Behavioural changes such as agitation and aggression occur in approximately 10 to 35% of people with non-congenital
brain damage, both in the acute and chronic phases. This can be a temporary phase or, in some cases, long-lasting.
In the first six months after brain injury, approximately one third of people with brain injury exhibit aggressive behaviour. That number drops to about a fifth of people after five years. Aggression in the first three months is nevertheless a reasonable indication of aggressive behaviour after years.
Verbal aggression is most common. Aggression and impulsiveness often occur together.


In the professional literature, the term 'aggression' is used to refer to symptoms of disinhibition, anger and irritability as a result of not being able to control behaviour and emotional impulses.


Aggressive behaviour after brain injury is often a direct result of damage to brain areas responsible for brain damage emotion and behaviour.
Neurobiological causes also play a role. Furthermore, if a person showed rebellious, agitated or aggressive behaviour or had a psychiatric condition before the brain injury, the aggression after the injury is not only due to damaged brain areas. Brain injury can also be accompanied by PTSD (post traumatic stress syndrome) that can have a major influence on behaviour.


Agitation defined

Agitation is 'non-intentional' behaviour, in which the inner restlessness leads to ineffective behaviour, with a highly repetitive character (Verenso, 2008).
Not intentional means that the person does not do it

A distinction is made:
motor agitation: continuously walking around, unable to sit or lie still, rattling on doors, tapping on the table, messing up everything;
verbal agitation: continuous talking, mumbling;
vocal agitation: whining, screaming, shouting, singing, making (stereotypical) sounds.

Aggression defined

Aggression, on the other hand, is 'intentional'
(Verenso, 2008). Intentional means that the person does it consciously, with a purpose.

A distinction is made:
verbal aggression: swearing, cursing, accusing, threatening;
action aggression: hitting, pushing, kicking, destroying, throwing objects, making threatening gestures, harming oneself (self-mutilation).

Damage to specific brain areas


The question is whether a person with brain damage is consciously and intentionally aggressive.
On the one hand, anger may indicate impaired cognitive control, such as emotion regulation.
But the brain's reward system also plays a special role in anger and a response to frustration.
Aggressive behaviour after brain injury is often a direct result of damage to brain areas and the neural circuits between the brain areas responsible for regulation of emotion and behaviour, such as
the frontal lobe (prefrontal cortex [PFC]).
That lobe plays an important role in problem solving, reasoning, and impulse control. For example, the frontal lobe inhibits the amygdala, one of the most important emotion centers of the brain.


Damage to the frontal lobe (prefrontal cortex) reduces this inhibition of the amygdala, which can result in higher levels of aggression.

All of these frontal lobe functions are all necessary to regulate a person's behaviour. When the frontal lobe becomes damaged, it can affect behavioural skills. This can lead to aggressive behaviour. There is great difficulty in controlling inappropriate behaviour. This is often seen in combination with risky behaviour and poor decision-making after brain damage. The other brain areas involved in aggressive behaviour can be found in the drop-down menu.

What other brain areas are involved in aggression?

Other brain areas associated with aggression after brain injury include the hypothalamus, the cerebellum (which can result in Cerebellar Cognitive Affective Syndrome), the pons, the hippocampus and the lenticulo-capsular basal areas. The
lentiform or lens-shaped nucleus is a collective name for two nuclei (the putamen and the globus pallidus) in the basal ganglia. Lesions in the basal ganglia can in some cases also lead to temporary psychotic symptoms such as delusions, hallucinations and altered psychomotor activity, for example after a cerebral infarction.
The hypothalamus is responsible for the regulation of the autonomic nervous system, which in turn regulates responses to emotions. Therefore, damage to this area can also lead to inappropriate aggressive responses.


In general, damage occurs in the right hemisphere and in the forehead (frontal syndrome) more behavioural and personality changes than in the left hemisphere. Injury to the left hemisphere, on the other hand, increases the risk of aphasia, which makes communication difficult and can frustrate a person considerably. In left-handed people, the brain functions may be different.
We have a specific page about behaviour after injury in the frontal lobe (frontal injury / frontal syndrome).
More brain areas and neurobiological causes are still being investigated.


Although aggressive behavior may seem unpredictable, it is often caused by emotional or physical discomfort.
The frustrations of the changes caused by the brain injury can put so much pressure on a person that it can cause an 'explosion'.
A person may feel so unworthy, dependent and no longer in control of life. By this he or she may be more likely to take something as an insult or reproach that this can be enough for an aggressive outburst.


