Genetic variation in dopaminergic activity is associated with the risk for psychiatric side effects of levetiracetam

Sex Differences in Adverse Effects of Antiseizure Medications in Adults with Epilepsy: A Systematic Review

BACKGROUND

Sex differences in epilepsy have been described in prevalence, seizure propensity and response to treatment. Therefore, taking into account sex-based differences in epilepsy is important for both diagnostic purposes and therapeutic considerations. However, little is known about sex differences in adverse effects of antiseizure medications (ASMs).

OBJECTIVES

We performed a systematic review searching for sex differences in adverse effects of ASMs in adult persons with epilepsy (PWE) as part of a wider project aimed to assess sex-based differences in efficacy and adverse effects of ASMs in PWE.

METHODS

We conducted a comprehensive literature search in the PubMed database. The search was conducted with no restriction on publication date, and all results up to April 2020 were included. We included articles written in English, Italian, Spanish, or French that evaluated adverse effects of one or more ASMs in PWE, with specific mention of the two sexes. When appropriate, Newcastle-Ottawa or Jadad scales were used to assess study quality.

RESULTS

Of 5164 identified studies, only 167 considered sex in the analysis and were therefore included. Significant sex-related differences were found in 58 of those studies. We found a consistently higher frequency of cutaneous adverse effects in females; higher risk of developing general adverse effects on different ASMs in females; stronger risk of adverse effects on bone metabolism in females, mainly on treatment with enzyme-inducing ASMs; a concordant higher risk of visual field loss was noted in males on vigabatrin; an overall worse lipid profile in males; as well as higher leptin levels and higher body mass index in females treated with various ASMs.

CONCLUSIONS

Our analysis has identified some important sex differences in the adverse effects of ASMs. Clinicians should be aware of these differences when informing patients about the risks associated with ASM treatment in PWE.

Epilepsy and psychosis

Psychotic disorders are eight times more frequent in epilepsy than in the general population. The various clinical syndromes are classified according to their chronology of onset in relation to epileptic seizures: ictal psychoses (during epileptic discharge), post-ictal psychoses (PIP, after a seizure), interictal psychoses (IIP, with no chronological link) and those related to complete seizure control. Antiepileptic drugs can cause psychotic disorders in all these situations. Post-ictal psychoses (PIP) are affective psychoses that occur after a lucid interval lasting 12 to 120hours following a cluster of seizures. They last an average of 10days, with an abrupt beginning and end. PIP are directly linked to epileptic seizures, and disappear when the epilepsy is controlled. Interictal psychoses are schizophrenias. The management of psychotic disorders in epilepsy is neuropsychiatric, and requires close collaboration between epileptologists and psychiatrists. Antipsychotics can be prescribed in persons with epilepsy. Even today, psychotic disorders in epilepsy are poorly understood, under-diagnosed and under-treated.

Normalization and cross-sectional validation of an extended Adverse Event Profile (E AEP) in a large cohort of patients with epilepsy

PURPOSE

The Liverpool Adverse Event Profile (L AEP) is commonly used in clinical practice and pharmacological trials for the monitoring of side effects of anti-seizure medication (ASM). However potentially unrelated, additional symptoms and normative data should be considered to put patients´ complaints into perspective.

METHODS

An extended 32-item AEP (E AEP) was given to 537 healthy subjects and 1,605 patients with epilepsy as part of the Bonn ASM side effect registry. The tool was factor-analyzed, corrected for age, gender, and repeated application, and related to drug load and individual substances (with N> 100) on item and scale level (total E AEP and its subscales cognition, dizziness, energy, mood, bodily symptoms, aggression, and sexuality).

RESULTS

Compared to non-normalized results, at item level, between one and two-thirds of responses suggesting impairment were found to be unlikely to be related to ASM treatment after normalization. Binary regression analyses revealed differential effects of medication choice, but also of antidepressants and neuroleptics on complaint domains. The explained variance was better for physical than psychological domains. The results reflect both known drug side effects and indications. Patients´ explicit attribution of problems to their medications barely improved the correlation of the E AEP and treatment parameters.

CONCLUSION

Application of a norm-referenced AEP is highly recommended to avoid overestimation of treatment related problems in patients with epilepsy. It allows evaluation on item and scale level for individuals as well as groups in drug trials. Plausible relations to individual drugs and to drug load can be demonstrated. The explanatory power was better for physical than psychological domains. Drug-related complaint patterns reflect known drug side effects (e.g. perampanel and brivaracetam with aggression) as well as drug indications (e.g. lamotrigine for depression). This is likely to be particularly relevant when side effects may have affected treatment decisions. Longitudinal evaluation with repeated application of the E AEP with changes of drug treatment is in progress.

Drug-induced delusion: A comprehensive overview of the WHO pharmacovigilance database

INTRODUCTION

A number of prescribed medicines have been reported in cases of drug-induced delusion, such as dopaminergic agents or psychostimulants. But to this day, most studies are based on a limited number of cases and focus on a few drug classes, so a clear overview of this topic remains difficult. To address this issue, we provide in this article a comprehensive analysis of drug-induced delusion, based on the World Health Organization (WHO) pharmacovigilance database.

METHODS

We performed a disproportionality analysis of this database using the information component (IC). The IC compares observed and expected values to find associations between drugs and delusion, using disproportionate Bayesian reporting. An IC0.25 (lower end of the IC 95% credibility interval) > 0 is considered statistically significant.

RESULTS

Here we present an analysis of 4559 suspected drug-induced delusion reports in the WHO pharmacovigilance database. These results identified 66 molecules statistically associated with delusion and an extensive analysis of confounding factors and coprescriptions was performed, using full database as background with an IC0.25 > 0. The main drug classes involved were antidepressants, antiepileptics, dopaminergic agents, opioids, antiinfective agents, benzodiazepines, anti-dementia drugs and psychostimulants.

CONCLUSION

These results will help clinicians identify potential suspected drugs associated with delusion and decide which drug to discontinue and eventually lead to a re-evaluation of drug labels for some molecules.

Psychiatric comorbidity in relation to clinical characteristics of epilepsy: A retrospective observational study

PURPOSE

Prevalence of psychiatric disorders in people with epilepsy is high. However, diagnostic validity and information about the nature of the seizure disorders are often poor in population-based studies. In a well validated and classified patient sample, we investigated psychiatric comorbidity according to clinical characteristics.

METHOD

Participants in The Trøndelag Health Study (HUNT) with ≥ 2 diagnostic epilepsy codes during 1987-2019 were identified. Medical records were reviewed, and epilepsy was validated and classified according to ILAE. Psychiatric comorbidity was defined by ICD-codes.

