About 25% of people of caucasion decent are (A,A) at rs4680, which is in the COMT gene whose enzyme degrades dopamine/epinephrine. Modafinil probably works by raising these catecholamines (at least in part). I haven't read it but the study is here: http://www.ncbi.nlm.nih.gov/pubmed/19037200?dopt=Abstract
There's tons of interesting studies about rs4680 (http://www.snpedia.com/index.php/Rs4680). Although I think all the data is still to broad to make any conclusions.
I think I might give modafinil a go just to see what happens.
Modafinil improved the cognitive performance of Val/Val's (G,G)s across most of the tests (memory tests, mood tests, "Vigor" tests, reaction rate tests, well-being, fatigue, are ones i remember). Met/Met's (A,A)s did not see any statistically significant improvement on most of the tests. One test where there was a small effect for Met/Met's was in subjective well-being.
The study also looked at sleep recovery after the prolonged wakefulness. All participants entered deep sleep faster than normal.
90% of Val/Val's correctly identified their group (placebo vs. drug). 66% of Met/Met's correctly identified their group.
There were 10 people in the Val/Val group and 12 in the Met/Met group. But the small number of participants should be accounted for in the p-tests, as far as I know.
However, like you, I'd still try it given the chance. Regardless, lets hear it for our naturally increased dopamine!
Has everyone on HN gone crazy for the day or something?
I'm seein' robots.
Searching for rs4680 did show a result though (I have the AA variant).
I recommend downloading your raw data from 23andme and using the prometheus program from SNPedia. This is how I found out about this gene. This program is very raw but includes a lot more research and points you to the relevant papers.
Keep in mind, this information is all AFAIK, as I am just browsing this information casually.
(edit) Oh, it's a crippleware. They want "optional $2 payment" so that the program would run in 5 minutes instead of 3 hours. How cute.
They had a special deal for $99 when I got it, but that was very limited and they haven't done it since. Still I'd say if you hold out for a year that price will be halved. I generally recommend people to wait unless they're really interested in these things. The industry is still in its infancy. Cost is going down quickly and quality is going up just as fast.
There's at least a couple other similar companies out there, with more well known ones being deCODE and Navigenics. Recently these companies were getting in trouble with california health regulators for providing medical information without a doctor (I think that was the complaint, but I don't remember the exact reason). But the California complaint included 12 companies so there must be other companies as well.