Can neurobiological pathogenic mechanisms of depression facilitate the development of seizure disorders?

Druggable genome-wide Mendelian randomization for identifying the role of integrated stress response in therapeutic targets of bipolar disorder

For bipolar disorder (BD), the inconsistency of treatment guidelines and the long phases of pharmacological adjustment remain major challenges. BD is known to be comorbid with many medical and psychiatric conditions and they may share inflammatory and stress-related aetiologies, which could give rise to this association. The integrated stress response (ISR) responds to various stress conditions that lead to alterations in cellular homeostasis. However, as a causative mechanism underlying cognitive deficits and neurodegeneration in a broad range of brain disorders, the impact of ISR on BD is understudied. Mendelian randomization has been widely used to repurpose licensed drugs and discover novel therapeutic targets. Thus, we aimed to identify novel therapeutic targets for BD and analyze their pathophysiological mechanisms, using the summary data-based Mendelian Randomization (SMR) and Bayesian colocalization (COLOC) methods to integrate the summary-level data of the GWAS on BD and the expression quantitative trait locus (eQTL) study in blood. We utilized the GWAS data including 41,917 BD cases and 371,549 controls from the Psychiatric Genomics Consortium and the eQTL data from 31,684 participants of predominantly European ancestry from the eQTLGen consortium. The SMR analysis identified the EIF2B5 gene that was associated with BD due to no linkage but pleiotropy or causality. The COLOC analysis strongly suggested that EIF2B5 and the trait of BD were affected by shared causal variants, and thus were colocalized. Utilizing data in EpiGraphDB we find other putative causal BD genes (EIF2AK4 and GSK3B) to prioritize potential alternative drug targets.

Effect of drug treatment changes and seizure outcomes on depression and suicidality in adults with drug-resistant focal epilepsy

OBJECTIVE

To investigate changes in depressive and suicidality status and their relationship with seizure outcomes after the addition or substitution of another antiseizure medication (ASM) in adults with drug-resistant focal epilepsy.

METHODS

Seven hundred seventy consecutively enrolled patients were assessed and followed prospectively for seizure outcome and depressive status over a 6-month period after starting treatment with a newly introduced ASM. The Neurological Disorders Depression Inventory for Epilepsy (NDDIE) was used to screen for depression and suicidality. Correlations of NDDIE results with clinical and treatment-related variables were assessed by using a stepwise logistic regression model.

RESULTS

At baseline, 50% of patients had a positive screening test result for depression and 13% had a positive screening test result for suicidal ideation. A psychiatric comorbidity at baseline was associated with a 2.3 times increased risk of an initially negative NDDIE screening result becoming positive at re-assessment after 6 months. In addition, the number of ASMs taken at baseline correlated with an increased risk of a change in depression screening test results from negative to positive during follow-up, whereas no association was identified with sociodemographic and epilepsy-related variables, including seizure outcomes. Approximately 6% of patients who were initially negative at screening for suicidal ideation became positive at the 6-month re-assessment. The risk of switch from a negative to a positive screening test result for suicidal ideation was increased more than two-fold in individuals who screened positive for depression at baseline, and was unrelated to the type of ASM introduced, sociodemographic variables, or seizure outcomes.

SIGNIFICANCE

Almost 1 in 5 adults with drug-resistant focal epilepsy who screen negative for depression become positive when re-assessed 6 months after a treatment change. At re-assessment 6 months later, 6.1% who screen initially negative for passive suicidal ideation become positive. These changes in screening status are independent of type of ASM introduced or seizure outcomes but correlate with psychiatric status at baseline.

Efficacy of rTMS for poststroke epilepsy and its effects on patients' cognitive function and depressive status

OBJECTIVE

This study aimed to investigate the efficacy of rTMS in the treatment of poststroke epilepsy and the effect of rTMS on patients' cognitive function and depressive status.

METHODS

One hundred and twenty-one poststroke epilepsy patients with mild cognitive impairment and depressive status admitted to the Department of Neurology of the Second People's Hospital of Nanning from January 1, 2017, to April 31, 2023, were selected and divided into the rTMS treatment group (treated group) and the control group. MMSE scores and HAMD scores were recorded before and after treatment. The frequency of EEG spiky waves recorded before and after treatment within 24 h and the frequency of any clinical seizure form (the number of clinical seizures within 1 month after treatment) and changes in observed indices before and after treatment were calculated. The differences between the data of the two groups were analyzed, to further assess the efficacy of rTMS in the treatment of poststroke epilepsy and the rTMS' effects on cognition and depression.

RESULTS

Compared with drug treatment alone, rTMS significantly decreased clinical seizures and epileptiform discharges after stroke, especially in patients with lesions in the frontal, temporal, and parietal lobes. Compared with drug treatment alone, rTMS treatment can effectively reduce cognitive impairment and mood disorders, such as depression, especially for patients with lesions in the frontal and temporal lobes. The results of this experiment suggest that rTMS treatment does not increase adverse effects.

CONCLUSION

rTMS reduces clinical seizures while improving cognitive impairment and depression in patients with epilepsy. Therefore, we suggest that low-frequency rTMS can be used as an adjunctive treatment for patients with epilepsy and provide some ideas and references for the treatment of epilepsy with cognitive impairment and depression.

Long-term physical and psychiatric morbidities and mortality of untreated, deferred, and immediately treated epilepsy

OBJECTIVE

In Australia, 30% of newly diagnosed epilepsy patients were not immediately treated at diagnosis. We explored health outcomes between patients receiving immediate, deferred, or no treatment, and compared them to the general population.

METHODS

Adults with newly diagnosed epilepsy in Western Australia between 1999 and 2016 were linked with statewide health care data collections. Health care utilization, comorbidity, and mortality at up to 10 years postdiagnosis were compared between patients receiving immediate, deferred, and no treatment, as well as with age- and sex-matched population controls.

RESULTS

Of 603 epilepsy patients (61% male, median age = 40 years) were included, 422 (70%) were treated immediately at diagnosis, 110 (18%) received deferred treatment, and 71 (12%) were untreated at the end of follow-up (median = 6.8 years). Immediately treated patients had a higher 10-year rate of all-cause admissions or emergency department presentations than the untreated (incidence rate ratio [IRR] = 2.0, 95% confidence interval [CI] = 1.4-2.9) and deferred treatment groups (IRR = 1.7, 95% CI = 1.0-2.8). They had similar 10-year risks of mortality and developing new physical and psychiatric comorbidities compared with the deferred and untreated groups. Compared to population controls, epilepsy patients had higher 10-year mortality (hazard ratio = 2.6, 95% CI = 2.1-3.3), hospital admissions (IRR = 2.3, 95% CI = 1.6-3.3), and psychiatric outpatient visits (IRR = 3.2, 95% CI = 1.6-6.3). Patients with epilepsy were also 2.5 (95% CI = 2.1-3.1) and 3.9 (95% CI = 2.6-5.8) times more likely to develop a new physical and psychiatric comorbidity, respectively.

SIGNIFICANCE

Newly diagnosed epilepsy patients with deferred or no treatment did not have worse outcomes than those immediately treated. Instead, immediately treated patients had greater health care utilization, likely reflecting more severe underlying epilepsy etiology. Our findings emphasize the importance of individualizing epilepsy treatment and recognition and management of the significant comorbidities, particularly psychiatric, that ensue following a diagnosis of epilepsy.

Seizure-related stress and arousal responses mediate a relationship between anxiety trait and state in epilepsy

BACKGROUND

Epilepsy causes substantial psychological distress and anxiety, primarily due to seizures. However, the impact of stress responses and changes in arousal and their association with anxiety patterns in patients with epilepsy (PWE) remains unclear. This study aimed to investigate the relationships among seizures, stress and arousal characteristics, and trait and state anxiety characteristics in PWE.

METHODS

Our sample consisted of 159 outpatients with epilepsy recruited from five institutions in Japan in 2020. Participants completed the State-Trait Anxiety Inventory-Form JYZ (STAI) and the Japanese-Stress Arousal Check List (J-SACL). We analyzed the correlations between inventory scores and clinical information. Using principal component analysis (PCA), we derived epilepsy-specific stress/arousal characteristics, which accounted for high arousal and low-stress levels, termed epilepsy-specific stress or arousal response (ESAR), from the J-SACL scores. We conducted a mediation analysis to assess the mediating role of ESAR in the relationship between traits and state anxiety.

