Bench & Bar of Minnesota is the official publication of the Minnesota State Bar Association.

Combat Trauma and Criminal Responsibility

Recognizing PTSD and assessing its impact on legal options

Since its formal addition to the Diagnostic and Statistical Manual of Mental Disorders (DSM) in 1980, post-traumatic stress disorder (PTSD) has been increasingly argued in both criminal and civil court. Subsequently, several states have accepted PTSD as both a mitigating and exculpatory factor in criminal cases.1 Estimates of PTSD prevalence rates vary depending on the study and the sample used. However, the DSM-52 places the annual prevalence rate for PTSD at 3.5 percent. Lifetime prevalence rates have been estimated closer to 8.7 percent, with women twice as likely to experience PTSD as men (10.4 percent vs. 5 percent).3 The most common experiences leading to PTSD were combat for men and sexual assault for women.4

While these estimates are based on the civilian population, estimated rates of PTSD are notably higher in veteran populations. Recent studies estimated that 18 percent of Afghanistan and Iraq veterans who were exposed to combat have PTSD.5 Dating back to the Vietnam era, it was estimated that 30 percent of male veterans had PTSD, and that half of them continued to have PTSD 15 years later.6 Estimates of PTSD rates in earlier theaters (e.g., Korea, WWII) are difficult to establish since PTSD was not formalized as a diagnosis until 1980.

Over the years, several widely validated and respected treatment modalities have been developed for PTSD (such as prolonged exposure therapy, cognitive processing therapy, SSRI medications). Although treatment for PTSD is becoming increasingly efficacious, some individuals continue to struggle with PTSD for years. It has been estimated that the median time to remission for PTSD is more than five years. Even for people who receive treatment, the median time to remission was estimated at three years.7 And over one-third of people do not show significant remission of PTSD after several years, even when receiving treatment. This data helps to explain the significant percentage of Vietnam veterans that continues to struggle with its symptoms.

Post-traumatic stress disorder is associated with several functional impairments stemming from difficulty working, difficulty at home, and difficulty in social settings. One of the difficulties associated with PTSD is the increased risk for legal charges.
Research comparing civilians with and without PTSD found that those with PTSD had significantly higher rates of arrest, being charged with violent offenses, and incarceration.8 Similarly, a sample of Iraq/Afghanistan veterans found that 9 percent reported having been arrested within one year of returning home from military service.9 Moreover, of those incarcerated, veterans with PTSD had more severe legal charges than those without PTSD.10

In order to survive the inherent threat of attack in combat situations, veterans became highly aware of their surroundings, reacted quickly to stimuli, rapidly executed decisions, and responded to perceived threats with force. While adaptive in the combat setting, these same behaviors are maladaptive in civilian settings—where they are often referred to as hypervigilance, hyperarousal, impulsivity, and aggression, and can result in criminal prosecution. Research has found that overall symptoms of PTSD,11 particularly hyperarousal,12 were related to increased aggressive behaviors. Re-experiencing or intrusive symptoms (e.g., flashbacks) were associated with higher levels of aggression through their association with hyperarousal.13 In particular, veterans with PTSD had higher levels of impulsive (as opposed to premeditated) aggression compared to veterans without PTSD,14 and irritability/anger were associated with higher rates of arrest for combat veterans with PTSD.15

In part due to an increasing knowledge of the role that PTSD plays in criminal behavior, courts have been increasingly willing to admit testimony related to PTSD.16 Furthermore, a recent survey of forensic psychiatrists found that 7 percent of their evaluations of defendants with PTSD resulted in a not guilty by reason of insanity (NGRI) exoneration.17 Moreover, 23 percent of the evaluated defendants received a reduction of charges, and 30 percent resulted in mitigation. 

Interestingly, this survey of forensic psychiatrists found that combat veterans had twice the NGRI acquittal rate of civilians (11 percent versus 5 percent), which is likely due to the inherent aggression (i.e., a response conditioned by military training) applied in reaction to the traumatic event. Although PTSD caused by non-aggressive acts (such as car accidents, natural disasters) is unlikely to be relevant in criminal court, it would be reckless to deny outright a nexus between trauma and a criminal act solely on account the type of traumatic event.

