Dissociative symptom trajectories during treatment with selective serotonin reuptake inhibitors for depressive or anxiety disorders.

BACKGROUND

Dissociative symptoms often co-occur with depressive and anxiety disorders and may worsen treatment outcomes. Little is known about how different forms of dissociation - psychoform and somatoform - change during pharmacotherapy with selective serotonin reuptake inhibitors (SSRIs).

OBJECTIVE

Our study examined changes in dissociative symptoms during SSRI treatment of depressive and anxiety disorders and whether they follow a distinct course or are associated with treatment outcomes.

METHOD: We conducted a longitudinal naturalistic, observational study of 100 outpatients with depressive and/or anxiety symptoms recruited at three outpatient psychiatric clinics, assessed at three time points during SSRI treatment. Measures used included the Hamilton Depression Rating Scale (HDRS), the Hamilton Anxiety Rating Scale (HAM-A), the Dissociative Experiences Scale-Revised (DES-R), and the Somatoform Dissociation Questionnaire-20 (SDQ-20). Changes in symptoms over time were analyzed using nonparametric tests, regression, and cross-lagged correlations.

RESULTS

All symptoms decreased significantly (p < 0.001), but dissociation declined more slowly than depression and anxiety. Psychoform dissociation declined steadily, whereas somatoform dissociation plateaued after early improvement. Baseline psychoform dissociation was not associated with symptom reduction but significantly reduced the odds of achieving remission of depression. Somatoform dissociation was strongly associated with anxiety, with core anxiety showing a temporal relationship with subsequent severity of dissociative symptoms. Mental anxiety decreased more rapidly than somatic, reflecting slower reduction of somatoform dissociation. Concurrent psychological support was not associated with outcomes.

CONCLUSIONS

Dissociative symptoms may reduce during SSRI treatment, but this reduction is slower and has a different course than that of depressive and anxiety symptoms. Somatoform dissociation is particularly persistent and closely associated with anxiety. Clinicians should screen for dissociation early and consider targeted interventions when appropriate to optimize treatment outcomes.

CLINICAL TRIAL NUMBER: Not applicable.