RESULTS

In 448 individuals with epilepsy, 35% had at least one psychiatric disorder (anxiety and related disorders 23%, mood disorders 15%, substance abuse and personality disorders 7%, and psychosis 3%). Comorbidity was significantly higher in women than in men (p = 0.007). The prevalence of psychiatric disorders was 37% in both focal and generalized epilepsy. In focal epilepsy, it was significantly lower when etiology was structural (p = 0.011), whereas it was higher when the cause was unknown (p = 0.024). Comorbidity prevalence was 35% both in patients achieving seizure freedom and in those with active epilepsy but 38% among 73 patients with epilepsy resolved.

CONCLUSION

Just over one third of people with epilepsy had psychiatric comorbidities. The prevalence was equal in focal and generalized epilepsy but was significantly higher in focal epilepsy of unknown cause compared to lesional epilepsy. Comorbidity was independent of seizure control at last follow-up but was slightly more common in those with resolved epilepsy, often having non-acquired genetic etiologies possibly linked to neuropsychiatric susceptibility.

Variation in prognosis and treatment outcome in juvenile myoclonic epilepsy: a Biology of Juvenile Myoclonic Epilepsy Consortium proposal for a practical definition and stratified medicine classifications

Reliable definitions, classifications and prognostic models are the cornerstones of stratified medicine, but none of the current classifications systems in epilepsy address prognostic or outcome issues. Although heterogeneity is widely acknowledged within epilepsy syndromes, the significance of variation in electroclinical features, comorbidities and treatment response, as they relate to diagnostic and prognostic purposes, has not been explored. In this paper, we aim to provide an evidence-based definition of juvenile myoclonic epilepsy showing that with a predefined and limited set of mandatory features, variation in juvenile myoclonic epilepsy phenotype can be exploited for prognostic purposes. Our study is based on clinical data collected by the Biology of Juvenile Myoclonic Epilepsy Consortium augmented by literature data. We review prognosis research on mortality and seizure remission, predictors of antiseizure medication resistance and selected adverse drug events to valproate, levetiracetam and lamotrigine. Based on our analysis, a simplified set of diagnostic criteria for juvenile myoclonic epilepsy includes the following: (i) myoclonic jerks as mandatory seizure type; (ii) a circadian timing for myoclonia not mandatory for the diagnosis of juvenile myoclonic epilepsy; (iii) age of onset ranging from 6 to 40 years; (iv) generalized EEG abnormalities; and (v) intelligence conforming to population distribution. We find sufficient evidence to propose a predictive model of antiseizure medication resistance that emphasises (i) absence seizures as the strongest stratifying factor with regard to antiseizure medication resistance or seizure freedom for both sexes and (ii) sex as a major stratifying factor, revealing elevated odds of antiseizure medication resistance that correlates to self-report of catamenial and stress-related factors including sleep deprivation. In women, there are reduced odds of antiseizure medication resistance associated with EEG-measured or self-reported photosensitivity. In conclusion, by applying a simplified set of criteria to define phenotypic variations of juvenile myoclonic epilepsy, our paper proposes an evidence-based definition and prognostic stratification of juvenile myoclonic epilepsy. Further studies in existing data sets of individual patient data would be helpful to replicate our findings, and prospective studies in inception cohorts will contribute to validate them in real-world practice for juvenile myoclonic epilepsy management.

Levetiracetam, from broad-spectrum use to precision prescription: A narrative review and expert opinion

Levetiracetam (LEV) is an antiseizure medication (ASM) whose mechanism of action involves the modulation of neurotransmitters release through binding to the synaptic vesicle glycoprotein 2A. It is a broad-spectrum ASM displaying favorable pharmacokinetic and tolerability profiles. Since its introduction in 1999, it has been widely prescribed, becoming the first-line treatment for numerous epilepsy syndromes and clinical scenarios. However, this might have resulted in overuse. Increasing evidence, including the recently published SANAD II trials, suggests that other ASMs are reasonable therapeutic options for generalized and focal epilepsies. Not infrequently, these ASMs show better safety and effectiveness profiles compared to LEV (partially due to the latter's well-known cognitive and behavioral adverse effects, present in up to 20% of patients). Moreover, it has been shown that the underlying etiology of epilepsy is significantly linked to ASMs response in particular scenarios, highlighting the importance of an etiology-based ASM choice. In the case of LEV, it has demonstrated an optimal effectiveness in Alzheimer's disease, Down syndrome, and PCDH19-related epilepsies whereas, in other etiologies such as malformations of cortical development, it may show negligible effects. This narrative review analyzes the current evidence related to the use of LEV for the treatment of seizures. Illustrative clinical scenarios and practical decision-making approaches are also addressed, therefore aiming to define a rational use of this ASM.

Association Between Antiepileptic Drugs and Incident Parkinson Disease

Importance

Recent studies have highlighted an association between epilepsy and Parkinson disease (PD). The role of antiepileptic drugs (AEDs) has not been explored.

Objective

To investigate the association between AEDs and incident PD.

Design, Setting, and Participants

This nested case-control study started collecting data from the UK Biobank (UKB) in 2006, and data were extracted on June 30, 2021. Individuals with linked primary care prescription data were included. Cases were defined as individuals with a Hospital Episode Statistics (HES)-coded diagnosis of PD. Controls were matched 6:1 for age, sex, race and ethnicity, and socioeconomic status. Prescription records were searched for AEDs prescribed prior to diagnosis of PD. The UKB is a longitudinal cohort study with more than 500 000 participants; 45% of individuals in the UKB have linked primary care prescription data. Participants living in the UK aged between 40 and 69 years were recruited to the UKB between 2006 and 2010. All participants with UKB-linked primary care prescription data (n = 222 106) were eligible for enrollment in the study. Individuals with only a self-reported PD diagnosis or missing data for the matching variables were excluded. In total, 1477 individuals were excluded; 49 were excluded due to having only self-reported PD, and 1428 were excluded due to missing data.

Exposures

Exposure to AEDs (carbamazepine, lamotrigine, levetiracetam, and sodium valproate) was defined using routinely collected prescription data derived from primary care.

Main Outcomes and Measures

Odds ratios and 95% CIs were calculated using adjusted logistic regression models for individuals prescribed AEDs before the first date of HES-coded diagnosis of PD.

Results

In this case-control study, there were 1433 individuals with an HES-coded PD diagnosis (cases) and 8598 controls in the analysis. Of the 1433 individuals, 873 (60.9%) were male, 1397 (97.5%) had their race and ethnicity recorded as White, and their median age was 71 years (IQR, 65-75 years). An association was found between AED prescriptions and incident PD (odds ratio, 1.80; 95% CI, 1.35-2.40). There was a trend for a greater number of prescription issues and multiple AEDs being associated with a greater risk of PD.

Conclusions and Relevance

This study, the first to systematically look at PD risk in individuals prescribed the most common AEDs, to our knowledge, found evidence of an association between AEDs and incident PD. With the recent literature demonstrating an association between epilepsy and PD, this study provides further insights.

