Long-Term Effects of Concussions, Including Alzheimer’s Risk

For those involved in the athletic community — especially those who play contact sports, concussions are always a potential risk. When an individual experiences this form of mild brain injury, the symptoms are not generally life-threatening, but are there any lasting effects?

What Is a Concussion and How Does It Affect the Brain?

Although we often recognize concussion risk within sports, this form of brain trauma can also occur when individuals fall, are involved in a motor vehicle accident, or any other incident that results in impact/rapid acceleration of the head. When someone experiences blunt force trauma, for instance, this will likely cause a primary injury.

This means, that the initial impact caused the brain to hit the interior of one’s skull, resulting in possible contusions. When someone is suffering from a concussion, this is generally associated with secondary injuries — some which will develop hours, or even days later.

So, once a concussion occurs, are there lasting effects?

The Long-Term Effects of Concussions

If you have experienced a concussion in the past, then you are already aware of the possible short-term effects, including:

  • Poor sleep quality
  • Headaches
  • Vertigo
  • Ringing in your ears
  • Nausea
  • Vomiting
  • Loss of consciousness
  • Depression
  • Anxiety
  • Lack of focus
  • Partial memory loss

These symptoms are troublesome to say the least — but it’s the long-term effects that both researchers, physicians, and patients are concerned with. Will a concussion lead to issues with one’s emotional stability and cognitive function in their later years?

Based on current research, it appears that there are possible symptoms that can last months — if not years. Unfortunately, concussions are also cumulative in nature, making the recovery process even more challenging. This means, that if you suffer from one concussion, it’s generally easier that you’ll suffer from another.

Although most individuals successfully recover from a single concussion, each repeated concussion can result in more severe effects — both short- and long-term. In this sense, please be aware of the possible consequences of temporary brain injury.

In addition, some of the possible long-term symptoms include, but are not limited to:


Unfortunately, approximately half of all people who suffer from a traumatic brain injury, are affected by depression within the first year. Of these individuals, more than half will also suffer from increased anxiety. This link has been well-established, as seen in a number of studies.

Within one key study, published in the American Journal of Psychiatry, it was found that following a head injury, patients increased their risk of a mental health disorder by up to 439 percent. Being the largest study of its kind, it was found that of those who experienced head trauma, they were:

  • 65 percent more likely to be diagnosed with schizophrenia
  • 59 percent more likely to suffer from depression
  • 28 percent more likely to develop bipolar disorder
  • 439 percent more likely to experience organic mental disorders — resulting in reduced mental function

After experiencing head trauma, such as a concussion, the greatest risk of reduced mental health generally occurs within the first year. With that being said, even after 15 years have passed, these individuals continue to experience an elevated risk.

Of course, each individual case is unique, but overall, symptoms of depression are generally due to:

  • Physical changes — After a brain injury, some individuals will experience damage within the areas of their brain that regulate emotion. Patients may also suffer from a neurochemical imbalance.
  • Emotional impact — As an individual tries to adjust, some struggle to cope with both temporary and lasting disability.
  • Predisposition — Some patients are already faced with an increased risk of depression due to genetic factors or personal history. This predisposition may be more easily activated following head trauma.

Unfortunately, an increased risk of depression is also typically associated with an increased risk of suicide. Recently, researchers discovered that even mild concussions may lead to detrimental effects. Of those who have experienced a concussion, their long-term risk of suicide increases threefold.

Long-term Memory Loss

More recently, researchers have been investigating the link between concussions and the possible long-term effects on cognition. It has long been established that this type of head injury can lead to both short- and long-term memory loss, but it’s only recently that researchers found a clear connection to Alzheimer’s.

Within a 2017 study, it was found that concussions do, in fact, accelerate cognitive decline and Alzheimer’s-related brain atrophy. More specifically, this associated risk was based on those who are at genetic risk for this condition. Published in Brain, it was found that:

  • Of the 160 war veterans studied, it was found that concussions are associated with a lower cortical thickness in brain regions, which are the first to be affected among Alzheimer’s patients.
  • When combined with genetic risk factors, even a mild concussion may accelerate memory decline within Alzheimer’s specific areas.

Although related brain injury research is still in infancy, researchers have long known of Chronic Traumatic Encephalopathy (CTE). Generally affecting athletes with a history of brain trauma, this degenerative disease can lead to memory loss, aggression, reduced judgement, poor impulse control, and over time, progressive dementia.

When comparing CTE and Alzheimer’s, these two diseases may also share biological mechanisms. Both classified as tauopathies, these diseases are characterized by abnormal protein clumps, or ‘tau’ in the brain. Toxic to neurons, these tangles are believed to encourage key behavioral and cognitive changes.

Reduced Motor Skills

After a concussion, it’s not uncommon for individuals to notice a decline in motor skills. Initially, most affected individuals will notice that their fine motor skills are impaired. For some, they experience issues with balance, a lack of coordination, or the ability to perform highly technical movements, such as playing the piano.

Within a recent study, published in Concussion, researchers examined cognitive-motor integration. What they found, was that after analyzing 102 National Hockey League prospects, a significant effect was found regarding reaction time and accuracy.

The takeaway: Previously concussed elite-level athletes may experience lasting neurological effects that are not generally detected through standard clinical assessments.

Suspect a Possible Concussion? Here’s What You Should Do

Concussions are fairly common, affecting anywhere between 1.6 to 3.8 million Americans each year. Whether you play sports or have hit your head at work, here’s what you need to know:

  1. Know the warning signs — If you have been hit in the head or suffered an injury, do not be left alone. Recognize warning signs, such as blurry vision, dizziness, vomiting, memory loss, slurred speech, numbness, headaches, etc.
  1. Seek a professional opinion — There’s a range of tests available, including CT and MRI scans, as well as neurological tests. Seeking an accurate diagnosis is important, especially if you’re not sure what to do next.

Rest — You need to allow your brain to rest in order to effectively recover. That means, resting both physically and cognitively. Following your injury, don’t even read or watch TV — truly rest your body and brain. If symptoms continue to persist (as discussed above), even if you have already seen the doctor, call your physician once again to ensure your safety.


https://www.scientificamerican.com/article/what-happens-to-the-brain/ https://www.ncbi.nlm.nih.gov/pubmed/24322397 http://www.bu.edu/cte/about/what-is-cte/ http://www.cmaj.ca/content/early/2016/02/08/cmaj.150790 https://www.ucsf.edu/news/2016/12/405096/alzheimers-and-concussion-related-cte-may-spread-brain-common-mechanism

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Krista Hillis has a B.A.Sc degree, specializing in neuroscience and psychology. She is actively involved in the mental health and caregiving community, aiming to help others. Krista is also passionate about nutrition and the ways in which lifestyle choices affect and influence the human brain.

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