Can a Mild Traumatic Brain Injury Cause Violence?

Head Trauma and Aggression

At year-end 2019, the total prison population in the U.S. numbered a staggering 1,430,800. And of these prisoners, 8% were serving time for a violent offense, according to the Bureau of Justice Statistics. What makes some people violent? If you’re like most people, you may think it’s due to poor parenting, a character flaw, or just being a “bad” person. Brain imaging shows there may be another reason.

Mounting scientific evidence shows that traumatic brain injury—even a mild one that doesn’t cause loss of consciousness—can lead to aggression or violent behavior in some people. Someone who has experienced a TBI may erupt with anger with little provocation. Something that seems inconsequential may set them off, and the severity of their reactions can range from irritability to verbal abuse to physical assault. Rather than writing off these individuals as bad people, it’s important to look at what’s happening in their brain.

What makes some people violent? If you’re like most people, you may think it’s due to poor parenting, a character flaw, or just being a “bad” person. Brain imaging shows there may be another reason: head injuries. Click To Tweet

The Link Between Head Trauma and Aggression

Aggression following head trauma is more common than you might think. Research in The Journal of Neuropsychiatry and Clinical Neurosciences conducted a study in 2009 to evaluate 67 individuals who had suffered a TBI for the first time. Within 3 months of the injury, over 28% of them displayed post-TBI aggression (primarily verbal). In most cases, the aggression was associated with the onset of depression among other psychosocial problems.

Among violent inmates, the prevalence of TBI is even higher. In a 2020 study in Frontiers in Psychiatry on violent offenders, over 77% reported experiencing one or more head injuries in their lifetime. Aggressive antisocial behaviors and substance use disorders were more common in those prisoners with a prior TBI.

Other findings in The Journal of Neuropsychiatry found that people with intermittent explosive disorder, a condition associated with impulsive aggression, are significantly more likely to have experienced a mild TBI compared with healthy people or those with psychiatric disorders. Such was the case with a 5-year-old boy who stabbed 3 members of his family over a juice box.

Although that case made national headlines, there are many more cases of domestic violence that go unreported and unseen. And expressions of violence can be quite frequent in some people. In a fascinating study in Brain Injury involving 46 people in a TBI neurobehavioral program, the researchers noted 3,914 acts of aggression over a two-week period. Of those acts, 443 were physical assaults while the rest were verbal.

Post-TBI Self-Harm and Suicide

The violent behavior some people experience after a concussion isn’t always directed at others. In some cases, it manifests in the form of hurting oneself. Research in the American Journal of Public Health shows that head injuries increase the risk of suicide. And findings in a 2009 study reveal that self-harm is more prevalent in those with a prior head injury. Experts suggest that feelings of depression that emerge or worsen after a TBI can increase the risk of self-harm and suicidal behaviors.

Related Consequences Associated with Head Injuries

A wealth of research shows that TBIs also increase the risk of depression, substance use disorders, ADD/ADHD, and more. These issues may indirectly contribute to violent behavior. For example, depressive symptoms are linked to an increase in the incidence of self-harm as you saw above. Drug or alcohol abuse impair thinking and judgment, increasing the chances of making poor decisions in relation to aggressive or violent behavior. ADD/ADHD, which is characterized by problems with impulse control, is associated with a tendency to act without thinking. Head trauma has also been linked to an increased risk of incarceration. In the U.S., 25-87% of all inmates say they have suffered a TBI compared with 25-38% in the general population.

How Even Minor Head Injuries Negatively Impact the Brain

Brain SPECT imaging, a well-respected technology that shows how the brain functions, reveals that suffering a TBI can have serious impacts on the brain. Amen Clinics has built the world’s largest database of functional brain scans related to behavior—over 170,000 scans and growing. These SPECT scans show that head injuries decrease blood flow to important brain regions that have been damaged. Some brain areas that are commonly impacted due to head trauma include:

Frontal Lobes

The brain’s frontal lobes are involved in impulse control, judgment, empathy, and more. When there is damage in this area it can increase the risk of aggression and violent behavior. Many people may think about committing violence or saying something abusive, but the vast majority of us work through the potential consequences of doing so and choose not to act out on those dark thoughts. When the frontal lobes are underactive, there’s a greater chance of acting out impulsively. In addition, decreased activity in the frontal lobes due to damage from a TBI is associated with a lack of empathy, meaning people don’t take others’ feelings into consideration. Instead, they blurt out hurtful things or lash out physically.

Temporal Lobes

The temporal lobes, located on either side of the eyes and underneath the temples, are involved in mood, emotional stability, and learning. Abnormal activity in this important brain region is associated with temper problems, anger, and unpredictable moods and behaviors.