A Systematic Review of Polygenic Models for Predicting Drug Outcomes

Polygenic models have emerged as promising prediction tools for the prediction of complex traits. Currently, the majority of polygenic models are developed in the context of predicting disease risk, but polygenic models may also prove useful in predicting drug outcomes. This study sought to understand how polygenic models incorporating pharmacogenetic variants are being used in the prediction of drug outcomes. A systematic review was conducted with the aim of gaining insights into the methods used to construct polygenic models, as well as their performance in drug outcome prediction. The search uncovered 89 papers that incorporated pharmacogenetic variants in the development of polygenic models. It was found that the most common polygenic models were constructed for drug dosing predictions in anticoagulant therapies (n = 27). While nearly all studies found a significant association with their polygenic model and the investigated drug outcome (93.3%), less than half (47.2%) compared the performance of the polygenic model against clinical predictors, and even fewer (40.4%) sought to validate model predictions in an independent cohort. Additionally, the heterogeneity of reported performance measures makes the comparison of models across studies challenging. These findings highlight key considerations for future work in developing polygenic models in pharmacogenomic research.

A pharmacogenomic assessment of psychiatric adverse drug reactions to levetiracetam

OBJECTIVE

Levetiracetam (LEV) is an effective antiseizure medicine, but 10%-20% of people treated with LEV report psychiatric side-effects, and up to 1% may have psychotic episodes. Pharmacogenomic predictors of these adverse drug reactions (ADRs) have yet to be identified. We sought to determine the contribution of both common and rare genetic variation to psychiatric and behavioral ADRs associated with LEV.

METHODS

This case-control study compared cases of LEV-associated behavioral disorder (n = 149) or psychotic reaction (n = 37) to LEV-exposed people with no history of psychiatric ADRs (n = 920). All samples were of European ancestry. We performed genome-wide association study (GWAS) analysis comparing those with LEV ADRs to controls. We estimated the polygenic risk scores (PRS) for schizophrenia and compared cases with LEV-associated psychotic reaction to controls. Rare variant burden analysis was performed using exome sequence data of cases with psychotic reactions (n = 18) and controls (n = 122).

RESULTS

Univariate GWAS found no significant associations with either LEV-associated behavioural disorder or LEV-psychotic reaction. PRS analysis showed that cases of LEV-associated psychotic reaction had an increased PRS for schizophrenia relative to contr ols (p = .0097, estimate = .4886). The rare-variant analysis found no evidence of an increased burden of rare genetic variants in people who had experienced LEV-associated psychotic reaction relative to controls.

SIGNIFICANCE

The polygenic burden for schizophrenia is a risk factor for LEV-associated psychotic reaction. To assess the clinical utility of PRS as a predictor, it should be tested in an independent and ideally prospective cohort. Larger sample sizes are required for the identification of significant univariate common genetic signals or rare genetic signals associated with psychiatric LEV ADRs.

Effects of antiseizure medications on alternative psychosis and strategies for their application

Forced normalization (FN) is a unique phenomenon that is often seen in the treatment of epilepsy. FN is characterized by abnormal mental behavior and disordered emotions in epilepsy patients despite a significantly improved electroencephalogram and successful seizure control; the occurrence of FN seriously affects patients’ quality of life. The causes of FN include antiseizure medications (ASMs), epilepsy surgery and vagus nerve stimulation, with ASMs being the most common cause. However, with the timely reduction or discontinuation of ASMs and the use of antipsychotic drugs, the overall prognosis is good. Here, we perform an extensive review of the literature pertaining to FN, including its epidemiology, possible mechanisms, clinical features, treatment and prognosis.

Levetiracetam Mechanisms of Action: From Molecules to Systems

Epilepsy is a chronic disease that affects millions of people worldwide. Antiepileptic drugs (AEDs) are used to control seizures. Even though parts of their mechanisms of action are known, there are still components that need to be studied. Therefore, the search for novel drugs, new molecular targets, and a better understanding of the mechanisms of action of existing drugs is still crucial. Levetiracetam (LEV) is an AED that has been shown to be effective in seizure control and is well-tolerable, with a novel mechanism of action through an interaction with the synaptic vesicle protein 2A (SV2A). Moreover, LEV has other molecular targets that involve calcium homeostasis, the GABAergic system, and AMPA receptors among others, that might be integrated into a single mechanism of action that could explain the antiepileptogenic, anti-inflammatory, neuroprotective, and antioxidant properties of LEV. This puts it as a possible multitarget drug with clinical applications other than for epilepsy. According to the above, the objective of this work was to carry out a comprehensive and integrative review of LEV in relation to its clinical uses, structural properties, therapeutical targets, and different molecular, genetic, and systemic action mechanisms in order to consider LEV as a candidate for drug repurposing.

Epilepsy & gambling: Risk factors for problem gambling behaviors in people with epilepsy

OBJECTIVE

Problem gambling results from the complex interaction of neurological factors with psychological, demographic, and socioeconomical influences. The vulnerabilities of people with epilepsy to many of these influences may increase their susceptibility to developing problematic gambling behaviors. The aim of this study was to establish the frequency of gambling participation and the clinical correlates of problem gambling behaviors in people with epilepsy.

METHODS

Lifestyle questions, including the Lie/Bet screening questionnaire were administered to 250 consecutive attendees at a neurology clinic. Valid data were available for 174 adults with epilepsy and 65 adults with other neurological conditions.

RESULTS

With the exception of people with frontal lobe epilepsy (FLE), gambling participation rates in people with epilepsy and those with other neurological conditions were lower than those reported in the general population. While the overall levels of gambling participation were relatively low in this sample, the number of gamblers who responded positively to the lie/bet questionnaire was ten times higher than that seen in the general population, with one in three gamblers in our series reporting signs of escalation. All had epilepsy and were more likely to be taking Levetiracetam or Brivaracetam than the other gamblers in our series. While epilepsy classification was not related to gambling escalation, patients with FLE were overrepresented in this group due to their significantly higher baseline levels of participation in gambling.

CONCLUSIONS

People with FLE may have a heightened vulnerability to developing problem gambling behaviors. The role of the neurological consultation in managing these risks is discussed.

Efficacy and safety of levetiracetam versus (fos)phenytoin for second-line treatment of epilepticus: a meta-analysis of latest randomized controlled trials

OBJECTIVES

To assess the efficiency and safety profiles of levetiracetam and (fos)phenytoin (phenytoin or fosphenytoin) for second-line treatment of seizures by performing a meta-analysis of RCTs.

METHODS

We systematically searched PubMed, Embase, Cochrane, FDA.gov, and ClinicalTrials.gov for RCTs (published before July 31, 2020; no language restrictions). Two independent reviewers screened abstracts and titles against inclusion and exclusion criteria published previously in the PROSPERO: CRD42020202736. Eleven studies fulfilled the established criteria. We assessed pooled data by using a random-effects model. Quality analysis was performed by using version 2 of the Cochrane risk-of-bias tool (RoB 2). RevMan v.5.3 was used to perform statistical analyses, and publication bias (egger's test) was assessed with Stata MP v.14.0.

