Which of the Concussion Subtypes are Driving Your Patient’s Symptoms?

A Psychological Type Deep-dive

Welcome to the last and final part of the deep dive into the 4 different mild traumatic brain injury subtypes: psychological conditions.

Psychological conditions can be extremely tricky to treat clinically because they vary so widely between patients, and we don’t fully understand how or why psychological conditions develop in some concussion patients and not others. However, mental health conditions can be the source of enormous symptom burden in your patients and is not something that should be overlooked.

While there is a wide variety of psychological symptoms to look for in patients, the main players in the development of post-concussion psychological symptoms include depression, anxiety, and trouble regulating emotions. (1)

Kontos and Collins (2) are well known for their classification system for concussions, and their “anxiety/mood profile” included the psychological symptoms of depression, anxiety, feeling more emotional, moodiness, and irritability.

In addition, patients may experience other symptoms indirectly through how their psychological symptoms impact other bodily systems. Some examples include, sleep dysregulation, exaggerated or inconsistent somatic symptoms, physiological alterations of the autonomic nervous system, and psychological behaviours such as avoidance, rumination, and hypervigilance. 

Incidence of Psychological Symptoms After Traumatic Brain Injury.

In previous blogs, it has been shown that the typical recovery length for a concussion is around 30 days for most people. However, a recent study showed that approximately 1 in 5 individuals may experience mental health symptoms up to six months after mild traumatic brain injury (mTBI). (3) 

Studies that have looked at self-reported neurobehavioral complaints after mTBI show that for most patients, the most severe symptoms are in the acute stage of injury (within 72 hours of injury). These symptoms start to improve over the next few days, and the majority of patients experience full recovery within weeks to up to 3 months. However, a small percentage of patients continue to complain of neurocognitive symptoms at 12 months post-injury. 

Depression and Anxiety.

Two of the most commonly reported psychological symptoms post-concussion are depression and anxiety. (1) However, it is important to note that these symptoms may both be a direct result of the concussive event and/or due to other factors, such as psychological stress from dealing with the injury. Healthcare professionals must assess patients thoroughly and consider their medical history to accurately diagnose and treat these symptoms.

While for most patients, the psychological symptoms that may accompany a concussion may resolve with the resolution of the concussion, it should not be underestimated the importance of being assessed and treated by a qualified healthcare practitioner. Research has shown there is up  to a 2-fold increase in the risk of a suicide attempt in both children and adults that have been diagnosed with a concussion compared to the general population. However, current evidence points to this likely stemming from post-traumatic stress surrounding the event in which they were injured rather than the concussion itself. (4)  Psychological symptoms can sometimes be the hardest to spot and assess and may still be affecting patients’ quality of life after the “physiologic” recovery from a concussion.

What are the Risk Factors That May Lead to the Development of Psychological Symptoms After a Concussion?

The link between psychological symptoms and concussions is an area of ongoing research, and currently, there is no definitive answer to that question. A recent 2022 study showed that compared to age-matched control subjects, young athletes who sustained a concussion had increased depressive symptoms as measured by the PHQ-9 for up to 1 month after injury. The symptoms returned back to baseline at 3, 6, and 12-month follow-ups, which suggests that these are not lifestyle factors causing mental health symptoms but something specific to the etiology of concussions themselves.

Currently, there are many factors that can influence whether or not a person develops a mental health condition after sustaining a concussion, and there are different proposed mechanisms for how or why a patient develops these symptoms. One thing that we do know is that there are biological, psychological, and social factors that can all play a role in the development of psychological symptoms post-concussion. We are going to review the current leading theories below.

Pre-existing mental illness

Pre-existing mental health disorders are an area of interest when it comes to persistent post-concussion symptoms (PPCS) and the experience of psychological conditions post-concussion, as almost half of all patients that develop PPCS were suffering from pre-morbid depression and anxiety disorders. There are several studies that show that pre-concussion mental health status correlates with post-concussion symptom burden in both adult and pediatric populations.

However, the issue of causality remains: is it that pre-existing mental illnesses increase the severity of concussion symptoms, or does prolonged withdrawal from everyday activities secondary to the concussion worsen pre-existing mental health disorders? Chicken or egg? Unfortunately, we do not know exactly, but based on the current research, it is safe to assume that there is some contribution of both in most patients.

