question: How do concussions lead to depression and suicide?
comment: A concussion is a minor brain injury. Brains are delicate things, and perhaps there are mood interactions. Are you talking about [CTE (chronic traumatic encephalopathy)]( URL_0 what’s been noted in some retired football players? Because that’s thought to be a cumulative effect of multiple concussions over a long period of time, but research is still being done.
passages: Concussions are proven to cause loss of brain function. This can lead to physical and emotional symptoms such as attention disorders, depression, headaches, nausea, and amnesia. These symptoms can last for days or week and even after the symptoms have gone, the brain still won't be completely normal. Players with multiple concussions can have drastically worsened symptoms and exponentially increased recovery time.
   PCS, which shares symptoms with a variety of other conditions, is highly likely to be misdiagnosed in people with these conditions. Cognitive and affective symptoms that occur following a traumatic injury may be attributed to mTBI, but in fact be due to another factor such as post-traumatic stress disorder, which is easily misdiagnosed as PCS and vice versa. Affective disorders such as depression have some symptoms that can mimic those of PCS and lead to a wrongful diagnosis of the latter; these include problems with concentration, emotional lability, anxiety, and sleep problems. Depression, which is highly common in persistent PCS, can worsen other PCS symptoms, such as headaches and problems with concentration, memory, and sleep. PCS also shares symptoms with chronic fatigue syndrome, fibromyalgia, and exposure to certain toxins. Traumatic brain injury may cause damage to the hypothalamus or the pituitary gland, and deficiencies of pituitary hormones (hypopituitarism) can cause similar symptoms to post-concussion syndrome; in these cases, symptoms can be treated by replacing any hormones that are deficient.
   In April 2012, Easterling was found dead from a self-inflicted gunshot wound in his home. An autopsy report concluded Easterling's brain had evidence of CTE, a degenerative brain disease associated with frequent blows to the head.
  
  One month later, former San Diego Chargers player Junior Seau also died of a self-inflicted gunshot wound, and a brain autopsy showed he suffered from CTE.
  
  Like Easterling and Seau, an autopsy of Bears safety Dave Duerson's brain after he committed suicide earlier that year revealed he also suffered from the same degenerative brain disease.
   Cumulative effects may include psychiatric disorders and loss of long-term memory. For example, the risk of developing clinical depression has been found to be significantly greater for retired American football players with a history of three or more concussions than for those with no concussion history. Three or more concussions is also associated with a fivefold greater chance of developing Alzheimer's disease earlier and a threefold greater chance of developing memory deficits.
  
  Section::::Prognosis.:CTE.
   Most of the severe mental injuries associated with AFL are developed later in life when the player has retired from the AFL; these injuries are a result of heavy contact to the player's head. From one hundred cases of concussion being reviewed, ninety seven of these involved direct contact to the head with majority of the contact coming from the head, upper body or upper limbs of the other player. Evidence suggests that some negative effects of concussion on cognitive and motor function may continue to harm the player many years after the initial injury; some research also links clinical depression to contact related concussion.
   Psychological conditions, which are present in about half of people with PCS, may include irritability, anxiety, depression, and a change in personality. Other emotional and behavioral symptoms include restlessness, aggression, and mood swings. Some common symptoms, such as apathy, insomnia, irritability, or lack of motivation, may result from other co-occurring conditions, such as depression.
  
