In a perspective paper published in the Medical Journal of Australia, the researchers said a review of relevant cases found adolescents with a history of concussions were up to 3.3 times more likely to experience depression in their lifetime than their uninjured counterparts.

But the researchers, led by Amanda Clacy of the University of the Sunshine Coast, said the data did not give enough information to make a definitive link.

"A longitudinal understanding of the neurobiological mechanisms associated with concussion recovery in adolescents is urgently needed," Dr Clacy and her colleagues wrote.

"The same structures in the frontal cortices and hippocampus that are known to undergo rapid development throughout adolescence are also implicated following concussion and in young people experiencing depression and suicidal behaviours."

The most recent data from the Australian Bureau of Statistics show young Australians are now more likely to take their own life than to die in a car crash, with suicide accounting for more than one-third of deaths (36 per cent) among Australians aged 15 to 24.

The matter was complicated, the team said, because there was significant evidence showing playing a team sport was beneficial to young people, both for physical health and social development.

"Given the overlap in the regions of the brain significantly associated with depression and concussion and those most sensitive during development, two main concerns are raised," the researchers wrote.

"First, whether these developmental neurophysiological changes render adolescents more susceptible to emotional disturbances following concussion; and second, what can be done to make these mechanisms more resilient to adverse and ongoing consequences of concussion."

In particular the team identified a contradiction in how teens were advised to recover from a concussion.

Current orthodoxy stresses the need to temporarily withdraw from usual activities, including school, work, physical activity and training, and screen time.

But the researchers said this could exacerbate feelings of social isolation and lead to the onset of depression.

They said the physical cost-benefit of playing sports where concussion was a possibility needed to be explored more thoroughly.

"An improved understanding of the neurological and developmental benefits of physical activity for the treatment of mood disorders in adolescents would offer the opportunity to concurrently promote neurological development and recovery, while also mitigating many of the known risks of depression and suicidality, such as social isolation and lack of engagement," Dr Clacy and colleagues concluded.

A Melbourne-based start-up is using high-tech mouthguards to give doctors objective data to help diagnose and rehabilitate athletes from brain injury.

HitIQ is monitoring players at four AFL and four NRL clubs to collect data which, if proven to be reliable, may help explain what separates a heavy hit from a potentially damaging one.

The research is being led by University of Newcastle neuroscientist Dr Andrew Gardner, a leading authority on concussion in sport.