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.
Common features of impulsivity:
- 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 promiscuity.