Influence of administration vehicles and drug formulations on the pharmacokinetic profile of lamotrigine in rats

Given that administration vehicles and drug formulations can affect drug bioavailability, their influence on the pharmacokinetic profile of lamotrigine (LTG), a new-generation anti-epileptic drug, was studied in rats. Three different formulations administered intraperitoneally at a dose of 10 mg/kg were used: (1) LTG suspended in a 0.25% methylcelulose solution, (2) LTG dissolved in a 50% propylene glycol solution, and (3) LTG isethionate dissolved in distilled water. Plasma and brain homogenate levels were determined in order to evaluate vehicle-dependent drug absorption. The results demonstrated rapid absorption of LTG when it was administered as an aqueous solution, in contrast to a slower and more erratic absorption after the injection of either the lipophilic solution or the suspension. A plasma peak was achieved 15 min post-dose with the aqueous solution, with a brain peak being achieved 15 min later, while with the other formulations both plasma and brain homogenate peaks were reached 2 h after LTG administration. This study suggests that LTG isethionate dissolved in distilled water is the most suitable formulation for successful LTG pharmacokinetic studies in rats.

Clinical indicators for the use of antidepressants in the treatment of bipolar I depression

OBJECTIVES

Current guidelines provide little practical information on the clinical characteristics of bipolar I patients who are likely to benefit from the combination of a mood stabilizer and an antidepressant. Rather, guidelines simply state that an adjunctive antidepressant is recommended in cases of 'severe' depression. Our objective was to evaluate the clinical and demographic differences between patients who remitted on a mood stabilizer alone and patients who subsequently required an adjunctive antidepressant to achieve stabilization.

METHODS

We retrospectively compared the pharmacological treatment strategies of 39 patients with bipolar I disorder who were in a current depressive episode. Patients who did not respond to mood stabilizer monotherapy were prescribed an adjunctive antidepressant. We evaluated the clinical differences at baseline and week 1, 2 and 3 of treatment between patients stabilizing on a mood stabilizer alone and patients that did not remit until they subsequently received an adjunctive antidepressant.

RESULTS

Patients who required an adjunctive antidepressant had significantly higher total Hamilton Depression Rating (HRS-D) scores at week 1, 2 and 3 of treatment, but not at baseline. Patients who remitted on mood stabilizer monotherapy were more likely to be married, achieved stabilization in less time, presented with higher Young Mania Rating Scale (YMRS) scores, and experienced the previous episode of depression more recently than patients who required an antidepressant.

CONCLUSIONS

Our findings suggest that rapid improvement after achieving a therapeutic dose of a mood stabilizer is clinically significant and represents a surrogate endpoint in the treatment of bipolar I depression. Larger, prospective, and controlled studies are needed to verify our results and to identify additional indicators for a mood stabilizer and antidepressant combination treatment strategy.

Changes in body weight and body mass index among psychiatric patients receiving lithium, valproate, or topiramate: an open-label, nonrandomized chart review

BACKGROUND

Subsets of psychiatric patients gain excess body weight while receiving mood-stabilizing agents such as lithium carbonate or valproate sodium. Patients who gain excess weight may discontinue therapy, with severe consequences. Among the newer anticonvulsant agents, topiramate is a candidate agent for bipolar disorder and is associated with weight loss when used as adjunctive treatment.

OBJECTIVE

This open-label, nonrandomized, chart-review study assessed changes in body weight and body mass index (BMI) in patients receiving topiramate, lithium, or valproate.

METHODS

Data were extracted from the medical charts of patients admitted in 1999 and 2000 to a state psychiatric hospital with either schizophrenia, schizoaffective disorder, bipolar disorder, or other psychiatric diagnoses who were prescribed valproate, lithium, or topiramate and were reviewed for changes in body weight and BMI. The use of concomitant psychotropic medicines was recorded (eg, antipsychotic agents, antidepressant agents, other mood stabilizers such as gabapentin or carbamazepine). Continuous variables were analyzed using a factorial analysis of variance and the Student t test. Contingency statistics were used to analyze categorical variables.

RESULTS

A total of 214 patients were included in the chart review (123 men, 91 women; mean age, 39.4 years). Significantly more women than men received topiramate (P = 0.004). Patients receiving either lithium or valproate gained a mean (SD) of 6.3 (9.0) kg and 6.4 (9.0) kg, respectively, whereas patients receiving topiramate lost a mean 1.2 (6.3) kg (F = 11.54, df = 2,198; P < 0.001). Lithium- or valproate-treated patients experienced an increase in BMI (mean, 2.1 [3.0] for both groups), whereas topiramate-treated patients experienced a reduction in BMI (mean, -0.5 [2.4]); this result was statistically significant (F = 11.40, df = 2,198; P < 0.001). Finally, lithium- or valproate-treated patients gained >8% of their baseline body weight (8.2% [11.5%] for lithium-treated patients and 8.5% [11.9%] for valproate-treated patients), whereas topiramate-treated patients lost 0.7% (7.2%) of their body weight (F = 9.93, df= 2,198; P < 0.001).

CONCLUSIONS

Controlled studies for the efficacy of topiramate therapy in various psychiatric conditions are awaited. These data indicate that patients receiving topiramate experience body weight loss and a reduction in BMI. This advantage of topiramate may promote long-term adherence to treatment among psychiatric patients and possibly decrease the medical risks associated with obesity.

Treatment of sexual disorders in people with epilepsy

Sexual dysfunction is underreported in persons with epilepsy. The evaluation of sexual physiology in small samples of epilepsy patients shows abnormal sexual functioning, and points to low free testosterone levels as a contributing factor. Abnormal sexual physiology in epilepsy patients may be due to antiseizure medication-related altered testosterone metabolism and abnormal central gonadotropin secretion due to epileptic physiology in the brain. More information exists on the sexual side effects of "classic" antiseizure medications than the "new generation" of antiseizure medications; barbiturates appear to have the greatest risk. More active surveying for sexual dysfunction should be undertaken in epilepsy clinics; a simple, self-reported scale of sexual functioning is available. Testosterone replacement for men, dehydroepiandrosterone for women, and sildenafil for restoring sexual performance are appropriate.

Adenosine induces inositol 1,4,5-trisphosphate receptor-mediated mobilization of intracellular calcium stores in basal forebrain cholinergic neurons

In the cholinergic basal forebrain, we found previously that the extracellular adenosine concentration increase that accompanies sleep deprivation, acting via the A1 receptor, led to activation of the transcription factor nuclear factor-kappaB and to the upregulation of A1 adenosine receptor mRNA. We thus began to examine intracellular signaling mechanisms. We report here that adenosine, acting in a dose-dependent manner and predominantly via A1 receptors, stimulated IP3 receptor-regulated calcium release from intracellular stores. To the best of our knowledge, this calcium signaling pathway effect is a novel action of the G(i)-coupled A1 adenosine receptor in neurons. Moreover, this calcium mobilization was not seen at all in noncholinergic neurons but was present in a large proportion of cholinergic neurons. These data suggest a potential role for a calcium-signaling pathway in adenosine-induced long-term effects of sleep deprivation and a key role for cholinergic neurons in this process.

