Introduction: Lupus fog is ill-defined. We aimed to study whether lupus fog is the result of dissociation by studying the prevalence of dissociation and dissociative fog in patients with SLE and neuropsychiatric manifestations of inflammatory and non-inflammatory origin.
Methods: Patients visiting the tertiary referral center for neuropsychiatric systemic lupus erythematosus (NPSLE) of the LUMC between 2007-2019 were included. Patients were classified as having neuropsychiatric symptoms of inflammatory or non-inflammatory origin. Dissociation was studied using the Dissociative Experience Scale-II (DES), in which the presence of 28 dissociative symptoms is rated (0-100% of the time), of which one question assesses the presence of a dissociative fog directly. Average scores are calculated and scores ≥ 25 are considered indicative of a dissociative disorder. A score of ≥ 30 on question 28 (dissociative fog) was considered indicative for the presence of a fog. Summary scores in the general adult population range from 4.4 to 14. Multiple regression analysis (MRA) was performed to study the association between inflammatory neuropsychiatric symptoms and dissociation. DES results are presented as median (range) and MRA as B and 95% confidence interval (CI).
Results: DES questionnaires were available for 337 patients, of which 69 had an inflammatory NPSLE phenotype (20%). Mean age in the total study population was 43 ± 14 years and the majority was female (87%). The median dissociation score was 7.1 (0-75) and did not differ between patients with neuropsychiatric symptoms of inflammatory or non-inflammatory origin (B: -0.04 (95% CI: -0.17; 0.09)). 35 patients (10%) had a score indicative of a dissociative disorder. The most common type of dissociation was absorption/imagination. 43 patients (13%) reported a dissociative fog.
Discussion: In most patients with SLE and neuropsychiatric symptoms, dissociative symptoms are within normal range, regardless of underlying etiology. Dissociative fog is present, but uncommon. Lupus fog is most likely not associated with dissociation.