RESULTS

Levetiracetam was similar to (fos)phenytoin in seizure termination rate (risk ratio [RR] 0.94; 95% CI 0.87 to 1.01), time of seizure termination (mean difference [MD] 0.44; -0.60 to 1.49), and drug resistance ([RR] 1.12, 0.86 to 1.45). The safety outcome showed a significant statistical difference between fosphenytoin group and levetiracetam group ([RR] 1.44, 1.14 to 1.81), while there was no significant difference observed between phenytoin treatment and levetiracetam treatment ([RR] 1.26, 0.99 to 1.60).

CONCLUSION

Levetiracetam was similar to (fos)phenytoin in cessation rate convulsive status epilepticus, and drug resistance, while it was superior (fos)phenytoin in pooled safety outcome. Further exploration is still needed as to whether it is the first choice for second-line drugs.

Levetiracetam, perampanel, and the issue of aggression: A self-report study

This study investigated to which degree levetiracetam (LEV) and perampanel (PER), antiseizure medications (ASM) that are both known to cause aggression and irritability, share the same or different, behavioral side-effect profiles. In this self-report study, 68 participants with epilepsy treated with LEV (n = 35) or PER (n = 33) as part of their medication were asked to rate their behavioral experience with the respective drug as positive, neutral, or negative. Results of a German adaptation of the Adverse Events Profile (AEP) and of the "FPZ", a German personality questionnaire, were analyzed as a function of drug and rating. Thirty-eight percent of the LEV group and 36% of the PER group experienced negative change after the evaluated drug was introduced. By subdividing participants in the LEV sample into those who attributed the negative effects to LEV and those with neutral or positive experience with LEV, a negative evaluation of LEV was associated with significantly worse scores in cognition, mood, and physical domains (80% versus 20-40%). Subdividing participants in the PER sample into those who attributed negative the side effects to PER, and those with a neutral or positive experience with PER, significance could be shown for mood domains only (100% versus 50%), and within this domain only for increased aggression and irritability. Comparing features of the behavioral negative side effects of LEV and PER revealed that LEV appears to have a negative impact on a much broader range of behaviors than PER, which specifically seems to induce aggression and irritability and no other psychiatric side effects. Further research should aim at different expression and different mechanisms of aggression and irritability underlying the superficially similar effects of the two drugs.

Differences in levetiracetam and perampanel treatment-related irritability in patients with epilepsy

PURPOSE

The present study evaluated whether patients with epilepsy who received both levetiracetam (LEV) and perampanel (PER) therapy showed side effects of irritability. The study also examined the relationship between patient characteristics and irritability when it occurred as a side effect.

METHODS

We retrospectively examined medical records of 98 patients with epilepsy who were treated with both LEV and PER at the Department of Psychiatry in the Epilepsy Center of Nishiniigata Chuo National Hospital in Japan. We performed multiple regression analyses with the presence/absence of irritability due to LEV or PER as the dependent variables and clinical characteristics of the patients as independent variables.

RESULTS

LEV and PER caused irritability in 7 and 17 of 98 patients, respectively. LEV- and PER-related irritability did not occur in the same patients. A logistic multiple regression analysis revealed that EEG findings of temporal focal epileptic discharge were significantly associated with increased incidence of irritability due to LEV. LEV-related irritability decreased significantly with higher dosages of LEV. Another logistic multiple regression analysis revealed that a psychiatric comorbidity of irritability and EEG findings of nontemporal focal epileptic discharge were significantly associated with increased incidence of irritability due to PER.

CONCLUSIONS

LEV and PER cause irritability in different patient groups. Additionally, irritability as a side effect was present only at low dosages of LEV, but PER tended to cause irritability even at high dosages.

Trait impulsivity in Juvenile Myoclonic Epilepsy

Objective

Impulsivity is a multidimensional construct that can predispose to psychopathology. Meta‐analysis demonstrates an association between response impulsivity and Juvenile Myoclonic Epilepsy (JME), a common genetic generalized epilepsy. Here, we test the hypotheses that trait impulsivity is (i) elevated in JME compared to controls; (ii) moderated by specific seizure characteristics; and (iii) associated with psychiatric adverse effects of antiepileptic drugs (AEDs).

Methods

322 participants with JME and 126 age and gender‐matched controls completed the Barratt’s Impulsiveness Scale (BIS‐brief) alongside information on seizure history and AED use. We compared group BIS‐brief scores and assessed associations of JME BIS‐brief scores with seizure characteristics and AED adverse effects.

Results

The mean BIS‐brief score in JME was 18.1 ± 4.4 compared with 16.2 ± 4.1 in controls (P = 0.0007). Elevated impulsivity was associated with male gender (P = 0.027), frequent absence seizures (P = 0.0004) and lack of morning predominance of myoclonus (P = 0.008). High impulsivity significantly increased the odds of a psychiatric adverse event on levetiracetam (P = 0.036), but not any other psychiatric or somatic adverse effects.

Interpretation

Trait impulsivity is elevated in JME and comparable to scores in personality and neurotic disorders. Increased seizure frequency and absence of circadian seizure pattern moderate BIS score, suggesting disruption of both cortico‐striatal and thalamocortical networks as a shared mechanism between seizures and impulsivity in JME. These findings warrant consideration of impulsivity as a distinct target of intervention, and as a stratifying factor for AED treatment in JME, and perhaps other types of epilepsy. The role of impulsivity in treatment adherence and psychosocial outcome requires further investigation.

Cognitive disorders in epilepsy II: Clinical targets, indications and selection of test instruments

This is the second of two narrative reviews on cognitive disorders in epilepsy (companion manuscript: Cognitive disorders in epilepsy I: Clinical experience, real-world evidence and recommendations). Its focus is on the clinical targets, indications, and the selection of neuropsychological test instruments. Cognitive assessment has become an essential tool for the diagnosis and outcome control in the clinical management of epilepsy. The diagnostics of basic and higher brain functions can provide valuable information on lateralized and localized brain dysfunctions associated with epilepsy, its underlying pathologies and treatment. In addition to the detection or verification of deficits, neuropsychology reveals the patient's cognitive strengths and, thus, information about the patient reserve capacities for functional restitution and compensation. Neuropsychology is an integral part of diagnostic evaluations mainly in the context of epilepsy surgery to avoid new or additional damage to preexisting neurocognitive impairments. In addition and increasingly, neuropsychology is being used as a tool for monitoring of the disease and its underlying pathologies, and it is suited for the quality and outcome control of pharmacological or other non-invasive medical intervention. This narrative review summarizes the present state of neuropsychological assessments in epilepsy, reveals diagnostic gaps, and shows the great need for education, homogenization, translation and standardization of instruments.