Glutamate and GABA systems as targets for novel antidepressant and mood-stabilizing treatments

Glutamate and gamma-amino butyric acid (GABA) systems are emerging as targets for development of medications for mood disorders. There is increasing preclinical and clinical evidence that antidepressant drugs directly or indirectly reduce N-methyl-D-aspartate glutamate receptor function. Drugs that reduce glutamatergic activity or glutamate receptor-related signal transduction may also have antimanic effects. Recent studies employing magnetic resonance spectroscopy also suggest that unipolar, but not bipolar, depression is associated with reductions in cortical GABA levels. Antidepressant and mood-stabilizing treatments also appear to raise cortical GABA levels and to ameliorate GABA deficits in patients with mood disorders. The preponderance of available evidence suggests that glutamatergic and GABAergic modulation may be an important property of available antidepressant and mood-stabilizing agents. Future research will be needed to develop and evaluate new agents with specific glutamate and GABA receptor targets in the treatment of mood disorders.

Bipolar I disorder: psychopathology, medical management and dental implications

BACKGROUND

The authors review the clinical features, epidemiology, pathophysiology, medical management, dental findings and dental management of patients who have bipolar I disorder, or BD, previously known as manic-depressive disorder.

TYPES OF STUDIES REVIEWED

The authors conducted a MEDLINE search for the period 1995 through 2001 using the key terms "bipolar disorder," "epidemiology," "pathophysiology," "treatment" and "dentistry." The articles they selected for further review included those published in English in peer-reviewed journals; they gave preference to articles reporting randomized, controlled trials.

RESULTS

BD is a psychiatric illness characterized by extreme mood swings. Mania is accompanied by euphoria, grandiosity, racing thoughts and lack of insight. Depression is characterized by marked sadness or loss of interest or pleasure in daily activities. The unpredictable mood swings can distress the person, can impair social function and quality of life and are associated with a significant increase in the risk for substance abuse and suicide. BD is common in the United States, with a lifetime prevalence rate of 1.6 percent and recurrence rate of more than 50 percent.

CLINICAL IMPLICATIONS

The prevalence of dental disease usually is extensive because of poor oral hygiene and medication-induced xerostomia. Preventive dental education, saliva substitutes and anticaries agents are indicated. To avoid adverse drug interactions with the usually prescribed psychiatric medications, special precautions should be taken when administering certain antibiotics, analgesics and sedatives.

Adenosine induces inositol 1,4,5-trisphosphate receptor-mediated mobilization of intracellular calcium stores in basal forebrain cholinergic neurons

In the cholinergic basal forebrain, we found previously that the extracellular adenosine concentration increase that accompanies sleep deprivation, acting via the A1 receptor, led to activation of the transcription factor nuclear factor-kappaB and to the upregulation of A1 adenosine receptor mRNA. We thus began to examine intracellular signaling mechanisms. We report here that adenosine, acting in a dose-dependent manner and predominantly via A1 receptors, stimulated IP3 receptor-regulated calcium release from intracellular stores. To the best of our knowledge, this calcium signaling pathway effect is a novel action of the G(i)-coupled A1 adenosine receptor in neurons. Moreover, this calcium mobilization was not seen at all in noncholinergic neurons but was present in a large proportion of cholinergic neurons. These data suggest a potential role for a calcium-signaling pathway in adenosine-induced long-term effects of sleep deprivation and a key role for cholinergic neurons in this process.

An open case series on the utility of tiagabine as an augmentation in refractory bipolar outpatients

BACKGROUND

Tiagabine (Gabitril) is a GABA uptake inhibitor recently introduced in the United States as an adjunctive treatment for partial complex seizures. Three published studies have addressed the use of tiagabine for bipolar disorder (BPD); two described positive results and one negative results. We assessed the efficacy of add-on tiagabine in a larger sample of adult BPD outpatients.

METHODS

Twenty-two adult outpatients with DSM-IV diagnosed BPD of some type who were considered unsatisfactory responders to standard medications for BPD were treated in an open fashion with adjunctive tiagabine in a low-dose range. After baseline demographic data and mood state at the time of entry were documented, each patient was monitored clinically for at least 6 months while the dose of tiagabine was adjusted according to the patient's clinical status. The subjects were rated using the clinical global impression-bipolar version scale (CGI-BP).

RESULTS

After 6 months, eight (36%) of the patients were responders to tiagabine by CGI-BP rating. The dose range of tiagabine for responders was 1-8 mg per day. All 14 nonresponders had to discontinue tiagabine because of unacceptable but reversible side effects; one nonresponder experienced breakthrough absence seizures.

LIMITATIONS

This study was performed in a nonrandom, open naturalistic clinical setting. The sample size was small.

CONCLUSIONS

Low-dose tiagabine appears to have mood-stabilizing and antimanic properties as an add-on medication for some adult outpatients who have BPD refractory to standard medications. Tiagabine appears to be safe for most adult BPD outpatients. The results of this preliminary open study await confirmation by double-blind controlled studies.

Multimodal neuroimaging studies and neurodevelopment and neurodegeneration hypotheses of schizophrenia

The interpretation of the huge number of results in schizophrenia research using neuroimaging is uncertain. However, the simultaneous use of complimentary data obtained with these techniques may yield more relevant information in this regard. In this paper we present a series of studies performed by our group in two schizophrenic samples with the use of structural (magnetic resonance imaging, MRI), functional [glucose positron emission tomography (PET) and N-acetyl-aspartate (NAA) magnetic resonance spectrocopy] and neurophysiological techniques (the P300 event-related potential). Transversal and longitudinal measurements were performed.The integrated vision of the results so obtained allows us to propose the hypothesis of a neurodevelopmentally determined state of prefrontal disinihibition, in which the degree of atrophy would directly relate to the metabolic rate. This state would already be present in the first stages of illness and could have neurotoxic consequences in the long term. This would explain the findings of an association between sulcal cerebrospinal fluid (CSF) and illness duration and decreased NAA levels in chronic but not in recent-onset cases. The prefrotnal disinhibition would overstimulate the limbic system and the hippocampus would become overactivated, the metabolic rate at this level being inversely related to P300 amplitude. Clozapine showed a more selective and intense action on that hyperactive metabolic tone than haloperidol.

Use of topiramate in treatment-resistant bipolar spectrum disorders

To evaluate the effectiveness and safety of topiramate as add-on, long-term therapy for treatment-resistant bipolar-spectrum disorders, 34 DSM-IV bipolar-spectrum patients, including bipolar I (n = 28), bipolar II (n = 3), bipolar not otherwise specified (n = 2), and schizoaffective disorder bipolar type (n = 1), considered to be resistant to treatment with lithium, carbamazepine, and valproate, received increasing doses of topiramate as adjunctive therapy for their manic (n = 17), depressive (n = 11), hypomanic (n = 3), or mixed (n = 3) symptoms. Outcome measures included the Young Mania Rating Scale (YMRS), the Hamilton Rating Scale for Depression (HAM-D), and the Clinical Global Impression (CGI) for Severity. Patients were followed up for 6 months. Twenty-five patients (74%) completed the 6-month follow-up. Nine patients (26%) dropped out early due to lost of follow-up (n = 4), worsening of symptoms (n = 2), side effects (n = 1), hospitalization due to intercurrent illness (n = 1), and noncompliance (n = 1). By intent-to-treat analysis, there was a significant reduction in YMRS, HAM-D, and CGI scores (p < 0.0001 for all measures at the endpoint) after the introduction of topiramate. Most therapeutic effects appeared between weeks 2 and 6. Fifty-nine percent of manic patients and 55% of depressed patients were considered to be responders to the drug, which was well tolerated; only one patient discontinued due to side effects. The most common side effect was paraesthesia (n = 2). Ten patients experienced moderate weight loss during the follow-up period. The mean topiramate dose at endpoint was 202 +/- 65 mg/day. These preliminary results indicate that adjunctive topiramate may be useful in the long-term treatment of bipolar spectrum disorders, even in the most difficult-to-treat patients.

