Tom’s troubled path from head injury to suicide spanned 21 years. It began with a road accident at age 22, which led to the subsequent onset of epilepsy, chronic insomnia, depression and muscular and skeletal pain.

Intermittent drug and alcohol problems followed, as did a series of let downs by health and social care professionals. While his anonymity was protected, his unfortunate story was publicised last year following a 2016 review by Somerset Safeguarding Adults Board. They uncovered a sequence of missed opportunities to change the trajectory of his life.

His demise highlights the complex chain of events – often over many years – that can push people to the take their own life following a brain injury.

Although perhaps not a typical case, it also shows why categorically explaining and proving the links between suicide and brain injury is so challenging. Brain injury can cause chaos where once there was relative calm.

The fallout can spread far and wide, internally and externally. Identifying a clear signal of when and why it might be a precursor to suicide is a huge challenge for scientists.

The latest researchers to take on this endeavour have produced possibly the most comprehensive brain injury/suicide data yet. Medical records of 7.4 million people aged 10 or over, from 1980 to 2014, were analysed in the Danish Research Institute of Suicide Prevention study.

The headline finding from their data is that people with a history of traumatic brain injury (TBI) are twice as likely as those with no TBI to commit suicide. Some 567,823 people, or 7.6 per cent, were found to have received treatment for a TBI. By the end of 2014, 34,529 people in the study were found to have taken their own lives. Among those with no history of TBI, the suicide rate was 20 per 100,000 people per year.

This compared with a rate of 41 per 100,000 per year among those with a history of TBI. Put another way, one in 20 suicides could be as a result of head injuries, if the data is to be believed.

At the same time, the researchers emphasise that suicide remains a rare event, with 0.62 per cent of all people treated for TBI dying this way.

Senior author Dr. Michael Eriksen Benros explained in the paper: “TBI can affect the brain’s functions by inducing an inflammatory reaction and potentially chronic neuro- inflammation, in addition to vascular damage and white matter degeneration, which may increase the risk of mental disorders and suicide.

“We have previously shown that TBI increases the risk of subsequent psychiatric disorders and consequently increase the risk of suicide as we show in this study.”

Lead study author Trine Madsen (pictured) tells NR Times: “TBI can also cause long-term problems with physical symptoms such as head ache, dizziness and neck pain, and cognitive symptoms like memory impairment and concentration problems. These may lead to social problems or psychiatric symptoms that could increase the risk of suicide. The consequences of TBI can therefore affect both one’s social relations and employment.”

Another finding of the study was a greater suicide risk in younger people with TBI. Madsen says: “We found that those who experienced a TBI in the 16 to 20 age group had the highest subsequent rate of suicide – a threefold higher risk – compared to the general population. This risk was also enhanced in those having a TBI in the ages between 21-40, where the suicide rate was more than twofold higher.”

The study also found that the risk increase was greatest within the first six months after initial treatment for brain injuries.

Madsen says: “For some individuals learning to live or accept living with physical, cognitive and emotional symptoms and impairments could play a role in developing post-TBI suicidal thoughts, that could lead to suicidal behaviour.”

Severity of injury, roughly measured by the length of hospital stay for each person, also correlated with a higher suicide risk.

Madsen adds: “In terms of future research, we are planning to look into how TBI is associated with a non-lethal suicide attempt as an outcome. Also, it would be interesting to carry out a large register-based study examining how TBI might be associated with more social consequences such as employment status in the years following the TBI incident.”

The Danish research is the latest part of a growing body of evidence linking brain injury and suicide – although data is inconsistent in terms of calculating the suicide risk following head injury.

A study published last year in the American Journal of Preventative Medicine outlined brain injury as one of several illnesses linked to heightened suicide risk.

Based on 2,674 suicide cases, it reported that brain injuries make people nine times more likely to commit suicide than members of the general population. This compares to a two-fold risk increase in sleep disorders and HIV/AIDS.

A separate study in Denmark in 2001, analysed 145,440 head injury cases and found that suicides were more than twice as prevalent after skull fracture and quadruple after brain haemorrhage.