RESULTS

We found significant correlations between J-SACL stress and arousal factors (r = -0.845, p < 0.001), ESAR and seizure frequency (r = -0.29, p < 0.001), ESAR and trait anxiety scores on the STAI (r = -0.77, p < 0.0001), and ESAR and state anxiety scores on the STAI (r = -0.60, p < 0.0001). Mediation analysis supported by the Monte Carlo method revealed that ESAR significantly mediated the association between trait and state anxiety.

CONCLUSIONS

These findings elucidate the epilepsy-specific stress and arousal characteristics and their roles in mediating traits and state anxiety. These results may reflect the long-term clinical course and unique emotion recognition tendencies in epilepsy.

Impact of psychiatric comorbidities on the treatment of epilepsies in adults

INTRODUCTION

Epilepsy is often accompanied by psychiatric comorbidities and the management of epilepsy in these patients presents unique challenges due to the interplay between the underlying neurological condition and the psychiatric symptoms and the combined use of multiple medications.

AREAS COVERED

This paper aims to explore the complexities associated with managing epilepsy in the presence of psychiatric comorbidities, focusing on the impact of psychiatric disorders on epilepsy treatment strategies and the challenges posed by the simultaneous administration of multiple medications.

EXPERT OPINION

Patients with epilepsy and psychiatric comorbidities seem to present with a more severe form of epilepsy that is resistant to drug treatments and burdened by an increased morbidity and mortality. Whether prompt treatment of psychiatric disorders can influence the long-term prognosis of the epilepsy is still unclear as well as the role of specific treatment strategies, such as neuromodulation, in this group of patients. Clinical practice recommendations and guidelines will prompt the development of new models of integrated care to be implemented.

Screening of Major Depression Disorder in Patients With Epilepsy in Indonesian National Referral Hospital

Background and Objectives

Major depressive disorder (MDD) is a common psychiatric disorder in patients with epilepsy (PWE). The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) is one of the MDD screening tools used in PWE. This study aims to determine the accuracy of the valid and reliable NDDI-E Indonesian version as an MDD screening tool in PWE and investigate the prevalence and risk factors for the development of MDD in PWE.

Methods

A diagnostic cross-sectional study was conducted at Cipto Mangunkusumo National Referral Hospital, Indonesia. Patients were PWE aged 18 years or older who visited the epilepsy outpatient clinic. The valid and reliable NDDI-E Indonesian version and Mini International Neuropsychiatric Interview (MINI) International Classification of Disease, 10th Revision (ICD-10) were used to diagnose MDD. In phase II of the study, diagnostic accuracy was evaluated using the receiver operative characteristic (ROC) curve method to obtain the area under the curve (AUC) and diagnostic 2 x 2 table to determine the cutoff point, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). During phase III of the study, eligible individuals were screened for MDD using the NDDI-E Indonesian version. Demographic and clinical data were collected. Data analysis was performed using the χ2 test, Mann-Whitney test, and multivariate logistic regression analysis.

Results

A total of 105 individuals were involved, and only 23 of them were found to experience MDD based on MINI ICD-10. The best cutoff point for the NDDI-E Indonesian version was ≥11, with a sensitivity of 91.3%, specificity 89%, PPV 70%, and NPV 97.3%. The AUC obtained from ROC analysis was 97.5% (95% CI 95-99%, p < 0.001). Then, the survey was completed by 79 individuals, predominantly male, mostly within the age range of 26-45 years. The prevalence of MDD in PWE was 50.6%, and the significant risk factors were seizure frequency ≥8 times a year and the presence of chronic diseases (p < 0.001).

Discussion

The NDDI-E Indonesian version was a screening tool with a high diagnostic accuracy to detect MDD in PWE at a cutoff point of 11. Poor seizure control and the presence of other chronic diseases were the risk factors correlated with MDD development in PWE.

Living with Epilepsy in Adolescence in Italy: Psychological and Behavioral Impact

BACKGROUND

People with epilepsy have a higher prevalence of behavioral and neuropsychiatric comorbidities compared to the general population and those with other chronic medical conditions, although the underlying clinical features remain unclear. The goal of the current study was to characterize behavioral profiles of adolescents with epilepsy, assess the presence of psychopathological disorders, and investigate the reciprocal interactions among epilepsy, psychological functioning, and their main clinical variables.

METHODS

Sixty-three adolescents with epilepsy were consecutively recruited at the Epilepsy Center, Childhood and Adolescence Neuropsychiatry Unit of Santi Paolo e Carlo hospital in Milan (five of them were excluded) and assessed with a specific questionnaire for psychopathology in adolescence, such as the Questionnaire for the Assessment of Psychopathology in Adolescence (Q-PAD). Q-PAD results were then correlated with the main clinical data.

RESULTS

55.2% (32/58) of patients presented at least one emotional disturbance. Body dissatisfaction, anxiety, interpersonal conflicts, family problems, uncertainty about the future, and self-esteem/well-being disorders were frequently reported. Gender and poor control of seizures are associated with specific emotional features (p < 0.05).

CONCLUSIONS

These findings highlight the importance of screening for emotional distress, recognition of the impairments, and provision of adequate treatment and follow-up. A pathological score on the Q-PAD should always require the clinician to investigate the presence of behavioral disorders and comorbidities in adolescents with epilepsy.

Contribution of the μ-opioid receptor system to affective disorders in temporal lobe epilepsy: A bidirectional relationship?

OBJECTIVE

Affective disorders are frequent comorbidities of temporal lobe epilepsy (TLE). The endogenous opioid system has been implicated in both epilepsy and affective disorders, and may play a significant role in their bidirectional relationship. In this cross-sectional study, we investigated the association between μ-opioid receptor binding and affective disorders in patients with TLE.

METHODS

Nine patients with TLE and depression/anxiety underwent ¹¹ C-carfentanil positron emission tomography (CFN PET) and neuropsychiatric assessment, including the Hospital Anxiety and Depression Scale and the Positive and Negative Affect Schedule. The normalized CFN PET scans were compared with those of 26 age-matched healthy controls. Correlation analyses with affective symptoms were performed by region of interest-based analysis focusing on the limbic circuit and orbitofrontal cortex.

RESULTS

We observed widely reduced CFN binding potential (BP) in bilateral frontal lobes and striata in patients with TLE compared to healthy controls. In the TLE group, more severe anxiety and negative affect were associated with decreased CFN BP in the posterior cingulate gyrus.

SIGNIFICANCE

In patients with TLE, interictally reduced binding in the opioid system was associated with higher levels of anxiety and negative affect. We speculate that seizure-related agonist-driven desensitization and downregulation of opioid receptors could be a potential underlying pathomechanism.

Increased interictal synchronicity of respiratory related brain pulsations in epilepsy

Respiratory brain pulsations have recently been shown to drive electrophysiological brain activity in patients with epilepsy. Furthermore, functional neuroimaging indicates that respiratory brain pulsations have increased variability and amplitude in patients with epilepsy compared to healthy individuals. To determine whether the respiratory drive is altered in epilepsy, we compared respiratory brain pulsation synchronicity between healthy controls and patients. Whole brain fast functional magnetic resonance imaging was performed on 40 medicated patients with focal epilepsy, 20 drug-naïve patients and 102 healthy controls. Cerebrospinal fluid associated respiratory pulsations were used to generate individual whole brain respiratory synchronization maps, which were compared between groups. Finally, we analyzed the seizure frequency effect and diagnostic accuracy of the respiratory synchronization defect in epilepsy. Respiratory brain pulsations related to the verified fourth ventricle pulsations were significantly more synchronous in patients in frontal, periventricular and mid-temporal regions, while the seizure frequency correlated positively with synchronicity. The respiratory brain synchronicity had a good diagnostic accuracy (ROC_AUC = 0.75) in discriminating controls from medicated patients. The elevated respiratory brain synchronicity in focal epilepsy suggests altered physiological effect of cerebrospinal fluid pulsations possibly linked to regional brain water dynamics involved with interictal brain physiology.

