Potheads take heed: scientists have discovered an increasingly recognized syndrome afflicting marijuana abusers worldwide. Addicts apparently experience severe vomiting and bouts of compulsive bathing. The researchers at Creighton University of Omaha, N.E., were studying the neurobiology of marijuana when they noticed this trend, which has also been observed by Australian scientists. There is no explanation for the syndrome at this point, but they want to spread the word, especially to high school students, who are among the most fervent cannabis smokers. The only way to stop the syndrome, say scientists: quit the bud.