[Interictal psychosis of epilepsy]

Interictal psychosis (IIP) refers to psychosis that occurs in clear consciousness in persons with epilepsy (PWE) with temporal onset not during or immediately following a seizure. The pooled prevalence estimate of psychosis in PWE is 5.6%. PWE and schizophrenia have very high mortality, and more than one in four persons with both disorders die between the age of 25 and 50years. IIP can manifest in brief or chronic forms. The chronic forms of IIP may closely resemble schizophrenia. However, some authors have described the typical presence of persecutory and religious delusions, sudden mood swings and the preservation of affect, as well as rarity of negative symptoms and catatonic states, but these differences remain controversial. Typically, IIP starts after many years of active temporal lobe epilepsy. Several epilepsy-related variables are considered pathogenically relevant in IIP including epilepsy type and seizure characteristics. Risk factors for developing IIP are family history of psychosis, learning disability, early age of onset of epilepsy, unilateral or bilateral hippocampal sclerosis, history of status epilepticus, history of febrile seizures, and poorly controlled temporal lobe epilepsy. In patients with epilepsy and psychosis, structural imaging studies have shown several relevant changes leading to conflicting findings. Altered neuronal plasticity and excitability have been described in epilepsy and psychotic disorders. Neuropathological data suggest that IIP are not the result of classic epileptic pathology of the temporal lobe. Forced normalization (FN) and alternating psychosis refer to patients with poorly controlled epilepsy (focal or generalized) who have had psychotic episodes associated with remission of their seizures and disappearance of epileptiform activity on their EEGs. FN mainly occurs in temporal lobe epilepsy when patients have frequent seizures that are abruptly terminated triggered by an antiepileptic drug, vagus nerve stimulation or epilepsy surgery. Treatment is based on withdrawal of the responsible drug, and by transient use of antipsychotics for acute symptomatic control on a case-by-case basis. FN is an entity whose pathophysiology remains uncertain. Antiepileptic drugs (AEDs) may sometimes induce psychotic symptoms and psychosis could be a direct effect of the AEDs. IIP has been reported more frequently following the initiation of zonisamide, topiramate, and levetiracetam when compared with other antiepileptic drugs. However, AEDs do not appear to be the only determinant of IIP. The management of IIP requires a multidisciplinary approach with early involvement of a liaison psychiatrist associated with a neurologist. IIP are underdiagnosed and mistreated. Existing recommendations are extrapolated from those established for the treatment of schizophrenia with some additional guidance from expert opinions. A two-step procedure, not necessarily consecutive, is suggested. The first step requires reevaluation of the antiepileptic treatment. The second step requires initiation of atypical neuroleptics. Antipsychotic drugs should be selected with consideration of the balance between pharmacological profiles, efficacy, and adverse effects. Regarding pharmacokinetic interactions, AEDs with inducing properties reduce the blood levels of all antipsychotics. It is important to consider implications of combining neuroleptics and AEDs with a similar spectrum of side effects. Regarding the duration of treatment, IIP episodes are more likely to be recurrent than in primary schizophrenia. In practice, atypical neuroleptics with few motor side effects such as risperidone can be used as first choice, given the low propensity for drug-drug interactions and the low seizure risk, with the added suggestion to start low and go slow. Clozapine could be prescribed in selected cases.

Brivaracetam: First Canadian Experience in an Intractable Epilepsy Population

Objective:

To evaluate the effectiveness and tolerability of brivaracetam (BRV) in a refractory epilepsy population in an outpatient clinical setting.

Methods:

Retrospective medical information system review and self-report questionnaire for all patients treated with BRV until the end of 2017.

Results:

Thirty-eight patients were included, 73.7% female and mean age 36.2. The mean number of antiepileptic drugs (AEDs) for previous use was 8.9, and for current use was 2.5. Mean seizure frequency in the last 3 months was 12 per month. At 3, 6, 12, and 15 months, the 50% responder rates were 36.1%, 32%, 41.2%, and 45.5%, respectively. Patients took BRV for a median duration of 8.25 months, ranging from 7 days to 60 months. Retention rate was 75.0%, 72.0%, 59.2%, and 47.9% at 3, 6, 12, and 15 months, respectively. Overall, the main reasons for discontinuation were adverse events (AEs) (52.3%), lack of efficacy (35.3%), or both (11.8%). The rate of total AEs was 60.5% according to medical records and 85.7% according to questionnaire, including mostly tiredness, psychiatric, and memory complaints. Psychiatric side effects occurred in 31.6% according to medical records and 47.4% according to questionnaire results, which is higher than previously reported and persisted throughout the study period.

Conclusions:

BRV appears to be a useful and safe add-on treatment, even in a very refractory group of patients. In this real-life clinical setting, psychiatric AEs were found at a higher rate than previously published.

Raloxifene potentiates the effect of fluoxetine against maximal electroshock induced seizures in mice

The evidence to guide clinicians regarding rationale polytherapy with current antiepileptic drugs (AEDs) is lacking, and current practice recommendations are largely empirical.  The excessive drug loading with combinatorial therapies of existing AEDs are associated with escalated neurotoxicity, and that emergence of pharmacoresistant seizures couldn't be averted. In pursuit of judicious selection of novel AEDs in combinatorial therapies with mechanism based evidences, standardized dose of raloxifene, fluoxetine, bromocriptine and their low dose combinations, were experimentally tested for their impact on maximal electroshock (MES) induced tonic hind limb extension (THLE) in mice. Hippocampal neuropeptide Y (NPY) levels, oxidative stress and histopathological studies were undertaken. The results suggest the potentiating effect of 4 mg/kg raloxifene on 14 mg/kg fluoxetine against MES induced THLE, as otherwise monotherapy with 4 mg/kg raloxifene was unable to produce an effect. The results also depicted better efficacy than carbamazepine (20 mg/kg), standard AED. Most profoundly, MES-induced significant (P < 0.001) reduction in hippocampal NPY levels, that were escalated insignificantly with the duo-drug combination, suggesting some other mechanism in mitigation of electroshock induced seizures. These results were later corroborated with assays to assess oxidative stress and neuronal damage. In conclusion, the results demonstrated the propitious therapeutic benefit of duo-drug low dose combination of drugs; raloxifene and fluoxetine, with diverse mode of actions fetching greater effectiveness in the management of generalized tonic clonic seizures (GTCS).

A case of dyskinesia after levetiracetam administration

Background

Antiepileptic drug (AED) induced dyskinesia is an unusual manifestation in the medical field. In the previous case reports describing first generation-AED related involuntary movements, the authors suggested that a plausible cause is pharmacokinetic interactions between two or more AEDs. To date, development of dyskinesia after levetiracetam (LEV) has not been reported.

Case presentation

A 28-year-old woman with a history of brain metastasis from spinal cord glioblastoma presented with several generalized tonic-clonic seizures without restored consciousness. LEV was administered intravenously. Thereafter no more clinical or electroencephalographic seizures were noted on video-EEG monitoring, while chorea movement was observed in her face and bilateral upper limbs.

