Post-concussion syndrome occurs when symptoms from a mild brain injury continue beyond the expected duration. Individuals experiencing persistent post-concussive symptoms may be at higher risk of developing depression. This article discusses post-concussion syndrome, its symptoms, and the risk of depression in individuals with persistent symptoms. It outlines the causes and how to manage symptoms.

Overview

Post-concussion syndrome (PCS), alternatively known as persistent post-concussive symptoms (PPCS), describes a cluster of symptoms that frequently occur after mild traumatic brain injury (TBI). Individuals who have had more than one brain injury are at increased risk.

A mild injury to the brain is known as a concussion. Often, it is caused by direct trauma to the head, like being in an auto accident, getting hit or falling. A concussion can also happen as a result of a rapid acceleration-deceleration of the head.

Common symptoms of post-concussion syndrome include fatigue, headache, vision changes, confusion, disturbances in balance, dizziness, insomnia, and difficulty concentrating. Most of them are temporary and improve within 10 to 14 days.

Persistent post-concussive syndrome occurs when symptoms continue for over three months. Studies have shown that mild traumatic brain injury leading to persistent post-concussive syndrome impacts cognition, learning and memory in the long term. Additionally, it affects executive function. Executive function is a set of abilities required to achieve a goal.¹ 

Is there a link between post-concussion syndrome and depression? 

Individuals with persistent post-concussive symptoms (PPCS) may be at greater risk of experiencing depressive symptoms (symptoms of depression). Scientists analysed 18 studies involving 9101 participants and identified a significant positive association between post-concussion syndrome (PCS) and depressive symptoms. However, the authors mentioned that they couldn't identify any factors that make it more or less likely for depressive symptoms to occur. This difficulty might have been due to the limited number of studies included in their analysis.²  

Another review found that children who experienced head injuries were more likely to show signs of depression when compared to those without injuries or other orthopaedic injuries. The authors also mentioned that certain factors related to the injury might make depressive symptoms more likely to appear. These factors include experiencing pain or brain lesions, as well as other factors like age or socioeconomic status.  They observed that depression was more likely to emerge due to a child’s experiences after the injury, rather than due to the damage of the actual head injury. In conclusion, they suggested that further research is necessary.³     

What are the symptoms of post-concussion syndrome?

Post-concussion symptoms are typically similar to those of concussion symptoms, with the difference that they last for a longer period. They can be divided into four groups:

• Sensory
• Physical
• Mental
• Emotional  

 Sensory symptoms

• Dizziness
• Double vision (diplopia)
• Blurred vision
• Vertigo
• Sensitivity to sound ⁴

 Physical symptoms

• Fatigue
• Headaches
• Nausea
• Balance problems
• Sleep problems like insomnia or hypersomnia⁴ 

Mental symptoms

• Difficulty concentrating
• Memory loss (amnesia)
• Diminished thought processes (e.g. needing more time to think)
• Brain fog⁴

Emotional symptoms

• Anxiety 
• Mood swings
• Feeling a sense of restlessness
• Irritability
• Experiencing unusual feelings of depression or sadness
• Suicidal or  thoughts of self-harm^1,4,5

What causes post-concussion syndrome?

Post-concussion syndrome is more commonly observed in individuals with mild brain injury from trauma (traumatic brain injury, TBI). TBI can vary in severity. It can be caused by blunt force trauma, closed head trauma, concussion, assault, or injuries related to sports.

A TBI is mild when the Glasgow Coma Score (GCS) falls between 13 and 15. The GCS is a tool used by healthcare providers to assess levels of consciousness. Additionally, mild TBI can be further categorised as either complicated or uncomplicated.

Complicated mild TBI involves symptoms of a concussion alongside abnormalities found on a head computerised tomography scan (CT). These abnormalities include haematomas,  bleeding inside the skull (subarachnoid or subdural bleeding), shifting brain tissue (midline shift), or skull fractures.

Uncomplicated mild TBI shows a normal head CT scan and individuals in this category are more likely to see their symptoms resolve within three months. Those with complicated TBI or more than one TBI are more likely to experience PCS or persistent PCS.¹

How is post-concussion syndrome diagnosed?

Post-concussion syndrome cannot be diagnosed directly because there is no definitive test to confirm concussion. Instead, a healthcare provider first diagnoses a concussion, and then later assesses the possibility of PCS. This is done by relying on the medical evaluation and the person's symptoms. This evaluation can involve using multiple tools and methods, including:

• A physical and neurological exam
• Imaging techniques like computerised tomography (CT) and magnetic resonance imaging (MRI)
• Discussing the injury that led to the fracture and the symptoms experienced since then with the patient

Additional tests recommended may vary depending on the individual’s medical history and symptoms.¹

Risk factors for post-concussion syndrome

Several risk factors can increase the likelihood of post-concussion syndrome occurring. Some of these factors include:

• Age (older adolescents and younger adults)
• People assigned female at birth
• A history of mental health problems 
• Previous concussions
• History of chronic pain syndrome^{1, 2} 

How is post-concussion syndrome treated?

Treatment for PCS (post-concussion syndrome) is individualised, with reassurance often being a key aspect. Most individuals experience improvement within three months. However,  for the 10-15% who still have symptoms after four weeks, management becomes crucial in restoring mental and physical function.

Healthcare professionals typically advise individuals to reduce physical and mental activity for 24 to 48 hours after the injury. Only when they are symptom-free at rest should they resume normal activities. This is to ensure they avoid the risk of sustaining another concussion while still symptomatic from the first one.

Studies indicate that resting for two days leads to faster recovery than resting for five days. Healthcare professionals may prescribe medications like amitriptyline and propranolol. Furthermore, they may recommend treatments such as a greater occipital nerve block to manage post-traumatic headaches. Active therapies such as cervical physical therapy, vision therapy, and vestibular rehabilitation, are often suggested. These therapies can help with ongoing visual and balance issues.

Finally, it is recognised that individuals with post-concussion syndrome who engage in gentle exercise tend to recover more quickly.¹

Summary

Post-concussion syndrome occurs when symptoms from a mild traumatic brain injury persist longer than expected. These symptoms can include headaches, trouble concentrating, memory problems, dizziness, fatigue, and nausea. While most symptoms improve within 10 to 14 days, post-concussion syndrome develops when symptoms persist for over three months. Individuals experiencing persistent post-concussive symptoms may face an increased risk of developing depressive symptoms. Similarly, children who have suffered a head injury are more likely to display signs of depression. Traumatic brain injury can result from blunt force trauma, closed-head injury (nonpenetrating injury), assault, or injuries related to sports. Diagnosis involves a physical and neurological examination, as well as imaging techniques such as CT and MRI. Persistent post-concussive symptoms don't have a specific treatment. Instead, healthcare providers focus on managing the symptoms.