Difficulties in emotion and social support in people with epilepsy: relationship with depression levels

Amaç: Bu çalışmada epilepsili bireylerde depresyon düzeyi ile duygu düzenleme güçlükleri ve sosyal destek arasındaki ilişkiyi incelemeyi amaçladık. Gereç ve Yöntem: Fokal epilepsi tanısı ile takip edilmekte olan hastalara Nörolojik Bozukluklarda Depresyon Ölçeği-Epilepsi (NDDI-E), Duygu Düzenleme Güçlükleri Ölçeği (DDGÖ) ve İki Yönlü Sosyal Destek Ölçeği (2-YSDÖ) verilmiştir. Bulgular: Çalışmaya 109 hasta dahil edilmiştir. Hastaların %25’inde depresyon saptanmıştır. Depresyonu olan olguların DDGÖ median değeri 45 (28-55), depresyon saptanmayan grubun ise 24 (18-33,5)’dür. Depresyonu olan grubun DDGÖ skorunun depresyonu olmayan gruba kıyasla anlamlı derecede yüksek olduğu tespit edilmiştir. Tüm çalışma popülasyonunda yapılan 2-YSDÖ (92 (69,5-102,5)) ve DDGÖ (27 (19-41)) skorlarının korelasyon analizinde sosyal destek ve duygu düzenleme güçlükleri arasında negatif bir ilişki mevcuttur. Regresyon analizine göre ise duygu düzenleme güçlükleri depresyonun ana belirleyicisidir ve depresyonu %16,8 oranında açıklamaktadır. Sonuç: Epilepsili bireylerde duygu düzenleme güçlükleri depresyonun ana belirleyicilerinden biridir ve yetersiz sosyal destek duygu düzenleme güçlükleri ile ilişkilidir. Epilepsili bireylerde depresyon sıklığını azaltmak için duygu düzenleme stratejilerini güçlendirecek rehabilitasyon programlarına ihtiyaç vardır.

Upper cerebellar glucose hypermetabolism in patients with temporal lobe epilepsy and interictal psychosis

OBJECTIVE

Psychosis is an important comorbidity in epilepsy, but its pathophysiology is still unknown. The imaging modality ¹⁸ F-fluorodeoxyglucose-positron emission tomography (¹⁸ F-FDG PET) is widely used to measure brain glucose metabolism, and we speculated that ¹⁸ F-FDG PET may detect characteristic alteration patterns in individuals with temporal lobe epilepsy (TLE) and psychosis.

METHODS

We enrolled 13 patients with TLE and interictal psychosis (TLE-P) and 21 patients with TLE without psychosis (TLE-N). All underwent interictal ¹⁸ F-FDG-PET scanning. Statistical Parametric Mapping (SPM)12 software was used for the normalization process, and we performed a voxel-wise comparison of the TLE-P and TLE-N groups.

RESULTS

Cerebral hypometabolic areas were observed in the ipsilateral temporal pole to hippocampus in both patient groups. In the TLE-P group, the voxel-wise comparison revealed significantly increased ¹⁸ F-FDG signals in the upper cerebellum, superior cerebellar peduncle, and midbrain. There were no significant between-group metabolic differences around the focus or other cerebral areas.

SIGNIFICANCE

Our results demonstrated significant hypermetabolism around the upper cerebellum in patients with TLE and interictal psychosis compared to patients with TLE without psychosis. These findings may reflect the involvement of the cerebellum in the underlying neurobiology of interictal psychosis and could contribute to a better understanding of this disorder.

A complex systems view on the current hypotheses of epilepsy pharmacoresistance

Drug-resistant epilepsy remains to this day as a highly prevalent condition affecting around one-third of patients with epilepsy, despite all the research and the development of several new antiseizure medications (ASMs) over the last decades. Epilepsies are multifactorial complex diseases, commonly associated with psychiatric, neurological, and somatic comorbidities. Thus, to solve the puzzling problem of pharmacoresistance, the diagnosis and modeling of epilepsy and comorbidities need to change toward a complex system approach. In this review, we have summarized the sequence of events for the definition of epilepsies and comorbidities, the search for mechanisms, and the major hypotheses of pharmacoresistance, drawing attention to some of the many converging aspects between the proposed mechanisms, their supporting evidence, and comorbidities-related alterations. The use of systems biology applied to epileptology may lead to the discovery of new targets and the development of new ASMs, as may advance our understanding of the epilepsies and their comorbidities, providing much deeper insight on multidrug pharmacoresistance.

Response to lithium and anticonvulsants among patients with bipolar disorder with and without comorbid epilepsy - A nation-wide population-based longitudinal study

OBJECTIVE

In a nation-wide population-based longitudinal register linkage study for the first time 1) to investigate long-term response to lithium in patients with bipolar disorder with and without comorbid epilepsy, and 2) within patients with bipolar disorder and comorbid epilepsy to compare differences in responses between lithium, valproate and lamotrigine.

METHODS

We used Danish nation-wide population-based longitudinal register linkage to identify 154 patients with bipolar disorder and comorbid epilepsy and 8381 patients with bipolar disorder without comorbid epilepsy during a study period from 1995 to 2017. Response was defined as continuous monotherapy with lithium, valproate or lamotrigine without switch to or add-on of an antipsychotic drug or an antidepressant or hospitalization during an up to ten-year follow-up period. We calculated standardized absolute risks and differences thereof with respect to age, gender, socioeconomic status and comorbidity with other physical disorders than epilepsy.

RESULTS

Response to lithium was decreased in patients with bipolar disorder with versus without comorbid epilepsy during the ten-year follow-up period and the difference remained after standardization for comorbidity with other physical disorders than epilepsy. Within patients with bipolar disorder and comorbid epilepsy, response to lithium was decreased compared with responses to valproate and lamotrigine.

CONCLUSIONS

The findings suggest that valproate and lamotrigine should be given priority in patients with comorbid bipolar disorder and epilepsy. The study highlights the need for closely clinical monitoring and psychological support for patients with bipolar disorder and comorbid epilepsy and emphasize the need for further long-term studies of effect of interventions.

Neuropsychiatric and Cognitive Comorbidities in Epilepsy

PURPOSE OF REVIEW

This article discusses psychiatric and cognitive comorbidities of epilepsy over the lifespan and illustrates opportunities to improve the quality of care of children and adults with epilepsy.

RECENT FINDINGS

One in 3 people with epilepsy have a lifetime history of psychiatric disorders, and they represent an important prognostic marker of epilepsy. Contributors are diverse and display a complex relationship. Cognitive comorbidities are also common among those living with epilepsy and are increasingly recognized as a reflection of changes to underlying brain networks. Among the cognitive comorbidities, intellectual disability and dementia are common and can complicate the diagnostic process when cognitive and/or behavioral features resemble seizures.

SUMMARY

Comorbidities require consideration from the first point of contact with a patient because they can determine the presentation of symptoms, responsiveness to treatment, and the patient's day-to-day functioning and quality of life. In epilepsy, psychiatric and cognitive comorbidities may prove a greater source of disability for the patient and family than the seizures themselves, and in the case of essential comorbidities, they are regarded as core to the disorder in terms of etiology, diagnosis, and treatment.

Neuropsychiatric Treatments for Epilepsy: Nonpharmacological Approaches

Neuropsychiatric conditions are frequently found in patients with epilepsy (PWE). These entities can be as disabling as epilepsy resulting in a significant negative impact on the quality of life of this population if not addressed and treated appropriately. In this article, we provide an overview of non-pharmacological treatments currently available to these patients-and review their effect on mood and anxiety disorders as well as epilepsy. These treatment strategies will allow the practitioner to optimize clinical care during the initial evaluation, which begins with the recognition of the neuropsychiatric condition followed by the appropriate individualized psychotherapeutic approach and/or neuromodulation therapy. To plan a comprehensive treatment for PWE, practitioners must be familiar with these therapeutic tools. Additional clinical research is needed to further create a multidisciplinary team in the assessment and management of neuropsychiatric disorders in PWE.

Beyond Seizure Control: Treating Comorbidities in Epilepsy via Targeting of the P2X7 Receptor

Epilepsy is one of the most common chronic diseases of the central nervous system (CNS). Treatment of epilepsy remains, however, a clinical challenge with over 30% of patients not responding to current pharmacological interventions. Complicating management of treatment, epilepsy comes with multiple comorbidities, thereby further reducing the quality of life of patients. Increasing evidence suggests purinergic signalling via extracellularly released ATP as shared pathological mechanisms across numerous brain diseases. Once released, ATP activates specific purinergic receptors, including the ionotropic P2X7 receptor (P2X7R). Among brain diseases, the P2X7R has attracted particular attention as a therapeutic target. The P2X7R is an important driver of inflammation, and its activation requires high levels of extracellular ATP to be reached under pathological conditions. Suggesting the therapeutic potential of drugs targeting the P2X7R for epilepsy, P2X7R expression increases following status epilepticus and during epilepsy, and P2X7R antagonism modulates seizure severity and epilepsy development. P2X7R antagonism has, however, also been shown to be effective in treating conditions most commonly associated with epilepsy such as psychiatric disorders and cognitive deficits, which suggests that P2X7R antagonisms may provide benefits beyond seizure control. This review summarizes the evidence suggesting drugs targeting the P2X7R as a novel treatment strategy for epilepsy with a particular focus of its potential impact on epilepsy-associated comorbidities.

