A recent study has found that students who watch TV and play video games on school nights have worse performance because of that TV watching or video game-playing.

The study, of 4,500 middle-school students in Vermont and New Hampshire, found that students themselves reported that their school performance was "below" average when they spent their afterschool days and evenings playing games or watching TV. Further, the study found that the more time that the students spent doing those activities, the worse they did in school.

The study, which also found that those kind of video-based activities done during the weekend had no effect on students' in-school performance, appears in the October issue of Pediatrics magazine.

Similar studies have been announced in recent weeks and years. What makes this study different is that the evaluations came from the students themselves, not from their teachers or parents or from outside observers.