Temporal Lobe Epilepsy Psychosis Research Articles

GL-II-73, a Positive Allosteric Modulator of α5GABAA Receptors, Reverses Dopamine System Dysfunction Associated with Pilocarpine-Induced Temporal Lobe Epilepsy.

Although seizures are a hallmark feature of temporal lobe epilepsy (TLE), psychiatric comorbidities, including psychosis, are frequently associated with TLE and contribute to decreased quality of life. Currently, there are no defined therapeutic protocols to manage psychosis in TLE patients, as antipsychotic agents may induce epileptic seizures and are associated with severe side effects and pharmacokinetic and pharmacodynamic interactions with antiepileptic drugs. Thus, novel treatment strategies are necessary. Several lines of evidence suggest that hippocampal hyperactivity is central to the pathology of both TLE and psychosis; therefore, restoring hippocampal activity back to normal levels may be a novel therapeutic approach for treating psychosis in TLE. In rodent models, increased activity in the ventral hippocampus (vHipp) results in aberrant dopamine system function, which is thought to underlie symptoms of psychosis. Indeed, we have previously demonstrated that targeting α5-containing γ-aminobutyric acid receptors (α5GABAARs), an inhibitory receptor abundant in the hippocampus, with positive allosteric modulators (PAMs), can restore dopamine system function in rodent models displaying hippocampal hyperactivity. Thus, we posited that α5-PAMs may be beneficial in a model used to study TLE. Here, we demonstrate that pilocarpine-induced TLE is associated with increased VTA dopamine neuron activity, an effect that was completely reversed by intra-vHipp administration of GL-II-73, a selective α5-PAM. Further, pilocarpine did not alter the hippocampal α5GABAAR expression or synaptic localization that may affect the efficacy of α5-PAMs. Taken together, these results suggest augmenting α5GABAAR function as a novel therapeutic modality for the treatment of psychosis in TLE.

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

Background: Despite the importance of psychosis as a comorbidity of temporal lobe epilepsy (TLE), the underlying neural mechanisms are still unclear. We aimed to investigate abnormalities specific to psychosis in TLE, using diffusion MRI parameters and graph-theoretical network analysis.Material and Methods: We recruited 49 patients with TLE (20 with and 29 without interictal schizophrenia-like psychosis) and 42 age-/gender-matched healthy controls. We performed 3-tesla MRI scans including 3D T1-weighted imaging and diffusion tensor imaging in all participants. Among the three groups, fractional anisotropy (FA), mean diffusivity (MD), and global network metrics were compared by analyses of covariance. Regional connectivity strength was compared by network-based statistics.Results: Compared to controls, TLE patients showed significant temporal and extra-temporal changes in FA, and MD, which were more severe and widespread in patients with than without psychosis. We observed distinct differences between TLE patients with and without psychosis in the anterior thalamic radiation (ATR), inferior fronto-occipital fasciculus (IFOF), and inferior longitudinal fasciculus (ILF). Similarly, for network metrics, global, and local efficiency and increased path length were significantly reduced in TLE patients compared to controls, but with more severe changes in TLE with psychosis than without psychosis. Network-based statistics detected significant differences between TLE with and without psychosis mainly involving the left limbic and prefrontal areas.Conclusion: TLE patients with interictal schizophrenia-like psychosis showed more widespread and severe white matter impairment, involving the ATR, IFOF and ILF, as well as disrupted network connectivity, particularly in the left limbic and prefrontal cortex, than patients without psychosis.

Graph Theoretical Analysis of Structural Neuroimaging in Temporal Lobe Epilepsy with and without Psychosis.

