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How does a brain injury cause impulsive behaviour?

The frontal lobe of the brain is responsible for executive functions, including controlling impulses. Damage to the frontal lobes and reduced ability to control impulses can be caused by trauma, alcohol and other drugs, dementia, other types of brain disorders, and mood disorders.

This inability to control urges can lead to impulsive and inappropriate social behaviour. For example, a previously shy person may become quite extroverted and talkative. In a more severe case, a normally reserved person might make crude or sexually inappropriate comments to strangers.

When others don’t understand how brain injury can cause impulsive behaviour, it often leads to rejection and criticism. Social isolation can result, as existing relationships break down and there is an inability to form new ones.


  • acting without thinking
  • inability to save money or regulate finances
  • irritability and temper outbursts
  • too familiar with strangers and sharing very personal details
  • asking personal questions that cause discomfort
  • yelling out answers before questions have been completed
  • intruding or interrupting conversations
  • unable to wait patiently for their turn
  • sexual promisculty.

Lack of insight

Another common outcome from a TBI is lack of awareness. The person may deny their behaviour is impulsive, fail to see the consequences of their actions, or understand how someone else is feeling.

How is impulsivity treated?

Treatment varies depending on the underlying cause – usually there will be several techniques used. The most common treatment is medication. Other options include behaviour therapy, parent training and school-based interventions for children. Doctors and rehabilitation specialists will advise on whether or not medication may be helpful.

Strategies for partners and family members

The more families know about impulsivity and TBI, the easier it is for them to respond positively when needed. Reacting negatively will only add to the problem.

As with so many aspects of a brain injury, impulsivity often arises when the person is confused or fearful, so predictable daily schedules and routines will help greatly.

Encourage self-monitoring techniques

A person with brain injury can monitor themselves by asking the following:

  • Do I really want to do this, am I ready?
  • What are the pros and cons of doing or saying this?
  • What will the outcome be?

A person should be encouraged to develop their listening and social skills again. Family and friends can role-play how to listen, introduce new topics, and how to politely interrupt two other people talking.

If the person engages in attention seeking behaviour such as yelling or interrupting, a positive response is to let them know that their behaviour is not a good way to get attention and offer an alternative strategy.

When people look for the message behind an impulsive behaviour, they will often see that it is caused by confusion and fear.

It is important to remember that the impulsivity is at fault, not the person. Generally, there is no intention to speak or act in ways that annoy or hurt people’s feelings. Separating the person from the behaviour can go a long way to coping with the situation.