History of concussions

There are various studies that have looked at different concussion characteristics to see if there is any correlation between the mechanism and severity of concussion and the risk of developing psychological symptoms, and the results are quite mixed. However, there are two factors that seem to lead to an increased risk of developing depressive symptoms: the number of previous concussions and whether or not the person lost consciousness.

In a study on teenage athletes, if a player had 3 or more previous concussions there was a threefold increase in the risk that they would develop depression. Additionally, in a study of retired NFL players, there was a 9% increase in the risk of developing depression for every 5 years that a player played in the league. This is also in line with the finding that players in the most high-risk positions (running back, linebackers, linemen) were at an increased risk of developing depression compared to other positions.

Furthermore, there was a 2-6x increase in the risk of developing depression if you sustained a second concussion while you were still not fully asymptomatic from a previous concussion, suggesting that there may be an additive effect of concussions within a short period of time in terms of risk of developing mental health symptoms.

Interestingly, that same study on retired NFL players found that if a player had lost consciousness when they sustained their concussion, they were 5.9 times more likely to develop depression and 6.1 times more likely to develop anxiety. However, the correlation between injury severity and risk of psychological symptoms has not been replicated in all studies. To add further mud to the water, other data show us that males participating in professional soccer and American football may have protection against mortality from mental health disorders, suicide, and even protection from cardiovascular disease and cancer. (5)  

Current theories as to the reason why multiple concussions, and possibly more severe concussions, increase the risk of developing psychological symptoms include the theory that repeated head injuries increase damage to the amygdala, which is an essential part of the limbic system regarding emotional processing, fear, and anxiety.

This theory was further corroborated by a study by Patel et. al that found considerable differences in white matter brain composition when comparing depressed retired athletes to a control group. Changes in regional blood flow within the white matter were also associated with diminished cognitive performance. (6)

Age and gender differences

Age and gender also seem to play a significant role in the development of psychological symptoms after sustaining a concussion. (7)

In one study, girls reported significantly higher levels of anxiety and depression post-concussion as compared to boys as measured by GAD-7 and PHQ-8 scores. Girls also reported a higher symptom level of headache, dizziness, light sensitivity, sound sensitivity, head pressure, feelings of fatigue, drowsiness, and feelings of being slowed down. When using a clinical profile (CP) screen, girls tend to endorse more severe symptom scores and more significant “anxiety/mood” profiles than their male counterparts. (8

Teenagers and adolescents also tend to report higher levels of psychological symptoms after a concussion compared to adults.

This is thought to stem less from the concussion itself but more from where adolescents and teens derive most of their meaning in life and identity: social engagement (i.e., school and extracurricular activities with friends). After a concussion, taking a teenager out of school, preventing them from playing sports, symptoms not allowing them to go to social events, etc, can all heavily increase the mental burden of concussion recovery and may be one of the driving factors in the development of psychological symptoms in this age group. Therefore, it is of utmost importance that we counsel patients on how to try and manage these symptoms, make sure that we are getting patients back into meaningful activities as soon as they are cleared to do so, and refer patients to the appropriate health professional if they need more specific treatment for their symptoms. 


Athletes specifically seem to have a higher psychological symptom burden than non-athletes. (3) A study by Kontos found that 36.5% of athletes demonstrated subclinical, long-term psychological symptoms after sustaining a concussion. Analysis showed that the predictors for the athletes with the most long-term and more severe symptoms included a previous history of a psychiatric disorder, substance use, a new medical diagnosis since the concussion, amnesia, another orthopedic injury since the concussion, number of days to return to play and psychiatric medication use.

What that seems to boil down to is that the longer that athletes are out of play (either from concussion symptoms or other injuries since the concussion) and the harder time they have dealing with the fact that they are not able to return to sport (substance use, medication use, etc), the worse their psychological symptoms are going to be. (9)

This suggests that there is not only a structural component of why concussions induce mental health symptoms, but there is also a large social component.

