A prospective case control study of psychiatric disorders in adults with epilepsy and intellectual disability

Rapid switching from levetiracetam to brivaracetam in pharmaco-resistant epilepsy in people with and without intellectual disabilities: a naturalistic case control study

BACKGROUND

Approximately one quarter of people with an intellectual disability (PwID) have epilepsy of whom nearly three-quarters are pharmaco-resistant. There are higher reported neuropsychiatric side-effects to anti-seizure medication (ASM) in this group. Levetiracetam (LEV) is a first-line ASM with a stronger association with neuropsychiatric symptoms for PwID than other ASMs. Brivaracetam (BRV) is a newer ASM. Recent studies suggest a beneficial effect of swapping people who experience neuropsychiatric events with LEV to BRV. However, there is limited evidence of this for PwID. This evaluation analyses real world outcomes of LEV to BRV swap for PwID compared to those without ID.

METHODS

We performed a multicentre, retrospective review of clinical records. Demographic, clinical characteristics and reported adverse events of patients switched from LEV to BRV (2016-2020) were recorded at 3 months pre and 6- and 12-month post-BRV initiation. Outcomes were compared between PwID and those without and summarised using cross-tabulations and logistic regression models. A Bonferroni correction was applied.

RESULTS

Of 77 participants, 46 had ID and 52% had a past psychiatric illness. 71% participants switched overnight from LEV to BRV. Seizure reduction of > 50% was seen in 40% patients. Psychiatric illness history was predictive of having neuropsychiatric side-effects with LEV but not BRV (p = 0.001). There was no significant difference for any primary outcomes between PwID versus without ID.

CONCLUSIONS

Switching from LEV to BRV appears as well tolerated and efficacious in PwID as those without ID with over 90% still on BRV after 12 months.

Is epilepsy related to psychiatric disorders in people with intellectual disability? A systematic review

The prevalence of psychiatric disorders in people with Intellectual Disability (ID) is statistically higher than in the general population. There is a lack of consensus on the role that epilepsy plays in psychiatric disorders in people with ID. We carried out a systematic review of articles published between 1960 and 2022, focusing on high-quality, case-control original research studies that only included adult populations. The primary outcome was the prevalence of psychiatric disorders in people with intellectual disability with and without epilepsy. Six articles were finally included. Results were varied; some reported a statistical increase, whereas others did not find any statistical difference. Due to the current controversy on the role of epilepsy in psychiatric disorders in people with ID and the small number of publications on the topic, we cannot affirm a relationship between epilepsy and psychiatric disorders in people with ID.

Impact of intellectual and developmental disability on quality-of-life priorities in adults with epilepsy

OBJECTIVE

Adults living with intellectual and developmental disability (IDD) and epilepsy (IDD-E) face challenges in addition to those faced by the general population of adults with epilepsy, which may be associated with distinct priorities for improving health-related quality of life (HR-QOL). This study sought to (1) conduct a survey of HR-QOL priorities identified by adults with IDD-E and caregivers, and (2) perform an exploratory cross-sectional comparison to adults with epilepsy who do not have IDD.

METHODS

This cross-sectional study recruited 65 adults with IDD-E and 134 adults with epilepsy without IDD and caregivers. Using a three-step development process, 256 items from existing quality-of-life scales recommended by the American Academy of Neurology (AAN) were rated by patients/caregivers for their importance as HR-QOL priorities. HR-QOL items identified as critical to the majority of the sample of adults with IDD-E were reported. Health-related quality of life priorities were compared between adults with IDD-E and adults with epilepsy without IDD.

RESULTS

Health-related quality of life was significantly lower in adults with IDD-E. Health-related quality of life domains identified as critical priorities by adults with IDD-E included seizure burden, anti-seizure medication side effects, seizure unpredictability, and family impact. Priorities for improving HR-QOL differed between adults with and without IDD-E, with concerns about family impact, difficulty finding appropriate living conditions, inadequate assistance, and difficulty transitioning from pediatric-to-adult care valued significantly more among those with IDD-E.

