At a glance

  • A concussion is caused by a strike or blow to the head.
  • The typical symptoms include headache, drowsiness, memory loss, nausea and vomiting.
  • They usually develop shortly after the head injury.
  • The symptoms usually go away completely after a couple of days of rest.
  • It is important to only gradually go back to daily and leisure activities afterwards.


Photo of a patient and doctor during an examination

During a fall or accident when out on the sports field or in traffic your head might be struck or jolted, or it could hit the ground, for instance. That kind of injury can stop the brain from working properly for a while. This is commonly described as a “concussion.” Experts refer to it as mild traumatic brain injury.

People with a concussion usually feel drowsy and have a headache. Dizziness and nausea are also common symptoms. Sometimes people can't remember what happened shortly before or after the accident.

It is important to seek (emergency) medical attention after a head injury. To be on the safe side, you are often kept in the hospital for 24 hours after a concussion so that doctors can watch you.

After taking a short break to rest mentally and physically, the symptoms usually go away after a few days or weeks. Long-term effects are rare.


Typical concussion symptoms affect

  • The body: These include headache, dizziness, balance problems, impaired vision, nausea and vomiting.
  • Perception and thinking: People often suffer from drowsiness, confusion, delayed reactions and thought; problems with concentration and orientation are also common right after the head injury.
  • Memory: A concussion sometimes causes memory loss (amnesia) which usually lasts less than 24 hours. You are then unable to remember what happened shortly before, during, or right after the accident.
  • Mood: Irritability, anxiety and problems falling asleep or sleeping through the night can also be caused by a concussion.

The severity of the symptoms depends mainly on how badly the brain was injured.

Some people briefly lose consciousness after a fall or accident. Immediate medical attention is then needed to check whether there is a serious injury like a hemorrhage. It is also important to call 112 (911 in the U.S.) in the following cases:

  • Memory loss
  • Constant headaches that get worse
  • Repeated vomiting
  • Severe or drowsiness
  • Unclear speech or vision
  • Unusual behavior
  • Different sized pupils
  • Seizures
  • Bleeding or loss of fluid from the ear or nose
  • Severely bleeding wounds to the head

Causes and risk factors

The brain is surrounded in the skull by a liquid called cerebrospinal fluid. This fluid normally protects the brain from injuries by cushioning movements.

Concussions are usually a result of falls, sporting injuries, or road traffic, occupational, and household accidents. If you hit the ground with your head, the jolt can shake up your brain. The brain may be damaged if it hits the hard inner wall of the skull. Some nerve connections are often torn as well, meaning that information is processed and passed on more slowly, or not at all. That means the brain doesn't work as well as usual after a concussion. That can affect thinking, perception and mood.

Image: Concussion: Impact of a strike to the head

Impact injuries often occur in contact sports like soccer and ice hockey. That is why athletes are at greater risk of concussions. Children and older people are also at greater risk because they fall more often.


Over 200,000 people have inpatient treatment for concussion every year in Germany. This number increases every year, mainly because there are more falls among older people. There are no exact figures on the prevalence of concussions because nowhere near all people affected seek medical attention.

Especially in sports, head injuries are often downplayed, or the symptoms are not properly recognized. But they happen frequently in contact sports: About 5 to 15% of all injuries there are concussions.


Symptoms like headaches and dizziness usually develop quickly after a head injury. Other symptoms can also develop only hours or days later.

The symptoms usually gradually go away after a few days or weeks. They go away after one to three months in about 85% of people with mild traumatic brain injury.

The symptoms sometimes last longer, though. They can have physical, emotional and behavioral effects, including headaches, nausea, , insomnia, listlessness, anxiety and irritability.

A concussion doesn’t usually cause any permanent damage. It is not clear whether multiple concussions in athletes can lead to long-term complications such as dementia.


It is important to seek medical attention whenever you think you might have a concussion. The doctor will first ask you

  • what exactly happened,
  • which symptoms you have had since the accident and how they have developed,
  • whether you have recently had another concussion, and
  • if you are taking any medication.

If you lost consciousness or can’t remember what happened, an eye-witness might be able to provide important information.

The doctor will then check your overall physical and mental condition, such as your:

  • Balance and ability to walk normally
  • Pupil function
  • Leg and arm reflexes
  • Orientation and coordination
  • Speech

Imaging techniques like CT scans can’t detect concussions. They are only used to rule out severe brain injury like hemorrhage, if the symptoms are especially severe or there is an increased risk of complications.


There are some protective measures you can take to reduce the risk of head injuries, such as:

  • wearing a helmet when cycling, skiing, inline skating or horse riding,
  • following road traffic rules, and
  • wearing a seatbelt in the car.

It is important to prevent falls in older age, for example by getting rid of tripping hazards in the home. Mobility and coordination exercises can also help to strengthen muscles and improve your sense of balance.

Athletes in particular ought to be well informed about the dangers of a concussion. Accidents with head injuries are often downplayed or accepted as being normal, and the symptoms are frequently not properly identified. Some people dismiss their symptoms because they want to carry on playing or don't want to leave their team in the lurch. But it is important to stop practice or the game and immediately seek medical attention if you think you might have a concussion. Another trauma to the head can cause a more serious injury and result in more severe symptoms or complications.


The brain needs time to recover and get back to its full strength. That is why treatment mainly includes lots of rest at first, especially in the first three days, with plenty of sleep, little physical and mental exertion, and hardly any external stimulation.

In rare cases, a concussion can lead to complications like bleeding inside the skull (intracranial hemorrhage). That is why you will often be kept in the hospital for observation for the first 24 hours after the accident. It is recommended not to be alone at home after that. If the symptoms don't go away or get worse, it's advisable to have someone take you back to the hospital.

After the 1 to 3 day recovery period, you can gradually return to daily activities like housework, exercise, and driving and do more of them. It is also possible to go back to work or school. It is important to listen to your body: If the symptoms come back, your body needs more rest. Acute symptoms like headaches and nausea can easily be relieved with medication.

If the symptoms persist, they can affect your daily activities and be distressing. Studies suggest that special rehabilitation programs, endurance training and psychotherapy methods like cognitive behavioral therapy can help. There are also some things you can do to cope with the symptoms in everyday life, including relaxation techniques and avoiding triggers like loud music that make the symptoms worse.

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IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Created on November 16, 2022

Next planned update: 2025


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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