While the studies addressed above demonstrate that PTSD can lead to behaviors that increase the likelihood of arrest, and that courts have increasingly recognized PTSD as an exculpatory or mitigating factor, they do not address the nexus between symptoms of PTSD and such exculpation or mitigation. As I will argue below, there are aspects of PTSD that could lead to mitigation or a successful insanity plea. This article focuses on combat veterans in particular, in part because persons exposed to combat had twice the NGRI rate of those not exposed to combat.18 The emphasis on combat veterans is also due to the inherent aggression (military response) as a reaction to the traumatic event. However, this analysis could apply to any trauma caused by interpersonal violence in which the person subsequently felt a need to act in self-defense (such as physical or sexual assault). 

Post-traumatic symptoms

While a review of all the major symptoms of PTSD is beyond the scope of this article, there are several symptoms that have been demonstrated to be particularly relevant in considering the responsibility for a person’s criminal behaviors. These symptoms are dissociations, flashbacks, hypervigilance, and hyperarousal.19

Dissociation occurs when a person disconnects from present reality and experiences an altered sense of consciousness or awareness. This can include feeling detached from the surrounding environment, a sense that things are moving slower, feeling oneself in a dreamlike state, and experiencing a distortion of perceptions. It can also include feeling outside of one’s own body, detached from one’s mental processes and actions, or experiencing a sense of physical or emotional numbness as can occur in depersonalization. 

A flashback is a conscious re-experience of a previous traumatic event as though it were occurring in present reality. The disconnection from present reality renders a flashback inherently dissociative in nature. A flashback does not have to exactly recreate the traumatic event, but typically recreates the emotional experience and general tone of the traumatic event. Flashbacks occur on a continuum based on the level of dissociation. In the most extreme forms, the person ceases to experience any awareness of present reality and is completely engrossed in the flashback.

During states of hypervigilance, a person experiences a heightened sense of awareness and reactivity to environmental stimuli, even when no threat exists. The person frequently scans the environment for potential threats and available escape routes, and can engage in exaggerated behaviors to maintain vigilance. This is often associated with elevated levels of anxiety, particularly in unfamiliar or chaotic situations.

Hyperarousal denotes physiological arousal at levels in excess of normal activation. Cortisol and subsequently adrenalin are released, which leads to the person feeling “jumpy” and leads to an exaggerated startle response. A hyperaroused state is often accompanied by anxiety and hypervigilance. Literal or symbolic reminders of the original trauma can often lead to such emotional or physiological hyperarousal.

Criminal responsibility

In order for a successful insanity defense, or mitigation evidence, there has to be an identified nexus between the posttraumatic symptom(s) and the alleged offense. This raises three issues that must be considered when presenting post-traumatic stress disorder in criminal court. First, just because a person was traumatized does not mean he or she has PTSD. To the contrary, most people who experience a significantly traumatic event (even combat) do not develop PTSD. Second, just because a person has PTSD does not mean it directly contributed to the alleged offense. Several relevant symptoms of PTSD (e.g., flashbacks or dissociations) are not always present during the commission of an alleged offense. Of the symptoms that are more pervasively present (such as hypervigilance), these do not necessarily contribute to a specific criminal behavior. Third, just because PTSD contributed to the alleged offense does not mean it satisfies a legal test. Much as psychosis does not ipso facto render a defendant insane, neither does any particular symptom of PTSD. Rather, there has to be a causal relationship between a symptom of PTSD and the alleged behavior. (Technically, the diagnosis of PTSD is not necessary, as long as the symptom is present and its nexus to the offense can be demonstrated.)

Most statutes require that an individual be unaware of the wrongfulness of his or her actions in order to meet the specific insanity defense standard. Thus, the individual must experience a break from reality. Two particular symptoms of PTSD can involve a loss in the accurate perception of reality: dissociations and flashbacks. In extreme cases, dissociations and flashbacks could arguably render a person unaware either of the nature of his or her actions, or that those actions were wrong. This is because dissociations and flashbacks inherently involve a loss of the accurate perception of reality.

As indicated above, during a dissociation the person experiences a fundamental disconnection from reality along with an altered sense of awareness. Because of this fundamental disconnect from reality, it can be questioned whether the person was really aware of the nature of his or her actions. If such a person is not laboring under a reasonably integrated consciousness, his or her actions might not be voluntary. Some commentators have suggested that this could fall under the legal notion of automatism.20 Stated differently, during a dissociated state the person does not fully appreciate external reality as happening, and the body’s actions can be thought of as taking on a mind of their own. The person in such a situation acts with no conscious connection between the self and the environment. Although the person might “see” the actions as they are happening, he or she might not perceive the self as being the agent engaging in those actions. In so doing, the person could engage in behaviors without having been able to form specific (or even general) intent to undertake those actions.