SIGNIFICANCE

Intellectual and developmental disability is an important determinant of HR-QOL among adults with epilepsy. We report HR-QOL priorities identified by adults with IDD-E and their caregivers. These results may help epilepsy clinicians and researchers develop tailored strategies to address priorities of the patient with IDD-E/caregiver community.

Association between epilepsy and psychiatric disorders in adults with intellectual disabilities: systematic review and meta-analysis

BACKGROUND

Psychiatric disorders, such as depression and anxiety, are commonly associated with epilepsy in the general population, but the relationship between psychiatric disorders and epilepsy among adults with intellectual disabilities is unclear.

AIMS

To conduct a systematic review and meta-analysis to assess whether epilepsy is associated with an increased rate of psychiatric disorders in adults with intellectual disabilities.

METHOD

We included literature published between 1985 and 2020 from four databases, and hand-searched six relevant journals. We assessed risk of bias by using SIGN 50 and the Cochrane risk of bias tool. Several meta-analyses were carried out.

RESULTS

We included 29 papers involving data on 9594 adults with intellectual disabilities, 3180 of whom had epilepsy and 6414 did not. Of the 11 controlled studies that compared the overall rate of psychiatric disorders between the epilepsy and non-epilepsy groups, seven did not show any significant inter-group difference. Meta-analysis was possible on pooled data from seven controlled studies, which did not show any significant inter-group difference in the overall rate of psychiatric disorders. The rates of psychotic disorders, depressive disorders and anxiety disorders were significantly higher in the non-epilepsy control groups compared with the epilepsy group, with effect sizes of 0.29, 0.47 and 0.58, respectively. Epilepsy-related factors did not show any definite association with psychiatric disorders.

CONCLUSIONS

It is difficult to pool data from such heterogeneous studies and draw any definitive conclusion because most studies lacked an appropriately matched control group, which will be required for future studies.

Late-onset epilepsy and subsequent increased risk of dementia

Inflammation is considered as a key pathogenesis factor of dementia and epilepsy. However, epilepsy's association with dementia, particularly its role in the development of dementia, remains unclear. To evaluate the association between epilepsy and the risk of dementia, in Taiwan, we have now conducted a retrospective cohort study comprising 675 individuals (age, ≥50 years) with epilepsy and 2,025 matched control subjects without epilepsy. In order to match individuals diagnosed with epilepsy with those with no diagnosis of epilepsy (comparison cohort), we utilized exact matching at a ratio of 1:3. Compared with those in the comparison cohort, individuals in the epilepsy cohort had a significantly increased risk of developing dementia (adjusted hazard ratio = 2.87, p < 0.001). A similar result has been observed after stratifying for sex (adjusted hazard ratio in males = 2.95, p < 0.001; adjusted hazard ratio in females = 2.66, p < 0.001). To conclude, based on these data, epileptic individuals ≥50 years were at a greater risk of developing dementia than people who do not have epilepsy, which indicates that a diagnosis of epilepsy presents a greater risk for the development of dementia.

Valproate prescribing practices for women with intellectual disability across Europe

BACKGROUND

Valproate (VPA) is a known teratogen associated with greater risk of major congenital malformations and other neurodevelopmental sequelae than all other licensed antiepileptic medicines. To reduce the potential for VPA-related teratogenicity, the European Medicines Agency issued recommendations in 2018. Over two-thirds of women/girls with intellectual disability (ID) may have treatment-resistant epilepsy that could benefit from VPA treatment.

AIMS

This investigation compared VPA prescribing practice for women/girls with ID between European countries, specifically evaluating the practice in the UK with that in other countries.

METHODS

An expert working group with representation from key stake-holding organizations developed a survey for dissemination to relevant professionals across Europe.

RESULTS

Seventy one responses were received (27 UK, 44 Europe). Clinicians in the UK were more likely to report that they are working to mandatory regulations compared with European respondents (P = .015). European respondents were less likely to be aware of user-independent contraception options (P = .06). In The UK, VPA regulations were more likely to be applied to women with ID than in Europe (P = .024).

CONCLUSION

There is heterogeneity in the application of VPA regulations across Europe for women/girls with ID. In both the UK and Europe, the regulations lack suitable adjustments for specific ID-related factors.

