Cognitive-behavioural therapy compared with standardised medical care for adults with dissociative non-epileptic seizures: the CODES RCT

How does cognitive behavior therapy for dissociative seizures work? A mediation analysis of the CODES trial

BACKGROUND

We compared dissociative seizure specific cognitive behavior therapy (DS-CBT) plus standardized medical care (SMC) to SMC alone in a randomized controlled trial. DS-CBT resulted in better outcomes on several secondary trial outcome measures at the 12-month follow-up point. The purpose of this paper is to evaluate putative treatment mechanisms.

METHODS

We carried out a secondary mediation analysis of the CODES trial. 368 participants were recruited from the National Health Service in secondary / tertiary care in England, Scotland, and Wales. Sixteen mediation hypotheses corresponding to combinations of important trial outcomes and putative mediators were assessed. Twelve-month trial outcomes considered were final-month seizure frequency, Work and Social Adjustment Scale (WSAS), and the SF-12v2, a quality-of-life measure providing physical (PCS) and mental component summary (MCS) scores. Mediators chosen for analysis at six months (broadly corresponding to completion of DS-CBT) included: (a) beliefs about emotions, (b) a measure of avoidance behavior, (c) anxiety and (d) depression.

RESULTS

All putative mediator variables except beliefs about emotions were found to be improved by DS-CBT. We found evidence for DS-CBT effect mediation for the outcome variables dissociative seizures (DS), WSAS and SF-12v2 MCS scores by improvements in target variables avoidance behavior, anxiety, and depression. The only variable to mediate the DS-CBT effect on the SF-12v2 PCS score was avoidance behavior.

CONCLUSIONS

Our findings largely confirmed the logic model underlying the development of CBT for patients with DS. Interventions could be additionally developed to specifically address beliefs about emotions to assess whether it improves outcomes.

The Financial Burden of Functional Neurological Disorders

PURPOSE OF REVIEW

Functional neurological disorder (FND) is a common and severely debilitating condition lacking clinical ownership, existing between neurology and psychiatry. This article reports the findings of recent research investigating the economic costs of FND diagnosis and management. We define what the costs are, why they exist, and suggest actionable steps to reduce them.

RECENT FINDINGS

The financial burden of FND exists across the globe characterized by high healthcare utilization resulting in exorbitant direct and indirect costs for the patient, healthcare system, and society. Inadequate medical education and stigmatization of the disorder prolong the time to diagnosis, during which cyclical utilization of inpatient and emergency department services drive up costs. Despite being cost-effective, lack of accessible treatment compounds the issue, leaving patients without a reliable exit. Recent findings support an increased awareness and the need for a cultural shift to overcome the financial burden associated with this underserved population.

Economic Cost of Functional Neurologic Disorders: A Systematic Review

BACKGROUND AND OBJECTIVES

Functional neurologic disorder (FND) represents genuine involuntary neurologic symptoms and signs including seizures, weakness, and sensory disturbance, which have characteristic clinical features, and represent a problem of voluntary control and perception despite normal basic structure of the nervous system. The historical view of FND as a diagnosis of exclusion can lead to unnecessary health care resource utilization and high direct and indirect economic costs. A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to assess these economic costs and to assess for any cost-effective treatments.

METHODS

We searched electronic databases (PubMed, PsycInfo, MEDLINE, EMBASE, and the National Health Service Economic Evaluations Database of the University of York) for original, primary research publications between inception of the databases and April 8, 2022. A hand search of conference abstracts was also conducted. Key search terms included "functional neurologic disorder," "conversion disorder," and "functional seizures." Reviews, case reports, case series, and qualitative studies were excluded. We performed a descriptive and qualitative thematic analysis of the resulting studies.

RESULTS

The search resulted in a total of 3,244 studies. Sixteen studies were included after screening and exclusion of duplicates. These included the following: cost-of-illness (COI) studies that were conducted alongside cohort studies without intervention and those that included a comparator group, for example, another neurologic disorder (n = 4); COI studies that were conducted alongside cohort studies without intervention and those that did not include a comparator group (n = 4); economic evaluations of interventions that were either pre-post cohort studies (n = 6) or randomized controlled trials (n = 2). Of these, 5 studies assessed active interventions, and 3 studies assessed costs before and after a definitive diagnosis of FND. Studies showed an excess annual cost associated with FND (range $4,964-$86,722 2021 US dollars), which consisted of both direct and large indirect costs. Studies showed promise that interventions, including provision of a definitive diagnosis, could reduce this cost (range 9%-90.7%). No cost-effective treatments were identified. Study comparison was limited by study design and location heterogeneity.