A person with a history of trauma could, if sufficiently startled and/or retraumatized, experience a significant dissociative episode. This person could then potentially begin firing a weapon while dissociated, and not be aware that he or she is the one that is firing the weapon or what is happening at the time. Under this dissociated state the person, unaware of what is happening, would not be able to assess the right- or wrongfulness of shooting a gun. 

During a flashback the person believes that an altered reality is occurring. In general the person believes that the traumatic experience, or one very similar to it, is occurring again and there can be little to no awareness of external reality. As such, the person reacts not to what is actually happening in objective reality, but rather to the content of the flashback. Because traumatic events that lead to flashbacks almost by definition put the person’s life in danger, the person will, during the flashback, seek to protect him- or herself. In such a situation the person could very well act in self-defense to a threat perceived as part of the flashback, even if no such threat is actually present. In so doing, although the person will be able to appreciate the nature of his or her actions, the person will not appreciate the wrongfulness of those actions. 

A combat veteran could experience a current stressor that triggers a flashback to a previous combat situation. During such a flashback the veteran might perceive the current environment as literally or symbolically a warzone, and perceive other people as being enemy soldiers. In such a situation, the flashback could cause the veteran to reasonably fear for his or her safety, and respond according to military protocol—the rules of engagement. A veteran experiencing such a flashback could conceivably start shooting at what he or she perceives to be enemy soldiers.

The other two symptoms of PTSD discussed here, hypervigilance and hyperarousal, do not lead to a loss of reality and therefore are unlikely to result in a successful insanity defense. However, they lead to a sensitization of the perception of threat in which the traumatized person needs less stimulus to exhibit the same reaction, or the same stimulus leads to a more intense reaction than before the trauma (such as when person with a migraine headache becomes sensitized to light). As such, a person with PTSD literally perceives more threat in the world than a similar person without a history of trauma. This sensitization could lead to a claim of self-defense, be argued as a mitigating factor at sentencing, or be argued to negate specific intent in jurisdictions with diminished capacity.

Hypervigilance makes a person very aware of what is going on in the environment. This results in the person scanning the environment with a heightened sensitivity to indicators of potential threat, while overlooking cues that point to an absence of threat/harm. This can easily lead a hypervigilant person to misinterpret otherwise benign behaviors, and perceive more threat in a situation than might be objectively warranted. This could be used to argue self-defense or a lack of deliberation and premeditation. 

A veteran might get into an argument with another individual in a bar. This subsequently becomes a heated argument—irritability is another common symptom of PTSD—during which an individual picks up a bottle of beer. In a state of hypervigilance, the veteran could perceive the individual as bringing the bottle up for a swing rather than a sip. In such a state of mind the veteran could strike first in self-defense. 

Hyperarousal leads a person to experience an elevated physiological and/or emotional reaction to a reminder of the original trauma. Given that traumatic events often cause a person to experience considerable fear and physiological/emotional arousal, reminders of a traumatic event often lead to a similar physiological and/or emotional reaction. This increased reaction often leads to an increased perception of present threat, and an increased behavioral reaction in response to that perception. As with hypervigilance, such hyperarousal could lead to an argument of self-defense, or an argument that premeditation or intent was not formed.

When confronted by a person with a weapon, a combat veteran could experience the physiological arousal of a reminder of combat trauma, which would be more intense than the arousal experienced by an ordinary person confronted with a weapon. The veteran could then react to that threat in self-defense with more aggression than might a non-traumatized civilian. There is no intent to harm, rather the intent is to act in self-defense, which could be argued to mitigate culpability. 


Post-traumatic stress disorder is an identified mental disease or defect within the mental health professions, and has been identified as legally relevant in several state and federal courts. Among the symptoms of PTSD that are most likely to be legally relevant are flashbacks, dissociations, hypervigilance, and hyperarousal. Dissociations and flashbacks could raise questions as to whether the defendant was able to adequately appreciate the nature of his or her actions, or appreciate that they were wrong. Hypervigilance and hyperarousal lead to a sensitized perception of threat that could lead the person to react with more aggression than might otherwise be warranted. Accordingly certain aspects of PTSD could be argued to satisfy the legal test for insanity, or otherwise mitigate criminal responsibility. 

One of the intricacies in such cases is determining not only whether the person genuinely experienced the reported symptoms of PTSD, but also whether the severity of the symptom(s) at the time of the alleged offense rose to a level that would satisfy a legal test (such as insanity, diminished capacity, or negating the formation of intent). In considering this, it is also important to recognize that people react to what they perceive as happening, not to what is objectively happening in reality.