Improving Transitional Services for Adolescents and Young Adults with Epilepsy and Intellectual Disability

The transition from pediatric to adult health care systems is challenging for many adolescents with epilepsy and their families, and those challenges are compounded for adolescents with comorbid intellectual disabilities and epilepsy (ID-E). Many traditional transition pathways to adult care are inadequate, as they fail to address important considerations unique to the ID-E population or are absent entirely. Poor organization of care during critical transition periods increases the risks of sudden unexpected death in epilepsy, suboptimal seizure control, inadequate management of comorbidities, and poor psychological and social outcomes. The literature lacks systematic studies on effective transition programs for this population. The present review provides an overview of the main themes important in care transitions for the ID-E population: (1) precise diagnosis and management of seizures; (2) mental health and medical comorbidities affecting care; (3) accessing behavioral, habilitative, legal, financial, and community resources; and (4) caretaker support. We propose a specific framework which includes targeted recommendations of minimum care standards for youth with ID-E transitioning to adult care.

Quality improvement in the management of people with epilepsy and intellectual disability: the development of clinical guidance

Introduction: This clinical guidance looks at the specific concerns of delivery of medical treatment for people with epilepsy and intellectual disability (ID). People with ID have not been included in licensing drug trials of AEDs. However, this population has an over-representation of seizure comorbidity, treatment resistance, and polypharmacy while also being vulnerable to not having their views considered.Areas covered: This review summarizes the current most robust evidence available for the use of licensed AEDs in people with epilepsy and ID. The article provides practical evidence-based clinical information to help prescribers choose the most appropriate AED from the drugs discussed. The article highlights other important individualized factors to consider before initiating or changing antiepileptic medication.Expert opinion: A 'traffic light' coding system is applied to commonly used AEDs based on the level of evidence and expert clinical experience. Managing epilepsy in the ID population requires specialist care. Treatment plans need to be holistic and tailored to accommodate an individual's comorbidities, concurrent medications, general health, social and environmental status. There is a need for large quality trial data to assess the most suitable AEDs on seizure control and quality of life in this population with complex needs.

Treatment of psychiatric comorbidities in patients with epilepsy and intellectual disabilities: Is there a role for the neurologist?

This paper will explore the nature of psychiatric co-morbidities in people with an intellectual disability (ID) who have epilepsy. The complexity of clinical presentations and associated co-morbidities require thorough assessment utilising both neurological and psychiatric skills. The neurologist plays a central role in the management of epilepsy in people with ID and therefore requires basic competencies in the assessment of neuropsychiatric co-morbidities. This is key to liaison with other specialist services to ensure individuals receive holistic person-centred care. This article is part of the Special Issue "Obstacles of Treatment of Psychiatric Comorbidities in Epilepsy".

Valproate MHRA Guidance: Limitations and Opportunities

Recent publication of the Medicines and Healthcare products Regulatory Agency (MHRA) in the United Kingdom has strengthened the regulatory measures for valproate medicines. It highlights the importance of making women of childbearing age with epilepsy aware of the teratogenic risks of valproate and encourages the withdrawal of it from those currently prescribed. While a significant directive, it raises concerns of not having considered the impact on special populations such as women with Intellectual Disability (ID). While it is important that women with ID are not excluded from such safety initiatives, due caution needs to be taken on a case by case basis preferably, to ensure their best interests are central to the decision making. Many women with moderate to profound ID cannot have informed consented sexual relationships not to mention cognitive incapability to make informed choices on medication suitability. These women are at potential risk of having their epilepsy control undermined due to the MHRA directives. Around 30% of people with moderate to profound ID have seizures of which 60% are considered treatment resistant. In this vulnerable population changes to medication without clear clinical and social insights could lead to increased harm levels. This paper enumerates the challenges of application of the new directive to these special populations and proposes a pathway based on individual cognitive ability to provide informed consent to facilitate the continuation or removal of valproate. It is important not to lose sight of individual circumstances and the importance of working collaboratively toward providing person center care.

