Concussions are surprisingly common injuries. Nearly 1 in 4 adults have suffered from a concussion, according to an NPR poll, and more than a third of those victims have had repeated concussions.

Perhaps because they’re so prevalent, concussions used to be regarded as no big deal. In recent years, however, the publicity surrounding NFL players has shed light on the lasting – and often significant – damage wrought by these traumatic brain injuries. Yet troubling gaps remain in our knowledge of such complications.

Just how damaging can a concussion be?

Concussions can cause a range of symptoms from short-term confusion to permanent cognitive impairments. For many concussion victims, the symptoms resolve within a few weeks. Approximately one in five experience post-concussion syndrome, in which the cognitive effects last longer than six weeks. These unfortunate patients often suffer from chronic problems such as:

  • Headaches
  • Memory loss
  • Trouble concentrating
  • Vision loss
  • Dizziness
  • Depression

Alarmingly, radiology scans of these patients sometimes show atrophy – that is, loss in brain volume – a year after the injury.

Risk factors for a worse outcome

Why do concussions take a crippling toll on some victims but not others?

The answer isn’t clear. It’s often difficult to nail down an accurate prognosis.

In general, the outcome seems to depend on many factors, including:

  • The severity of the injury
  • Any history of prior concussions (and how recently they occurred)
  • Preexisting conditions such as anxiety, depression or chronic migraines
  • Individual variations in brain and skull anatomy

Gender may also play a role. Among college students, female athletes are more likely to suffer concussions than men. Some studies also show that women are more likely to have lasting impacts from concussions, although it’s not fully understood how or why.

The takeaway

Because of these unknowns, it’s wise to take every concussion seriously. Of course, athletes in high-contact sports are most at risk. But concussions can also happen in car accidents, falls and other mishaps. Get medical help as soon as possible after experiencing a potential concussion, and follow up on all recommended tests and treatments.