Examples of physical discomfort:

intense fatigue (neurofatique), the physical effort it takes to wash or dress yourself, a full bladder or hunger, low blood sugar, pain, sensory stimuli such as light, sound, an overly busy environment

Examples of emotional discomfort

depressed mood as a result of the brain injury, goals for rehabilitation that are too high, expectations that do not come true, difficulty asking for help, grief for what has been lost, etc.

these other causes must be excluded

1. It must be ruled out whether there are any side effects of medication or the use of substances that increase the risk of aggression (alcohol, drugs, coffee, etc.).
2. A mood disorder (depression/mania), anxiety disorder or possible psychosis must be excluded.
3. Delirium must also be ruled out. Delirium is a state of mental confusion, usually caused by a physical illness.

Prevention is better than ...

Anyone who can recognize and prevent most triggers will go a long way in helping you learn to control aggression.
Relatively simple environmental changes can often lead to a major reduction in problem behavior.
A low-stimulus environment, a fixed daily structure and a consistent, directive approach are of great importance.


We sympathize with all parties. That is, we sympathize with people with brain injury and with people who are confronted with aggression from someone with brain injury.


Coping strategies for the person with aggression due to brain injury

  • Take a Time-out. Get away from the situation that made you so angry.
  • Ask yourself what caused the aggressive outburst. Were you in pain? Were you very tired? Did everything take a lot of effort? Did you search for words? Couldn't you express yourself? Did you feel ashamed of who you are? Did you feel helpless? powerless, disappointed? Did you feel like you were a burden to those around you? Were you afraid? Were you hungry and did you have low blood sugar? Was there too much noise, too much bustle or too much bright light? Did you have to do too much? too much was expected of you? Did everything happen too fast? Is the recovery too slow or do you see that there is no recovery? Did you feel a sense of grief? Did you use alcohol or some form of drugs? If so, do you understand that your emotions are even less inhibited by alcohol and drugs? That this can lead to dangerous situations?
  • Always apologize when you have calmed down. People can't see into your head what happened. You can try to explain this later at a quiet moment. Realize that others may be very shocked.
  • Share how you felt and what caused it.
  • Understanding is always essential.
  • A large part of emotional outbursts is a result of damage in specific brain areas. With this knowledge into why it works this way, you can ask for help from a professional.
  • Find out how you can find a better balance between resilience and effort. Realize that people with brain injuries can get tired very quickly. It has been scientifically proven that brains with injuries tire more quickly (neurofatigue).
  • If your anger stems from pain and physical discomfort, ask a doctor, physiotherapist or occupational therapist to look at your situation. Look for help, for example here or here
  • Try to think together about ways for future anger to be expressed differently. Depending on the cause (emotional or physical discomfort), a punching bag may be used or pulling on a towel or hitting with a towel. 
  • Don't be ashamed to seek help with aggression. There are different ways to learn to deal with it. A good care provider who understands brain injuries can teach you these ways. For example, a behavioral therapist, neuropsychologist, behavioral neurologist, etc.
  • Medicines may provide some relief.


For bystanders who are confronted with aggressive behavior

  • Safety: Always ensure the safety of children, adults and pets.
  • Withdraw: Take a time-out and avoid the argumentative person for a while.
  • Always explain (as calmly as possible) why you are leaving for a while and taking a time-out.
  • Make sure you have your own space to go to for a while. Your space.
  • When peace is restored, try to find out together with the person who had such an aggressive discharge, what caused it. Make it negotiable.
  • Strategy: Try to think together about ways to express future anger differently.
  • Help: Ask for help from a behavioral therapist, neuropsychologist, behavioral neurologist, relationship counselor specifically for brain injuries, etc. Find someone who has knowledge of brain injuries. Unfortunately, not everything can be learned.



Brein areas that are sensitive to threat

Image from:


Most important brain areas with threat sensitivity and reward sensitivity as a prerequisite for reactive aggression:
Amygdala: almond-shaped areas
Caudatus nucleus /Nucleus caudatus: tail nucleus, part of the basal nuclei
Hypothalamus: part of the limbic system
dACC: dorsal anterior cingulate cortex, girdle coil, just in front of the back
dlPFC: dorsolateral pre-frontal cortex = Cerebral cortex of the frontal lobe at the posterior side
dmPFC: dorsomedial pre-frontal cortex = Cerebral cortex of the frontal lobe at the posterior-middle side
IFG: inferior frontal gyrus Gyrus = inferior gyrus, the brain folds in the forehead
Insula = island of Reil
IPL: inferior parietal lobes
Medial orbito frontal cortex: Cerebral cortex of the frontal lobe near the center of the eye sockets
Peri-aqueductal gray
Ventrolateral prefrontal cortex = Cerebral cortex of the frontal lobe on the ventral side
Ventromedial prefrontal cortex = Cerebral cortex of the frontal lobe on the ventral side
Ventral striatum (the striated body on the ventral side) Part of the basal nuclei.


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