DISCUSSION

FND is associated with a significant use of health care resources, resulting in economic costs to both the patient and the taxpayer and intangible losses. Interventions, including accurate diagnosis, seem to offer an avenue toward reducing these costs.

[Functional Neurological Disorders - A Common but Often Unrecognized Diagnosis]

Functional Neurological Disorders - A Common but Often Unrecognized Diagnosis Abstract: Functional neurological disorders are frequent and diverse in the clinical presentation. Psychological factors are part of the development and perpetuation of symptoms; psychiatric comorbidities may be present, but are not an obligatory diagnostic criterion. The diagnosis is primarily made on the basis of anamnesis and positive clinical signs. The commonness and reversibility of the symptoms should be emphasised in the clinical consultation, and the positive clinical signs should be demonstrated. Science-based explanations as well as the bio-psycho-social model can help patients to understand their diagnosis, which is relevant for a successful therapeutic outcome. It is recommended to use the neutral and descriptive term "functional neurological disorder". Treatment of the potentially reversible disease will be interdisciplinary and multimodal.

Performance of the GAD-7 in adults with dissociative seizures

PURPOSE

Little is known about the accuracy of the GAD-7, a self-report anxiety measure, in detecting generalised anxiety disorder (GAD) in people with dissociative seizures (DS). We evaluated the reliability, validity and uniformity of the GAD-7 using a diagnosis of GAD on the Mini-International Neuropsychiatric Interview as a reference.

METHODS

We assessed 368 adults with DS at the pre-randomisation phase of the CODES trial. Factor analysis for categorical data assessed GAD-7 uniformity. Diagnostic accuracy was assessed by estimating the area under the curve (AUC). We evaluated discriminant validity, reviewed data on convergent validity and calculated internal consistency. We explored correlations between GAD-7 scores and monthly DS frequency, frequency of severe seizures and measures of behavioural and emotional avoidance.

RESULTS

Internal consistency of the GAD-7 was high (α = 0.92). Factor analysis elicited one main factor and general measurement invariance. Diagnostic accuracy was fair (AUC = 0.72) but the best balance of sensitivity and specificity occurred at a cut-off of ≥12 and still had a specificity rate of only 68%. Discriminant and convergent validity were good. GAD-7 scores correlated positively with DS frequency, severe seizure frequency, behavioural and emotional avoidance (all p < 0.001).

CONCLUSION

Findings regarding internal consistency and factor structure parallel previous psychometric evaluations of the GAD-7. Correlations between GAD-7 scores and DS occurrence/severity and avoidance are evidence of the concept validity of GAD-7 and provide further support for a fear-avoidance treatment model for DS. However, the utility of the GAD-7 as a diagnostic instrument for generalised anxiety disorder is limited in patients with DS.

Moderators of cognitive behavioural therapy treatment effects and predictors of outcome in the CODES randomised controlled trial for adults with dissociative seizures

OBJECTIVE

We explored moderators of cognitive behavioural therapy (CBT) treatment effects and predictors of outcome at 12-month follow-up in the CODES Trial (N = 368) comparing CBT plus standardised medical care (SMC) vs SMC-alone for dissociative seizures (DS).

METHODS

We undertook moderator analyses of baseline characteristics to determine who had benefited from being offered CBT 12 months post-randomisation. Outcomes included: monthly DS frequency, psychosocial functioning (Work and Social Adjustment Scale - WSAS), and health-related quality of life (Mental Component Summary (MCS) and Physical Component Summary (PCS) SF-12v2 scores). When moderating effects were absent, we tested whether baseline variables predicted change irrespective of treatment allocation.

RESULTS

Moderator analyses revealed greater benefits (p < 0.05) of CBT on DS frequency for participants with more (≥22) symptoms (Modified PHQ-15) or ≥ 1 current (M.I.N.I.-confirmed) comorbid psychiatric diagnosis at baseline. The effect of CBT on PCS scores was moderated by gender; women did better than men in the CBT + SMC group. Predictors of improved outcome included: not receiving disability benefits, lower anxiety and/or depression scores (PCS, MCS, WSAS); shorter duration, younger age at DS onset, employment, fewer symptoms and higher educational qualification (PCS, WSAS); stronger belief in the diagnosis and in CBT as a "logical" treatment (MCS). Some variables that clinically might be expected to moderate/predict outcome (e.g., maladaptive personality traits, confidence in treatment) were not shown to be relevant.

CONCLUSION

Patient complexity interacted with treatment. CBT was more likely to reduce DS frequency in those with greater comorbidity. Other patient characteristics predicted outcome regardless of the received intervention.