PurposePsychosis is one of the most important psychiatric comorbidities in temporal lobe epilepsy (TLE), and its pathophysiology still remains unsolved. We aimed to explore the connectivity differences of structural neuroimaging between TLE with and without psychosis using a graph theoretical analysis, which is an emerging mathematical method to investigate network connections in the brain as a small-world system.Materials and MethodsWe recruited 11 TLE patients with unilateral hippocampal sclerosis (HS) presenting psychosis or having a history of psychosis (TLE-P group). As controls, 15 TLE patients with unilateral HS without any history of psychotic episodes were also recruited (TLE-N group). For graph theoretical analysis, the normalized gray matter images of both groups were subjected to Graph Analysis Toolbox (GAT). As secondary analyses, each group was compared to 14 age- and gender-matched healthy subjects.ResultsThe hub node locations were found predominantly in the ipsilateral hemisphere in the TLE-N group, and mainly on the contralateral side in the TLE-P group. The TLE-P group showed significantly higher characteristic path length, transitivity, lower global efficiency, and resilience to random or targeted attack than those of the TLE-N group. The regional comparison in betweenness centrality revealed significantly decreased connectivity in the contralateral temporal lobe, ipsilateral middle frontal gyrus, and bilateral postcentral gyri in the TLE-P group. The healthy subjects showed well-balanced nodes/edges distributions, similar metrics to TLE-N group except for higher small-worldness/modularity/assortativity, and various differences of regional betweenness/clustering.ConclusionIn TLE with psychosis, graph theoretical analysis of structural imaging revealed disrupted connectivity in the contralateral hemisphere. The network metrics suggested that the existence of psychosis can bring vulnerability and decreased efficiency of the whole-brain network. The sharp differences in structural networks between morphologically homogeneous groups are remarkable and may contribute to a better understanding of psychosis in TLE.

The prevalence of psychosis in epilepsy; a systematic review and meta-analysis.

BackgroundEpilepsy has long been considered to be a risk factor for psychosis. However there is a lack of consistency in findings across studies on the effect size of this risk which reflects methodological differences in studies and changing diagnostic classifications within neurology and psychiatry. The aim of this study was to assess the prevalence of psychosis in epilepsy and to estimate the risk of psychosis among individuals with epilepsy compared with controls.MethodsA systematic review and meta-analysis was conducted of all published literature pertaining to prevalence rates of psychosis in epilepsy using electronic databases PUBMED, OVIDMEDLINE, PsychINFO and Embase from their inception until September 2010 with the following search terms: prevalence, incidence, rate, rates, psychosis, schizophrenia, schizophreniform illness, epilepsy, seizures, temporal lobe epilepsy.ResultsThe literature search and search of reference lists yielded 215 papers. Of these, 58 (27%) had data relevant to the review and 157 were excluded following a more detailed assessment. 10% of the included studies were population based studies. The pooled odds ratio for risk of psychosis among people with epilepsy compared with controls was 7.8. The pooled estimate of prevalence of psychosis in epilepsy was found to be 5.6% (95% CI: 4.8-6.4). There was a high level of heterogeneity. The prevalence of psychosis in temporal lobe epilepsy was 7% (95% CI: 4.9-9.1). The prevalence of interictal psychosis in epilepsy was 5.2% (95% CI: 3.3-7.2). The prevalence of postictal psychosis in epilepsy was 2% (95% CI: 1.2-2.8).ConclusionsOur systematic review found that up to 6% of individuals with epilepsy have a co-morbid psychotic illness and that patients have an almost eight fold increased risk of psychosis. The prevalence rate of psychosis is higher in temporal lobe epilepsy (7%). We suggest that further investigation of this association could give clues to the aetiology of psychosis.

Postictal psychosis in temporal lobe epilepsy

Postictal psychosis in temporal lobe epilepsy

Postictal psychosis in temporal lobe epilepsy: Risk factors and postsurgical outcome?

Postictal psychosis (PIP) occurs in ∼7% of patients with temporal lobe epilepsy (TLE). The aims of this study were to identify risk factors that may predispose patients to developing PIP and determine whether the severity of PIP predicts postsurgical outcome. We compared 20 patients with a history of TLE+PIP to 60 age-matched TLE patients without any psychiatric history (TLE-only), with respect to pre-surgical clinical and neuropsychological variables. Group differences in postsurgical psychiatric, histopathological, cognitive and seizure outcomes were also examined. TLE+PIP patients were significantly less likely to have localised ictal epileptiform activity than the TLE controls (p=0.05) and were significantly more likely to have a positive family psychiatric history than TLE controls (p=0.04). Other pre-surgical clinical and neuropsychological variables did not distinguish between the groups. Patients with two or more PIP episodes had significantly increased odds of developing de novo psychopathology within 4 years of surgery, after controlling for comorbid pre-surgical psychiatric status and a history of SGTCS (OR: 9.11, 95% CI: 1.53-54.10, p=0.02). A history of PIP did not significantly predict other postsurgical outcomes (seizure freedom (ILAE=1) or cognitive outcome). Our results suggest that more widespread or diffuse brain abnormalities as reflected by pre-surgical EEG findings and positive genetic determinants may contribute to the development of PIP. Furthermore, patients with recurrent PIP episodes who undergo TLE surgery are at increased risk of developing de novo psychiatric disorders, particularly mood disorders. This has implications for pre-operative counselling and highlights a need for postsurgical psychiatric monitoring for these patients.