  Section::::Signs and symptoms.:Higher mental functions.
   For a period of minutes to days after a concussion, the brain is especially vulnerable to changes in intracranial pressure, blood flow, and anoxia. According to studies performed on animals (which are not always applicable to humans), large numbers of neurons can die during this period in response to slight, normally innocuous changes in blood flow.
   Depression, post-traumatic stress disorder, and chronic pain share symptoms resembling those of PCS. One study found that while people with chronic pain without TBI do report many symptoms similar to those of post-concussion syndrome, they report fewer symptoms related to memory, slowed thinking, and sensitivity to noise and light than people with mTBI do. Additionally, it has been found that neuroendocrinology may account for depressive symptoms and stress management due to irregularities in cortisol regulation, and thyroid hormone regulation. Lastly, there is evidence that major depression following TBI is quite common, but may be better accounted for with a diagnosis of dysexecutive syndrome.
   Not all people with PCS have abnormalities on imaging, however, and abnormalities found in studies such as fMRI, PET, and SPECT could result from other comorbid conditions such as depression, chronic pain, or post-traumatic stress disorder (PTSD). 
   There are also theorized research that suggest early CTE might result from damaged blood vessels within the brain. That could trigger brain inflammation and, eventually, the development of proteins such as Tau believed to play a key role in CTE. This hypothesis was tested on adult mice; the researchers state that their brains possess similar attributes to that of human brains. Using a special device, the mice were given precise impacts that would lead to mild brain traumas similar to what an athlete would suffer in contact sports. The mice, whose brains were scanned using a specialized MRI, immediately showed changes to the electrical functions of their brains.
   Concussion involves diffuse (as opposed to focal) brain injury, meaning that the dysfunction occurs over a widespread area of the brain rather than in a particular spot. It is thought to be a milder type of diffuse axonal injury, because axons may be injured to a minor extent due to stretching. Animal studies in which rodents were concussed have revealed lifelong neuropathological consequences such as ongoing axonal degeneration and neuroinflammation in subcortical white matter tracts. Axonal damage has been found in the brains of concussion sufferers who died from other causes, but inadequate blood flow to the brain due to other injuries may have contributed. Findings from a study of the brains of deceased NFL athletes who received concussions suggest that lasting damage is done by such injuries. This damage, the severity of which increases with the cumulative number of concussions sustained, can lead to a variety of other health issues.
   Post-concussion syndrome (PCS), is a set of symptoms that a person may experience for weeks, months, or occasionally years after a concussion with a prevalence rate of 38–80% in mild traumatic brain injuries, it may also occur in moderate and severe cases of traumatic brain injury. A diagnosis may be made when symptoms resulting from concussion, depending on criteria, last for more than three to six months after the injury, in which case it is termed persistent postconcussive syndrome (PPCS). In a study of the prevalence of post concussion syndrome symptoms in patients with depression utilizing the British Columbia Postconcussion Symptom Inventory: "Approximately 9 out of 10 patients with depression met liberal self-report criteria for a postconcussion syndrome and more than 5 out of 10 met conservative criteria for the diagnosis." These self reported rates were significantly higher than those obtained in a scheduled clinical interview. Normal controls have exhibited symptoms of PCS as well as those seeking psychological services. There is considerable debate over the diagnosis of PCS in part because of the medico-legal and thus monetary ramifications of receiving the diagnosis.
   Section::::Concussions in the National Football League.:Research.
  
  Other organizations continued to publish study results that linked repeated concussions and long-term health problems contrary to reports by the MTBI Committee. A 2003 report by the Center for the Study of Retired Athletes at the University of North Carolina, for example, found a connection between numerous concussions and depression among former professional football players. Further, the Center's follow-up study in 2005 associated both brain impairment and Alzheimer's disease with retired NFL players who had histories of concussions.
   Some experts believe post-concussion symptoms are caused by structural damage to the brain or disruption of neurotransmitter systems, resulting from the impact that caused the concussion. Others believe that post-concussion symptoms are related to common psychological factors. Most common symptoms like headache, dizziness, and sleep problems are similar to those often experienced by individuals diagnosed with depression, anxiety, or post traumatic stress disorder. In many cases, both physiological effects of brain trauma and emotional reactions to these events play a role in the development of symptoms.
  
  Section::::Causes.:Physiological.
   Chronic traumatic encephalopathy, or "CTE", is an example of the cumulative damage that can occur as the result of multiple concussions or less severe blows to the head. The condition was previously referred to as "dementia pugilistica", or "punch drunk" syndrome, as it was first noted in boxers. The disease can lead to cognitive and physical handicaps such as parkinsonism, speech and memory problems, slowed mental processing, tremor, depression, and inappropriate behavior. It shares features with Alzheimer's disease.
  
  Section::::Prognosis.:Second-impact syndrome.
   The debate over whether concussion is a functional or structural phenomenon is ongoing. Structural damage has been found in the mildly traumatically injured brains of animals, but it is not clear whether these findings would apply to humans. Such changes in brain structure could be responsible for certain symptoms such as visual disturbances, but other sets of symptoms, especially those of a psychological nature, are more likely to be caused by reversible pathophysiological changes in cellular function that occur after concussion, such as alterations in neurons' biochemistry. These reversible changes could also explain why dysfunction is frequently temporary. A task force of head injury experts called the Concussion In Sport Group met in 2001 and decided that "concussion may result in neuropathological changes but the acute clinical symptoms largely reflect a functional disturbance rather than structural injury."
   Section::::Media coverage.
  
