Antiepileptic drugs in the treatment of psychiatric disorders

Myoclonus in renal failure: Two cases of gabapentin toxicity

Gabapentin, an AED approved for the adjunctive treatment of partial seizures with/without secondary generalization and for the treatment of postherpetic neuralgia, is frequently used off-label for the treatment of both psychiatric and pain disorders. Since gabapentin is cleared solely by renal excretion, dosing requires consideration of the patient's renal function. Myoclonic activity may occur as a complication of gabapentin toxicity, especially with acute kidney injury or end-stage renal disease. We report 2 cases of myoclonic activity associated with gabapentin toxicity in the setting of renal disease which resolved with discontinuation of gabapentin and treatment with hemodialysis and peritoneal dialysis. As gabapentin has multiple indications and off-label uses, an understanding of myoclonus, neurotoxicity, and renal dosing is important to clinicians in multiple specialties.

Psychiatric comorbidity and social aspects in pregnant women with epilepsy - the Norwegian Mother and Child Cohort Study

OBJECTIVE

The objective of this study was to investigate psychiatric disease and social aspects in young women with epilepsy before and during pregnancy.

METHOD

The study included self-reported data from 106,935 pregnancies.

RESULTS

Seven hundred eleven women reported having epilepsy, and 45.9% of them were using antiepileptic drugs (AEDs). Compared to the reference group, self-reported eating disorders and depression were increased in the untreated epilepsy group before pregnancy. Both AED-treated and untreated women with epilepsy reported higher depression scores as assessed by the Hopkins Symptom Checklist, and the Lifetime Major Depression scale was increased in AED-treated women. Antiepileptic drug treatment was linked to low income (27.4% vs. 18.4%, p<0.001) and no income (5.5% vs. 2.6%, p=0.001). Low educational level was associated with epilepsy in AED-treated and untreated women (50.5%, p<0.001 and 46.9%, p<0.001 vs. 32.2%), as was unemployment due to disability (7.9%, p<0.001 and 6.5%, p<0.001 vs. 1.5%) and single parenting (4.4%, p=0.016 and 4.5%, p=0.007 vs. 2.4%). No difference was found for smoking, alcohol use, or narcotic use.

CONCLUSION

Symptoms of depression were associated with epilepsy both during and before pregnancy. Epilepsy was linked to eating disorders before pregnancy. Unemployment, single parenting, and low educational level were linked to epilepsy in young pregnant females. Efforts aiming at treatment and screening for psychiatric comorbidity in pregnant women with epilepsy are important in the follow-up of these patients.

Apparent dose-dependent levetiracetam-induced de novo major depression with suicidal behavior

Levetiracetam (LEV) is a novel antiepileptic drug (AED) approved for the adjunctive treatment of generalized and partial seizures. LEV has no clinically significant drug interactions and has limited adverse effects. The psychiatric adverse effects of LEV include de novo psychosis, affective disorder, and aggression. LEV-induced suicidal behavior has been reported infrequently with a past history of affective disorders. The authors report an apparent dose/concentration-dependent LEV-induced de novo major depression with near fatal suicide attempt in a patient without prior history of affective disorder. Psychiatric evaluation with emphasis on historic/current affective disorders, impulsive-aggressive behaviors, and assessment of risk factors for suicidal behaviors is indicated in treating patients with epilepsy with LEV. Clinicians should consider therapeutic drug monitoring to optimize therapeutic LEV treatment.

Antiepileptic drug monotherapy versus polytherapy: pursuing seizure freedom and tolerability in adults

PURPOSE OF REVIEW

Despite the availability of many new antiepileptic drugs (AEDs), only around 50% of people with epilepsy will become seizure free on their first drug. This article explores treatment options and issues influencing whether AEDs should be substituted or combined in the remainder of the patient population.

RECENT FINDINGS

Prior to the introduction of novel AEDs, it was generally opined that combining traditional agents did not necessarily lead to an improvement in seizure control and might increase the propensity for side effects. Newer AEDs, many with different mechanisms of action, have increased the potential for polytherapy regimens, although robust data to support or refute this therapeutic strategy are sparse. It seems sensible to substitute rather than combine when the first AED produces an idiosyncratic reaction, is poorly tolerated at a low/moderate dose or shows no efficacy. Polytherapy may be preferred if the patient tolerates their first or second AED well, but with a suboptimal response, particularly when there is an identifiable anatomical substrate for the seizures. AED selection requires consideration of many factors some of which are discussed in this study.

SUMMARY

There are no definitive answers on whether to combine or substitute AEDs. Different strategies are required for different scenarios in different patients.

