Laughing with friends, singing along to their favorite songs, chattering on their cell phones – typical teenage life recorded on video moments before a fatal or near-fatal car accident.

Statistics confirm distracted driving is the leading cause of teen car accidents, but how do we really know? Who’s to say exactly what these teenagers were doing before impact?

Police piece together information based on cellphone data and eyewitness accounts, but like a puzzle with missing pieces, how do we see the whole story? Enter video evidence.

A new study found that teens who have suffered a concussion or traumatic brain injury(TBI) are more likely to have harmful behaviours such as smoking cigarettes and contemplating suicide.

“Many harmful behaviours in adolescence can be precursors to addiction and mental health issues later in life,” said Dr. Robert Mann, a senior scientist at the Centre for Addiction and Mental Health.

The study used data from the 2011 Ontario Student Drug Use and Health survey where researchers investigated 13 harmful health behaviours among 9,300 Grade 7 to 12 students.

Interesting results varied between different sexes with a history of TBI.

Boys were found 6% more likely to experience a concussion but girls were more likely to have increased psychological distress.