If fish oil gives you those horrible repeats all afternoon, that is a fixable problem rather than a reason to stop. Keep the capsules in the freezer, ask about an enteric coated version, or try a flavoured liquid.

One senior researcher in this field is approached by ADHD app startups roughly once a month and no longer takes part, on the view that the companies are not seriously trying to build something that works.

Cutting sugar does not improve ADHD, and nor does stripping out additives. Both have been tested repeatedly, including under conditions where nobody knew which child had eaten what.

When you read that a treatment worked, look for who judged the improvement and whether they knew what the child had been given. In much of this literature, they knew.