(I don't represent this study in any way whatsoever.)
A multi-university study about the genetic components of depression is looking for volunteers. It looks completely legitimate.
Info here:
http://depressiongenetics.stanford.edu/
From the site:
Solving the Genetics of Major Depression
The study will create a DNA collection from over 2,000 people to permit scientists to search for depression-related genes. These scientists will not be given any information that could identify you or your family.
Benefits of Participating
ˇFinding relevant genes could lead to the development of better treatments.
ˇYou will receive reimbursement for participation.
Who Can Participate?
● People who have had 2 or more periods of depression.
● The first depression started by age 30 or younger.
● At least one brother, sister or parent has also had depression (by age 40 or younger).
● We are unable to include people with bipolar disorder, or with bipolar disorder in the
immediate family (but there is a similar study of bipolar disorder, click here:
http://www.bipolargenes.org/).