Brain glycogen decreases with increased periods of wakefulness: implications for homeostatic drive to sleep

Sleep is thought to be restorative in function, but what is restored during sleep is unclear. Here we tested the hypothesis that increased periods of wakefulness will result in decreased levels of glycogen, the principal energy store in brain, and with recovery sleep levels of glycogen will be replenished, thus representing a homeostatic component of sleep drive. Using a high-energy focused microwave irradiation method to kill animals and thereby snap-inactivate glycogen-producing and -metabolizing enzymes, we determined, with accuracy and precision, levels of brain glycogen and showed these levels to decrease significantly by approximately 40% in brains of rats deprived of sleep for 12 or 24 hr. Recovery sleep of 15 hr duration after 12 hr of sleep deprivation reversed the decreases in glycogen. Using a novel histochemical method to stain brain glycogen, we found glycogen to be concentrated in white matter; this finding was confirmed biochemically in white matter dissected from rats killed with microwave irradiation. Levels of glycogen, as determined histochemically, were significantly decreased in gray and white matter with sleep deprivation, and these decreases were reversed with recovery sleep. The observed decreases in levels of brain glycogen may be a consequence of increased wakefulness and/or a component integral to the homeostatic drive to sleep.

Post-insult exposure to (+/-) kavain potentiates N-methyl-D-aspartate toxicity in the developing hippocampus

Kavapyrone extracts of the pepper plant Piper methysticum Forst. have been reported to be pharmacologically active in the brain by modulating the function of several ionotropic receptor systems and voltage-sensitive ion channels. While kavapyrones have previously demonstrated neuroprotective effects against several forms of neurotoxicity, the possibility remains that perturbed function of neuronal ion transport may prove to be neurotoxic in some instances. The present studies were designed to examine the effects of the kavapyrone, (+/-) kavain, on viability of organotypic hippocampal explants exposed to the excitotoxin N-methyl-D-aspartate (NMDA). Exposure to (+/-) kavain (1-600 microM) for 24 h did not alter neuronal viability in the CA1, CA3, or dentate gyrus regions of hippocampal explants. However, higher concentrations of (+/-) kavain (> or =300 microM) produced marked neurotoxicity in the lacunosum moleculare layer of the hippocampus. One hour of exposure to NMDA (20 microM) produced significant neuronal death in both the CA3 and CA1 pyramidal cell regions, effects prevented by co-exposure to MK-801 (30 microM). Co-exposure of explants to (+/-) kavain (1-100 microM) with NMDA did not alter the severity of NMDA-induced neurotoxicity. However, exposure of NMDA-treated explants to (+/-) kavain (> or =10 microM) for 24 h after insult produced significant increases in neurotoxicity in the CA1 and dentate gyrus regions of explants. In conclusion, while the kavapyrone (+/-) kavain is neurotoxic only at high concentrations when exposed alone to the developing hippocampus, it appears to adversely affect neuronal recovery following excitotoxic insults.

Mood disorders in patients with epilepsy: epidemiology and management

Patients with epilepsy are at high risk for depression because of an incompletely understood combination of factors that may be both psychosocial and neurological. Interictal depression in patients with epilepsy is an undertreated condition, in part because of concern regarding drug interactions and the risk of exacerbating seizures with antidepressant treatment. Bipolar disorder is not described as occurring with a higher than expected frequency in the population with epilepsy, but high rates of depression and suicide are well recognised, highlighting the need for more emphasis on antidepressive treatment in this group of at-risk patients. Neurological factors, including site and lateralisation of seizure focus, may be important for the development of depression, with left-sided seizure foci having a higher association with depressive symptoms. Forced normalisation may be a factor in the paradoxical onset of depression in patients with epilepsy whose seizures suddenly become well controlled by anti-seizure treatment. Lowering of folic acid levels by some antiepileptic drugs (AEDs) may also influence the expression of depression in patients with epilepsy. New AEDs continue to emerge as beneficial treatments themselves for mood disorders, with lamotrigine, gabapentin and, to a lesser extent, topiramate having clinical trials data to support their use in patients with bipolar disease. Similar positive data are available for vagal nerve stimulation. Mood effects of AEDs can be complicated, however, as many of these drugs (e.g. tiagabine) have also been reported to cause depression as an adverse effect. Electroconvulsive therapy in depressed patients with epilepsy requires special consideration. The selective serotonin reuptake inhibitors (SSRIs) and antidepressants that act at multiple receptors (e.g. nefazodone, venlafaxine) are the most appropriate treatments for depressed patients with epilepsy. Among these agents, citalopram has a low risk of interactions with AEDs. Bupropion, clomipramine and maprotiline are associated with a greater risk of seizures compared with other antidepressants and consequently should be used with caution in the treatment of depression in patients with epilepsy.

Orexin neurons of the hypothalamus express adenosine A1 receptors

Adenosine is a putative sleep factor with effects mainly mediated by the A1 receptor. Recent studies have implicated the hypothalamic orexin/hypocretin-containing neurons in the control of sleep-wakefulness. To help determine if adenosine might play a role in the control of orexin neurons, immunohistochemistry was used to characterize the distribution of adenosine A1 receptor protein on the orexinergic neurons. About 30% of orexin-containing neurons were labeled. The data supports the presence of adenosine A1 receptors on orexinergic neurons and suggests a possible substrate for a functional role of adenosine in the regulation of orexinergic activity.

Are bipolar I depressive patients less responsive to treatment with antidepressants than unipolar depressive patients? Results from a case control study

The increasing evidence that bipolar and unipolar affective disorders have different biological etiologies and courses of illness has been associated with an intensifying interest in specific treatment regimens for both disorders during the last decade. In this context, the question arose whether antidepressants exert similar efficacy in the acute treatment of bipolar compared to unipolar depression. Although the clinical impression does not indicate substantial differences in the efficacy of antidepressants between these groups of patients, empirical databases concerning this topic are rare. The present study compared the efficacy of antidepressants in 50 unipolar and 50 bipolar depressed inpatients (ICD-9 criteria) under naturalistic treatment conditions. Both groups of patients were matched for age, gender and duration of illness. Clinical assessments of status at the time of admission and at discharge were used to rate response to antidepressant treatment. Analyses of the data revealed that both groups of patients needed the same time for treatment response and did not show any significant differences in outcome measures at discharge. These findings do not concur with the hypothesis formulated by some experts in the field of affective disorders that antidepressants are less effective in the acute treatment of bipolar depressed patients compared to unipolar depressed patients.

The use of topiramate in mood stabilization

OBJECTIVE

To review data on the effectiveness of topiramate as a mood stabilizer.

DATA SOURCES

Clinical literature accessed through MEDLINE (1985-September 2001) and the manufacturer. Key search terms included topiramate, mania, mood stabilizer, and bipolar disorder.

