Decoupled but Intertwined Association Between Dissociation and Depression: The Impact of Sleep and Gastrointestinal Symptoms.

Objective: Whether dissociation and depression are distinct constructs remains controversial. The aim of this study was to explore the interrelations and associated factors between them.

Methods: This study included inpatients with major depressive disorder (MDD) and bipolar disorder with major depressive episode (BD). Clinical rating scales were used to measure levels of depression, dissociation, and psychotic symptoms. Generalized estimating equations were used to estimate interrelations between dissociation and related factors over time, including depression. Moreover, the impacts of individual items of the Hamilton Depression Rating Scale (HAMD) on dissociation were evaluated after multiple adjustments.

Results: A total of 91 participants were included into the analysis, of whom 59 had MDD and 32 had BD. After standardized treatment, levels of depression and psychotic symptoms significantly decreased, whereas the level of dissociation did not. However, the level of dissociation significantly decreased in the high-dissociation group, and this was positively associated with the change in depression and psychotic symptoms. Female sex and comorbidity with borderline personality disorder were also positively correlated with dissociation. Among items of the HAMD, insomnia and gastrointestinal symptoms contributed to the association between depression and dissociation.

Conclusion: We identified a decoupled but intertwined relationship between dissociation and depression. Clinicians should be aware of this comorbidity and provide timely interventions for dissociation during clinical practice.