Discussion and conclusions

To our knowledge, there is no case report of dyskinesia after administration of LEV. Considering the temporal relationship and absence of ictal video-EEG findings, we suggest that development of choreoathetosis was closely associated with the undesirable effects of LEV. We propose that dopaminergic system dysregulation and genetic susceptibility might underlie this unusual phenomenon after LEV treatment.

Mechanisms Underlying Aggressive Behavior Induced by Antiepileptic Drugs: Focus on Topiramate, Levetiracetam, and Perampanel

Antiepileptic drugs (AEDs) are effective against seizures, but their use is often limited by adverse effects, among them psychiatric and behavioral ones including aggressive behavior (AB). Knowledge of the incidence, risk factors, and the underlying mechanisms of AB induced by AEDs may help to facilitate management and reduce the risk of such side effects. The exact incidence of AB as an adverse effect of AEDs is difficult to estimate, but frequencies up to 16% have been reported. Primarily, levetiracetam (LEV), perampanel (PER), and topiramate (TPM), which have diverse mechanisms of action, have been associated with AB. Currently, there is no evidence for a specific pharmacological mechanism solely explaining the increased incidence of AB with LEV, PER, and TPM. Serotonin (5-HT) and GABA, and particularly glutamate (via the AMPA receptor), seem to play key roles. Other mechanisms involve hormones, epigenetics, and “alternative psychosis” and related phenomena. Increased individual susceptibility due to an underlying neurological and/or a mental health disorder may further explain why people with epilepsy are at an increased risk of AB when using AEDs. Remarkably, AB may occur with a delay of weeks or months after start of treatment. Information to patients, relatives, and caregivers, as well as sufficient clinical follow-up, is crucial, and there is a need for further research to understand the complex relationship between AED mechanisms of action and the induction/worsening of AB.

HLA-A*11:01 is associated with levetiracetam-induced psychiatric adverse events

Levetiracetam (LEV) is effective for focal and generalized epilepsy and is used worldwide because of its relatively few drug interactions and favorable tolerability. However, some psychiatric adverse events (PAEs) have been reported, resulting in drug withdrawal. The pathophysiology of LEV-induced PAE has not yet been elucidated. In this study, we investigated the relationship between PAEs and human leukocyte antigen (HLA) genes. Eleven epilepsy patients, who developed PAEs after the administration of LEV and spontaneously improved after drug withdrawal, were enrolled retrospectively. Genomic DNA from the peripheral blood was extracted, and four-digit allele genotyping of HLA genes was performed. The genotype frequencies of HLA genes were compared to those of 80 patients in which LEV was well tolerated, as well as to 485 individuals from the general Korean population. The frequency of the HLA-A*1101 allele was significantly higher in the LEV-induced PAEs group compared to both the LEV-tolerant group (p = 0.021, OR 4.80, 95% CI 1.30-17.74) and the general Korean population (p = 0.015, OR 4.62, 95% CI 1.38-15.45). This study is the first attempt at investigating the relationship between the HLA system and LEV-induced PAE. The results of this study suggest that the HLA-A*1101 allele could be a risk factor for the development of PAEs.

Development of forced normalisation psychosis with ethosuximide

A 50-year-old man with known multidrug resistant coexistent focal and generalised epilepsy was commenced on ethosuximide, with normalisation of his electroencephalogram and cessation of absence seizures. Within 3 weeks, he developed a rapidly worsening paranoid psychosis with visual and olfactory hallucinations. A month after the cessation of ethosuximide and concurrent treatment with olanzapine, his psychosis resolved and permitted reinitiation of ethosuximide at a lower dose without recurrence of psychotic symptoms.

The influence of levetiracetam on psychosocial and behavioral functioning in children: A case-control and follow-up study

BACKGROUND

Levetiracetam, a widely used antiepileptic drug in children, has been associated with psychosocial and behavioral problems, which are also influenced by epilepsy variables, including duration or seizure frequency.

PURPOSE

The objective of this study is to investigate the frequency and timing of treatment-emergent psychosocial and behavioral problems in children receiving levetiracetam, irrespective of seizure variables which are possible confounders.

METHODS

A prospective, case-control study with a 3-month follow-up was conducted. Consecutive children aged 6 to 16years with new-onset partial seizures were included in case of starting treatment with either levetiracetam or valproic acid. Psychosocial and behavioral functioning were assessed using a set of standardized questionnaires including Strengths and Difficulties Questionnaire (SDQ) and Children's Depression Inventory (CDI) at baseline, 1 and 3-month follow-up. Patients' baseline scores were compared to healthy subjects. The difference in the follow-up SDQ and CDI scores was evaluated in patients receiving levetiracetam and valproic acid.

RESULTS

A total of 101 participants were analyzed; 32 patients in levetiracetam group, 19 patients in valproic acid group and 50 healthy controls. Baseline SDQ and CDI scores were not statistically different between patients and healthy subjects (p>0.05). No statistically significant difference was observed in CDI, total and subscale SDQ scores between patients receiving levetiracetam or valproic acid during the study period (p>0.05). A girl aged 15years receiving levetiracetam had a CDI score of 18 without suicidal ideation at baseline. She developed suicidal ideation and depression, which resolved after switching of levetiracetam to valproic acid, at the 1-month follow-up. No other psychiatric or behavioral side-effects were observed in other patients.

CONCLUSION

Psychosocial and behavioral side-effects of levetiracetam treatment are not frequent and they don't emerge in most of children at lower doses. At this dose, and after 3months, using these specific instruments, we did not observe any difference between the valproic acid and levetiracetam treatment groups.

Forced Normalization: Antagonism Between Epilepsy and Psychosis

The antagonism between epilepsy and psychosis has been discussed for a long time. Landolt coined the term "forced normalization" in the 1950s to describe psychotic episodes associated with the remission of seizures and disappearance of epileptiform activity on electroencephalograms in individuals with epilepsy. Since then, neurologists and psychiatrists have been intrigued by this phenomenon. However, although collaborative clinical studies and basic experimental researches have been performed, the mechanism of forced normalization remains unknown. In this review article, we present a historical overview of the concept of forced normalization, and discuss potential pathogenic mechanisms and clinical diagnosis. We also discuss the role of dopamine, which appears to be a key factor in the mechanism of forced normalization.

