The organic contribution to depressive illness in patients with epilepsy

Effects of psychotropic drugs on seizure threshold

Psychotropic drugs, especially antidepressants and antipsychotics, may give rise to some concern in clinical practice because of their known ability to reduce seizure threshold and to provoke epileptic seizures. Although the phenomenon has been described with almost all the available compounds, neither its real magnitude nor the seizurogenic potential of individual drugs have been clearly established so far. In large investigations, seizure incidence rates have been reported to range from approximately 0.1 to approximately 1.5% in patients treated with therapeutic doses of most commonly used antidepressants and antipsychotics (incidence of the first unprovoked seizure in the general population is 0.07 to 0.09%). In patients who have taken an overdose, the seizure risk rises markedly, achieving values of approximately 4 to approximately 30%. This large variability, probably due to methodological differences among studies, makes data confusing and difficult to interpret. Agreement, however, converges on the following: seizures triggered by psychotropic drugs are a dose-dependent adverse effect; maprotiline and clomipramine among antidepressants and chlorpromazine and clozapine among antipsychotics that have a relatively high seizurogenic potential; phenelzine, tranylcypromine, fluoxetine, paroxetine, sertraline, venlafaxine and trazodone among antidepressants and fluphenazine, haloperidol, pimozide and risperidone among antipsychotics that exhibit a relatively low risk. Apart from drug-related factors, seizure precipitation during psychotropic drug medication is greatly influenced by the individual's inherited seizure threshold and, particularly, by the presence of seizurogenic conditions (such as history of epilepsy, brain damage, etc.). Pending identification of compounds with less or no effect on seizure threshold and formulation of definite therapeutic guidelines especially for patients at risk for seizures, the problem may be minimised through careful evaluation of the possible presence of seizurogenic conditions and simplification of the therapeutic scheme (low starting doses/slow dose escalation, maintenance of the minimal effective dose, avoidance of complex drug combinations, etc.). Although there is sufficient evidence that psychotropic drugs may lower seizure threshold, published literature data have also suggested that an appropriate psychotropic therapy may not only improve the mental state in patients with epilepsy, but also exert antiepileptic effects through a specific action. Further scientific research is warranted to clarify all aspects characterising the complex link between seizure threshold and psychotropic drugs.

People with intellectual disability, sensory impairments and behaviour disorder: a case series

BACKGROUND

Sensory impairments (SIs) are more prevalent in people with intellectual disability (ID). Both conditions lead to higher rates of emotional and behavioural problems than in the general population. The identification of psychiatric disorders in this group can be difficult, particularly in those with severe ID and limited communication skills.

METHOD

The present paper presents a series of 18 case reports of individuals with ID, SI and behavioural problems.

RESULTS

The majority of cases were young male caucasians with congenital rubella syndrome and autistic spectrum disorder, referred because of self-injurious behaviour (SIB) or aggression. Nine cases were treated with autidepressants, five underwent environmental changes and two had medication reduced. All showed some improvement.

CONCLUSIONS

The benefits of comprehensive assessments, the use of standardized assessment tools and trials of treatments are discussed in the context of making psychiatric diagnoses.

The Frontal Lobes, Epilepsy, and Behavior

The frontal lobes have been overshadowed by the temporal lobes in the vast literature addressing the neurobehavioral and psychological perspectives of epilepsy. The purpose of this review is to summarize contemporary anatomicobehavioral correlations and to highlight the frontal lobe contributions to the neurology, neuropsychology, and neuropsychiatry of epilepsy, in general, and to temporal lobe epilepsy (TLE) and frontal lobe epilepsy (FLE), in particular. Much evidence has accumulated suggesting that focal epileptogenic tissue may have effects on distant neural systems. Data supporting the case that the frontal regions are preferentially affected in TLE are presented. Emphasis is placed on the results of numerous functional imaging studies demonstrating correlations between frontal hypoperfusion and cognitive or mood impairments in patients with TLE.

Comorbid psychiatric symptoms in temporal lobe epilepsy: association with chronicity of epilepsy and impact on quality of life

Purpose. The goals of this work were to determine: (1) the nature and extent of differences in self-reported psychiatric symptoms between patients with temporal lobe epilepsy and matched healthy controls, (2) the relationship between chronicity (duration) of temporal lobe epilepsy and comorbid interictal psychiatric symptoms, and (3) the impact of comorbid psychiatric symptoms on self-reported health-related quality of life. Methods. Patients with temporal lobe epilepsy (n = 54) and healthy controls (n = 38) were administered the Symptom Checklist-90-Revised (SCL-90-R) to assess the nature and severity of psychiatric symptomatology and epilepsy patients completed the Quality of Life in Epilepsy-89 (QOLIE-89) to define health-related quality of life. Among epilepsy patients the SCL-90-R scales were examined in relation to chronicity of temporal lobe epilepsy as well as the impact of comorbid emotional-behavioral distress on health-related quality of life. Results. Compared with healthy controls, patients with epilepsy exhibited significantly higher (worse) scores across all but one of the 12 SCL-90-R scales. Among patients with epilepsy, increasing chronicity was associated with significantly higher (worse) scores across all SCL-90-R scales and increased emotional-behavioral distress was associated with lower (worse) scores across all 17 QOLIE-89 scales. Conclusion. Comorbid interictal psychiatric symptoms are elevated among patients with temporal lobe epilepsy compared with healthy controls and appear to be modestly associated with increasing chronicity (duration) of epilepsy. This comorbid emotional-behavioral distress is specifically associated with a significantly poorer health-related quality of life, and suggests that quality-of-life research should devote greater attention to the potential impact of comorbid psychiatric distress.