Parvalbumin Role in Epilepsy and Psychiatric Comorbidities: From Mechanism to Intervention

Parvalbumin is a calcium-binding protein present in inhibitory interneurons that play an essential role in regulating many physiological processes, such as intracellular signaling and synaptic transmission. Changes in parvalbumin expression are deeply related to epilepsy, which is considered one of the most disabling neuropathologies. Epilepsy is a complex multi-factor group of disorders characterized by periods of hypersynchronous activity and hyperexcitability within brain networks. In this scenario, inhibitory neurotransmission dysfunction in modulating excitatory transmission related to the loss of subsets of parvalbumin-expressing inhibitory interneuron may have a prominent role in disrupted excitability. Some studies also reported that parvalbumin-positive interneurons altered function might contribute to psychiatric comorbidities associated with epilepsy, such as depression, anxiety, and psychosis. Understanding the epileptogenic process and comorbidities associated with epilepsy have significantly advanced through preclinical and clinical investigation. In this review, evidence from parvalbumin altered function in epilepsy and associated psychiatric comorbidities were explored with a translational perspective. Some advances in potential therapeutic interventions are highlighted, from current antiepileptic and neuroprotective drugs to cutting edge modulation of parvalbumin subpopulations using optogenetics, designer receptors exclusively activated by designer drugs (DREADD) techniques, transcranial magnetic stimulation, genome engineering, and cell grafting. Creating new perspectives on mechanisms and therapeutic strategies is valuable for understanding the pathophysiology of epilepsy and its psychiatric comorbidities and improving efficiency in clinical intervention.

Response to antidepressants among patients with unipolar depression with and without comorbid epilepsy-a nation-wide population-based longitudinal study

OBJECTIVE

In a nation-wide population-based longitudinal register linkage study to investigate long-term response to antidepressants in patients with depression with and without comorbid epilepsy.

METHODS

We used Danish nation-wide population-based longitudinal register linkage to identify 1487 patients with depression and comorbid epilepsy and 71,163 patients with depression without comorbid epilepsy during a study period from 1995 to 2017. Response was defined as continuous monotherapy with an antidepressant drug without switch to or add-on of another antidepressant drug, an antipsychotic drug or lithium or hospitalization during an up to ten-year follow-up period. We calculated standardized absolute risks and differences thereof with respect to age, gender, socioeconomic status and comorbidity with other physical disorders than epilepsy.

RESULTS

In patients with depression, response to antidepressants was decreased with versus without comorbid epilepsy during the ten-year follow-up period. One year after start of antidepressant treatment the proportion of responders was 12% (CI: 10%-14%) lower in patients with versus without comorbid epilepsy in the standardized population. Response to antidepressants were specifically decreased among younger and unemployed patients with depression and comorbid epilepsy.

LIMITATIONS

We did not include sub-analyses according to subtypes of epilepsy.

CONCLUSIONS

Response to antidepressants was decreased in patients with comorbid epilepsy versus without comorbid epilepsy at all time points during a ten-year follow-up period. The study highlights the need for closely clinical monitoring and psychological support for patients with depression and comorbid epilepsy and emphasize the need for further long-term studies of effect of interventions.

Neurobiological mechanisms of psychosis in epilepsy: Findings from neuroimaging studies

Despite the high prevalence and clinical importance of comorbid psychosis in epilepsy, its neurobiological mechanisms remain understudied. This narrative mini-review aims to provide an overview of recent updates in in vivo neuroimaging studies on psychosis in epilepsy, including structural and diffusion magnetic resonance imaging (MRI) and functional and molecular imaging, and to discuss future directions in this field. While the conventional morphological analysis of structural MRI has provided relatively inconsistent results, advanced methods, including brain network analysis, hippocampal subregion volumetry, and machine learning models, have recently provided novel findings. Diffusion MRI, for example, has revealed a reduction in white matter integrity mainly in the frontal and temporal lobes, as well as a disruption of brain white matter networks. Functional neuroimaging, such as perfusion single-photon emission computed tomography (SPECT) or fluorodeoxyglucose positron emission tomography (FDG-PET), often identifies hyperactivity in various brain regions. The current limitations of these more recent studies may include small and sometimes heterogeneous samples, insufficient control groups, the effects of psychoactive drugs, and the lack of longitudinal analysis. Further investigations are required to establish novel treatments and identify clinical diagnostic or disease-monitoring biomarkers in psychosis in epilepsy.

Bidirectional Relations Among Depression, Migraine, and Epilepsy: Do They Have an Impact on Their Response to Treatment?

The evaluation and treatment of patients with epilepsy is not limited to the type of epilepsy, but it must incorporate the common comorbid neurologic, psychiatric, and medical disorders, as the latter can bare an impact on the course and response to treatment of the seizure disorder and vice versa. In this article we review the bidirectional relations among epilepsy and two of its most common comorbidities, mood disorders and migraine and examine the implications of these relations on the selection of therapies of these three disorders and their response to treatment. We also review the most salient common pathogenic mechanisms that may explain such relations.

Metabolic Brain Network and Surgical Outcome in Temporal Lobe Epilepsy: A Graph Theoretical Study Based on 18F-fluorodeoxyglucose PET

Drug-resistant temporal lobe epilepsy (TLE) is a potential candidate for surgery; however, nearly one-third subjects had a poor surgical prognosis. We studied the underlying neuromechanism related to the surgical prognosis using graph theory based on metabolic brain network. Sixty-four unilateral TLE subjects with preoperative ¹⁸F-fluorodeoxyglucose (FDG) PET scanning were retrospectively enrolled and divided into Ia (Engel class Ia, n = 32) and non-Ia (Engel class Ib-IV, n = 32) groups according to more than 3-year follow-up after unilateral anterior temporal lobectomy (ATL). The metabolic brain network was constructed and the changed metabolic connectivity of Ia and non-Ia was detected compared with 15 matched healthy controls (HCs). Further, the network properties, including small-worldness and global efficiency, were calculated and hub nodes were also identified for the 3 groups respectively. Non-Ia group exhibited increased connectivity between contralateral fusiform gyrus and contralateral lingual gyrus; while Ia showed decreased connectivity mainly among bilateral frontal, temporal and parietal cortex. Graph theoretical analysis revealed that non-Ia group showed increased small-worldness (35%<s < 55%, P ≤ 0.05) compared to HCs; and elevated global efficiency (P = 0.05) and decreased L_p (P = 0.05) compared to Ia group. Ia group showed reduced C_p (55%<s < 63%, P < 0.05) and increased small-worldness (35%<s < 37%, P < 0.05) compared to HCs; Furthermore, disrupted hub nodes distribution pattern with the midcingulate gyrus disappeared, was also found in non-Ia group compared with the Ia group. All those results revealed that elevated network integration and metabolic connectivity, redistributed hub nodes pattern is associated with ongoing postoperative seizures in subjects with intractable TLE.

Individuals who develop drug-resistant epilepsy within a year after initial diagnosis have higher burden of mental and physical diseases one-year prior to epilepsy diagnosis as compared to those whose seizures were controlled during the same interval

INTRODUCTION

Epilepsy is a neurological disease characterized by recurrent, unprovoked seizures and its impact on biological, cognitive, psychological, and social outcomes. An unmet need for finding effective treatment options exists. Identifying medical diagnoses present prior to a diagnosis of epilepsy is an important step in increasing our understanding of how people with epilepsy may respond to therapy, help guide clinicians in managing associated comorbid conditions, and inform future research.

METHODS

A population-based retrospective comparative cohort study was conducted using administrative claims data to explore differences in medical diagnoses prior to an initial diagnosis of epilepsy between patients with and without drug-resistant epilepsy (DRE) identified within one-year post diagnosis by evaluating standardized mean differences between the groups.

RESULTS

A total of 205,183 patients with newly diagnosed epilepsy were identified. Of those, 4.1% (n = 8340) were considered drug resistant one-year post diagnosis. Pain and mood disorders were the common physical and psychiatric diagnoses in both cohorts. Differences between the newly diagnosed epilepsy and DRE cohorts were observed. Patients in the DRE cohort were younger, had more encounters with the healthcare system, and higher burden of disease for both physical (e.g., headache, neuropathy, muscular-skeletal disorders, and traumatic brain injury) and psychiatric diagnoses (e.g., depression, anxiety, bipolar disorder, suicidal thoughts, drug dependency, and sleep disorders).

