Causes
Disorders of consciousness can occur if the parts of the brain responsible for consciousness are injured or damaged.
The main causes can generally be divided into:
- traumatic brain injury
 - non-traumatic brain injury
 - progressive brain damage
 
Traumatic brain injury
Traumatic brain injury occurs when an object or outside force causes severe trauma to the brain.
This is most often caused by:
- falls
 - traffic accidents
 - violent assault
 
Find out more about head injury
Non-traumatic brain injury
Non-traumatic brain damage is usually caused by a health condition, such as:
- a condition that deprives the brain of oxygen (without a continuous supply of oxygen, brain tissue begins to die)
 - a condition that directly attacks brain tissue
 
Specific causes of non-traumatic brain injury include:
- strokes
 - heart attacks
 - severe brain infections (such as meningitis, an infection of the outer layer of the brain, or encephalitis, an infection of the brain itself)
 - drug overdoses
 - poisoning
 - almost drowning or other types of suffocation, such as smoke inhalation
 - a blood vessel bursting, leading to bleeding inside the brain (the medical term for this is a ruptured brain aneurysm)
 
Progressive brain damage
In some cases, brain damage can gradually occur over time.
Examples of conditions that cause progressive brain damage include: