“Popular media tends to perpetuate the idea that the prevalence of mental disorders is increasing,” writes Dr. Ian Colman, Canada Research Chair in Mental Health Epidemiology and associate professor at the University of Ottawa, Ottawa, Ontario, with coauthors. “However, research supporting this position has been inconsistent.”
Dr. Colman and colleagues sought to better understand whether symptoms of mental illness are increasing, specifically hyperactivity, aggression, depression and anxiety, suicidal thinking and behaviour. They looked at data from the National Longitudinal Survey of Children and Youth, which involves a group of children and adolescents from across the country who are followed every two years. Their study included 11 725 children aged 10-11 years (1994/95-2004/05), 10 574 aged 12-13 years (1996/97-2006/07) and 9835 aged 14-15 years (1998/99-2008/09). Participants were asked by confidential questionnaire to describe their feelings and behaviours and the frequency at which they experienced them in the previous week.