Social contributions

From a psychosocial standpoint, individuals experiencing PPCS often face increased social isolation, academic difficulties, frustration surrounding activity limitations, anxiety related to prognosis uncertainties, and prolonged disengagement from usual roles and identity structures—all factors that may contribute to feelings of hopelessness and emotional distress.

As mentioned previously, social factors like removal from routine, friends, school, etc. can play a significant and independent role in depression/anxiety. Additionally, in adult populations, we can see similar impacts on removal from work and financial instability.

Further study in adults showed that concussion patients are at an increased risk of substance abuse disorders and that its use may have both a direct and indirect association on anxiety and depression symptoms, and may be linked to the prolonged disengagement from usual activities and roles. 

Mechanism of Injury

How the person sustained their concussion may also predispose a person to the development of prolonged psychological symptoms via the development of post-traumatic stress disorder (PTSD).

In military personnel who sustained a concussion while deployed, up to one-third of members reported symptoms of PTSD after their concussion. In those who lost consciousness, that number increases to 44%. In service members who did not sustain a concussion while deployed, the rate of PTSD is approximately 9%.

This is also seen in non-military personnel as well. Between 5% and 14% of civilians who sustained a concussion will have symptoms of acute stress disorder before being discharged from the hospital, and 80% of these individuals will go on to develop PTSD. Even in those who did not go to the emergency room, post-traumatic symptoms occur in 13-40% of patients who have sustained a concussion.

Many post-concussion symptoms (e.g., sleep difficulties, irritability, and concentration problems) are similar to symptoms of the hyperarousal dimension of post-traumatic stress disorder (PTSD), which may occur following exposure to severe, often life-threatening events (motor vehicle accidents, blast injuries, etc).

This is another reason why referring patients that you believe are struggling with psychological symptoms to the appropriate healthcare practitioner is the best course of action, as there can be multiple mental health concussions whose symptoms are overlapping and interacting, and a multidisciplinary approach will lead to the best care of your patient.

Other factors 

Patient beliefs are also thought to play a role in the development or exacerbation of psychological symptoms after a concussion, and it relates to a person’s mindset around their injury. How patients view their injury, symptoms, and outlook on life going forward can all influence their symptom burden during recovery.

For example, the “good old days” bias is when patients inaccurately remember their symptom burden before the injury, which causes them to overestimate their current symptom load. For example: “I never used to forget where I left my phone.” We all forget where we put our phones – it happens. But before the concussion, we had no reason to blame; we just forgot. After a concussion, many patients believe that it is the concussion that is causing this forgetfulness, and that can increase feelings of hopelessness, despair, and other psychological symptoms.

Another interesting example is the nocebo effect. The nocebo effect is when negative expectations of a patient regarding a treatment or condition cause it to have a more negative effect than it otherwise would have. With concussions, the patients who have the worst outlook of their condition immediately after injury have the highest level of symptom burden and recover significantly slower than patients who have a positive outlook on their prognosis, independent of injury severity.

As practitioners, these examples highlight the importance of evidence-based concussion education early in the treatment plan to ensure that your patients do not hold any beliefs or ideologies that may negatively impact their ability to recover.


The treatment of psychological symptoms after a concussion is 2-fold: good health behaviours in the acute stage and referral for additional treatment from a mental health professional if needed.

Like every good concussion protocol, a short period of cognitive and physical rest for the first 48 hours is recommended. Still, then patients should be encouraged and counseled on gradually returning to everyday activities as symptoms allow. Research has suggested that a good treatment plan that addresses many positive lifestyle changes can help reduce the psychological symptom burden in the acute phase. Behaviours such as adequate diet/hydration, proper sleep, gradual increases in daily activity levels, symptom-limited aerobic exercise, and stress management strategies are all good interventions in the first few weeks of concussion recovery. (1)

Research in athletes on a 6-week active rehabilitation program showed an improvement in anxiety and anger scores and lower subjective complaints by parents regarding anxiety, depression, and somatic complaints. The rehabilitation program consisted of low-intensity aerobic exercise, sports drills, relaxation exercises, concussion education, and interpersonal support.

