At one point or another, all of us have had a bad dream. Some are pretty common, including a dream in which you're in school and the teacher is about to test the class on a subject you have not studied. Other common dreams include visions of falling, being chased, flying and showing up to work or school in your birthday suit.

People who have been in serious car accidents sometimes have nightmares for months about the violent events they have experienced. According to researchers, the recurring visions are linked to long-term problems with sleep that can have a negative impact on your health.

However, researchers add that not all nightmares following a traumatic event last for months and not all bad dreams are necessarily bad for you. In the first few weeks following a car accident, revisiting the incident in dreams might be a way our brains have of processing stress, said the director of the Sleep and Chronobiology Center at the University of Pittsburgh.

"We think nightmares are so common that they have some purpose to process stressors," said Anne Germain, the center's director. She acknowledges that there is no evidence showing that nightmares are beneficial, and says that chronic disturbing dreams "are very detrimental to well-being."

About 1 in 5 people who have been in car accidents continue to have nightmares about the incident 3 months after the crash occurred. The continuing bad dreams are associated with problems falling asleep, staying asleep and having difficulties functioning during the day.

Sleep disorders are sometimes indications of deeper emotional problems triggered by the trauma of the motor vehicle collision. An experienced Pennsylvania personal injury attorney wants to know about your physical injuries as well as the emotional problems you are dealing with as the result of a crash. In that way, full compensation for all damages can be pursued.