Background Studies have reported elevated rates of dissociative symptoms and comorbid dissociative disorders in functional neurological disorder (FND); however, a comprehensive review is lacking. Aims To systematically review the severity of dissociative symptoms and prevalence of comorbid dissociative disorders in FND and summarise their biological and clinical associations. Method We searched Embase, PsycInfo and MEDLINE up to June 2021, combining terms for FND and dissociation. Studies were eligible if reporting dissociative symptom scores or rates of comorbid dissociative disorder in FND samples. Risk of bias was appraised using modified Newcastle–Ottawa criteria. The findings were synthesised qualitatively and dissociative symptom scores were included in a meta-analysis (PROSPERO CRD42020173263). Results Seventy-five studies were eligible (FND n = 3940; control n = 3073), most commonly prospective case–control studies (k = 54). Dissociative disorders were frequently comorbid in FND. Psychoform dissociation was elevated in FND compared with healthy (g = 0.90, 95% CI 0.66–1.14, I2 = 70%) and neurological controls (g = 0.56, 95% CI 0.19–0.92, I2 = 67%). Greater psychoform dissociation was observed in FND samples with seizure symptoms versus healthy controls (g = 0.94, 95% CI 0.65–1.22, I2 = 42%) and FND samples with motor symptoms (g = 0.40, 95% CI −0.18 to 1.00, I2 = 54%). Somatoform dissociation was elevated in FND versus healthy controls (g = 1.80, 95% CI 1.25–2.34, I2 = 75%). Dissociation in FND was associated with more severe functional symptoms, worse quality of life and brain alterations. Conclusions Our findings highlight the potential clinical utility of assessing patients with FND for dissociative symptomatology. However, fewer studies investigated FND samples with motor symptoms and heterogeneity between studies and risk of bias were high. Rigorous investigation of the prevalence, features and mechanistic relevance of dissociation in FND is needed.

Objectives/AimsDissociation is a potential mechanism in FND. Although scientific studies report elevated rates of dissociative symptoms in FND, a systematic assessment of the biological and clinical correlates of dissociation in FND is lacking. We aimed to systematically review the current evidence describing dissociative symptoms and disorders in functional neurological disorder (FND), and additionally conduct a meta-analysis of dissociative symptom severity in FND. We also aimed to synthesise the existing data on biological and clinical correlates of dissociation in FND.MethodsWe systematically searched Embase, PsycINFO, and Medline, combining terms for FND and dissociation. Studies were eligible for inclusion if reporting on dissociative symptom scale scores or rates of dissociative disorder in FND samples. Studies were appraised for methodological quality using modified Newcastle-Ottawa criteria. Findings pertaining to dissociative symptoms or disorders, as well as biological and clinical correlates of dissociation in FND samples, were synthesised qualitatively. Dissociative symptom scores were included in a meta-analysis using random and mixed effects models.ResultsTwo-thousand and eighty-eight records were screened and seventy-nine studies were included in the final review. Dissociative symptoms were elevated in FND. The meta-analysis demonstrated a significant elevation in dissociation in FND samples relative to neurological and healthy controls, but not psychiatric controls. Dissociative disorders were frequently co-morbid in FND samples. Psychoform (cognitive) dissociation was more prominent in FND-seizures, whereas somatoform (physical) dissociation tended to be more prominent in FND-motor symptom samples. Dissociation was associated with FND symptom severity or frequency, general psychopathology, and reduced quality of life. Biological correlates of elevated dissociation included structural and functional brain alterations in regions that have previously been implicated in FND, such as the anterior cingulate cortex.ConclusionsDissociative symptoms and disorders are common in FND, and different FND subgroups appear to endorse varying degrees of psychoform or somatoform dissociation. Presence of dissociative symptoms in FND is associated with adverse clinical features; there is therefore a clinical need to assess patients with FND for dissociative symptomatology and to address these symptoms during treatment. Future research should examine dissociation further in different FND subgroups, using measures that distinguish between different types of dissociation, alongside measures of underlying pathophysiology.

Objectives To examine whether discharge destination is a useful predictor variable for the length of admission within psychiatric intensive care units (PICUs). Methods A clinician-led process separated PICU admissions by discharge destination into three types and suggested other possible variables associated with length of stay. Subsequently, a retrospective study gathered proposed predictor variable data from a total of 368 admissions from four PICUs. Bayesian models were developed and analysed. Results Clinical patient-type grouping by discharge destination displayed better intraclass correlation (0.37) than any other predictor variable (next highest was the specific PICU to which a patient was admitted (0.0585)). Patients who were transferred to further secure care had the longest PICU admission length. The best model included both patient type (discharge destination) and unit as well as an interaction between those variables. Discussion Patient typing based on clinical pathways shows better predictive ability of admission length than clinical diagnosis or a specific tool that was developed to identify patient needs. Modelling admission lengths in a Bayesian fashion could be expanded and be useful within service planning and monitoring for groups of patients. Conclusion Variables previously proposed to be associated with patient need did not predict PICU admission length. Of the proposed predictor variables, grouping patients by discharge destination contributed the most to length of stay in four different PICUs.