Canadian researchers in 2016 brought further such evidence. Of 100,000 concussion patients, 31 committed suicide – three times the population average.

While figures vary, there is clearly a common theme; head injuries play at least some part in influencing suicides. But deciphering exactly what that role might be from case to case can be an immense challenge for researchers. A recent paper (Palladino, 2017) underlines why.

The study aimed to gauge the suicide risk of US veterans who were homeless and had experienced a TBI. According to the US Department of Veteran Affairs, with adjustments made for age and sex, suicide risk in veterans is 22 per cent higher than the general adult population.

Brain injury, like suicide risk, is also relatively high in veteran groups. Paladino and colleagues, therefore, set out to test for a correlation between the two.

The study indicated that, although veterans reporting low-to-moderate risk of suicide were demographically similar to those experiencing high risk—and have suffered approximately the same number of TBIs— their reporting of post-TBI symptoms were significantly different.

Veterans expressing high risk of suicide more frequently experienced blurred vision, difficulty managing stress, struggles with memory and problem-solving and seizures following a TBI; the presence of these symptoms may be an indication of a more severe TBI.

In addition, these veterans also more frequently reported symptoms consistent with PTSD which overlap to a large degree with symptoms of TBI.

Perhaps PTSD, homelessness and brain injury make such a poisonous concoction that all three elements contribute to suicide risk.

Untangling these factors and calculating their specific link seems an a near impossible task for scientists. Demand for such understanding is increasing, however, especially in the US where awareness of suicide and brain injury is rising. This follows a stream of high profile suicides by former stars of American football – which remains under attack for its poor record on head injuries.

The NFL has spent recent years dealing with lawsuits from families of players whose premature death or struggles in later life can be attributed to concussion.

As well as possible links to brain disorders like dementia and Parkinson’s, suicide has also been investigated as one of the ugly consequences of chronic traumatic encephalopathy (CTE).

In September, former NFL star Jason Hairston, who previously spoke in interviews about having “all the symptoms of CTE” took his own life at age 47.

In 2012, ex-San Diego player Junior Seau committed suicide two years after retirement. As with scores of other deceased ex-players, his brain tested positively for CTE.

Among other such cases is ex-NFL player Terry Long, who took his own life by drinking a gallon of antifreeze.

In 2012, Jovan Belcher murdered his girlfriend and then drove to an American football training facility, where he then took his own life. Dave Duerson and Adrian Robinson are also on what is a shameful list for the sport’s official custodians. All committed suicide and all showed signs of CTE in a post-mortem.

In the UK, meanwhile, the recent appointment of the first Minister for Suicide Prevention may put suicide awareness higher up the agenda.

The landmark hire of Jackie Doyle-Price, a junior minister in the Department of Health, came on World Mental Health Day.

Perhaps she’ll have her ear bent by members of Westminster’s increasingly vocal brain injury lobby, as organised through the brain injury APPG.

ABI will hopefully be an important consideration as she sets about her work leading the push to reduce suicide rates and the stigma that prevents people in despair from seeking help.

“Where words fail, music speaks”

Music therapy could help to reduce risk factors that influence a person’s journey towards suicide, writes Dan Thomas, director of Chroma.

According to the literature, music can play an important role in the facilitation of making a connection (Stern, 1985; Trevathan, 2011); a connection between a person and their music therapist; a connection between music and feelings which the brain injury survivor may struggle to put into words.

The literature (Dileo, 1999; Jones, 2005) and clinical practice highlights musical connections as a protective factor to stabilise low emotional states and to focus on living/ the future. Making music connectionscis also seen as a necessary component of suicidal treatment (Erbacher, 2008).

Music therapy participants often identify the connections they make in sessions as an important protective factor, thereby giving music the role of facilitating connection.

Music also plays a role in improving mood, on a social, chemical and physical level. And for people living with a brain injury, the role of music as a tool to express their experience of life without the need to find the “right” words can be invaluable.

Chroma is a leading provider of neurologic music therapy (NMT).