Pituitary Gland

The pituitary gland is a pea-sized structure that lies in the back of the brain that is involved in hormone production. The pituitary gland sits in a bony area of the skull called the sella turcica, making it vulnerable to damage, especially from whiplash injuries. Damage to the pituitary gland can result in hormonal imbalances that increase the likelihood of a wide range of symptoms, such as anger, temper outbursts, depression, and more.

Where’s the good news in all this? People who display aggression or act out violently may have a hidden brain injury. And there is hope for healing a damaged brain. When you put the brain in a healing environment, it can boost brain health and improve emotional stability and behavior.

Violence, aggression, head injuries, and other brain health issues can’t wait. At Amen Clinics, we’re here for you. We offer in-clinic brain scanning and appointments, as well as mental telehealth, clinical evaluations, and therapy for adults, teens, children, and couples. Find out more by speaking to a specialist today at 888-288-9834 or visit our contact page here.


  1. WOW ..This makes sense.

    Comment by Mary C Dermody — August 20, 2021 @ 6:05 AM

  2. My son had a difficult birth. I was in labor over 22 hours, given pitosen and Demerol for pain. He was stuck in the birth canal, and I pushed for 2 hours before they extracted him with forceps. 2 hours later, I began to have burning, intense pain – it was unbearable, but until my physician, who is now deceased, arrived, there was nothing that could be done. This was November, 1979. Turns out to be a vaginal hematoma, and I was rushed to surgery. The 2 hours waiting for my doctor was the worst pain I ever experienced – worse than labor and childbirth. Fast forward a couple of years, and I have a very oppositional little boy to deal with. His behavior problems became overwhelming to me, and I required antidepressants, etc… He was “Baker Acted” (Florida) 3 times. Once by us, once by police, and once by a Psychologist when he was 14 years old. We sent him to a Jr. Boarding school because I could no longer handle him, and while there, proceeded to steal two way radios (an intense obsession his entire life – hold 3 patents in “voice over radio technology), and other things like a laptop computer from another student. Everything was sent back to their owner when we found it. Then the stealing continued, and we sent him to a “Behavioral Growth school” in GA. We consulted with Educational Consultants before doing so, to find a good one. He had just turned 15. That worked out ok, because when he returned he had been “reprogrammed” and was afraid we would send him back. He loved to play tennis, and was quite good at it, and so, we had him in a tennis program after school every day. He managed to finish high school, and won tennis awards. College was a disaster… At 35 he began a relationship with a woman in Chicago, who was getting her grad degree in Communications tech. She used his inventions for her Masters thesis and he helped her write it. He spent outrageous sums of money (at this point he had his own company and was doing well) – sending her flowers each week, high priced shoes and clothing from Neiman Marcus, going to the Kentucky Derby and the U.S. Open etc… She dumped him after graduation, and other things happened where he felt she and her girlfriend wronged him. He began to send horrible, threatening letters and texts. Long story, short… he was arrested by the FBI and sent to Federal prison for 15 months. We hired a criminal defense attorney, who was recommended to us, flew to Chicago 10 times visiting him, and put money in his commissary. When he got out, we allowed him to do his Probation period (3) years, with us. Part of his defense involved us hiring a Forensic Psychiatrist well known in Chicago. She interviewed him for 5 hours, and us over the phone for 2 hours. It was $10,000. Her diagnosis – Autism Spectrum, ADHD and Bipolar Disorder NOS. When he was 20, I brought him to the Amen Clinic in between San Francisco and Sacramento from South Florida, where we live. He cooperated because he wanted to see California, and I must have bribed him in some way (can’t recall, it was May of 2000). Anyway, the diagnosis for ADHD and BiPolar NOS was made. Also, the physician we were working with, never mentioned birth trauma evidence, although I must have mentioned it on our incoming evaluation sheets. I have always thought that his traumatic birth caused an injury in his soft, infant head. Is this indeed a possibility, and if so, would the SPECT test done then, have caught it? My husband is a Georgetown U. doctor, and I am a college graduate. There is some genetic evidence for Aspergers in my husbands father, and bipolar mania/depression in my mother. She required ECT. I don’t think there is much we can do now. He’s going to be 42, and says “I don’t believe in Western medicine”. But as his mom, I know that I was very conscientious, loving and involved in his life, as was my husband. I’ve always had this thought in the back of my mind. Can you please comment and get back to me? Thank you.