CARLO A. GIACOMONI, PsyD, ABPP is a psychologist at North Star Mental Health, LLC in the Twin Cities. He is board-certified in clinical psychology, and has considerable experience in a variety of forensic evaluations. Dr. Giacomoni has extensive training and experience in conducting evaluations for both adjudicative competence and criminal responsibility.



1 Berger, O., McNiel, D. E., & Binder, R. L. (2012). PTSD as a criminal defense: A review of case law. Journal of the American Academy of Psychiatry and the Law, 40, 509-521.

2 American Psychiatric Association (2013). Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition). Washington, DC.

3 Kessler, R. C., Berglund, P., Demler, O., Jin, R., Merikangas, K. R., & Walters, E. E. (2005). Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the national comorbidity survey replication. Archives of General Psychiatry, 62, 593-602.

4 Kessler, R. C., Sonnega, A., Bromet, E., Hughes, M., & Nelson, C. B. (1995). Posttraumatic stress disorder in the national comorbidity survey. Archives of General Psychiatry, 52, 1048-1060.

5 Hoge, C. W., Riviere, L. A., Wilk, J. E., Herrell, R. K, & Weathers, F. W. (2014). The prevalence of post-traumatic stress disorder (PTSD) in US combat soldiers: a head-to-head comparison of the DSM-5 versus DSM-IV-TR symptom criteria with the PTSD checklist. The Lancet Psychiatry, 1(4), 269-277.

6 Kulka, R.A., Schlenger, W.E., Fairbank, J.A., Hough, R.L., Jordan, B.K., Marmar, C.R., et al. (1990). Trauma and the Vietnam War generation. New York: Brunner/ Mazel. 

7 Kellse, R. C (1995) ibid.

8 Donley, S., Habib, L., Jovanovic, T, Kamkwalala, A., Evces, M., Egan, G., et at. (2012). Civilian PTSD symptoms and risk for involvement in the criminal justice system. Journal of the American Academy of Psychiatry and the Law, 40, 522-529.

9 Elbogen, E. B., Johnson, S. C., Newton, V. M., Straits-Troster, K., Vasterling, J. J., Wagner, H. R, et al. (2012). Criminal justice involvement, trauma, and negative affect in Iraq and Afghanistan war era veterans. Journal of Consulting and Clinical Psychology, 80, 1097-1102.

10 Saxon A. J., Davis T. M., Sloan K. L., McKnight K. M., McFall M. E., & Kivlahan D. R. (2001). Trauma, symptoms of posttraumatic stress disorder, and associated problems among incarcerated veterans. Psychiatric Services, 52, 959–964. 

11 Kivisto, A. J., Moore, T. M., Elkins, S. R., & Rhatigan, D. L. (2009). The effects of PTSD symptomology on laboratory-based aggression. Journal of Traumatic Stress, 22, 344-347. Cohen Z. E., & Appelbaum, P. S. (2016). Experience and opinions of forensic psychiatrists regarding PTSD in criminal cases. Journal of the American Academy of Psychiatry and the Law, 44, 41-52.

12 Taft, C. T., Kaloupek, D. G., Schumm, J. A., Marshall, A. D., Panuzio, J., King, D. W., & Keane, T. M. (2007). Posttraumatic stress disorder symptoms, physiological reactivity, alcohol problems, and aggression among military veterans. Journal of Abnormal Psychology, 116, 498-507.

13 Taft, C. T. (2007) ibid.

14 Teten, A. L., Miller, L. A., Stanford, M. S., Petersen, N. J., Bailey, S. D., Collins, R. L., et al. (2010). Characterizing aggression and its association to anger and hostility among male veterans with post-traumatic stress disorder. Military Medicine, 175, 405-410.

15 Elbogen, E. B. (2012) ibid.

16 Berger, O. (2012) ibid.

17 Cohen, Z. E. (2016) ibid.

18 Cohen Z. E. (2016) ibid.

19 Technically hyperarousal is not a symptom of PTSD. It is used here to include a combination of psychological distress and physiological responses at reminders, and an exaggerated startle response.

20 Goldstein, A. M., Morse, S. J, & Packer, I. K. (2013) Evaluation of Criminal Responsibility. In R. K. Otto & I. B. Weiner (Eds.), Handbook of Psychology, Volume 11: Forensic Psychology (pp. 440-472). Hoboken, NJ: John Wiley & Sons.

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