The course of dissociation in the general population: a 3-year follow-up study

There have been no previous general population studies on the stability of dissociative symptoms. The aim of this study was to examine the course of and the changes in dissociative symptoms and factors associated with these changes during a 3-year follow-up of a Finnish general population sample.

The general population sample included a cohort of 1497 subjects. Dissociative symptoms were assessed with the Dissociative Experiences Scale (DES) and the DES-taxon (DES-T). Depressive symptoms and suicidal ideation were measured with the Beck Depression Inventory (BDI). The sample was categorized into low dissociators with DES scores less than 20 and high dissociators with DES scores of 20 or more.

At baseline, 98 subjects were high dissociators. On follow-up, 28 of them were still high dissociators, whereas among 70 subjects, the DES score declined below the cutoff score. During the follow-up period, 28 of 1399 subjects became new high dissociators, and constantly low dissociators consisted of 1371 of 1399 subjects. Dissociative taxon membership was detected in 39 subjects either at baseline or at follow-up, but only 4 of them met the criteria at both assessments. Stable high dissociation was associated with an increase in the BDI score on follow-up, baseline suicidal ideation, a younger age, a reduced working ability, and smoking. Risk factors for becoming a new high dissociator were an increase in the BDI score, a younger age at baseline, and a reduced working ability. Among the baseline high dissociators, recovery from high dissociation was associated with a decline in the BDI score at follow-up and with no suicidal thoughts, older age, and a good working ability at baseline.

Only a small proportion of the general population had constantly high levels of dissociative symptoms. The stability of dissociative taxon membership was weaker than the stability of the continuous variables of dissociation. The dissociative experiences had a tendency to change, and these changes were associated with changes in the BDI scores. Further studies are needed to reveal the factors associated with the changes in dissociative symptoms.