Trends in adolescent (15-19 years) suicide rates from 1979-1996 were compared with suicide trends in individuals 20 years & over in 30 countries & with trends in rates of deaths due to undetermined causes in adolescents in 17 countries of the World Health Organization European Region. In 21 of the 30 countries, male adolescent suicide rates increased during the study period accompanied by far less increases or decreases in suicide rates of males 20 years and over. Part of the observed increase in some countries can be attributed to improved statistics. Female adolescent suicide rates rose less markedly than in males in 18 countries. Increases in female suicide rates were marginally affected by changes in classification practices & were accompanied primarily by declining suicide rates in females 20 years & over. (47 refs.)