Depression in patients with temporal lobe epilepsy is related to mesial temporal sclerosis

Depression is a frequent psychiatric symptom in epilepsy and has been related to epilepsy of temporal origin, especially of left-sided foci. No study differentiated the precise localization of the epileptogenic lesion within the temporal lobe. Regarding this issue, we evaluated depression assessed by the Beck Depression Inventory in 60 patients with temporal lobe epilepsy, with particular consideration of morphological abnormalities within the temporal lobe (mesial temporal sclerosis (MTS) versus neocortical lesions) and lateralization of the lesion. Multivariate analyses indicated significant higher depression scores in MTS independent of the lateralization of the lesion. Depression was a good indicator for MTS but not vice versa. Hence, MTS can be discussed as a predisposing factor for the development of mood disorders in focal epilepsy.

Moderators of the effect of preoperative emotional adjustment on postoperative depression after surgery for temporal lobe epilepsy

PURPOSE

Other outcome measures besides seizure control must be considered when assessing the benefit of epilepsy surgery. We investigated the effect of preoperative psychosocial adjustment on postoperative depression in epilepsy patients followed up prospectively for 2 years after temporal lobectomy.

METHODS

The Washington Psychosocial Seizure Inventory (WPSI) evaluated psychosocial functioning; the Centre for Epidemiological Studies Depression Scale (CES-D) measured depression. Both were completed at baseline and follow-up.

RESULTS

Follow-up occurred in 39 temporal lobectomy patients at 2 years after surgery. Greatest improvement in depression scores was limited to patients with good seizure outcomes (seizure free, or marked reduction in seizure frequency), and seizure outcome was a significant predictor of postoperative depression. Despite this, preoperative scores on the emotional adjustment scale of the WPSI were most highly correlated with depression 2 years after surgery. To clarify this relation, moderated hierarchic regression suggested that good preoperative emotional adjustment (WPSI) was generally associated with less depression after surgery. Moreover, poorer preoperative adjustment combined with older age, generalized seizures, the finding of preoperative neurologic deficits, a family history of psychiatric illness, and/or a family history of seizures was related to higher depression scores 2 years after surgery.

CONCLUSIONS

Depression after temporal lobectomy is dependent on a complex interaction of variables and can have a significant effect on indices of postoperative adjustment. The WPSI emotional adjustment scale may help to predict which patients are likely to be chronically depressed after surgery.

Depression in epilepsy: a common but often unrecognized comorbid malady

Depressive disorders (DDs) represent the most frequent psychiatric comorbidity in epilepsy (1-5). Despite their relatively high prevalence, DDs remain unrecognized and untreated in many patients with epilepsy. The purpose of this review is to examine the reasons behind the failure to recognize and treat DDs in epilepsy. We highlight the essential epidemiologic, etiopathogenic, and clinical aspects that need to be considered in the evaluation of every epileptic patient and dedicate the last section of this paper to the review of the most relevant treatment issues. If we are successful in our goals, the reader will be impressed by the significant impact of DDs on the quality of life of these patients, and by the need to investigate treatment modalities with the same scientific rigor used in the assessment of efficacy of antiepileptic drugs in the control of seizures.

Antidepressant drugs and seizure susceptibility: from in vitro data to clinical practice

The use of antidepressant drugs (ADs) in patients with epilepsy still raises uncertainties because of the widespread conviction that this class of drugs facilitates seizures. A detailed knowledge of this issue in its various aspects may help in optimal management of patients suffering concurrently from epilepsy and depression. This article reviews the available data in vitro in animals and humans concerning the known potential of various ADs to induce epileptic seizures. Emphasis has been placed on those variables that may generate confusion in interpreting the results of the various studies. Most ADs at therapeutic dosages exhibit in nonepileptic patients a seizure risk close to that reported for the first spontaneous seizure in the general population (i.e., <0.1%). In patients taking high AD doses, seizure incidence rises markedly and may reach values up to 40%. With a patient history of epilepsy and/or concomitant drugs that act on neuronal excitability, low or therapeutic AD doses may be sufficient to trigger seizures. Experimental data are in partial conflict with human data on the relative potential seizure risk of the various ADs. Therefore, a reliable scale for assigning a relative value to an individual AD or to single AD classes cannot be made. It appears fair to say that maprotiline and amoxapine exhibit the greatest seizure risk, whereas trazodone, fluoxetine, and fluvoxamine exhibit the least. Some ADs may also display antiepileptic effects, especially in low doses, in experimental models of epilepsy and in humans, but the mechanism of this action is largely unknown. The available data suggest that ADs may display both convulsant and anticonvulsant effects and that the most important factor in determining the direction of a given compound in terms of excitation/inhibition is drug dosage. It is probable that drugs that increase serotonergic transmission are less convulsant or, even, more anticonvulsant than others. Because of mutual pharmacokinetic interactions between antiepileptic drugs and ADs, with consequent marked changes in plasma concentrations, it remains to be established whether or not plasma AD levels that are effective against depression also facilitate seizures. Finally, exploring the mechanisms through which ADs modulate neuronal excitability might open new possibilities in antiepileptic drug development.

