On the feasibility of country-specific and country-general explanations for the increase over time in psychosomatic complaints among Nordic adolescents.

Aims: This study examines the evidence for similar increases in psychosomatic complaints among 15-year-olds in the Nordic countries over the period 2002-2022. A distinction is made between the level and shape of these time trends.

Methods: A dataset from the Health Behaviour in School-aged Children survey from 2002 to 2022 was used. Time trends for psychosomatic complaints were analysed for five Nordic countries: Denmark, Finland, Iceland, Norway and Sweden.

Results: A significant increase in psychosomatic complaints over the last two decades was found among 15-year-old boys and girls in all countries, especially among girls. The shapes of the time trends were very similar for adolescents in all Nordic countries. There were significant differences in the time trends between the countries. Here, the countries with high or low levels of psychosomatic complaints in 2022 were largely the same as those with high or low levels of psychosomatic complaints years earlier.

Conclusions: The high degree of similarity observed in the shapes of the time trends for psychosomatic complaints among Nordic adolescents, as evidenced by this study, suggests that explanations for the observed increases in these psychosomatic complaints should be sought in conditions common to the five countries. However, country-specific explanations are more likely to be candidates for understanding differences in the levels of these time trends. The potential for differentiation between shapes and levels using the aggregate technique when comparing countries also provides an opportunity to empirically examine country-general and country-specific explanations for trends in measures in other areas of research.