A systematic review of neuropsychiatric comorbidities in patients with both epilepsy and intellectual disability

Epilepsy is a neurological condition that is particularly common in people with intellectual disability (ID). The care for people with both epilepsy and ID is often complicated by the presence of neuropsychiatric disorders, defined as psychiatric symptoms, psychiatric disorders, and behavioral problems. The aim of this study was to investigate associations between epilepsy or epilepsy-related factors and neuropsychiatric comorbidities in patients with ID and between ID and neuropsychiatric comorbidities in patients with epilepsy. We performed a systematic review of the literature, published between January 1995 and January 2015 and retrieved from PubMed/Medline, PsycINFO, and ERIC and assessed the risk of bias using the SIGN-50 methodology. Forty-two studies were identified, fifteen of which were assessed as having a low or acceptable risk-of-bias evaluation. Neuropsychiatric comorbidities were examined in relation to epilepsy in nine studies; in relation to epilepsy-related factors, such as seizure activity, seizure type, and medication in four studies; and in relation to the presence and degree of ID in five studies. We conclude that the presence of epilepsy only was not a clear determinant of neuropsychiatric comorbidity in patients with ID, although a tendency towards negative mood symptoms was identified. Epilepsy-related factors indicating a more severe form of epilepsy were associated with neuropsychiatric comorbidity as was the presence of ID as compared to those without ID in patients with epilepsy, although this should be validated in future research. A large proportion of the studies in this area is associated with a substantial risk of bias. There is a need for high quality studies using standardized methods to enable clear conclusions to be drawn that might assist in improving the quality of care for this population.

Prevalence of depression and anxiety among patients with epilepsy attending the epilepsy clinic at Sheikh Khalifa Medical City, UAE: A cross-sectional study

Depression and anxiety are highly prevalent in patients with epilepsy (PWE), with prevalence rates ranging from 20% to 55%. Unfortunately, the rates, patterns, and risk factors have not been well studied in the Middle East and, to our knowledge, have not been studied at all in the UAE. We screened 186 patients attending an epilepsy clinic using standardized screening tools to determine the rates of both depression and anxiety and compared these rates with that of age- and sex-matched controls. Almost one-third of our patients scored in the depression and anxiety ranges, which was significantly higher compared with the age- and sex-matched controls. Using a multiregression model, none of the studied variables were associated with an increased risk of having either disorder. Depression or anxiety symptoms independently and significantly increased the risk of association with the other disorder. Almost two-thirds of patients with depression and anxiety were not prescribed antidepressant or antianxiety medications.

Delivery of epilepsy care to adults with intellectual and developmental disabilities

Epilepsy is common in people with intellectual and developmental disabilities (IDD). In adulthood, patients with IDD and epilepsy (IDD-E) have neurologic, psychiatric, medical, and social challenges compounded by fragmented and limited care. With increasing neurologic disability, there is a higher frequency of epilepsy, especially symptomatic generalized and treatment-resistant epilepsies. The causes of IDD-E are increasingly recognized to be genetic based on chromosomal microarray analysis to identify copy number variants, gene panels (epilepsy, autism spectrum disorder, intellectual disability), and whole-exome sequencing. A specific genetic diagnosis may guide care by pointing to comorbid disorders and best therapy. Therapy to control seizures should be individualized, with drug selection based on seizure types, epilepsy syndrome, concomitant medications, and comorbid disorders. There are limited comparative antiepileptic drug data in the IDD-E population. Vagus nerve and responsive neural stimulation therapies and resective surgery should be considered. Among the many comorbid disorders that affect patients with IDD-E, psychiatric and sleep disorders are common but often unrecognized and typically not treated. Transition from holistic and coordinated pediatric to adult care is often a vulnerable period. Communication among adult health care providers is complex but essential to ensure best care when these patients are seen in outpatient, emergency room, and inpatient settings. We propose specific recommendations for minimum care standards for people with IDD-E.

Pharmacological interventions for epilepsy in people with intellectual disabilities

BACKGROUND

The prevalence of epilepsy among people with intellectual disabilities is much higher than in the general population. Seizures in this population are often complex and refractory to treatment and antiepileptic medication may have a profound effect upon behaviour (Kerr 1997).This is an updated version of a Cochrane Review first published in Issue 3, 2007.

OBJECTIVES

To assess the data available from randomised controlled trials (RCTs) of the efficacy of antiepileptic drug (AED) interventions in people with epilepsy and intellectual disabilities.