CONCLUSION

Physical and psychiatric diagnoses are common one year prior to first diagnosis of epilepsy in administrative claims data. Compared to patients without DRE, those who develop DRE within one-year post initial diagnosis demonstrated a higher burden of disease.

PERMIT study: a global pooled analysis study of the effectiveness and tolerability of perampanel in routine clinical practice

The PERaMpanel pooled analysIs of effecTiveness and tolerability (PERMIT) study was a pooled analysis of data from 44 real-world studies from 17 countries, in which people with epilepsy (PWE; focal and generalized) were treated with perampanel (PER). Retention and effectiveness were assessed after 3, 6, and 12 months, and at the last visit (last observation carried forward). Effectiveness assessments included 50% responder rate (≥ 50% reduction in seizure frequency from baseline) and seizure freedom rate (no seizures since at least the prior visit); in PWE with status epilepticus, response was defined as seizures under control. Safety and tolerability were assessed by evaluating adverse events (AEs) and discontinuation due to AEs. The Full Analysis Set included 5193 PWE. Retention, effectiveness and safety/tolerability were assessed in 4721, 4392 and 4617, respectively. Retention on PER treatment at 3, 6, and 12 months was 90.5%, 79.8%, and 64.2%, respectively. Mean retention time on PER treatment was 10.8 months. The 50% responder rate was 58.3% at 12 months and 50.0% at the last visit, and the corresponding seizure freedom rates were 23.2% and 20.5%, respectively; 52.7% of PWE with status epilepticus responded to PER treatment. Overall, 49.9% of PWE reported AEs and the most frequently reported AEs (≥ 5% of PWE) were dizziness/vertigo (15.2%), somnolence (10.6%), irritability (8.4%), and behavioral disorders (5.4%). At 12 months, 17.6% of PWEs had discontinued due to AEs. PERMIT demonstrated that PER is effective and generally well tolerated when used to treat people with focal and/or generalized epilepsy in everyday clinical practice.

ATP and adenosine-Two players in the control of seizures and epilepsy development

Despite continuous advances in understanding the underlying pathogenesis of hyperexcitable networks and lowered seizure thresholds, the treatment of epilepsy remains a clinical challenge. Over one third of patients remain resistant to current pharmacological interventions. Moreover, even when effective in suppressing seizures, current medications are merely symptomatic without significantly altering the course of the disease. Much effort is therefore invested in identifying new treatments with novel mechanisms of action, effective in drug-refractory epilepsy patients, and with the potential to modify disease progression. Compelling evidence has demonstrated that the purines, ATP and adenosine, are key mediators of the epileptogenic process. Extracellular ATP concentrations increase dramatically under pathological conditions, where it functions as a ligand at a host of purinergic receptors. ATP, however, also forms a substrate pool for the production of adenosine, via the action of an array of extracellular ATP degrading enzymes. ATP and adenosine have assumed largely opposite roles in coupling neuronal excitability to energy homeostasis in the brain. This review integrates and critically discusses novel findings regarding how ATP and adenosine control seizures and the development of epilepsy. This includes purine receptor P1 and P2-dependent mechanisms, release and reuptake mechanisms, extracellular and intracellular purine metabolism, and emerging receptor-independent effects of purines. Finally, possible purine-based therapeutic strategies for seizure suppression and disease modification are discussed.

Divergent Anatomical Correlates and Functional Network Connectivity Patterns in Temporal Lobe Epilepsy with and Without Depression

Epilepsy and depression were proposed to facilitate each other reciprocally through common neurobiological anomalies, especially the prefrontal-limbic-subcortical abnormalities. Yet neuroimaging patterns of higher-order cognitive networks and neuroanatomical correlates were rarely compared in temporal lobe epilepsy patients with (TLE-D) and without depression (TLE-N). We collected T1-weighted structural and resting-state functional MRI data from 20 TLE-D, 31 TLE-N and 20 healthy controls (HCs) and performed analyses including hippocampal volume (HCV), cortical thickness, gray matter volume (GMV) and whole-brain functional network connectivity (FNC) across three groups. Imaging differences were related to clinical and psychological measurements. TLE-D demonstrated disrupted functional role of subcortical (SUB) and higher-order cognitive networks compared to TLE-N and HCs. In TLE-D, GMV in the right supplementary motor area (SMA) and FNC between the dorsal attention (DAN) and SUB were attenuated compared to TLE-N and HCs, FNC between SUB and the visual network (VIS) decreased compared to HCs. GMV in the right SMA was negatively correlated with depression severity and some symptoms. Combined, explicit emotion regulation may be impaired in TLE-D. Meanwhile, compared to HCs, TLE-N showed smaller HCVs, TLE-D and TLE-N showed smaller GMV in the medial orbital frontal gyrus and right hippocampus and hippocampal gyrus, possibly implying predisposition of epileptic activities to co-morbid depression. Our findings suggest distinct anatomical and FNC patterns in TLE-D and TLE-N. More than prefrontal-limbic-subcortical anomalies, disrupted higher-order cognitive network may contribute to depression in TLE, providing new potential treatment targets for depression and calling attention to relation between cognitive dysfunction and co-morbid depression.

Maternal behavior and the neonatal HPA axis in the Wistar Audiogenic Rat (WAR) strain: Early-life implications for a genetic animal model in epilepsy

Epileptogenesis is a multistage process and seizure susceptibility can be influenced by stress early in life. Wistar Audiogenic Rat (WAR) strain is an interesting model to study the association between stress and epilepsy, since it is naturally susceptible to seizures and present changes in the hypothalamus-pituitary-adrenal (HPA) axis activity. All these features are related to the pathogenic mechanisms usually associated with psychiatric comorbidities present in epilepsy. Therefore, the current study aimed to evaluate the neonate HPA axis function and maternal care under control and stress conditions in the WAR strain. Maternal behavior and neonate HPA axis were evaluated in Wistar and WAR strains under rest and after the presence of stressors. We observed that WAR pups present higher plasmatic corticosterone concentration as compared to Wistar pups. Although WAR dams do not show significant altered maternal behavior at rest, there is a higher latency to recover the litter in the pup retrieval test, while some did not recover all the litter. Wistar Audiogenic Rat dams presented similar behaviors to Wistar dams to a female intruder and maternal care with the pups in the maternal defense test. Taken together, these findings indicate that the WAR strain could show HPA axis disruption early in life and dams present altered maternal behavior under stressful events. Those alterations make the WAR strain an interesting model to evaluate vulnerability to epilepsy and its associated neuropsychiatric comorbidities.

Epilepsy Associated Depression: An Update on Current Scenario, Suggested Mechanisms, and Opportunities

Depression is one of the most frequent psychiatric comorbidities associated with epilepsy having a major impact on the patient's quality of life. Several screening tools are available to identify and follow up psychiatric disorders in epilepsy. Out of various psychiatric disorders, people with epilepsy (PWE) are at greater risk of developing depression. This bidirectional relationship further hinders pharmacotherapy of comorbid depression in PWE as some antiepileptic drugs (AEDs) worsen associated depression and coadministration of existing antidepressants (ADs) to alleviate comorbid depression has been reported to worsen seizures. Selective serotonin reuptake inhibitors (SSRIs) and selective serotonin and norepinephrine reuptake inhibitors (SNRIs) are first choice of ADs and are considered safe in PWE, but there are no high-quality evidences. Similar to observations in people with depression, PWE also showed pharmacoresistant to available SSRI/SNRIs, which further complicates the disease prognosis. Randomized double-blind placebo-controlled clinical trials are necessary to report efficacy and safety of available ADs in PWE. We should also move beyond ADs, and therefore, we reviewed common pathological mechanisms such as neuroinflammation, dysregulated hypothalamus pituitary adrenal (HPA) axis, altered neurogenesis, and altered tryptophan metabolism responsible for coexistent relationship of epilepsy and depression. Based on these common pertinent pathways involved in the genesis of epilepsy and depression, we suggested novel targets and therapeutic approaches for safe management of comorbid depression in epilepsy.

A systematic review of neuroimaging studies of depression in adults with epilepsy

OBJECTIVE

Depression is a relatively common comorbidity in people with epilepsy with a lifetime history identified in 1 in 4 individuals. In this paper, we aimed to provide a systematic review of structural and functional brain region-specific group differences of adults with epilepsy and depression and to discuss existing evidence as compared to that in people with depression.

