Fish oil capsules significantly reduce the rate of psychotic disorders in young people, aged 13 to 24, a new study finds. This dietary supplement full of omega-3 fatty acids, also naturally present in fatty fish such as salmon and mackerel, may even prevent the development of schizophrenia. Seven years ago, researchers found out that teenagers and young adults at risk of developing schizophrenia could benefit from taking capsules of omega-3 fatty acids. A follow-up study published this week gives even more conclusive results: the scientists report that 4 out of 41 of those who took fish oil for three months seven years ago had developed psychosis, compared with 16 out of 40 who received a placebo capsule during the trial.