Yes I believe there currently is a dystopian trend in novels for teenagers. Many teens feel they are facing struggles throughout life and enjoy seeing that others face immeasurable odds as well. When they can relate to others who have faced extreme difficulties this can motivate them to try harder and be better people. That's why this is a popular theme.
There is a dystopian trend, encouraged by books like The Hunger Games.
There is also a vampire romance trend, thanks to Twilight, and a
sweet romance trend spawned by series by authors like Sarah Dessen.
Then there is the magical fantasy trend, full of delightful books like A
Wizard of Earthsea and all the Harry Potter novels. The teen audience
is as varied as the adult one, and in fact, many teens read books written
for adult audiences, and like them.
There is a dystopian trend on many novels including those for teenagers. Books such as the Hunger Games have a very obvious influence from it and are centered around it. Other books, such as the Pretty Little Liars series, have a less obvious influence that is reflected in the teenage social circles.
I think a lot of novels these days seem to have a more bleak and dystopian feel to them in terms of atmopshere. It's something that teenagers seem to relate to especially this day and age since people seem to face more constant depression due to technology. I think the more these novels sell, the more the trend will continues.
I do not believe there is a dystopian trend in novels for teenagers. I believe there are a lot of novels available to teens and they cover a lot of different styles. I believe there have always been dystopian pieces in the novels for this age group, it's not merely a new trend.