Epilepsy, Antiepileptic Drugs, and Aggression: An Evidence-Based Review

Antiepileptic drugs (AEDs) have many benefits but also many side effects, including aggression, agitation, and irritability, in some patients with epilepsy. This article offers a comprehensive summary of current understanding of aggressive behaviors in patients with epilepsy, including an evidence-based review of aggression during AED treatment. Aggression is seen in a minority of people with epilepsy. It is rarely seizure related but is interictal, sometimes occurring as part of complex psychiatric and behavioral comorbidities, and it is sometimes associated with AED treatment. We review the common neurotransmitter systems and brain regions implicated in both epilepsy and aggression, including the GABA, glutamate, serotonin, dopamine, and noradrenaline systems and the hippocampus, amygdala, prefrontal cortex, anterior cingulate cortex, and temporal lobes. Few controlled clinical studies have used behavioral measures to specifically examine aggression with AEDs, and most evidence comes from adverse event reporting from clinical and observational studies. A systematic approach was used to identify relevant publications, and we present a comprehensive, evidence-based summary of available data surrounding aggression-related behaviors with each of the currently available AEDs in both adults and in children/adolescents with epilepsy. A psychiatric history and history of a propensity toward aggression/anger should routinely be sought from patients, family members, and carers; its presence does not preclude the use of any specific AEDs, but those most likely to be implicated in these behaviors should be used with caution in such cases.

Monoaminergic Mechanisms in Epilepsy May Offer Innovative Therapeutic Opportunity for Monoaminergic Multi-Target Drugs

A large body of experimental and clinical evidence has strongly suggested that monoamines play an important role in regulating epileptogenesis, seizure susceptibility, convulsions, and comorbid psychiatric disorders commonly seen in people with epilepsy (PWE). However, neither the relative significance of individual monoamines nor their interaction has yet been fully clarified due to the complexity of these neurotransmitter systems. In addition, epilepsy is diverse, with many different seizure types and epilepsy syndromes, and the role played by monoamines may vary from one condition to another. In this review, we will focus on the role of serotonin, dopamine, noradrenaline, histamine, and melatonin in epilepsy. Recent experimental, clinical, and genetic evidence will be reviewed in consideration of the mutual relationship of monoamines with the other putative neurotransmitters. The complexity of epileptic pathogenesis may explain why the currently available drugs, developed according to the classic drug discovery paradigm of "one-molecule-one-target," have turned out to be effective only in a percentage of PWE. Although, no antiepileptic drugs currently target specifically monoaminergic systems, multi-target directed ligands acting on different monoaminergic proteins, present on both neurons and glia cells, may represent a new approach in the management of seizures, and their generation as well as comorbid neuropsychiatric disorders.

Looking for reward in all the wrong places: dopamine receptor gene polymorphisms indirectly affect aggression through sensation-seeking

Individuals with genotypes that code for reduced dopaminergic brain activity often exhibit a predisposition toward aggression. However, it remains largely unknown how dopaminergic genotypes may increase aggression. Lower-functioning dopamine systems motivate individuals to seek reward from external sources such as illicit drugs and other risky experiences. Based on emerging evidence that aggression is a rewarding experience, we predicted that the effect of lower-functioning dopaminergic functioning on aggression would be mediated by tendencies to seek the environment for rewards. Caucasian female and male undergraduates (N = 277) were genotyped for five polymorphisms of the dopamine D2 receptor (DRD2) gene; they reported their previous history of aggression and their dispositional reward-seeking. Lower-functioning DRD2 profiles were associated with greater sensation-seeking, which then predicted greater aggression. Our findings suggest that lower-functioning dopaminergic activity puts individuals at risk for violence because it motivates them to experience aggression's hedonically rewarding qualities.

A Girl with Idiopathic Epilepsy Showing Forced Normalization after Levetiracetam Administration

BACKGROUND

Forced normalization has been reported in association with almost all anti-epileptic drugs.

PATIENT

We report on a 9-year-old girl with idiopathic epilepsy who showed forced normalization after administration of levetiracetam (LEV). She initially presented with generalized tonic-clonic seizures when she was 4 years old. Diffuse sharp and slow wave complexes (SWCs) were observed on electroencephalography (EEG). We prescribed sodium valproate (VPA) and benzodiazepines, but the seizures and EEG findings worsened gradually. Although subsequent administration of LEV stopped the seizures, the patient became subject to episodes of rage and violent behavior. Forced normalization was confirmed by the disappearance of SWCs on EEG. We reduced the dose of LEV and tried in various ways to resolve the situation, but finally we had to abandon LEV.

CONCLUSIONS

To the best of our knowledge, this is the first report of a patient with idiopathic epilepsy but without disabilities in everyday life showing forced normalization associated with LEV administration.

Third International Congress on Epilepsy, Brain, and Mind: Part 2

Epilepsy is both a disease of the brain and the mind. Here, we present the second of two papers with extended summaries of selected presentations of the Third International Congress on Epilepsy, Brain and Mind (April 3-5, 2014; Brno, Czech Republic). Humanistic, biologic, and therapeutic aspects of epilepsy, particularly those related to the mind, were discussed. The extended summaries provide current overviews of epilepsy, cognitive impairment, and treatment, including brain functional connectivity and functional organization; juvenile myoclonic epilepsy; cognitive problems in newly diagnosed epilepsy; SUDEP including studies on prevention and involvement of the serotoninergic system; aggression and antiepileptic drugs; body, mind, and brain, including pain, orientation, the "self-location", Gourmand syndrome, and obesity; euphoria, obsessions, and compulsions; and circumstantiality and psychiatric comorbidities.

Self-reported aggressiveness during treatment with levetiracetam correlates with depression

PURPOSE

The purpose of this study was to identify clinical correlates of self-reported aggressiveness (SRA) in patients with epilepsy treated with levetiracetam (LEV) with special reference to the role of depression.

METHODS

A consecutive sample of adult outpatients with epilepsy was assessed with the Neurological Disorder Depression Inventory for Epilepsy, the Adverse Event Profile (AEP), and the Emotional Thermometer.

RESULTS

From a total sample of 163 consecutive patients treated with LEV, SRA at any level (from rarely a problem to always) was associated with a 7-fold increased risk of being depressed (95% CI: 3.0-17.5; p<0.001). Self-reported aggressiveness was reported as "always" a problem by 9.8% of the patients. In these patients, apart from depression, SRA was associated with high AEP total scores (55.1 vs. 39.3; p<0.001) and polytherapy (43.8% vs. 19.8%; p=0.034). Anxiety scores were not elevated (4.9 vs. 3.6; p=0.183).

CONCLUSIONS

Self-reported aggressiveness during treatment with LEV is not an isolated symptom but is associated with depressed mood. Anxiety-mediated mechanisms do not seem to be involved.

Brivaracetam for the treatment of epilepsy in adults

Brivaracetam (BRV) is a new antiepileptic drug structurally related to levetiracetam but with a 15 to 30-fold increased affinity for the same molecular target, namely the SV2A ligand. BRV is currently under Phase III development as adjunctive treatment for partial onset seizures but data from some Phase III suggest also potential efficacy for primary generalized seizures. Although two studies are negative for the primary efficacy endpoint, global results seem to suggest a wide spectrum of efficacy for both partial onset and primary generalized seizures and a favourable safety and pharmacokinetic profile. This article is aimed at providing a comprehensive overview of current evidence about BRV in the treatment of epilepsy taking into account emerging concerns regarding clinical trials in epilepsy.