DATA SYNTHESIS

The traditional standard therapy for bipolar disorder has been lithium. Other mood stabilizers are increasingly being used to manage this complex disorder. Studies that used topiramate in bipolar disorders were evaluated.

CONCLUSIONS

The present data from open trials suggest that topiramate may possibly possess antimanic properties. Controlled, double-blind studies are required to confirm this efficacy.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of bipolar disorders. Part I: Treatment of bipolar depression

These practice guidelines for the biological, mainly pharmacological treatment of bipolar depression were developed by an international task force of the World Federation of Societies of Biological Psychiatry (WFSBP). Their purpose is to supply a systematic overview of all scientific evidence pertaining to the treatment of bipolar depression. The data used for these guidelines have been extracted from a MEDLINE and EMBASE search, and from recent proceedings of key conferences and various national and international treatment guidelines. Their scientific rigor was categorised into four levels of evidence (A-D). As these guidelines are intended for clinical use, the scientific evidence was not only graded, but also commented on by the experts of the task force to ensure practicability.

Motor cortical excitability in schizophrenia

BACKGROUND

Transcranial magnetic stimulation (TMS) provides a method to examine cortico-cortical motor excitability and hemispheric asymmetry in unmedicated and medicated schizophrenia patients.

METHODS

Fourteen right-handed schizophrenia patients (seven on conventional neuroleptics and seven medication-free) were compared with seven right-handed, age- and gender-matched normal control subjects. Motor threshold for induction of motor-evoked potentials (MEPs) and bihemispheric intracortical inhibition and facilitation were measured with single-pulse and paired-pulse TMS.

RESULTS

Medicated patients showed an approximately 5% higher motor thresholds in both hemispheres than unmedicated patients and control subjects. Normal control subjects had a nearly 10% higher threshold for the left than the right hemisphere, whereas the opposite was true for the patient groups (5-10% higher threshold on the right than the left). Medicated patients showed significantly decreased intracortical inhibition relative to unmedicated patients and control subjects. This difference was more pronounced for the right than for the left hemisphere.

CONCLUSIONS

Treatment with conventional neuroleptics is associated with increased motor threshold and decreased intracortical inhibition, whereas unmedicated patients did not differ from normal control subjects on these measures; however, schizophrenia may be characterized by a reversed pattern of interhemispheric corticospinal excitability.

Neocortical potassium currents are enhanced by the antiepileptic drug lamotrigine

PURPOSE

We used field-potential recordings in slices of rat cerebral cortex along with whole-cell patch recordings from rat neocortical cells in culture to test the hypothesis that the antiepileptic drug (AED) lamotrigine (LTG) modulates K+-mediated, hyperpolarizing currents.

METHODS

Extracellular field-potential recordings were performed in neocortical slices obtained from Wistar rats aged 25-50 days. Rat neocortical neurons in culture were subjected to the whole-cell mode of voltage clamping under experimental conditions designed to study voltage-gated K+ currents.

RESULTS

In the in vitro slice preparation, LTG (100-400 microM) reduced and/or abolished epileptiform discharges induced by 4-aminopyridine (4AP, 100 microM; n = 10), at doses that were significantly higher than those required to affect epileptiform activity recorded in Mg2+-free medium (n = 8). We also discovered that in cultured cortical cells, LTG (100-500 microM; n = 13) increased a transient, 4AP-sensitive, outward current elicited by depolarizing commands in medium containing voltage-gated Ca2+ and Na+ channel antagonists. Moreover, we did not observe any change in a late, tetraethylammonium-sensitive outward current.

CONCLUSIONS

Our data indicate that LTG, in addition to the well-known reduction of voltage-gated Na+ currents, potentiates 4AP-sensitive, K+-mediated hyperpolarizing conductances in cortical neurons. This mechanism of action contributes to the anticonvulsant effects exerted by LTG in experimental models of epileptiform discharge, and presumably in clinical practice.

Paroxetine for the treatment of interferon-alpha-induced depression in chronic hepatitis C

BACKGROUND

Psychiatric side-effects may require dose reduction or premature discontinuation of interferon therapy in chronic hepatitis C. New strategies are needed in order to prevent the premature termination of interferon therapy.

AIM

To evaluate prospectively the efficacy and tolerability of antidepressant therapy (paroxetine, a selective serotonin reuptake inhibitor) in patients with chronic hepatitis C treated with interferon-alpha who have developed interferon-induced major depression.

METHODS

A sub-group of 14 individuals from 121 consecutively treated hepatitis C patients developed substance-induced major depression without suicidal ideation during interferon-alpha treatment. The individuals in this sub-group received paroxetine after the occurrence of depression (20 mg daily until termination of interferon therapy). Diagnostic scores for depression (and anger-hostility) were obtained in a repeated measures design (Hospital Anxiety and Depression Scale and Symptom Checklist 90 Items Revised).

RESULTS

Eleven of the 14 patients (78.6%) with interferon-induced major depression were able to complete interferon-alpha therapy as scheduled under concomitant paroxetine treatment (three dropouts: insufficient improvement of depression, occurrence of epileptic seizures, paroxetine-induced nausea/dizziness). Within 4 weeks after the start of paroxetine medication, depression scores declined significantly in all patients.

CONCLUSIONS

Our data suggest that concomitant therapy with paroxetine is an effective way to treat interferon-induced depression in patients with chronic hepatitis C.

Circuit analysis of NMDAR hypofunction in the hippocampus, in vitro, and psychosis of schizophrenia

NMDA antagonists provide the best pharmacological model of psychosis-related schizophrenia. Data from circuit analysis of the effects of the antagonism of NMDA receptors in the CA1 region of the hippocampus of rats in vitro suggest a hypothesis concerning cortical circuit dysfunction responsible for NMDA antagonist-dependent psychosis, relevant to the psychosis associated with schizophrenia. The NMDA antagonists may act by causing a selective, partial, disinhibition of cortical projection cells. The effects are partially due to the partial role of NMDA-dependent transmission in the excitatory glutamate drive of interneurons. Characterization of the selectivity is incomplete, but includes disinhibition of the recurrent inhibitory circuit and is concentration-sensitive. It may result from differences in NMDA receptors (NMDARs) on interneurons. At higher concentrations, antagonism of all NMDA-dependent transmission results in anesthesia. At low concentration, selective blockade of NMDA-dependent LTP of the recurrent inhibitory circuit may disrupt particular aspects of information processing involving learning and/or memory, consistent with the generation of abnormal associations. An endogenous peptide, NAAG, is shown to antagonize NMDARs in a manner similar to known psychotogenic agents like ketamine or phencyclidine. Finally, mechanisms that could enhance NMDAR function are discussed as possible therapeutic strategies for psychosis.

Substance P and affective disorders: new treatment opportunities by neurokinin 1 receptor antagonists?

Substance P (SP) is a neuropeptide which is abundant in the periphery and the central nervous system, where it is colocalized with other neurotransmitters such as serotonin or dopamine. SP has been proposed to play a role in the regulation of pain including migraine and fibromyalgia, asthma, inflammatory bowel disease, emesis, psoriasis as well as in central nervous system disorders. This review summarizes our current knowledge of the role of SP in the pathogenesis of neuropsychiatric disorders with special emphasis on affective disorders including bipolar disorders. It also reviews current treatment approaches with neurokinin 1 receptor antagonists which appear to be promising drugs for the future treatment of affective disorders.

