Brian De Palma's adaptation is Trier's immediate reference, but where that feature elicits screams from Carrie's maturation (and possesses an opening scene leering in its horror), Thelma analyzes where the independent spirit of a person takes over.
Because the screenplay so blatantly cribs from Carrie — everything from the meek heroine to the religious-fanatic family to the linking of supernatural powers with teenage sexuality — Trier seems to be toying with his audience, practically daring us to see the comparisons and then letting us wonder where he will deviate from the Brian De Palma film.
While that plot description could fit another film named for its female protagonist, the Brian De Palma classic Carrie, Thelma is less interested in supernatural horror than in contemplating the effects of an oppressive religious environment on personal development and the challenges of taking control of one’s destiny.