A larval zebrafish model of bipolar disorder as a screening platform for neuro-therapeutics

Modelling neurological diseases has proven extraordinarily difficult due to the phenotypic complexity of each disorder. The zebrafish has become a useful model system with which to study abnormal neurological and behavioural activity and holds promise as a model of human disease. While most of the disease modelling using zebrafish has made use of adults, larvae hold tremendous promise for the high-throughput screening of potential therapeutics. The further development of larval disease models will strengthen their ability to contribute to the drug screening process. Here we have used zebrafish larvae to model the symptoms of bipolar disorder by treating larvae with sub-convulsive concentrations of the GABA antagonist pentylenetetrazol (PTZ). A number of therapeutics that act on different targets, in addition to those that have been used to treat bipolar disorder, were tested against this model to assess its predictive value. Carbamazepine, valproic acid, baclofen and honokiol, were found to oppose various aspects of the PTZ-induced changes in activity. Lidocaine and haloperidol exacerbated the PTZ-induced activity changes and sulpiride had no effect. By comparing the degree of phenotypic rescue with the mechanism of action of each therapeutic we have shown that the low-concentration PTZ model can produce a number of intermediate phenotypes that model symptoms of bipolar disorder, may be useful in modelling other disease states, and will help predict the efficacy of novel therapeutics.

Impact of the chronic use of benzodiazepines prescribed for seizure control on the anxiety levels of patients with epilepsy

In a cross-sectional study, we evaluated the impact of the chronic use of benzodiazepines (BDZ) prescribed for seizure control on the anxiety levels of patients with temporal lobe epilepsy. We assessed the anxiety level of 99 patients with temporal lobe epilepsy with (n=15) or without (n=84) BDZ for seizure control, using the Beck Anxiety Inventory (BAI) or the Hamilton Anxiety Scale (HAMA). Independent risk factors for high anxiety levels were being a female patient (O.R.=2.93; 95% C.I.=1.05-8.16; p=0.039), having uncontrolled seizures (O.R.=4.49; 95% C.I.=1.66-12.11; p=0.003) and having a history of a psychiatric disorder (O.R.=4.46; 95% C.I.=1.63-12.21; p=0.004). However, there were no statistically significant differences in anxiety levels between patients utilizing or not utilizing BDZ prescribed exclusively for seizure control. We concluded that in our study, patients with chronic use of BDZ prescribed exclusively for seizure control showed similar anxiety levels than patients who were not using this class of drug. Additional studies are needed to define better strategies for the treatment of anxiety disorders in epilepsy.

Suicidality in temporal lobe epilepsy: measuring the weight of impulsivity and depression

OBJECTIVE

The aim of the work described here was to measure the role of psychopathological features, specifically impulsivity and depression, in suicidality in patients with temporal lobe epilepsy (TLE).

METHODS

Neuropsychiatric evaluation of 66 outpatients with TLE was performed with the following instruments: a structured clinical interview (Mini International Neuropsychiatric Interview Plus), the Barratt Impulsiveness Scale, the Hamilton Anxiety Scale, the Beck Depression Inventory, and the Brief Psychiatric Rating Scale.

RESULTS

A current Axis I psychiatric diagnosis, mainly mood and anxiety disorders, was assigned to 37 subjects (56.1%) Presence of suicide risk was identified in 19 patients (28.8%), and 14 (21.2%) had attempted suicide. Frequency of seizures (P=0.012), current major depression (P=0.001), and motor impulsivity (P=0.005) were associated with suicide risk on univariate analysis. Logistic regression stressed the main relevance of major depression (OR=12.82, 95% CI=2.58-63.76, P=0.002) and motor impulsivity (OR=1.21, 95% CI=1.06-1.38, P=0.005) to suicide risk.

CONCLUSION

Depression has a major influence on suicidality in epilepsy. Motor impulsivity is also relevant and may be an important component of depression in TLE associated with suicide risk.

Off-label gabapentin masking ictal triphasic waves: case analysis of neuropsychiatric and electrographic correlates

Antiepileptic drugs (AEDs) are frequently used off-label for the treatment of psychiatric, pain, and other neurological disorders. Off-label AED use may confound the diagnosis for acute neuropsychiatric changes associated with delirium by fortuitously treating, or partially treating, underlying seizure disorders while masking ictal electrographic patterns on EEGs. Standard video/EEG monitoring includes weaning from AEDs to maximize ictal activity and better determine seizure focus. We report a case of off-label gabapentin use masking ictal electrographic activity, the neuropsychiatric and electrographic consequences of discontinuing gabapentin, and the therapeutic response when gabapentin was re-initiated and titrated to a total daily dose greater than that at time of admission. Weaning from AEDs with concurrent video/EEG monitoring is an important diagnostic tool in these complex cases.

Gabapentin-induced sexual dysfunction

Sexual dysfunction is a key adverse effect leading to medication noncompliance. Psychotropic drugs associated with sexual dysfunction include antiepileptic drugs, antidepressants, and antipsychotics. Gabapentin, frequently used off-label to treat psychiatric and pain disorders, has previously been reported to cause sexual dysfunction at a minimum total daily dose of 900 mg. This report addresses dose-dependent gabapentin-induced sexual dysfunction reaching total sexual dysfunction (loss of libido, anejaculation, anorgasmia, and impotence) at a total daily dose of only 300 mg.