Psychosomatic complaints are indicative of stress in young individuals: findings from a Swedish national cohort study

Psychosomatic complaints are common in youth and are often assumed to indicate stress. Although several studies have confirmed that a cross-sectional association exists, few have empirically investigated whether or not perceived stress influences psychosomatic complaints. The objective of the present study was to build upon previous research by exploring whether changes in perceived stress over time are associated with corresponding changes in psychosomatic complaints. This analytical approach takes unmeasured time-invariant confounding into account, thereby offering more robust evidence for a causal association between the variables under study. Data was derived from the Swedish national cohort study Futura01, with information from 2,708 participants aged 17-18 in 2019 and 20-21 in 2022. Perceived stress was measured by Cohen's Perceived Stress Scale. Psychosomatic complaints were measured by questions on the frequency of stomach aches, headaches and difficulties falling asleep, which were added to an index. Information on gender, parental education, and parental country of birth was derived from registries. Linear regression analyses were conducted and the first difference (FD) approach was used. Perceived stress and psychosomatic complaints exhibited cross-sectional associations at both time points. The FD analyses showed that increases in perceived stress were associated with increases in psychosomatic complaints, and this was the case irrespective of sociodemographic characteristics.