-defense, only one, Instruction 34, discusses the relationship between domestic violence or the battered woman syndrome and X' claim of self-defense. Instruction 34 did not properly encompass X' theory of the case. the instruction limits the consideration of the battered woman syndrome evidence to X' perceptions that X's conduct put her in imminent fear of her life or great bodily harm. It did not reflect that the syndrome could be used to evaluate X' state of mind at the time of the shooting and her claim that the shooting was an "accident." The failure to give an instruction regarding X' state of mind was compounded by the wording of the eleven other instructions encompassing the law on self-defense. Many of the instructions did not contain any language that the reasonableness of a person's belief must be considered under the circumstances that existed when the belief was formed. for example, Instruction 23 indicated that deadly force was only authorized when a person believes "with good reason" that such force is necessary to prevent great bodily harm. "Good reason" is not the equivalent of "good reason under the circumstances." The lack of consistency amongst the various self-defense instructions together with the failure to give an instruction regarding the relationship between a person's state of mind and the battered woman syndrome constitutes error. Although we are mindful of the fact, as pointed out by the dissent, that X was not convicted of first degree murder, we cannot conclude that the failure to properly instruct the jury is harmless error. CONCLUSION The district court allowed evidence of the battered woman syndrome and correctly refused to allow the expert witness to testify on the ultimate issue that appellant was suffering from the syndrome. See Townsend v. State, 103 Nev. 113, 734 P.2d 705 (1987). However, the trial court failed to properly instruct the jury on X' theory that battered woman syndrome should be considered by the jury not only as to the reasonableness of X' conduct, but as to her state of mind at the time of the shooting. Therefore, the case must be reversed and remanded for a new trial. at the new trial, the court should give the following instruction: You have heard expert testimony concerning the effect of domestic violence on the beliefs, behavior, and perception of a woman who may be suffering from battered woman syndrome. the defendant asserts that she was suffering from battered woman syndrome at the time of the killing. This, in itself, is not a legal defense. However, if you believe that the defendant was suffering from battered woman syndrome, you may consider such evidence when determining the defendant's state of mind at the time of the killing and whether she acted in self-defense. You may also consider such evidence as to the defendant's credibility and the reasonableness of her belief that she was about to suffer imminent death or great bodily harm and the need to slay an aggressor. By reason of the foregoing, the case is reversed and remanded for a new trial in accordance with the views expressed herein.