Psychiatric illnesses including depression are not linked to future violence, according to a long-term study by academics at Northwestern University.
The research, published in the Journal of the American Academy of Child & Adolescent Psychiatry, used data from the Northwestern Juvenile Project which looked at 1,659 young offenders detained at the Cook County Juvenile Temporary Detention Centre in Chicago between 1995 and 1998.
The subjects self-reported psychiatric disorders and violence and they were followed up in interviews between three and five years after their sentences.
"Our findings are relevant to the recent tragic plane crash in the French Alps. Our findings show that no one could have predicted that the pilot - who apparently suffered from depression - would perpetrate this violent act," said co-author Linda Teplin.