Some people say that fish oils help to reduce the symptoms of Attention Deficit Hyperactivity Disorder (ADHD).
Some independent scientists seem to say that it helps with oppositional behaviour. They say that it does not improve attention, though.
They think it may benefit a particular group of children who are highly oppositional, especially if their normal blood levels of EPA are low. They found that it helped 50% of the oppositional children in their research group. They say that more research is needed to be sure. Click icon and look under the heading Results for more detail.
It would probably be wise, though, to be aware of what the NHS website has to say about the benefits of supplements of omega-3 and omega-6 fatty acids for people with ADHD. They think that the evidence supporting such benefits is very limited. Click icon for their ADHD treatment page. The comment is near the bottom of the page under Supplements.