Concussions are extremely dangerous illnesses that are common in contact sports. Severe concussions can cause long-term brain damage or even death. Depending on the degree of your injury, you may experience the following symptoms: confusion, depression, irritability, memory problems, headaches, dizziness, nausea or vomiting. If you suffer from any of these symptoms after being hit in the head, see a doctor right away. Concussions can be diagnosed using various tests, such as a CT scan or MRI of the brain. The doctor will also want to know about your previous medical history and whether you have been drinking alcohol or taking drugs. It is important to seek medical attention after a concussion. Doctors can perform different tests to determine the extent of the damage done to the brain by the concussion and decide what type of treatment is best for you. In some cases, doctors may recommend that a patient avoid physical activity for a period of time to allow the brain to recover.