NMDA receptor regulation of memory and behavior in humans

N-methyl-D-aspartate (NMDA) receptor hypofunction is associated with a range of effects on cognition and behavior in whole animal and human studies. NMDA receptor hypofunction within the brain, which can be induced experimentally in vivo using NMDA receptor antagonist drugs, produces adverse effects on memory function. The results suggest that NMDA receptor hypofunction can preferentially affect neural mechanisms regulating the efficiency of encoding and consolidation into longer-term storage. More pronounced NMDA receptor hypofunction can produce a clinical syndrome that includes core features of psychosis, as well as dissociation. Finally, sustained and severe underexcitation of NMDA receptors in the adult brain is associated with a neurotoxic process with well-characterized neuropathological features. Progressive increases in severity of NMDA receptor hypofunction within the brain can produce a range of effects on brain function, involving local and distributed circuitry, which may underlie the observed changes in behavior. As the brain ages, the NMDA receptor system becomes progressively hypofunctional, potentially contributing to further age-related decreases in memory and learning performance. Pharmacological and genomic methods for preventing NMDA receptor hypofunction, or for preventing the upstream or downstream consequences modeled by treatment with NMDA antagonists, may be applicable to the prevention and treatment of memory and behavioral dysfunction in a variety of neuropsychiatric disease conditions.

Lamotrigine update and its use in mood disorders

OBJECTIVE

To provide a qualitative, systematic update and review of the pharmacology, pharmacokinetics, efficacy in mood disorders, adverse effects, and costs of lamotrigine.

DATA SOURCES

Citations obtained from MEDLINE searches (1985-September 2001) using lamotrigine as a text word, articles identified in reference lists of pertinent articles, abstracts presented at conferences, and research data from GlaxoSmithKline.

DATA EXTRACTION

English-language articles were considered for possible inclusion. Each title and abstract was examined to determine whether the publication contained up-to-date information relevant to the objective. Twenty clinical trials that provided data on response rates in mood disorders were tabulated.

DATA SYNTHESIS

Lamotrigine's primary action is to modulate voltage-gated sodium channels. Evidence suggests that it decreases glutamate transmission, directly reduces calcium influx, mildly blocks transmitter reuptake, and alters intracellular mechanisms of resting transmitter release. The average half-life of lamotrigine is approximately 24 hours, but decreases to approximately 7.4 hours when used concurrently with phenytoin, and increases to approximately 59 hours with valproic acid. Seven of the 20 clinical trials were randomized, double-blind, and controlled. Existing data are inadequate to evaluate lamotrigine use in major depression. The pooled response rates for patients with depressed, manic, mixed, and rapid cycling bipolar disorder were similar, ranging from 52% to 63%. Adverse effects are infrequent when the drug is used alone, but become more frequent when lamotrigine is combined with other anticonvulsants. While most rashes are mild, approximately 1 in 500 patients develops exfoliative dermatitis. A slow upward dose titration is recommended to reduce the incidence of serious rash, but this may delay the attainment of adequate dosage for 6 weeks. Lamotrigine has positive effects on cognitive function, but occasionally produces insomnia. Lamotrigine costs 2-4 times more than lithium, carbamazepine, and generic valproic acid.

CONCLUSIONS

When efficacy, adverse effects, and cost are considered, lamotrigine should probably be reserved as a second-line agent for bipolar depression.

Interferon alpha (IFNalpha) and psychiatric syndromes: a review

Interferon alpha (IFNalpha) is used for the treatment of several disorders, such as chronic hepatitis or malignant melanoma. During the therapy, IFNalpha may cause severe neuropsychiatric syndromes including depression with suicidal ideation, paranoid psychoses, or confusional states. The reasons and management of these side effects are widely unknown. Our aim is to review research evidence for the contribution of IFNalpha for the etiopathology of psychiatric syndromes. Therefore, research findings of neuropsychiatric syndromes induced by IFNalpha treatment, the putative mechanisms underlying those syndromes, and their treatment are-reviewed. Furthermore, neuropsychiatric syndromes in diseases with high IFNalpha levels such as systemic lupus erythematosus (SLE) are discussed. Finally, the question is addressed whether IFNalpha may contribute to the etiopathology of endogenous psychiatric disorders. IFNalpha may cause psychiatric syndromes in a subset of treated patients. The underlying pathogenetic mechanisms include various effects on neuroendocrine, cytokine, and neurotransmitter systems. Research data on the role of IFNalpha in the pathogenesis of endogenous psychiatric disorders are conflicting. Future research should improve our understanding of the role of IFNalpha for the etiopathology of psychiatric syndromes and has an impact on treatment of IFNalpha-induced psychiatric syndromes.

The expanding pharmacopoeia for bipolar disorder

Over the past decade, the number of treatments available for bipolar disorder has undergone an extraordinary expansion. In that period, valproate and olanzapine have received regulatory approval in the United States for the acute treatment of mania, and carbamazepine has been indicated for this condition in many other countries. In addition to those agents, a number of other anticonvulsants (in particular lamotrigine, gabapentin, and topiramate) are in trials, as are the atypical antipsychotics clozapine and risperidone, and other novel compounds. This article critically reviews the evidence from controlled trials of these proposed "mood stabilizers," highlighting the strengths and limitations of the data for each compound. A major challenge to the field is the capacity to prove the prophylactic properties of agents for which effectiveness in acute mania and/or bipolar depression has been demonstrated. Finally, as the mechanisms of agents such as lithium are now becoming apparent, and the possibility of understanding the molecular defects underpinning the condition is no longer highly fanciful, the prospect of targeted therapies is considered feasible by both academia and the pharmaceutical industry.

Visual functions in epilepsy patients on valproate monotherapy

Gamma-aminobutyric acid-induced ion transport changes in the retinal pigment epithelium are described. Valproate acts as an inhibitor of gamma-aminobutyric acid transaminase. The purpose of this study was to investigate whether early visual impairment is related to valproate in patients with and without visual symptoms. Thirty-two patients, presenting with a history of seizures currently being treated with valproate, were included in the study. A complete clinical neuroophthalmologic examination was performed, including electroretinogram and visual field test. The electroretinogram parameters of epileptic patients were compared with those of 28 age- and sex-matched healthy volunteers. There was no significant difference in ERG parameters between the two groups. The visual field and visual acuity of all patients were within normal limits. When valproate is not used in conjunction with other antiepileptic drugs and serum levels are within therapeutic levels, it does not cause electrophysiologically detectable retinal dysfunction or any functional defect in visual perception that can be determined clinically.