In patients who have prolonged psychological symptoms that do not resolve in the first few weeks post-concussion, it is best to refer patients to a mental health professional for ongoing care and multidisciplinary support. It has been suggested that the treatment of anxiety and depression should focus on cognitive behavioural therapy to eliminate counterproductive thought processes such as pain catastrophizing and limiting behaviours, along with helping patients recognize and work through some of the cognitive biases that may be affecting their recovery.

Several randomized clinical trials show that treating symptoms of depression following an mTBI will lead to both improvements in mental health outcomes but also improvements in somatic and cognitive symptoms. This suggests, an interplay between various domains of concussion symptoms and further highlights the need for interdisciplinary management of concussion symptoms in PCSS patients.


In conclusion, psychological symptom burden should be something that all clinicians are assessing in their concussion patients, especially if your patient has a pre-existing history of mental illness. It is currently unknown if the main driver of psychological symptoms after a mild concussion is structural changes to specific areas of the brain, such as the amygdala, or if they are a reaction to changes in lifestyle during the recovery process. Likely, it is a combination of both. While there are many risk factors for the development of psychological symptoms, treatment for these symptoms is similar to current concussion protocols. In the acute stage, the focus is on positive health behaviours such as symptom-limited physical activity, adequate sleep, proper nutrition, and patient education. If symptoms persist, do not hesitate to refer to other mental health professionals for additional support in treating concurrent conditions such as anxiety, depression, and PTSD, as these conditions have been shown to prolong psychological, cognitive, and somatic symptoms if not treated.

  1. Barela, Matthew MS; Wong, Allen MD; Chamberlain, Rachel MD. Concussion and Psychological Effects: A Review of Recent Literature. Current Sports Medicine Reports 22(1):p 24-28, January 2023. | DOI: 10.1249/JSR.0000000000001031
  2. Kontos, A. P. (2017). Concussion in sport: Psychological perspectives.Sport, Exercise, and Performance Psychology, 6(3), 215–219. https://doi.org/10.1037/spy0000108
  3. Stein MB et al. Posttraumatic stress disorder and major depression after civilian mild traumatic brain injury: A TRACK-TBI study. JAMA Psychiatry. January 30, 2019. 
  4. Fisher, L. B., Bomyea, J., Thomas, G., Cheung, J. C., He, F., Jain, S., … Zafonte, R. D. (2020). Contributions of posttraumatic stress disorder (PTSD) and mild TBI (mTBI) history to suicidality in the INTRuST consortium. Brain Injury, 34(10), 1339–1349. https://doi.org/10.1080/02699052.2020.1807054
  5. Morales JS, Castillo-García A, Valenzuela PL, Saco-Ledo G, Mañas A, Santos-Lozano A, Lucia A. Mortality from mental disorders and suicide in male professional American football and soccer players: A meta-analysis. Scand J Med Sci Sports. 2021 Dec;31(12):2241-2248. doi: 10.1111/sms.14038. Epub 2021 Aug 30. PMID: 34416791.
  6. Patel H, Polam S, Joseph R. Concussions: A Review of Physiological Changes and Long-Term Sequelae. Cureus. 2024 Feb 17;16(2):e54375. doi: 10.7759/cureus.54375. PMID: 38505457; PMCID: PMC10948337.
  7. Nahman, J. C., Staples, C., Irwin Harper, L. N., Ahumada, L., Rehman, M., Irani, S., Mularoni, P. P., & Ransom, D. M. (2024). Psychological resilience, emotional symptoms, and recovery duration in adolescent sport-related concussion. Applied Neuropsychology: Child. Advance online publication. https://doi.org/10.1080/21622965.2024.2317307
  8. Stephenson, K., Womble, M. N., Frascoia, C., Eagle, S. R., Covassin, T., Kontos, A. P., … & Elbin, R. J. (2023). Sex differences on the concussion clinical profiles screening in adolescents with sport-related concussion. Journal of athletic training, 58(1), 65-70.
  9. Burns, C., Jo, J., Williams, K., Davis, P., Amedy, A., Anesi, T. J., Prosak, O. L., Rigney, G. H., Terry, D. P., & Zuckerman, S. L. (2024). Subclinical, long-term psychological symptoms following sport-related concussion: Are athletes more depressed than we think? Brain Injury. Advance online publication. https://doi.org/10.1080/02699052.2024.2334352