There is a distinction in the business between Shouenen and Seinen (Boy and Man) and between Shoujo and Josei (Girl and Woman). In manga, intrestingly enough, a good part of this distinction is drawn on whether or not Furigana (sp?), reading aids, are presented to help readers deal with complicated or vague Kanji.
http://en.wikipedia.org/wiki/Seinen
I think one problem is what you mean by 'targeted' towards adults. Surely some shows like Bokurano (see my sig), Now and Then Here and There, and others have a more 'serious' tone to them.... But where would a show like Gundam SEED fall? (More violence than previous Gundam series, but disposed to fanservice and focus on high-octane battles). A show like Evangelion also blurs the lines.
although, if this is a trend or not, who knows? One thing is for sure, and it's that the most watched animes in Japan are almost all shows clearly targeted for children (Shin Chan, Pokemon, etc). This strongly suggests, to me, that MORE anime will be created targeted toward younger audiences. Also, alot of the anime that is popular on this board appear in obscure, seldomly viewed time slots (Death Note airing at 1am in Japan while many here considered it a 'prime' anime of the season).