Supercool or dehydrate? An experimental analysis of overwintering strategies in small permeable arctic invertebrates

Soil invertebrate survival in freezing temperatures has generally been considered in the light of the physiological adaptations seen in surface living insects. These adaptations, notably the ability to supercool, have evolved in concert with surface invertebrates' ability to retain body water in a dry environment. However, most soil invertebrates are orders of magnitude less resistant to desiccation than these truly terrestrial insects, opening the possibility that the mechanisms involved in their cold-hardiness are also of a radically different nature. Permeable soil invertebrates dehydrate when exposed in frozen soil. This dehydration occurs because the water vapor pressure of supercooled water is higher than that of ice at the same temperature. The force of this vapor pressure difference is so large that even a few degrees of supercooling will result in substantial water loss, continuing until the vapor pressure of body fluids equals that of the surrounding ice. At this stage, the risk of tissue ice formation has been eliminated, and subzero survival is ensured. Here we show that these soil invertebrates do not base their winter survival on supercooling, as do many other ectotherms, but instead dehydrate and equilibrate their body-fluid melting point to the ambient temperature. They can achieve this equilibration even at the extreme cooling rates seen in polar soils.

Glutamatergic mechanisms in schizophrenia

Schizophrenia is a chronic, severely disabling brain disorder with symptomatic onset in early adulthood. Typical antipsychotic medications that block dopamine D2 receptors are most effective in treating the psychosis but have limited effects on the negative symptoms and cognitive impairments. Considerable research has demonstrated that noncompetitive NMDA receptor antagonists, the dissociative anaesthetic like phencyclidine and ketamine, reproduce the cardinal symptomatic features of schizophrenia. Postmortem studies reveal variable alterations in glutamate receptors and their modulators in schizophrenia. Several clinical trials indicate agents that enhance NMDA receptor function via the glycine modulatory site reduce negative and variably improve cognitive function in schizophrenics receiving typical antipsychotics. Thus, hypofunction of a subpopulation of cortico-limbic NMDA receptors may participate in the pathophysiology of schizophrenia.

Lamotrigine induced selective changes in 5-HT(1A) receptor mediated response in rat brain

A new anticonvulsant drug lamotrigine (LTG) has recently been reported to be effective in treating patients with bipolar affective disorder, depression and schizoaffective disorder, suggesting that it is a mood stabilizer. However, the mechanism of action underlying its efficacy in mood disorders is not understood. This study examined the in vivo effect of LTG on 5-HT(1A) receptor-mediated adenylyl cyclase (AC) response in regions of rat brain, as this pathway has been implicated in the therapeutic action of various classes of mood stabilizers. The density of 5-HT(1A) receptors was measured by radioligand binding assay using [(3)H]8-OH-DPAT (0.05-0.8nM) in frontal cortex and hippocampus of rats treated orally with LTG (5mg/kg) for 7 days. AC activity was assayed using [(3)H]ATP. The oral administration of LTG significantly decreased the density of cortical (50%, P<0.001) but not hippocampal 5-HT(1A) receptors, without significant change in the affinity of [(3)H]8-OH-DPAT to 5-HT(1A) receptor in these regions. There was no significant alteration in basal or forskolin-stimulated AC activity in either of regions. However, a significant decrease (P<0.01) in the inhibition of forskolin-stimulated AC activity by 8-OH-DPAT was observed only in cortical membranes of LTG treated rats when compared to control. These results suggest that one mode of action of LTG may be by the downregulation of cortical 5-HT(1A) receptor-mediated AC response.

Enhanced semantic priming in schizophrenia: a computer model based on excessive pruning of local connections in association cortex

BACKGROUND

Many studies have found that people with schizophrenia exhibit abnormally high levels of semantic priming. Post-mortem and neuroimaging studies of schizophrenia suggest a reduction of neuritic processes (dendrites and synapses).

AIMS

To demonstrate that reductions in neuritic processes can produce excessive priming in patients with schizophrenia.

METHOD

Associative memory was simulated using a computer-based neural network system consisting of two interactive neural groups, one coding for individual memories and the other for the category to which each memory belonged.

RESULTS

Variation of a single parameter determining the density of local connections within the two neuronal groups gave a close approximation to levels of memory access and semantic priming previously reported in normal subjects and in patients with schizophrenia.

CONCLUSIONS

This study suggests that schizophrenia arises from excessive pruning of local connections in association cortex. Its findings shed light on the mechanisms underlying cognitive priming more generally, and how it might emerge developmentally.

The Bech-Rafaelsen Mania Scale in clinical trials of therapies for bipolar disorder: a 20-year review of its use as an outcome measure

Over the last two decades the Bech-Rafaelsen Mania Scale (MAS) has been used extensively in trials that have assessed the efficacy of treatments for bipolar disorder. The extent of its use makes it possible to evaluate the psychometric properties of the scale according to the principles of internal validity, reliability, and external validity. Studies of the internal validity of the MAS have demonstrated that the simple sum of the 11 items of the scale is a sufficient statistic for the assessment of the severity of manic states. Both factor analysis and latent structure analysis (the Rasch analysis) have been used to demonstrate this. The total score of the MAS has been standardised such that scores below 15 indicate hypomania, scores around 20 indicate moderate mania, and scores around 28 indicate severe mania. The inter-observer reliability has been found to be high in a number of studies conducted in various countries. The MAS has shown an acceptable external validity, in terms of both sensitivity and responsiveness. Thus, the MAS was found to be superior to the Clinical Global Impression scale with regard to responsiveness, and sensitivity has been found to be adequate, with the MAS able to demonstrate large drug-placebo differences. Based on pretreatment scores, trials of antimanic therapies can be classified into: (i) ultrashort (1 week) therapy of severe mania; (ii) short-term therapy (3 to 8 weeks) of moderate mania; (iii) short-term therapy of hypomanic or mixed bipolar states; and (iv) long-term (12 months) therapy of bipolar states. The responsiveness of MAS is such that the scale has been able to demonstrated that typical antipsychotics are effective as an ultrashort therapy of severe mania; that lithium and anticonvulsants are effective in the short-term therapy of moderate mania; and that atypical antipsychotics, electroconvulsive therapy (ECT) and transcranial magnetic stimulation seem to have promising effects in the short-term therapy of moderate mania. In contrast, the scale has been used to demonstrate that calcium antagonists (e.g. verapamil) are ineffective in the treatment of mania. MAS has also been used to add to the literature on the evidence-based effect of lithium as a short-term therapy for hypomania or mixed bipolar states and as a long-term therapy of bipolar states.

An adenosine A2a agonist increases sleep and induces Fos in ventrolateral preoptic neurons

Considerable evidence indicates that adenosine may be an endogenous somnogen, yet the mechanism through which it promotes sleep is unknown. Adenosine may act via A1 receptors to promote sleep, but an A2a receptor antagonist can block the sleep induced by prostaglandin D(2). We previously reported that prostaglandin D(2) activates sleep-promoting neurons of the ventrolateral preoptic area, and we hypothesized that an A2a receptor agonist also should activate these neurons. Rats were instrumented for sleep recordings, and an injection cannula was placed in the subarachnoid space just anterior to the ventrolateral preoptic area. After an 8-10-day recovery period, the A2a receptor agonist CGS21680 (20 pmol/min) or saline was infused through the injection cannula, and the animals were killed 2 h later. The brains were stained using Fos immunohistochemistry, and the pattern of Fos expression was studied in the entire brain. CGS21680 increased non-rapid eye movement sleep and markedly increased the expression of Fos in the ventrolateral preoptic area and basal leptomeninges, but it reduced Fos expression in wake-active brain regions such as the tuberomammillary nucleus. CGS21680 also induced Fos in the shell and core of the nucleus accumbens and in the lateral subdivision of the central nucleus of the amygdala. To determine whether these effects may have been mediated through A1 receptors, an additional group of rats received subarachnoid infusion of the A1 receptor agonist N(6)-cyclopentyladenosine (2 pmol/min). In contrast to CGS21680, infusion of N(6)-cyclopentyladenosine into the subarachnoid space produced only a small decrease in rapid eye movement sleep, and the pattern of Fos expression induced by N(6)-cyclopentyladenosine was notable only for decreased Fos in regions near the infusion site. These findings suggest that an adenosine A2a receptor agonist may activate cells of the leptomeninges or nucleus accumbens that increase the activity of ventrolateral preoptic area neurons. These ventrolateral preoptic area neurons may then coordinate the inhibition of multiple wake-promoting regions, resulting in sleep.

