I just read a promotional article on the mental health benefits of omega-3 fatty acids. There seems to be some research, I recall if from NPR a few years ago, that this really helps depression, etc. Is this true or hype? I’m always supicious of books that sell medical ideas that have yellow covers with bright red bold titles.
There has been some research indicating that omega-3 are good for depression.
There don’t seem to be any downsides to taking fish oil (a good source of omega-3’s). They’re also good for heart and stroke protection, joints, and certain eye problems. Fish oil supplements are also have less mercury than fish usually do.
This is the focus (locus?) of research in the lab I am in. Quick answer seems to be that, yes, there is a positive correlation between dietary omega-3 fatty acids and a reduction in depression. 22:6 n-3, aka DHA, which is an essential fatty acid (can’t be made in the human body) is especially important in this regards.
The head of my lab was instrumental in convincing infant formula makers to supplement their product with DHA–there is also a positive correlation between DHA and normal childhood development.
What about omega 6 and 9? And why is it called omega? Sounds sci-fi deathmachine stuff. 
They should put it in WIC packages for moms.
I am certainly no expert in the area, but note that your statement seems to be a bit stronger than is justified by considering all available sources.
No relation of dietary omega-3 fatty acids and depression
No effect of omega-3 supplementation in major depression
I am not saying there is no relationship, only that it is far from proven that depression and low dietary omega-3 fatty acids are linked.
They’re called ‘omega-3’ or ‘omega-6’ because there’s a double bond three or six carbon atoms from the end. The last carbon atom in the fatty acid chain (the one furthest from the -COOH group) is called the ‘omega carbon’, and so ‘omega-3’ means ‘third from the end’. Which brings me to a very important point – it’s ‘omega minus three’, not ‘omega three’.
I heard it too and saw some studies done in Japan (where fish is eaten more often), but i would take Karl Gauss’s articles more seriously.
If you are looking for supplements for depression something like SAM-e, 5-htp, TMG or DL-phenylalanine might work.
Considering all available sources is kind of hard to do. I’d note that the first link you gave is on dietary omega-3 and the second is on delivering DHA in a pill. Not sure what significance that can have, but I assume that a pill would not, regardless of content, be “dietary”. The second study looked usefull, but I wouldn’t expect every study with such a small n to have significant results.