 Hypotheses will be tested in a placebo-controlled, double-blind, randomized trial involving 8 to18 year-old adolescents drawn from primary and secondary schools in Hong Kong. Omega-3 supplementation will be in the form of a Norwegian fruit juice drink. 300 adolescents will be randomly assigned into: 1 omega-3 supplemented drink, 2 placebo drink, 3 treatment-as-usual controls. Behavioral, neurocognitive, and psychophysiological measures will be assessed at baseline 0 months, end of treatment 6 months, and 6 months post-treatment 12 months. 