Semantic bias, homograph comprehension, and event-related potentials in schizophrenia

OBJECTIVES

It is controversial whether a semantic processing bias for strong associates is present in schizophrenia, and unknown whether the language abnormalities observed in schizophrenia can be attributed to dysfunctions early or late in cognitive processing. Combined behavioral and event-related potential (ERP) data can indicate the nature and timing of such abnormalities.

METHODS

Sensibility judgements of dominant and subordinate homograph sentences were measured in 12 schizophrenia patients and 13 normal controls. ERPs were recorded to the disambiguating sentence-ending word.

RESULTS

All subjects showed greatest misinterpretation of subordinate homograph sentences, but schizophrenia patients particularly misinterpreted these sentence types. For control subjects, subordinate homograph sentences that were classified as nonsensical showed greater N400 than those classified as sensible. By contrast, the N400 of patients was large, regardless of the sensibility judgement--patients' brains initially responded to all subordinate sentences as if nonsensical. These data are consonant with a semantic bias. However, the patients' N400 to dominant homograph sentence endings was also larger than that of controls, a finding not consonant with a semantic bias.

CONCLUSIONS

The behavioral results indicate a selective comprehension abnormality in schizophrenia dependent on the content of verbal memory. The ERP results suggest a pervasive contextual memory failure. A semantic activation decay model is proposed to explain these results.

Epilepsy, psychosis and clozapine

Six patients with epilepsy and severe psychosis were treated with the atypical antipsychotic clozapine. The use of clozapine might be complicated in epileptic patients because of an increased risk of seizures. However, none of the reported patients had an increase of their seizure frequency, in contrast, three patients had a substantial reduction of seizures. One patient had a reduction of non-epileptic seizures as well. In the second part of this paper, combinations of clozapine with newer and older anticonvulsants as well as their interactions and associated risks are discussed.

The "good enough" mood stabilizer: a review of the clinical evidence

A growing family of medications is used for mood stabilization in bipolar disorder. These medications fall into two broad categories according to likely mechanisms of action. Within the categories, specific drugs may vary in their efficacy for different phases of the disorder. The first category, including lithium, anticonvulsants, and some novel treatments, appears to have mechanisms related to intracellular second messengers. These medications have more pronounced antimanic than antidepressant effects, except for lamotrigine, which has antidepressant effects without precipitating mania. The second group of mood stabilizers is the atypical antipsychotics, which act through dopamine and other monoamines. Olanzapine and in all likelihood other drugs in the class possess marked, acute antimanic properties and possible antidepressant properties, but require further study before they can be used as routine options in long-term care. It is clear that the advent of multiple mood stabilizer candidates has not yet led to a single ideal therapy for bipolar disorder, but rather to options that can be flexibly tailored to the lifetime needs of individual patients, in sequences or combinations, and perhaps in conjunction with other classes of psychotropics.

Lamotrigine reduces spontaneous and evoked GABAA receptor-mediated synaptic transmission in the basolateral amygdala: implications for its effects in seizure and affective disorders

Lamotrigine (LTG) is an antiepileptic drug that is also effective in the treatment of certain psychiatric disorders. Its anticonvulsant action has been attributed to its ability to block voltage-gated Na(+) channels and reduce glutamate release. LTG also affects GABA-mediated synaptic transmission, but there are conflicting reports as to whether inhibitory transmission is enhanced or suppressed by LTG. We examined the effects of LTG on GABA(A) receptor-mediated synaptic transmission in slices from rat amygdala, a brain area that is particularly important in epileptogenesis and affective disorders. In intracellular recordings, LTG (100 microM) reduced GABA(A) receptor-mediated IPSPs evoked by electrical stimulation in neurons of the basolateral nucleus. In whole-cell recordings, LTG (10, 50 and 100 microM) decreased the frequency and amplitude of spontaneous IPSCs, as well as the amplitude of evoked IPSCs, but had no effect on the kinetics of these currents. LTG also had no effects on the frequency, amplitude or kinetics of miniature IPSCs recorded in the presence of TTX. These results suggest that in the basolateral amygdala, LTG suppresses GABA(A) receptor-mediated synaptic transmission by a direct and/or indirect effect on presynaptic Ca(++) influx. The modulation of inhibitory synaptic transmission may be an important mechanism underlying the psychotropic effects of LTG.

Early physical and sexual abuse associated with an adverse course of bipolar illness

BACKGROUND

There is growing awareness of the association between physical and sexual abuse and subsequent development of psychopathology, but little is known, however, about their relationship to the longitudinal course of bipolar disorder.

METHODS

We evaluated 631 outpatients with bipolar I or II disorder for general demographics, a history of physical or sexual abuse as a child or adolescent, course of illness variables, and prior suicide attempts, as well as SCID-derived Axis I and patient endorsed Axis II comorbidity.

RESULTS

Those who endorsed a history of child or adolescent physical or sexual abuse, compared with those who did not, had a history of an earlier onset of bipolar illness, an increased number of Axis I, II, and III comorbid disorders, including drug and alcohol abuse, faster cycling frequencies, a higher rate of suicide attempts, and more psychosocial stressors occurring before the first and most recent affective episode. The retrospectively reported associations of early abuse with a more severe course of illness were validated prospectively.

CONCLUSIONS

Greater appreciation of the association of early traumatic experiences and an adverse course of bipolar illness should lead to preventive and early intervention approaches that may lessen the associated risk of a poor outcome.

Mechanisms of action of carbamazepine and its derivatives, oxcarbazepine, BIA 2-093, and BIA 2-024

Carbamazepine (CBZ) has been extensively used in the treatment of epilepsy, as well as in the treatment of neuropathic pain and affective disorders. However, the mechanisms of action of this drug are not completely elucidated and are still a matter of debate. Since CBZ is not very effective in some epileptic patients and may cause several adverse effects, several antiepileptic drugs have been developed by structural variation of CBZ, such as oxcarbazepine (OXC), which is used in the treatment of epilepsy since 1990. (S)-(-)-10-acetoxy-10,11-dihydro-5H-dibenz [b,f]azepine-5-carboxamide (BIA 2-093) and 10,11-dihydro-10-hydroxyimino-5H-dibenz[b,f] azepine-5-carboxamide (BIA 2-024), which were recently developed by BIAL, are new putative antiepileptic drugs, with some improved properties. In this review, we will focus on the mechanisms of action of CBZ and its derivatives, OXC, BIA 2-093 and BIA 2-024. The available data indicate that the anticonvulsant efficacy of these AEDs is mainly due to the inhibition of sodium channel activity.