  In 2012, film producer Steve James created the documentary film "Head Games", interviewing former NHL player Keith Primeau, and the parents of Owen Thomas, who hanged himself after sustaining brain damage during his football career at Penn. The documentary also interviewed former athletes Christopher Nowinski, Cindy Parlow, and "New York Times" reporter Alan Schwarz, among other athletes, journalists, and medical researchers.
   Though no pharmacological treatments exist for PCS, doctors may prescribe medications used for symptoms that also occur in other conditions; for example, antidepressants are used for the depression that frequently follows mTBI. Side effects of medications may affect people suffering the consequences of mTBI more severely than they do others, and thus it is recommended that medications be avoided if possible; there may be a benefit to avoiding narcotic medications. In addition, some pain medications prescribed for headaches can cause rebound headaches when they are discontinued.
  
  Section::::Treatment.:Psychotherapy.
   Section::::Concussions.:Prognosis (short/long-term effects).
  
  Section::::Concussions.:Prognosis (short/long-term effects).:Short-term effects.
  
  Short-term effects deal mostly with Post-concussion Syndrome, which has no clearly defined definition. A person suffering from a single concussive incident typically has a strong recovery rate. The most common Post-concussion symptom is a persistent headache which usually disappears within 1–2 weeks. Other common short-term effects include dizziness, vomiting, nausea, sensitivity to light and sound, irritability, cognitive lapses and memory impairment. 20-90% of the persons affected develop one symptom within a month of the incident, after 3 months 40% of the affected persons show at least 3 symptoms.
  
  Section::::Concussions.:Prognosis (short/long-term effects).:Long-term effects.
   Concussions in American football
  
  Concussions and other types of repetitive play-related head blows in American football have been shown to be the cause of chronic traumatic encephalopathy (CTE), which has led to player deaths and other debilitating symptoms after retirement, including memory loss, depression, anxiety, headaches, and sleep disturbances.
  
  The list of ex-NFL players that have either been diagnosed "post-mortem" with CTE or have reported symptoms of CTE continues to grow.
   Brain injuries are very hard to predict in outcome. Many tests and specialists are needed to determine the likelihood of the prognosis. People with minor brain damage can have debilitating side effects; not just severe brain damage has debilitating effects. The side- effects of a brain injury depend on location and the body’s response to injury. Even a mild concussion can have long term effects that may not resolve.
  
  Section::::History.
   According to the Boston University CTE Center, CTE is a brain degenerative disease found in athletes, military veterans, and others with history of repetitive brain trauma. Although CTE is highly controversial and misunderstood; it is believed that a protein called Tau forms clumps that slowly spread throughout the brain, killing brain cells.
   Section::::Mechanism.:Pathophysiology.
  
  In both animals and humans, MTBI can alter the brain's physiology for hours to years, setting into motion a variety of pathological events. As one example, in animal models, after an initial increase in glucose metabolism, there is a subsequent reduced metabolic state which may persist for up to four weeks after injury. Though these events are thought to interfere with neuronal and brain function, the metabolic processes that follow concussion are reversible in a large majority of affected brain cells; however, a few cells may die after the injury.
   A 2009 study found that individuals with a history of concussions might demonstrate a decline in both physical and mental performance for longer than 30 years. Compared to their peers with no history of brain trauma, sufferers of concussion exhibited effects including loss of episodic memory and reduced muscle speed.
  
  Section::::Prognosis.:Post-concussion syndrome.
   Medications may be prescribed to treat sleep problems and depression. Analgesics such as ibuprofen can be taken for headaches, but paracetamol (acetaminophen) is preferred to minimize the risk of intracranial hemorrhage. Concussed individuals are advised not to use alcohol or other drugs that have not been approved by a doctor as they can impede healing. Activation database-guided EEG biofeedback has been shown to return the memory abilities of the concussed individual to levels better than the control group.
  