SEARCH METHODS

For the latest update of this review, we searched the Cochrane Epilepsy Group Specialised Register (2 September 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO) (2 September 2014), MEDLINE (Ovid, 1946 to 3 September 2014) and PsycINFO (EBSCOhost, 1887 to 3 September 2014).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials (RCTs) of pharmacological interventions for people with epilepsy and a learning disability.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors for additional information. We assessed epilepsy/seizure, behavioural and cognitive outcomes, as well as quality of life and adverse effects.

MAIN RESULTS

We included 14 RCTs (1116 participants) in the present review. Data were heterogenous and a descriptive analysis is presented. In the majority of cases where antiepileptic drugs (AEDs) were trialled in this population, we found moderate reductions in seizure frequency in that there was a significantly higher rate of responders (reduction of 50% or more) in the treatment group compared with the placebo group, with some studies reporting a higher incidence of seizure freedom in the treatment group. In general, AEDs that are proven to be effective in the general epilepsy population are also effective for refractory epilepsy in people with intellectual disability. It is not possible to comment on the relative efficacy of medications, making clinical decisions difficult.In trial settings patients continued on treatment in the majority of cases. Placebo groups often experienced fewer adverse events. Where adverse events were experienced they appeared similar to those in the general population. The methods by which adverse events were recorded and reported appeared to be inconsistent, resulting in very large variation between studies. This is problematic as clinically relevant interpretation of these findings is limited.The quality of evidence provided in the present review is low to moderate. Additionally the majority of studies lacked or used non-reliable measures of behavioural exacerbation. However, where measured, little obvious impact on behaviour was seen in terms of behaviour disorder.

AUTHORS' CONCLUSIONS

This review broadly supports the use of AEDs to reduce seizure frequency in people with refractory epilepsy and intellectual disability. The evidence suggests that adverse events are similar to those in the general population and that behavioural adverse events leading to discontinuation are rare; however, other adverse effects are under-researched.

Epidemiology of epilepsy in older adults with an intellectual disability in Ireland: associations and service implications

There are limited studies on the prevalence of epilepsy and co-morbid conditions in older adults with an ID. To begin to address this prevalence of epilepsy was estimated for participants in the Intellectual Disability Supplement to the Irish Longitudinal Study on Ageing. Associations with demographic variables and co morbid health conditions were examined. It was found that prevalence was high (30.7%); but declined as people aged. Those with epilepsy were less likely to live with family, independently or in community settings, rates of refractory epilepsy were high and, despite medication over half of those with epilepsy still reported experiencing seizures. Given these findings, people with ID and their careers have considerable needs for information about epilepsy management, and for support from specialist ID and epilepsy services.

Research on psychosocial aspects of epilepsy in Arab countries: a review of literature

This study reviewed research conducted on the psychological aspects of epilepsy in Arab countries. Several databases (Medline, PubMed, Science Direct, Springer Link, and PsycInfo) were searched using the following two sets of search words: (1) Arab, Jordan, Lebanon, United Arab Emirates (UAE), Bahrain, Qatar, Kuwait, Oman, Saudi Arabia, Syria, Iraq, Egypt, Yemen, Tunisia, Libya, Morocco, Algiers, Palestine, Mauritania, Djibouti, Sudan, Comoros, and Somalia; and (2) epilepsy, seizure disorders, and convulsive disorders. Fifty-one studies were conducted in 12 Arab states. Social/emotional, employment, and other problems; knowledge and attitudes; and quality of life (QOL) were the most commonly measured parameters of psychosocial aspects of epilepsy in Arab countries. Results revealed elevated levels of depression and anxiety, a decline in cognitive function, various behavioral problems, sexual dysfunction, and underemployment among persons with epilepsy (PWE). Misconceptions about epilepsy were found to be prevalent. While many studies reported limited knowledge of epilepsy, some studies found an average knowledge. Negative attitudes toward epilepsy were reported in most studies, and moderately positive attitudes were reported in some studies. Finally, PWE showed low overall QOL scores in the majority of studies.