Depression and anxiety in people with epilepsy

Many recent epidemiological studies have found the prevalence of depression and anxiety to be higher in people with epilepsy (PWE) than in people without epilepsy. Furthermore, people with depression or anxiety have been more likely to suffer from epilepsy than those without depression or anxiety. Almost one-third of PWE suffer from depression and anxiety, which is similar to the prevalence of drug-refractory epilepsy. Various brain areas, including the frontal, temporal, and limbic regions, are associated with the biological pathogenesis of depression in PWE. It has been suggested that structural abnormalities, monoamine pathways, cerebral glucose metabolism, the hypothalamic-pituitary-adrenal axis, and interleukin-1b are associated with the pathogenesis of depression in PWE. The amygdala and the hippocampus are important anatomical structures related to anxiety, and γ-aminobutyric acid and serotonin are associated with its pathogenesis. Depression and anxiety may lead to suicidal ideation or attempts and feelings of stigmatization. These experiences are also likely to increase the adverse effects associated with antiepileptic drugs and have been related to poor responses to pharmacological and surgical treatments. Ultimately, the quality of life is likely to be worse in PWE with depression and anxiety than in PWE without these disorders, which makes the early detection and appropriate management of depression and anxiety in PWE indispensable. Simple screening instruments may be helpful for in this regard, particularly in busy epilepsy clinics. Although both medical and psychobehavioral therapies may ameliorate these conditions, randomized controlled trials are needed to confirm that.

Disentangling the relationship between epilepsy and its behavioral comorbidities - the need for prospective studies in new-onset epilepsies

It has been long recognized that there is more to epilepsy than seizures. The prevalence of such neurobehavioral abnormalities as cognitive and mood disorders, autism spectrum disorder, and attention deficit and hyperactivity disorder (ADHD) is significantly higher among patients with epilepsy than in the general population. A long-held view that comorbidities of epilepsy represent mere epiphenomena of seizures has undergone substantial transformation during the past decade, as emerging clinical evidence and experimental evidence suggest the involvement of specific neurobiological mechanisms in the evolution of neurobehavioral deficits in patients with epilepsy. Developmental aspects of both epilepsy and its comorbidities, as well as the frequently reported reciprocal connection between these disorders, both add other dimensions to the already complex problem. In light of progress in effective seizure management in many patients with epilepsy, the importance of neurobehavioral comorbidities has become acute, as the latter are frequently more detrimental to patients' quality of life compared with seizures. This calls for a serious increase in efforts to effectively predict, manage, and ideally cure these comorbidities. Coordinated multicenter clinical, translational, and basic research studies focusing on epidemiology, neuropsychology, neurophysiology, imaging, genetics, epigenetics, and pharmacology of neurobehavioral comorbidities of epilepsy are absolutely instrumental for ensuring tangible progress in the field. Clinical research should focus more on new-onset epilepsy and put particular emphasis on longitudinal studies in large cohorts of patients and groups at risk, while translational research should primarily focus on the development of valid preclinical systems which would allow investigating the fundamental mechanism of epilepsy comorbidities. The final goal of the described research efforts would lie in producing an armamentarium of evidence-based diagnostic tools and therapeutic interventions which would at minimum mitigate and at maximum prevent or abolish neurobehavioral comorbidities of epilepsy and, thus, improve the quality of life of those patients with epilepsy who suffer from the said comorbidities.

Implications of pharmacogenetics for the therapeutic use of antiepileptic drugs

INTRODUCTION

Epilepsy is a chronic neurological disease manifesting as recurrent seizures. Despite the availability of numerous antiepileptic drugs (AEDs), one-third of the patients are not responsive to treatment. Such inter-individual variability in the response to AEDs may be partly explained by genetic differences. This review summarizes the pharmacogenetics (PGx) of AEDs. In addition, a model-based approach is presented that enables the integration of PGx data with other relevant sources of variability, such as demographic characteristics and co-medications.

AREAS COVERED

A comprehensive overview is provided of the data available in the literature on the evidence for correlations between genetic mutations and pharmacokinetic (PK) and/or pharmacodynamics (PD) of AEDs. This information is then used in an integrated manner in the second part, where PGx differences are parameterized as covariates in PK and PKPD models.

EXPERT OPINION

Polymorphisms are profuse in the PK and PD of AEDs. However, understanding of their clinical implication remains limited due to the lack of methodologies that discriminate the contribution of other sources of variability in CNS exposure to drugs. A model-based approach, in which other intrinsic (e.g., demographic covariates) and extrinsic (e.g., drug-drug interactions) factors are evaluated concurrently is needed to ensure optimization and individualization of treatment in epileptic patients.

Compulsive gambling possibly associated with antiepileptic medication

Compulsive gambling is recognized with Parkinson's disease treatment with dopamine agonists but has not been reported with antiepileptic medications (AEMs) in epilepsy. This is the first report regarding possible compulsive gambling, provoked by AEMs in a patient with idiopathic generalized epilepsy, who presented with nonconvulsive status epilepticus, having previously not achieved seizure control with carbamazepine, valproate, (VPA), topiramate, gabapentin (GPT), lamotrigine (LTG), and clobazam. Levetiracetam (LEV) was added to VPA and GPT, which the patient was already taking and LTG subsequently retrialed. Following the reintroduction of LTG, she lost $4000-5000, which she concealed. With better seizure control, VPA and GPT were withdrawn, leaving her on LEV and LTG. With increased LTG dosage, she lost $50,000, prompting discovery of her gambling.

The role of dopamine signaling in epileptogenesis

Clinical and experimental studies implicate most neuromodulatory systems in epileptogenesis. The dopaminergic system has a seizure-modulating effect that crucially depends on the different subtypes of dopamine (DA) receptors involved and the brain regions in which they are activated. Specifically, DA plays a major role in the control of seizures arising in the limbic system. Studies performed in a wide variety of animal models contributed to illustrate the opposite actions of D1-like and D2-like receptor signaling in limbic epileptogenesis. Indeed, signaling from D1-like receptors is generally pro-epileptogenic, whereas D2-like receptor signaling exerts an anti-epileptogenic effect. However, this view might appear quite simplistic as the complex neuromodulatory action of DA in the control of epileptogenesis likely requires a physiological balance in the activation of circuits modulated by these two major DA receptor subtypes, which determines the response to seizure-promoting stimuli. Here we will review recent evidences on the identification of molecules activated by DA transduction pathways in the generation and spread of seizures in the limbic system. We will discuss the intracellular signaling pathways triggered by activation of different DA receptors in relation to their role in limbic epileptogenesis, which lead to the activation of neuronal death/survival cascades. A deep understanding of the signaling pathways involved in epileptogenesis is crucial for the identification of novel targets for the treatment of epilepsy.