    Comment by Angela Calabrese — August 20, 2021 @ 7:23 AM

  3. On October 31, 1998, I was put into a coma due to blunt force trauma to the base of the skull. My martial arts training has helped control my anger issues. During my coma, my skull was drained of fluids at the opposite side of the injury, something caused damage to my frontal lobe. The trauma to the base of the skull caused injury to the cerebral cortex by pushing the spinal cord up into the brain stem cracking the skull up and to the right. One has to deal with the brain injury the best way possible because the injury affects the thinking part controlling math skills, dictionary skills, short term/working memory. One must have self-control over anger, frustration, and aggravation because as the brain heals, it is finding new ways of getting the job done. The LIMBIC SYSTEM near the brain stem thought to control emotions, behavior, smell, etc. is the main concern when violence arises. Migraines are possible from the trauma because of the pain coming from both halves of the brain acting like they are at war with each other and the cerebral cortex is in the middle trying to control everything. Thus the rage sets in. From rage comes the violence as a distraction from the pain in the skull. What can be done, at least, I have been sitting down and go immediately into a mediated state of mind. The war is only a war when there is conflict. When one knows the routine from being through it. One adopts an alternative, mediation calms the mind by bringing down the blood pressure. Controlling the heart rate and regulate breathing brings more oxygen into the body to mix with the blood making the flow much more compatible. The massaging of the temporal lobes and between the eyes does not solve the problem, you cannot get to it from there. So calm down, sit down, or lay down, meditate, bring in the peace, the quiet, and breathe. It is the best medicine. I know I tried it because the pain gets massive and more medicine on top of the other medicine is not helping the body. Doctors treat the symptoms. The conglomeration can cause its own symptom and should there be an allergy to some part of the conglomeration the body will reject its presents. Thus a cause of the pain…probability is only a factor until you find the sum of all the facts. Respectfully, Bruce R. Kuzma

    Comment by Bruce Kuzma — August 20, 2021 @ 2:18 PM

  4. My grandson was a victim of shaken baby when he was 3 months old. A shunt was placed to evacuate the subdural hematomas. I would love to have Dr. Amen, personally, help with my grandson. Both of my daughters have had scans in New York, one had a concussion and the other had anxiety/learning disabilities. With the help from Amen clinic, both my daughters are doing well. I’m a practicing trauma nurse and know that TBI’s show up in all different ways. My grandson will be 2 in a month and it would be helpful if we could have Dr. Amen’s thoughts on this.

    Comment by Donna D P — August 20, 2021 @ 2:40 PM

  5. Rarely does the general public hear about the relationship of TBI and violence. Perhaps with additional research, it will be discovered that even for violent offenders brain healing can at least partially assist in restoration to soundness of mind and spirit, thus helping them to moderate their impulsivity. Please continue to do the good work of bringing healing and hope to the brain-injured.

    Comment by David Begany — August 20, 2021 @ 8:05 PM

  6. Have head injuries in 2004 car accident had snd have treat as a squizofrenia many different medication that most don’t work. Inclusive Dr give one that had use for many years but split in two times a day, the pase and continued walking for hours seems that medication is not working. How can I know or get help regarding this

    Comment by Willy cobb — August 21, 2021 @ 3:40 AM

  7. Thanks for this important article. Please keep spreading the word that our children’s heads need to be protected !

    Comment by Mary Seelbach — August 21, 2021 @ 3:51 AM

  8. What treatment is available?
    I’m extremely sensitive to meds/supplements I also have genetics NTHFR, MTRR, COMT. Is there a diagnostic questionnaire?
    Thank you

    Comment by Lin Mills — August 21, 2021 @ 6:17 AM

  9. Thank You for this article. My son has served 19 years of a 23 year sentence for 3 separate crimes which were mis-joined to reach that excessive amount of time. In 2017 he reoffended by assaulting a prison guard who had provoked him with racial slurs on MLK Jr. Day & triggered his aggression. He is a part of the statistics in your report. I do not have the funds or the connections to get him the fair & humane help that I feel he needs.

    Comment by Alice Stoneman — August 21, 2021 @ 10:33 PM

  10. Hello Lin. At Amen Clinics, we understand that no two patients—and no two brains—are alike. Because of this, we offer a wide range of services to meet the individual needs of our diverse patient population:

    Comment by Amen Clinics — August 23, 2021 @ 12:22 PM

  11. I have the 24 years old son Diagnosed with bipolar one and schizophrenic with lots of anger me and my wife give him lots of love and attention many doctors many treadtment center any many defernt medicines all this places stabilize my son only for one week after that start all over again I need helpe me and my wife we don’t know what to do to fix him and I’m emotionaly tired please let me know if you have any idea or Dircetion for me.

    Comment by BOBBY H. — May 25, 2022 @ 10:50 PM

  12. My sister passed out and fell from a standing position, hitting her head hard on the cement driveway. Ambulance was called and she was told she became violent on the way to the hospital which continued into the ED. She has no memory of the event at all… from the fall all the way into the next day. Twenty days later, and due to her symptoms, she was finally diagnosed with a concussion with unknown loss of consciousness status.
    Here is the million dollar question… Is the violence she displayed a "side effect of the head trauma?
    We are trying to figure out why she became so aggressive and has no memory of it.
    Thank you very much

    Comment by Wendy — September 11, 2023 @ 2:35 PM

RSS feed for comments on this post.

Leave a comment

Contact Us