Psychometric evaluation of a Dutch version of the Mini PAS-ADD for assessing psychiatric disorders in adults with different levels of intellectual disability

BACKGROUND

People with intellectual disabilities (ID) have an increased vulnerability to develop psychiatric problems. Moreover, the early recognition and the accurate diagnosis of psychiatric disorders in the population of persons with ID are challenging.

METHOD

A Dutch version of the Mini PAS-ADD, which is a screening instrument for identification of mental health problems in people with ID, was evaluated in terms of internal consistency, interinformant reliability, item grouping and criterion validity based on a large-scale random sample (n = 377) and a clinical sample (n = 99) of adults with ID.

RESULTS

The Dutch version of the Mini PAS-ADD showed moderate internal consistency, and moderate concordance among informants. Both aspects of the reliability were comparable for different levels of ID. A factor analysis largely confirmed the scale structure. Concurrent validity with the Reiss Screen for Maladaptive Behavior was high for the Depression, Psychosis and Autism scale. The outcome of the criterion-validity analysis indicated high specificity. The sensitivity for specific psychiatric disorders by the corresponding scales was moderate, but the general sensitivity for the presence of psychopathology on the basis of any of the scales was satisfying.

CONCLUSIONS

The present research reconfirmed the use of the Mini PAS-ADD as a primary screening device for the identification of mental health problems among people with ID.

Lamotrigine positively affects the development of psychiatric comorbidity in epileptic animals, while psychiatric comorbidity aggravates seizures

Several clinical and preclinical studies have focused on the relationship between epilepsy and psychological disturbances. Although behavior in some experimental models of epilepsy has been studied, only few of them can be considered as models of epilepsy and mood disorder comorbidity. Since several models of epilepsy or psychiatric disorders are already available, we wondered whether a mixture of the two could experimentally represent a valid alternative to study such comorbidity. Here, we present a possible experimental protocol to study drug effects and physiopathogenesis of psychiatric comorbidity in epileptic animals. Pentylentetrazol-kindled animals were subjected to the chronic mild stress (CMS) procedure; furthermore, we tested the effects of chronic lamotrigine treatment on the development of comorbidity. We found that epileptic-depressed animals showed more pronounced behavioral alterations in comparison to other mice groups, indicating that kindled animals develop more pronounced CMS-induced behavioral alterations than nonepileptic mice; lamotrigine was able to prevent the development of comorbidities such as anxiety, depression-like behavior, and memory impairment.

Treatment of behavioral problems in intellectually disabled adult patients with epilepsy

Behavioral disorders are common in people with epilepsy and intellectual disability. Although in some genetic disorders behavioral problems are part of the established phenotype, they may also be a manifestation of underlying physical or mental illness, or may be unrecognized seizure activity. In light of this, assessment of behavioral disorders should take into account person factors such as the physical health and mental state of the person and environmental factors such as the quality of their interactions with carers and their living conditions. Video-electroencephalography ( EEG) is recommended where possible. We review potential pharmacologic and behavioral management strategies for behavioral disorders in people with intellectual disability.

The impact of epilepsy on patients' lives

The impact of epilepsy is multifaceted and extensive on its effects. The occurrence of seizures is unpredictable and often dangerous, increasing the risk of injury, hospitalization and mortality, and adversely affecting a patient's mental health, often resulting in anxiety, depression or cognitive impairment. Seizures can also result in stigmatization and social exclusion, with detrimental effects on an individual's confidence and self-esteem. However, the burden of epilepsy extends beyond the effects of seizures themselves. In particular, individuals with epilepsy are significantly more likely to have medical or psychiatric comorbidities than those without epilepsy, and comorbidity in patients with epilepsy has been shown to be strongly correlated with negative impacts on subjective health status and quality of life (QoL). In addition, antiepileptic drug (AED) treatment is commonly associated with side effects, which further impair patients' QoL. Patient surveys provide valuable insights into what matters to patients in their daily lives and highlight important discrepancies between the perceptions of patients and their physicians. For example, survey data show that physicians underestimate the number of patients experiencing AED side effects and the impact of these on patients. Screening questionnaires can help physicians to quickly identify problems with treatment side effects; also, to recognize comorbidities such as depression that are otherwise difficult to identify in a time-limited consultation. Ultimately, successful management of epilepsy requires a holistic approach to care, with treatment tailored to the individual patient's needs; this can only be achieved through effective doctor-patient communication and the full involvement of a multidisciplinary care team.

