 This a randomised, double-blind, placebo-controlled trial with 4 x 3 x 4 x 2 4 treatments groups x 3 diagnostic groups x 4 time measurements of an outcome variable x 2 genders between-subject design to evaluate whether Omega-3 supplement, when combined with social skills training, is more effective than either approach alone in reducing childhood conduct disorder and attention deficit hyperactivity disorder. 