Indirect aggression has been associated with antisocial personality traits like Machiavellianism, but there is a lack of evidence on their longitudinal development across adolescence. Therefore, the joint developmental trajectories of adolescent indirect aggression and Machiavellianism across 3 years of high school (Grades 10 to 12) were…

Deception is a common phenomenon in everyday life, yet some people generally lie more than others and some people consider lying more acceptable than others do. Current knowledge about lie acceptability across development or about the individual differences in emotion or personality which shape it is still in an incipient stage. We aimed to expand…

Objective: The primary objective of this study was to evaluate the prevalence of multiple types of sleep problems in young adolescents with ADHD. Method: 262 adolescents comprehensively diagnosed with ADHD and their caregivers completed well-validated measures of sleep problems and daytime sleepiness. Participants also completed measures related…

The joint development of trajectories of bullying perpetration and peer victimization from Grade 5 to Grade 8 and concurrent and predictive associations with parent- and child-reported symptoms of psychopathology (anxiety, depression, attention-deficit/hyperactivity disorder, and somatization) were examined in a large sample (N = 695) of Canadian…