METHODS

We undertook a systematic review of neuroimaging studies of depression in adults with epilepsy through MEDLINE/PubMed, Embase and PsycInfo searches until June 2020.

RESULTS

A total of 44 studies were included in the qualitative synthesis: 21 on structural neuroimaging, 9 on functional, and 14 on pharmaco/metabolic neuroimaging. Almost all studies focused on temporal lobe epilepsy (TLE). Patterns of changes in the hippocampi and subcortical structures seem to be different from those reported in depression outside epilepsy. Cortical changes are grossly similar as well as the lack of any laterality effect. Serotonin dysfunction seems to be due to different mechanisms with reduced synaptic availability for depression in epilepsy as compared to reduced 5HT1 receptor density outside epilepsy. Depressive symptoms seem to correlate with a dysfunction in temporolimbic structures contralateral to the epileptogenic zone especially in patients with de novo postsurgical depression.

CONCLUSIONS

Depression, at least in TLE, seems to be associated with a different pattern of brain changes as compared to major depression, potentially supporting the notion of phenomenological peculiarities of depression in epilepsy.

Fatigue and cognitive functions in epilepsy: A review of the literature

Epilepsy is a common neurological disorder affecting people of all ages and inducing cognitive impairments. While research has advanced in terms of neuropsychological enquiries of the various epileptic syndromes, the understanding of more complex and ill-defined phenomena such as fatigue is still unclear for epilepsy. It is suggested that fatigue is not just physical, but there can also be a cognitive element to it. Although studies in other conditions have been able to identify a relationship between fatigue and particular cognitive components, similar evidence is sparse in patients with epilepsy. This review is an attempt to gather, analyze, integrate, and critically discuss available information on fatigue and its rapport with various aspects of epilepsy, particularly focusing on cognition. Future directions are discussed urging researchers to target cognitive components of fatigue.

Disrupted White Matter Integrity and Structural Brain Networks in Temporal Lobe Epilepsy With and Without Interictal Psychosis

Background: Despite the importance of psychosis as a comorbidity of temporal lobe epilepsy (TLE), the underlying neural mechanisms are still unclear. We aimed to investigate abnormalities specific to psychosis in TLE, using diffusion MRI parameters and graph-theoretical network analysis.

Material and Methods: We recruited 49 patients with TLE (20 with and 29 without interictal schizophrenia-like psychosis) and 42 age-/gender-matched healthy controls. We performed 3-tesla MRI scans including 3D T1-weighted imaging and diffusion tensor imaging in all participants. Among the three groups, fractional anisotropy (FA), mean diffusivity (MD), and global network metrics were compared by analyses of covariance. Regional connectivity strength was compared by network-based statistics.

Results: Compared to controls, TLE patients showed significant temporal and extra-temporal changes in FA, and MD, which were more severe and widespread in patients with than without psychosis. We observed distinct differences between TLE patients with and without psychosis in the anterior thalamic radiation (ATR), inferior fronto-occipital fasciculus (IFOF), and inferior longitudinal fasciculus (ILF). Similarly, for network metrics, global, and local efficiency and increased path length were significantly reduced in TLE patients compared to controls, but with more severe changes in TLE with psychosis than without psychosis. Network-based statistics detected significant differences between TLE with and without psychosis mainly involving the left limbic and prefrontal areas.

Conclusion: TLE patients with interictal schizophrenia-like psychosis showed more widespread and severe white matter impairment, involving the ATR, IFOF and ILF, as well as disrupted network connectivity, particularly in the left limbic and prefrontal cortex, than patients without psychosis.

Depression and Anxiety in the Epilepsies: from Bench to Bedside

PURPOSE OF REVIEW

Depression and anxiety substantially contribute to interictal disability in patients with epilepsy (PWE). This review summarizes current studies that shed light on mechanisms of comorbidity.

RECENT FINDINGS

Mounting epidemiological data implicate shared risk factors for anxiety/depression and seizure propensity, but these remain largely elusive and probably vary by epilepsy type. Within PWE, these symptoms appear to be associated with unique genetic, neuropathological, and connectivity profiles. Temporal lobe epilepsy has received enormous emphasis particularly in preclinical studies of comorbidity, where candidate neurobiological mechanisms underlying bidirectionality have been tested without psychopharmacological confounds. Depression and anxiety in epilepsy reflect dysfunction within broadly distributed limbic networks that may be the cause or consequence of epileptogenesis. In refractory epilepsy, seizures and/or certain anticonvulsants may distort central emotional homeostatic mechanisms that perpetually raise seizure risk. Developing future safe and effective combined anticonvulsant-antidepressant treatments will require a detailed understanding of anatomical and molecular nodes that pleiotropically enhance seizure risk and negatively alter emotionality.

Respiratory-related brain pulsations are increased in epilepsy-a two-centre functional MRI study

Resting-state functional MRI has shown potential for detecting changes in cerebral blood oxygen level-dependent signal in patients with epilepsy, even in the absence of epileptiform activity. Furthermore, it has been suggested that coefficient of variation mapping of fast functional MRI signal may provide a powerful tool for the identification of intrinsic brain pulsations in neurological diseases such as dementia, stroke and epilepsy. In this study, we used fast functional MRI sequence (magnetic resonance encephalography) to acquire ten whole-brain images per second. We used the functional MRI data to compare physiological brain pulsations between healthy controls (n = 102) and patients with epilepsy (n = 33) and furthermore to drug-naive seizure patients (n = 9). Analyses were performed by calculating coefficient of variation and spectral power in full band and filtered sub-bands. Brain pulsations in the respiratory-related frequency sub-band (0.11-0.51 Hz) were significantly (P < 0.05) increased in patients with epilepsy, with an increase in both signal variance and power. At the individual level, over 80% of medicated and drug-naive seizure patients exhibited areas of abnormal brain signal power that correlated well with the known clinical diagnosis, while none of the controls showed signs of abnormality with the same threshold. The differences were most apparent in the basal brain structures, respiratory centres of brain stem, midbrain and temporal lobes. Notably, full-band, very low frequency (0.01-0.1 Hz) and cardiovascular (0.8-1.76 Hz) brain pulses showed no differences between groups. This study extends and confirms our previous results of abnormal fast functional MRI signal variance in epilepsy patients. Only respiratory-related brain pulsations were clearly increased with no changes in either physiological cardiorespiratory rates or head motion between the subjects. The regional alterations in brain pulsations suggest that mechanisms driving the cerebrospinal fluid homeostasis may be altered in epilepsy. Magnetic resonance encephalography has both increased sensitivity and high specificity for detecting the increased brain pulsations, particularly in times when other tools for locating epileptogenic areas remain inconclusive.

Depressive symptoms and difficulties in emotion regulation in adult patients with epilepsy: Association with quality of life and stigma

OBJECTIVE

The objective of the study was to assess depressive symptoms (DS) and difficulties in emotion regulation (ER) in adult people with epilepsy (PWE) and their correlation with quality of life and stigmatization feelings of patients.

MATERIALS AND METHODS

We enrolled consecutively 110 PWE who completed the Beck Depression Inventory-II (BDI-II) questionnaire and, for the first time, the Italian translation of Difficulties in Emotion Regulation Scale (DERS) to evaluate DS and ER. They also fulfilled the Italian version of the Stigma Scale of Epilepsy (SSE), which allowed the quantification of the stigma perception by our cohort of patients and a 3-item Jacoby's Stigma Scale (JSS) and QOLIE-31 (Q31) for the evaluation of stigma and the quality of life. The results of BDI-II and DERS were correlated with clinical details of PWE, as well as the Q31 and SSE scores. Finally, a multiple stepwise regression analysis was applied to identify the main factors affecting DS and ER difficulties in these patients.

RESULTS

About 30% of PWE evidenced DS, of which 17.3% showed a BDI-II score higher than 19, suggestive of moderate to severe DS. Several factors related to epilepsy (seizure frequency, number of antiepileptic drugs (AEDs)) as well as ER and quality of life/stigmatization perception resulted significantly correlated with DS. As a new finding, the main factors affecting DS in PWE turned out to be the difficulties in ER and quality of life and stigma perception (as evaluated through Q31 and JSS scores).

CONCLUSIONS

Our findings evidenced that DS in PWE are highly prevalent and strongly correlated with ER difficulties that mostly influence DS together with quality of life and stigma perception. Depressive symptoms and emotion dysregulation are linked by a bidirectional relationship and are significantly associated with worse quality of life and higher stigmatization feelings.