Pharmacologic treatment of geriatric mania

The prevalence of geriatric mania is uncertain. Although there are high rates of mania in clinical and residential facilities, community based epidemiologic studies are limited. Given the difficulty in making an accurate diagnosis, geriatric mania appears to be underreported. Although the commonly held opinion is that onset and prevalence of mania decreases with age, there is contradictory evidence that, particularly in men, the incidence of new onset mania increases with age. Clinically, the diagnosis and treatment of geriatric mania is challenging, because these patients present with comorbid medical, neurologic, and dementing illnesses. This paper reviews presentations of mania in the elderly and updates the pharmacologic treatment of mania in the elderly. Although few of the studies target the elderly, the published data in younger patients on the use of the atypical antipsychotics, as well as the advent of newer anticonvulsants, have demonstrated promise in the treatment of older patients.

Clinical predictors of response to lamotrigine and gabapentin monotherapy in refractory affective disorders

BACKGROUND

The objective of the current study was to examine possible clinical predictors of positive response to lamotrigine or gabapentin monotherapy in treatment-refractory affectively ill patients.

METHODS

Forty-five patients with treatment refractory bipolar (n = 35) or unipolar (n = 10) affective disorder participated in a clinical study evaluating six weeks of treatment with lamotrigine, gabapentin, or placebo monotherapy given in a double-blind, randomized fashion with two subsequent cross-overs to the other agents. Patients received daily mood ratings and weekly cross-sectional scales. Much or very much improved on the Clinical Global Impression scale modified for bipolar illness was considered a positive response. Degree of response was correlated with a number of baseline demographic and course of illness variables in a univariate analysis and then by linear regression.

RESULTS

Response rates to lamotrigine (51%) exceeded those to gabapentin (28%) and placebo (21%). A positive response to lamotrigine monotherapy was associated with a bipolar diagnosis; fewer hospitalizations; fewer prior medication trials; and male gender (of which the latter two variables survived logistic regression). For gabapentin, degree of response correlated with shorter duration of illness; younger age; and lower baseline weight (with the latter two surviving linear regression).

CONCLUSIONS

In this highly treatment-refractory population, lamotrigine appeared most effective for male patients with fewer prior medication trials. Gabapentin monotherapy, although not better than placebo, appeared most effective in those with younger age and lower baseline weight. These preliminary data in a treatment refractory subgroup may help in the further definition of the range of clinical utility of these widely used anticonvulsants.

Emerging options in the treatment of bipolar disorders

Bipolar disorder is a common and severe condition, and has a clinical outcome that is frequently sub-optimal. Only a small number of therapeutic options are currently available for the disorder. A growing range of novel therapeutic options for the treatment of bipolar disorder are under investigation. These include the anticonvulsants, atypical antipsychotics and options such as the omega-3 fatty acids and transcranial magnetic stimulation. Of the anticonvulsants, lamotrigine is currently the agent for which the greatest amount of controlled clinical data is accumulating, particularly in the depressed and rapid cycling phases of the illness. Olanzapine is currently the atypical antipsychotic with the largest body of evidence in mania, although data is emerging on other atypical antipsychotics including risperidone and ziprasidone. Data regarding the atypical agents in other phases of the illness are awaited. The options available for this difficult to treat condition is increasing with the new range of agents.

Bipolar disorder

Bipolar, or manic-depressive, disorder is a frequent, severe, mostly recurrent mood disorder associated with great morbidity. The lifetime prevalence of bipolar disorder is 1.3 to 1.6%. The mortality rate of the disease is two to three times higher than that of the general population. About 10-20% of individuals with bipolar disorder take their own life, and nearly one third of patients admit to at least one suicide attempt. The clinical manifestations of the disease are exceptionally diverse. They range from mild hypomania or mild depression to severe forms of mania or depression accompanied by profound psychosis. Bipolar disorder is equally prevalent across sexes, with the exception of rapid cycling, a severe and difficult to treat variant of the disorder, which arises mostly in women. Because of the high risk of recurrence and suicide, long-term prophylactic pharmacological treatment is indicated. Lithium salts are the first choice long-term preventive treatment for bipolar disorder. They also possess well documented antisuicidal effects. Second choice prophylactic treatments are carbamazepine and valproate, although evidence of their effectiveness is weaker.

Behavioural effects of the new anticonvulsants

Of the 9 new anticonvulsants that have been marketed recently in the UK or US, a number appear to have either adverse or beneficial effects on behaviour. There is now a considerable database of information, in terms of the number of patients treated and/or the number of published reports, on vigabatrin, lamotrigine, gabapentin and topiramate. Oxcarbazepine has been available in some centres for several years and there is extensive experience with the drug in Scandinavia. It appears that the profile of adverse and beneficial effects is similar to that of carbamazepine. Behavioural effects have probably been greatest with vigabatrin, with psychosis, depression and other behavioural problems recorded, but the use of this drug has been limited because of the concern about visual field constriction. The cognitive and behavioural effects of topiramate have caused concern, but these may be much less of a problem if lower starting dosages and escalation rates are used. Psychosis and depression have been associated with topiramate, as they have with another carbonic anhydrase inhibiting drug, zonisamide. Although zonisamide has been used for many years in Japan and Korea, experience elsewhere with this drug is currently very limited. Gabapentin seems to be less associated with adverse behavioural effects than some of the other new anticonvulsant drugs. The reports of behavioural disturbance with gabapentin in children may be related to dose escalation. Behavioural disturbance as a direct result of lamotrigine seems to be uncommon, although indirect effects on behaviour, through the so-called 'release phenomenon' from improved seizure control and consequent ability to misbehave, can occur. Positive behavioural effects have been described with several of the new anticonvulsants, particularly gabapentin, lamotrigine and oxcarbazepine; all of these drugs may have mood-levelling effects that could be of value in treating affective disorders. The information on tiagabine and levetiracetam is too limited to allow any firm conclusions to be drawn with regard to positive or negative behavioural effects. When interpreting reports of behavioural changes with anticonvulsants, it is important to avoid attributing the effect to the drug when one or more of the other multiple causes of behavioural disturbance in people with epilepsy may be responsible or when an indirect effect such as 'forced normalisation' may be the cause. Many of the published studies are retrospective and unblinded rather than double-blind, placebo-controlled, prospective trials, implying that much of the data must be interpreted with caution at this stage.

Comparative efficacy and tolerability of drug treatments for bipolar disorder

Lithium has been the backbone of treatment for bipolar disorder for several decades, although recent advances have identified a number of other medications that have efficacy in treating various phases of the illness. These include the antiepileptic drugs valproate semisodium (divalproex sodium) and carbamazepine and some new antiepileptic drugs (e.g. lamotrigine and topiramate), and the atypical antipsychotics (e.g. olanzapine, clozapine and risperidone). Conventional antipsychotics continue to be used frequently in bipolar disorder, although they may be somewhat less effective than other treatments. Otherwise, to date, none of these treatments have been shown to be consistently more effective than any other, so that drug adverse effects and tolerability often dictate which agents are used in an individual patient. Drugs commonly used for the treatment of bipolar disorder are generally tolerated by most patients in large samples. However, the unique adverse effect signature of a drug will often suggest that it will be less tolerable in some patients than in others. Identifying a specific treatment for a specific patient requires a careful individualised assessment of the risk of adverse effects for that patient's unique circumstances.