Postictal psychosis in temporal lobe epilepsy: a case–control study

To investigate the prevalence of postictal psychosis (PP) in patients with temporal lobe epilepsy (TLE) and to estimate the predictive value of various variables for the development of PP. By retrospectively reviewing the charts of all patients evaluated with video-electroencephalogram (EEG)-monitoring at our unit between January 1995 and February 2012, we identified 684 patients with TLE, of which 48 patients had a history of PP. Patients with TLE and PP were compared with 200 controls (patients with TLE without a psychotic history) on demographic, clinical, EEG and magnetic resonance imaging (MRI) variables. The prevalence of PP in our TLE sample was 7.0%. Aggressive behaviour during PP was present in 22.9% of the sample. Univariate analysis revealed that PP was significantly associated with early age at epilepsy onset (P = 0.007), longer duration of epilepsy (P = 0.002), presence of ictal fear (P = 0.005), impaired intellectual function (P = 0.045), and bilateral ictal and interictal epileptiform activity (both P < 0.0001). Using logistic regression analysis, ictal fear [odds ratio (OR) 2.88; P = 0.015] and bilateral interictal EEG activity (OR 6.40; P < 0.0001) were predictive of PP development. No association of PP with MRI pathology or epilepsy-relevant aetiological factors was found. PP is a frequent and potentially dangerous complication within the course of TLE. Bilateral or widespread functional central nervous system disturbances rather than distinct structural brain alterations or certain predisposing aetiologies of epilepsy appear to be a risk factor for the development of PP. Ictal fear may be a predictive clinical variable of PP in TLE.

Psychiatric Comorbidities in Temporal Lobe Epilepsy: Possible Relationships between Psychotic Disorders and Involvement of Limbic Circuits

Mounting evidence suggests that the limbic system is pathologically involved in cases of psychiatric comorbidities in temporal lobe epilepsy (TLE) patients. Our objective was to develop a conceptual framework describing how neuropathological and connectivity changes might contribute to the development of psychosis and to the potential neurobiological mechanisms that cause schizophrenia-like psychosis in TLE patients. In this review, clinical and neuropathological findings, especially brain circuitry of the limbic system, were examined together to enhance our understanding of the association between TLE and psychosis. Finally, the importance of animal models in epilepsy and psychiatric disorders was discussed. TLE and psychiatric symptoms coexist more frequently than chance would predict. Damage and deregulation among critical anatomical regions, such as the hippocampus, amygdala, thalamus, and the temporal, frontal and cingulate cortices, might predispose TLE brains to psychosis. Studies of the effects of kindling and injection of neuroactive substances on behavior and electrophysiological patterns may offer a model of how limbic seizures in humans increase the vulnerability of TLE patients to psychiatric symptoms.

Neuroanatomical correlates of psychosis in temporal lobe epilepsy: voxel-based morphometry study

Temporal lobe epilepsy is associated with a significant risk of psychosis but there are only limited studies investigating the underlying neurobiology. To characterise neuroanatomical changes in temporal lobe epilepsy and comorbid psychosis. The study population comprised all individuals with temporal lobe epilepsy on the epilepsy database at the National Centre for Epilepsy and Epilepsy Neurosurgery in Ireland (Beaumont Hospital) between 2002 and 2006. Ten people with temporal lobe epilepsy with psychosis were matched for age, gender, handedness, epilepsy duration, seizure laterality, severity of epilepsy and anti-epileptic medication with ten comparison participants with temporal lobe epilepsy only. Participants received a magnetic resonance imaging scan and voxel-based morphometry analyses were applied to grey and white matter anatomy. Significant grey matter reduction was found bilaterally in those with temporal lobe epilepsy with psychosis in the temporal lobes in the inferior, middle and superior temporal gyri and fusiform gyri, and unilaterally in the left parahippocampal gyrus and hippocampus. Significant extratemporal grey matter reduction was found bilaterally in the insula, cerebellum, caudate nuclei and in the right cingulum and left inferior parietal lobule. Significant white matter reduction in those with temporal lobe epilepsy with psychosis was found bilaterally in the hippocampus, parahippocampal/fusiform gyri, middle/inferior temporal gyri, cingulum, corpus callosum, posterior thalamic radiation, anterior limb of internal capsule and white matter fibres from the caudate nuclei, and unilaterally in the left lingual gyrus and right midbrain and superior temporal gyrus. Significant grey and white matter deficits occur in temporal lobe epilepsy with psychosis. These encompass the medial temporal lobe structures but also extend to lateral temporal and extratemporal regions. Some of these deficits overlap with those found in schizophrenia.