The Progress in Diagnosis and Treatment of Exosomes and MicroRNAs on Epileptic Comorbidity Depression

The occurrence of epilepsy can increase the incidence of depression, and the risk of epilepsy in the patients with depression is also high, both of which have an adverse effect on the life and the psychology of the patient, which is not conducive to the prognosis of the patients with epilepsy. With lucubrating the function of exosomes and microRNAs, some scholars found that the exosomes and its microRNAs have development prospect in the diagnosis and treatment of the disease. MicroRNAs are involved in the regulation of seizures and depression, as biomarkers, that can significantly improve the management of epileptic patients and play a preventive role in the occurrence of epilepsy and epilepsy depressive disorder. Moreover, due to its regulation to genes, appropriate application of microRNAs may have therapeutic effect on epilepsy and depression with the characteristics of long distance transmission and stability of exosomes, to a certain extent. This provides a great convenience for the diagnosis and treatment of epileptic comorbidity depression.

Epilepsy Benchmarks Area I: Understanding the Causes of the Epilepsies and Epilepsy-Related Neurologic, Psychiatric, and Somatic Conditions

The 2014 NINDS Benchmarks for Epilepsy Research included area I: Understand the causes of the epilepsies and epilepsy-related neurologic, psychiatric, and somatic conditions. In preparation for the 2020 Curing Epilepsies Conference, where the Benchmarks will be revised, this review will cover scientific progress toward that Benchmark, with emphasize on studies since 2016.

Mechanisms of Psychiatric Comorbidities in Epilepsy

Psychiatric illnesses, including depression and anxiety, are highly comorbid with epilepsy (for review see Josephson and Jetté (Int Rev Psychiatry 29:409-424, 2017), Salpekar and Mula (Epilepsy Behav 98:293-297, 2019)). Psychiatric comorbidities negatively impact the quality of life of patients (Johnson et al., Epilepsia 45:544-550, 2004; Cramer et al., Epilepsy Behav 4:515-521, 2003) and present a significant challenge to treating patients with epilepsy (Hitiris et al., Epilepsy Res 75:192-196, 2007; Petrovski et al., Neurology 75:1015-1021, 2010; Fazel et al., Lancet 382:1646-1654, 2013) (for review see Kanner (Seizure 49:79-82, 2017)). It has long been acknowledged that there is an association between psychiatric illnesses and epilepsy. Hippocrates, in the fourth-fifth century B.C., considered epilepsy and melancholia to be closely related in which he writes that "melancholics ordinarily become epileptics, and epileptics, melancholics" (Lewis, J Ment Sci 80:1-42, 1934). The Babylonians also recognized the frequency of psychosis in patients with epilepsy (Reynolds and Kinnier Wilson, Epilepsia 49:1488-1490, 2008). Despite the fact that the relationship between psychiatric comorbidities and epilepsy has been recognized for thousands of years, psychiatric illnesses in people with epilepsy still commonly go undiagnosed and untreated (Hermann et al., Epilepsia 41(Suppl 2):S31-S41, 2000) and systematic research in this area is still lacking (Devinsky, Epilepsy Behav 4(Suppl 4):S2-S10, 2003). Thus, although it is clear that these are not new issues, there is a need for improvements in the screening and management of patients with psychiatric comorbidities in epilepsy (Lopez et al., Epilepsy Behav 98:302-305, 2019) and progress is needed to understand the underlying neurobiology contributing to these comorbid conditions. To that end, this chapter will raise awareness regarding the scope of the problem as it relates to comorbid psychiatric illnesses and epilepsy and review our current understanding of the potential mechanisms contributing to these comorbidities, focusing on both basic science and clinical research findings.

Factors for cognitive impairment in adult epileptic patients

OBJECTIVE

To analyze factors for cognitive impairment in epileptic patients.

METHODS

A total of 257 epileptic patients completed clinical memory scale (CMS) and 70 of them were further surveyed with mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA), digital symbol test (DSy), verbal fluency test, digit span test (DSp), Hamilton anxiety scale (HAMA) and Hamilton depression scale (HAMD). Monadic linear related analysis and multiple stepwise regression analysis were performed to evaluate the potential factors for cognitive impairment.

RESULTS

Educational level was correlated with scores of cognitive tests (p < .01), with a difference between the junior high school group and senior high school group (p < .01 or p < .05). Seizure frequency was negatively correlated with CMS scores (p < .01), with a difference between the group with a seizure frequency of less than once a year and other groups (p < .01). The kind of antiepileptic drugs (AEDs) was negatively correlated with CMS scores (p < .01), with a difference between the single-drug group and the group taking more than two kinds of AEDs (p < .01). Depression scores were negatively correlated with MMSE, MoCA, DSy, DSp (p < .01 or p < .05), disease duration negatively with DSy (p < .01), and age negatively with MoCA (p < .05). Seizure type was correlated with DSy, and general seizure fared worse in the tests than other seizure types (p < .05).

CONCLUSION

Educational level, seizure frequency, kinds of AEDs and depression can affect the cognitive function of epileptic patients. High educational level, good seizure control, single-drug treatment and healthy psychological state are protective factors for cognitive function of epileptic patients.

Psychiatric aspects of posttraumatic epilepsy: A still unexplored area

Traumatic brain injury (TBI) represents one of the most common causes of death and disability in young people, and posttraumatic epilepsy (PTE) accounts for 10% to 20% of all symptomatic epilepsies. However, PTE is still a relatively underappreciated condition. This paper aimed at reviewing current knowledge about psychiatric comorbidities of PTE, looking in particular at the nature of the relationship between TBI, psychiatric problems, and epilepsy, at the phenomenology of psychiatric disorders in PTE, and how to manage them. Data on psychiatric comorbidities of PTE are almost nonexistent, and this is a paradox considering that TBI itself is burdened by a number of cognitive and psychiatric sequelae, which can profoundly affect the everyday life of these patients. Preliminary data seem to suggest that the bidirectional relationship between epilepsy and psychiatric disorders is maintained in TBI and people with a psychiatric condition at the time of the TBI, or as a consequence of it, are at increased risk of developing PTE and vice versa. However, a number of questions are still unanswered concerning the genetic and environmental contributors, the phenomenology of psychiatric disorders in PTE, and how to prevent and address them properly. Further research in this area is urgently needed in order to provide the best possible care to people with PTE. Special Issue: Epilepsy & Behavior's 20th Anniversary.

Neurobiologic properties of mood disorders may have an impact on epilepsy: Should this motivate neurologists to screen for this psychiatric comorbidity in these patients?

Epilepsy and psychiatric comorbidities have a complex relation, which can be manifested by their relatively high comorbid occurrence and the existence of a bidirectional relation, whereby not only are people with epilepsy (PWE) at greater risk of developing psychiatric disorders, but patients with primary psychiatric disorders are at higher risk of developing epilepsy. The existence of common pathogenic mechanisms operant in primary psychiatric disorders and epilepsy has been postulated as one of the leading hypothesis to explain their close and very complex relation. The neurobiologic characteristics of mood disorders can be used as a model to test this hypothesis. In this manuscript, we highlight data that suggest how several neurobiologic aspects of mood disorders can facilitate the epileptogenic process in animal models and explain the increased risk of patients with primary mood disorders to develop epilepsy in general and treatment-resistant epilepsy in particular. It is our hope that the inclusion of these data in this Special Issue will motivate neurologists to screen common psychiatric comorbidities in PWE. This article is part of the Special Issue "Obstacles of Treatment of Psychiatric Comorbidities in Epilepsy".

Cognitive impairment in the WAG/Rij rat absence model is secondary to absence seizures and depressive-like behavior

Neuropsychiatric comorbidities are common in patients with epilepsy, remaining still an urgent unmet clinical need. Therefore, the management of epileptic disorders should not only be restricted to the achievement of seizure-freedom but must also be able to counteract its related comorbidities. Experimental animal models of epilepsy represent a valid tool not only to study epilepsy but also its associated comorbidities. The WAG/Rij rat is a well-established genetically-based model of absence epilepsy with depressive-like comorbidity, in which learning and memory impairment was also recently reported. Aim of this study was to clarify whether this cognitive decline is secondary or not to absence seizures and/or depressive-like behavior. The behavioral performance of untreated and ethosuximide-treated (300 mg/kg/day; 17 days) WAG/Rij rats at 6 and 12 months of age were assessed in several tests: forced swimming test, objects recognition test, social recognition test, Morris water maze and passive avoidance. According to our results, it seems that cognitive impairment in this strain, similarly to depressive-like behavior, is secondary to the occurrence of absence seizures, which might be necessary for the expression of cognitive impairment. Furthermore, our results suggest an age-dependent impairment of cognitive performance in WAG/Rij rats, which could be linked to the age-dependent increase of spike wave discharges. Consistently, it is possible that absence seizures, depressive-like behavior and cognitive deficit may arise independently and separately in lifetime from the same underlying network disease, as previously suggested for the behavioral features associated with other epileptic syndromes.