Manifestations of depression in people with intellectual disability

The symptoms of 36 people with varying degrees of intellectual disability (ID) who had had an ICD-10 depressive syndrome in the preceding year were compared with 46 non-depressed people with comparable degrees of ID. Throughout the spectrum of ID, symptoms of depressed affect and sleep disturbance were significantly different between the groups. While symptoms in people with mild ID were reflected in the standard diagnostic criteria, this was not the case in people with moderate and severe ID. With increasing disability there was a move towards 'behavioural depressive equivalents' such as aggression, screaming and self-injurious behaviour. Diagnostic criteria for depression among people with severe ID, should place more emphasis on behavioural 'depressive equivalents'.

Epilepsy and psychiatric disturbance. A cross-sectional study

One hundred patients with cryptogenic epilepsy and normal intelligence and 100 age- and sex-matched controls were submitted to psychiatric interview using the Clinical Interview Schedule. Nineteen patients and 15 controls were identified as having psychiatric disorders. Anxiety and depression were the predominating diagnoses in both groups. Personality disorders were occasionally present in subjects with epilepsy. The study shows that patients with cryptogenic epilepsy and normal neuropsychological abilities should not be considered at any higher risk of psychiatric disturbance than a non-neurological patient population.

Vigabatrin and depression

Ten patients who developed a major depressive episode in association with vigabatrin treatment for intractable epilepsy are reported. The depression usually occurred early in the course of treatment, but when delayed followed a recent increase in dose. Depressive symptoms occurred at doses varying between 1.5 g and 4 g a day, often but not always when patients were experiencing a decrease in their seizure frequency. Most patients had a history of affective disturbance, sometimes in association with other GABAergic drugs. The observations support a possible role for GABAergic mechanisms in the biology of mood disorders.

[Depression and temporal epilepsy. The possible role of laterality of the epileptic foci and of gender]

From a prospective study of 47 epileptic patients (26 men and 21 women) 25 with a left and 22 with a right temporal epileptic focus, the authors show that depression measured by the HARD score, is more severe in males, with a left epileptic focus. These results and the vulnerability to depression of left temporal lobe epileptic patients are analyzed.

Mood state in unilateral temporal lobe epilepsy

The purpose of this investigation was to reexamine the relationship between self-reported depression and laterality of temporal lobe epilepsy and to determine the contribution of associated frontal lobe dysfunction in predisposing patients to depression. Sixty-four patients with complex partial seizures of left (n = 26) or right (n = 38) temporal lobe origin were administered several self-report measures of mood state (Beck Depression Inventory, Center for Epidemiological Studies-Depression scale, Beck Anxiety Inventory), and a test of frontal lobe function [Wisconsin Card Sorting Test (WCST)]. There were no overall differences between the left and right temporal lobe groups on the measures of depression and anxiety. However, the left temporal lobe group exhibited a significant relationship between the degree of associated frontal lobe dysfunction (as indicated by increased perseverative responding on the WCST) and dysphoric mood state. For the right temporal lobe group there was a nonsignificant inverse relationship between mood state and indices of frontal lobe dysfunction. These results (1) are consistent with the broader psychiatric literature, which has implicated a relationship between depression and left frontal lobe dysfunction, (2) suggest that previous conflicting reports of depression/left temporal lobe epilepsy relationships are due in part to variations in the intactness of frontal lobe function, and (3) suggest that the presence of associated frontal lobe dysfunction may be a consideration in understanding interictal psychopathology in epilepsy.

Psychological factors affecting neurological conditions. Depression and stroke, multiple sclerosis, Parkinson's disease, and epilepsy

As a contribution to the proposed revision of the DSM-III-R category "Psychological Factors Affecting Physical Condition" for DSM-IV, this article reviews the history of how the relationship of psychiatric illness to neurological illness has been understood with respect to depression. Since both psychiatric and neurological illness are aspects of brain functioning, any statement of the relationship of these categories entails certain epistemological assumptions, some of which have undergone considerable change and rapid evolution in the course of the last century.