The main aim of the present study is to examine the frequency and corr
elates of behavioral disorders. Symptoms of conduct disorder and oppos
itional disorder were assessed by means of the 'Revised Ontario Child
Health Study Scales'. The subjects were 215 adolescents, aged 11-19 ye
ars. Boys showed more symptoms of conduct and oppositional disorders t
han girls, especially when the symptoms were related to direct aggress
ive acts against objects, persons and animals. Almost all symptoms of
conduct disorder showed a significant age effect. Most symptoms, espec
ially those related to aggressive behavior and object destruction, dec
rease with age. The implication for clinical practice and research was
discussed.