The effect of fluoxetine on penicillin-induced epileptiform activity

AIM

Depression is the most frequent psychiatric comorbidity in patients with epilepsy. Fluoxetine is the most widely used selective serotonin reuptake inhibitor (SSRI) in depression. The aim of the present study was to evaluate the dose-dependent effect of fluoxetine on penicillin-induced seizure by electrocorticogram (ECoG), a model for simple partial epilepsy.

METHOD

The epileptiform activity was induced by intracortical (i.c.) microinjection of penicillin into the left sensorimotor cortex. Thirty minutes after penicillin injection, 5, 10, or 20 mg/kg doses of fluoxetine were administered intraperitoneally (i.p.). An ECoG recording was performed for 180 min using the data acquisition system. The frequency and the amplitude of the epileptiform activity were analyzed.

RESULTS

Penicillin induced bilateral spikes and spike-wave complexes within 2-5 min. The 5 and 10 mg/kg doses of fluoxetine significantly reduced the frequency (58%, p < 0.05 and 69%, p < 0.01, 40 and 50 min after fluoxetine injection, respectively) and amplitude (60%, p < 0.01 and 73%, p < 0.05, 40 and 120 min after fluoxetine injection, respectively) of epileptiform activity compared with penicillin-induced seizure group (control). Five-milligram fluoxetine (i.p.) was the most effective dose to decrease frequency and amplitude on penicillin-induced epileptiform activity. However, a higher fluoxetine dose (20 mg/kg) significantly increased frequency (147%, p < 0.01) and amplitude (123%, p < 0.05) of epileptiform activity 40 and 120 min after fluoxetine administration compared with control group. Also, bursts of population spikes were seen in 20 mg/kg fluoxetine doses.

CONCLUSION

Results of the present study indicate that low and moderate fluoxetine doses have an anticonvulsant effect while high doses have proconvulsant effect on penicillin-induced epileptic activity.

Developments in depression in epilepsy: screening, diagnosis, and treatment

INTRODUCTION

Depression is one of the most frequent comorbidities in epilepsy affecting between 17% and 22% of patients, but it is still underdiagnosed and undertreated. Areas covered: This paper discusses recent advances about screening, diagnosis, and treatment of depression in epilepsy taking into account the heterogeneity of clinical scenarios where depression can occur. Expert opinion: A number of screening instruments are now validated for adults with epilepsy, and their psychometric properties are discussed but the NDDI-E is the most practical and cost-effective. Challenges in diagnosing depression in epilepsy are discussed including reasons for the atypical features of mood disorders in epilepsy. Psychological treatments and/or SSRIs are indicated, but the level of evidence is still low. Even if there is no reason to hypothesise that internationally accepted guidelines of treatment of depression outside epilepsy may not be valid, rigorous studies are needed in order to have proper outcome measures. Epilepsy centers should have well-defined care pathways for depression in order to provide access to mental health support when needed.

Prevalence of psychiatric disorders in Thai patients with epilepsy

BACKGROUND

Many studies have shown that the prevalence of psychiatric disorders in patients with epilepsy (PWE) appears higher than that in general population. However, most epidemiological studies regarding psychiatric comorbidities among PWE were conducted in Western countries. This work aimed to determine the prevalence of psychiatric disorders in Thai PWE, including potential variables that could be associated with psychiatric disorders.

METHODS

A cross-sectional study was conducted at Ramathibodi Hospital. A total of 170 patients (aged 18 years or older) diagnosed as having epilepsy by a neurologist were recruited at the outpatient neurology clinic. Demographic and clinical characteristics were collected. Participants were evaluated for any psychiatric disorders according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, using a structured diagnostic interview. The prevalence of psychiatric disorders was determined. The associations between potential variables and the presence of psychiatric disorders in PWE were analyzed using chi-square or Fisher's exact tests, t-test, and logistic regression.

RESULTS

Among 170 patients, 43 (25.3%) fulfilled diagnostic criteria for one or more psychiatric disorders. The prevalence of depressive disorders was shown to be highest at 17.1%, followed by psychotic disorders (8.2%), bipolar disorder (7.1%), anxiety disorders (5.3%), and obsessive-compulsive disorder (OCD) (2.9%). Electroencephalogram (EEG) abnormalities in the temporal lobe was found to be a significant predictor of having psychiatric disorders in PWE (adjusted odds ratio (OR): 4.01, 95% confidence interval (CI): 1.47-10.92, P-value = 0.007).

CONCLUSIONS

The prevalence of psychiatric disorders among Thai PWE was higher than that in general population. Screening for psychiatric disorders in PWE is recommended, especially among those who have EEG abnormalities in the temporal lobe.

Validation of the Chinese version of the Hamilton Rating Scale for Depression in adults with epilepsy

OBJECTIVE

This study aimed to validate the Chinese version of the 17-item Hamilton Rating Scale for Depression (C-HRSD-17) for use in adult patients with epilepsy (PWE).

METHODS

A consecutive sample of Chinese adult PWE from a tertiary hospital was examined using the C-HRSD-17 and the Mini International Neuropsychiatric Interview (MINI) Plus Chinese Version 5.0.0.

RESULTS

A total of 191 PWE completed the assessment of depression. According to the MINI, thirty patients (15.7%) had current major depressive disorder (MDD). The Cronbach's α coefficient for the C-HRSD-17 was 0.832. Receiver operating characteristic (ROC) analysis showed an area under the curve (AUC) of 0.983 (95% CI = 0.968-0.998). With a cutoff score of 9, the C-HRSD-17 demonstrated the best psychometric properties, with a sensitivity of 96.7%, a specificity of 93.8%, a positive predictive value (PPV) of 74.4%, and a negative predictive value (NPV) of 99.3%.

CONCLUSION

The C-HRSD-17 proved to be a valid and reliable assessment tool, with a cutoff score of 9 for screening of current MDD in Chinese adult PWE.

Bidirectional relations among common psychiatric and neurologic comorbidities and epilepsy: Do they have an impact on the course of the seizure disorder?

The treatment of epilepsy is not limited to the achievement of a seizure‐free state. It must also incorporate the management of common psychiatric and neurologic comorbidities, affecting on average between 30 and 50% of patients with epilepsy, which have a significant impact on their lives at various levels, including quality of life and the prognosis of the seizure disorder. Mood and anxiety disorders are the most frequent psychiatric comorbidities, whereas stroke and migraine are among the more common neurologic comorbidities, migraine among the younger patients and stroke among the older patients. Not only do these psychiatric and neurologic comorbidities each have a bidirectional relation with epilepsy, but primary mood disorders have a bidirectional relation with these 2 neurologic disorders. Furthermore, depression and migraine have been each associated with a more severe epilepsy course, whereas depression has been associated with a more severe course of stroke and migraines. The purpose of this article is to review the clinical implications of the complex relations among epilepsy and these 3 comorbid disorders, and to identify any clinical and/or experimental evidence that may suggest that having more than one of these comorbid disorders may increase the risk of and course of epilepsy.

Current and emerging drug therapies for the treatment of depression in adults with epilepsy

INTRODUCTION

Depression is the most frequent psychiatric comorbidity among people with epilepsy. It can impact on quality of life and increases the risk of morbidity and premature mortality.

AREAS COVERED

The authors review the available data on current and emerging drug treatments for depression in epilepsy. Sources have been identified through Medline/PubMed searches while ongoing clinical trials have been identified through a ClinicalTrials.gov search

EXPERT OPINION

SSRIs are the drug class with the largest amount of data. Though promising, the level of evidence provided by these studies is still low as the majority have relevant methodological limitations. Antiepileptic drugs under development have the unique opportunity to be of multi-use in the treatment of epilepsy and depression. The serotoninergic system has already been identified as a potential area of interest, but new targets are still needed in epilepsy and depression. For this reason, it is important that basic scientists working on these two conditions develop collaborative projects and integrate findings.