Epilepsy in four genetically determined syndromes of intellectual disability

BACKGROUND

Epilepsy occurs with increased frequency in people with an intellectual disability (ID) compared to the rest of the population. A variety of research has in recent years shed light on genetic and biochemical aetiologies of epilepsy and, often in a different literature, on syndromes of ID. The aims of this annotation are to review developments in understanding of the pathophysiology of several ID syndromes in which epilepsy is a frequent co-occurrence and to relate these observations to recent advances in understanding of how these pathophysiological disturbances may lead to epilepsy.

METHOD

The ID syndromes selected for review were fragile X (FXS), Rett (RTT) and Angelman syndromes (AS) and tuberous sclerosis complex (TSC). Epilepsy is a significant aspect of these syndromes and relevant research into the genetic and biochemical pathophysiology of these four ID syndromes may be informative in establishing the association between epilepsy and ID. Employing a structured approach the authors initially searched the PubMed database for large case series describing the characteristics of epilepsy as manifested in these ID syndromes. The criteria for inclusion of the case series in the review were a sample size of greater than 50 and the description of several of the characteristic features of epilepsy, namely prevalence of seizures, age of seizure onset, seizure frequency, seizure semiology, severity and treatment. Following this, studies of the genetic and biochemical pathophysiology of these four ID syndromes were reviewed and the potential relevance of this research in understanding the association with epilepsy highlighted. Findings were considered in a focused manner in terms of effects on excitatory and inhibitory neurotransmitter systems and on glial function.

RESULTS

Diverse genetic pathologies underlying several ID syndromes can lead to alterations in the functioning of the glutamatergic and GABAergic neurotransmitter systems. The mechanisms involved include transcriptional regulation in RTT, translational regulation in FXS and TSC, and UBE3A-mediated proteolysis in AS. Expression or functioning of receptor subunits, uptake sites and enzymes involved in neurotransmitter metabolism are often affected by these changes, and may lead to modifications in network excitability and neuronal plasticity that may contribute to epileptogenesis and ID. Dysfunction in astrocytes may also contribute to epileptogenesis and ID in FXS, RTT and TSC with potential mechanisms including failure of astrocytic support functions, glial inflammation and homeostatic disturbances that affect the excitability and architecture of neuronal networks.

CONCLUSIONS

The annotation highlights research describing disturbances in excitatory and inhibitory neurotransmitter systems, neuronal ion channel and glial functions that provide possible explanations for the co-occurrence of seizures within several ID syndromes, in some cases suggesting possible avenues for research into novel therapeutic targets. Phenotypic overlaps between syndromes may also relate to roles for the implicated genes in different disturbances in linked biochemical pathways.

Antiepileptic drugs with mood stabilizing properties and their relation with psychotropic drug use in institutionalized epilepsy patients with intellectual disability

A large number of patients with epilepsy and intellectual disability take medication, amongst which antiepileptic and psychotropic drugs, often simultaneously. Certain antiepileptic drugs have mood-stabilizing properties, e.g. carbamazepine, valproic acid and lamotrigine. The aim of this study was to investigate whether the use of these mood-stabilizers is associated with a different use of psychotropic drugs in a population of institutionalized epilepsy patients with intellectual disability. We performed a retrospective, cohort study of adults with intellectual disability and epilepsy at the long-stay department of an epilepsy centre in The Netherlands. 246 residents were included. In patients using lamotrigine we found a statistically significant lower use of antidepressants. We also found significant less prescriptions of anxiolytics in patients using AEDs with mood-stabilizing properties (carbamazepine, valproic acid and lamotrigine). When considering the effect of gender, we found that male patients took significantly more antipsychotics. Most important, we found an inverse relation between the drug load of carbamazepine and/or valproic acid and/or lamotrigine and the use of psychotropic drugs. In a population of institutionalized epilepsy patients with intellectual disability, higher drug loads of mood-stabilizing antiepileptic drugs correspond with less use of psychotropic drugs.