100 years of Epilepsia: Landmark papers and their influence in neuropsychology and neuropsychiatry

As part of the 2009 International League Against Epilepsy (ILAE) Centenary Celebration, a special symposium was dedicated to Epilepsia (100 Years of Epilepsia: Landmark Papers and Their Influence). The Associate Editors were asked to identify a particularly salient and meaningful paper in their areas of expertise. From the content areas of neuropsychology and neuropsychiatry two very interesting papers were identified using quite different ascertainment techniques. One paper addressed the problem of psychosis in temporal lobe epilepsy, whereas the other represents the first paper to appear in Epilepsia presenting quantitative assessment of cognitive status in epilepsy. These two papers are reviewed in detail and placed in historical context.

Enhancement of central dopaminergic activity in the kainate model of temporal lobe epilepsy: implication for the mechanism of epileptic psychosis.

There is an increased incidence of schizophrenia-like psychosis in temporal lobe epilepsy (TLE), and several risk factors have been implicated, including the duration of epilepsy and temporal lobe neuropathology. To investigate the biological mechanism of epileptic psychosis, we examined alterations of central dopaminergic systems in the kainate model of TLE. In adult rats, kainate was microinjected into the left amygdala to induce status epilepticus. An indirect dopamine agonist methamphetamine (MAP, 2 mg/kg, i.p.) was administered before and 1 month after the kainate treatment. MAP-induced locomotor activity was significantly enhanced in the kainate group compared with the baseline (pre-kainate) level, which was antagonized by pretreatment with haloperidol. The enhancement of locomotor activity in the kainate group was significantly correlated with the density of hippocampal CA1 neurons. Although the basal extracellular dopamine concentration was significantly lower in the striatum in the kainate group than in the control group (5.5 vs 39.2 fmol/20-min sample), the maximal concentration following MAP administration did not differ between the two groups. These results clearly demonstrate that hypersensitivity of the dopamine systems develops in the chronic phase of the kainate-induced TLE model, which may be responsible for the mechanism of epileptic psychosis.

Models for understanding the antagonism between seizures and psychosis

Pollock, Daniel C. : Models for Understanding the Antagonism Between Seizures and Psychosis. Prog. Neuro-Psychopharmacol. & Biol. Psychiat. 1987, 11 : 483–504 1. 1. The relationship between seizures and psychosis is reviewed using incidence and association studies, and experimental models of kindling and behavioral sensitization. 2. 2. While there are conflicting data on the association of psychopathology with epilepsy, studies illustrating the antagonism between seizures and psychosis are examined along with the phenomenon of “Forced Normalization”. 3. 3. Electrical kindling of the amygdala provides a model of temporal lobe epilepsy while pharmacologic kindling/behavioral sensitization or dopaminergic kindling provides a model for psychosis. 4. 4. A model explaining both the etiology and the reciprocal nature of seizures and psychosis in temporal lobe epilepsy is developed. Preictal and interictal spikes kindle both proconvulsive and inhibitory pathways of seixure expression and behaviorally relevant limbic systems. That system currently expressive, either seizure or psychosis, while under high synchronous drive would tend to fail allowing for the emergence of the opposing system.

Similarities in mental content of psychotic states, spontaneous seizures, dreams, and responses to electrical brain stimulation in patients with temporal lobe epilepsy.

The present study was guided by the hypothesis that temporal lobe epilepsy psychosis is associated with a definable syndrome of deficits in the higher cortical functions. Comparison was made of the mental content and mechanisms observed during psychotic episodes, seizures, dreams, and responses to electrical brain stimulation occurring in diverse combinations in 5 patients with drug-refractory temporal lobe epilepsy referred for neurosurgical treatment. Neurological, neuroradiological, EEG, and neuropsychiatric base lines were available before onset of the psychosis. Psychiatric manifestations were related to the interaction of disturbances in specific higher cortical functions and individual dynamic configurations. Interpatient variation in psychotic symptomatology arose from significant elements in the patient's past and current emotional life which provided the psychosis with form and content.