"I have read large doses of fish oil (maybe 5000 mg) or so can change a schizophrenic to the point when tested during a study they show no signs of the disease and the pet scan shows a complete change in the area of the brain that formerly showed up with the same person when they where told to push a button whenever they were having an hallucination (a certain area of the brain would show this on the pet scan yet after taking the fish oil in large doses this area looked different..at the same time the person no longer showed signs of it. My brother tried it but I think only 3000 mg and stopped after just 2 months and gave it too soon IMO and at too low a dose. I did not buy the book I saw this in and when I went back it was gone so I can't give the reference but the book showed fish oil helping with all kinds of mental disorders like bipolar, dyslexia, agoraphobia, depression, etc..just about every mental disease is helped by taking fish oil and most of these when backed up by studies using the pet scan. Get a good quality fish oil....."
The book you talk about might just be "The Omega-3 Connection" by Andrew Stoll, M. D. psychiatrist and director of psychopharmacology research at Harvard. He writes about several small studies involving Omega-3 and schizophrenia - with positive results. I just now skimmed that section and he indicated some improvements in as little as 6 weeks to 2 months. However, elsewhere in the book he has indicates that benefits for some mental issues using Omega-3 take 6 or more months to manifest themselves. He also writes that all of the clinic studies (for a host of things) used a minimum of 3,000 mg of Omega-3 per day and that many used more than that.
I have taken 3,000 mg of Omega-3 now for about 10 months for physical concerns and believe that it has helped me with irregular heart beats/atrial fibrillation. I know for certain from when I started taking just 300 mg a day three years ago that it brought my triglycerides down from over 300 to 65. There are a host of benefits from it. Omega-3 used to be in our diet from free range animals and since the advent of almost factory conditions for them we no longer get this benefit.
By the way, that book talks about one study indicating that infants who were not breast fed had a significantly higher risk of schizophrenia. Breast milk is high in Omega-3.
I have at least 3 books on Omega 3 which point out the benefits for both mental and physical health. How the benefits of it were learned was in studies of the Inuit of Greenland - before they introduced Western foods. The key is the ratio of Omega 6 to Omega 3 and the Inuit ingested a ratio of 1:1 and rarely had either heart disease or cancer (until they added Western foods). They ate very little vegetable food and subsisted on seals, fish and anything from the sea - and were very healthy. Fish oil is the recommended source in each of the books I have and they have a ratio of 2:1 Omega 6 to 3. The SAD diet is a ratio of 20 to 50 to 1. Flax oil capsules is 6:1 and are not recommended as an Omega 3 supplement. A prescription fish oil has been developed which is completely toxin free, but it is very expensive and deep sea fish oil capsules claim they are also toxin free.