Psychiatric uses of antiepileptic treatments

Antiepileptic drugs (AEDs) possess potent negative or positive psychotropic effects. Clear evidence of benefit exists for valproate, carbamazepine, and lamotrigine in bipolar disorder. Reports of benefit from various AEDs in mood, anxiety, impulse control, and personality disorder are reviewed. Further research is needed to clarify which patients are likely to benefit. Clinicians must closely attend to the ongoing risk/benefit analysis and consider possible iatrogenic worsening of neuropsychiatric symptoms.

Clinical outcome of adjunctive topiramate treatment in a sample of refractory bipolar patients with comorbid conditions

Topiramate, a novel antiepileptic agent, has shown promise in the treatment of bipolar disorder. Patients attending a bipolar specialty clinic and treated with topiramate were identified by chart review, and data were harvested from systematic prospective assessments used routinely in the clinic. Fourteen patients who received topiramate for an average of 22.4 weeks were identified. All but one of these patients were considered to be highly refractory to standard treatment and 13 met the criteria for at least one comorbid psychiatric condition. Nine of these patients (64%) experienced an increased level of functioning and decrease in symptom severity during treatment with adjunctive topiramate. Eleven patients remained on treatment for longer than 2 weeks. Eight of these patients (73%) experienced a significant improvement in their comorbid conditions. Patients with a body mass index (BMI) of > or = 28 (n = 4) experienced a mean weight loss of 29.7 lb while on topiramate. Topiramate appears to be a promising agent for the treatment of bipolar disorder associated with comorbid psychiatric conditions and obesity.

Treatment of acute mania with topiramate in hospitalized patients

The purpose of this study was to evaluate the efficacy of topiramate in the treatment of acute manic symptoms. Fourteen patients, admitted with an acute manic episode, were treated with topiramate. All required supplementation therapy with benzodiazepines. Nine patients received topiramate as monotherapy; four of them required zuclopenthixol acutard 100 mg/48 h intramuscularly (im) for not more than 6 days. In three treatment-resistant patients, topiramate was added to the existing therapy. Finally, in two patients topiramate was coadministered with an antipsychotic from the beginning. Patients were assessed every week for 4 weeks with the Bech and Rafaelsen Mania Scale (BRMS). Mean BRMS scores declined from 26.2 to 11.6 in the fourth week (P<.001); a significant decline (P<.001) was observed after the first week. Response rate (> or = 50% reduction of BRMS) was 61.5% (8 out of 13 patients). All patients tolerated topiramate well. Reduced appetite and weight loss was observed in four patients; however, two patients presented weight gain. These preliminary findings provide support for a modest efficacy of topiramate, especially as monotherapy, in the treatment of acute mania.

Long-range synchronization of gamma and beta oscillations and the plasticity of excitatory and inhibitory synapses: a network model

The ability of oscillating networks to synchronize despite significant separation in space, and thus time, is of biological significance, given that human gamma activity can synchronize over distances of several millimeters to centimeters during perceptual and learning tasks. We use computer simulations of networks consisting of excitatory pyramidal cells (e-cells) and inhibitory interneurons (i-cells), modeling two tonically driven assemblies separated by large (>or=8 ms) conduction delays. The results are as follows. 1) Two assemblies separated by large conduction delays can fire synchronously at beta frequency (with i-cells firing at gamma frequency) under two timing conditions: e-cells of (say) assembly 2 are still inhibited "delay + spike generation milliseconds" after the e-cell beat of assembly 1; this means that the e-cell inhibitory postsynaptic potential (IPSP) cannot be significantly shorter than the delay (2-site effect). This implies for a given decay time constant that the interneuron --> pyramidal cell conductances must be large enough. The e-cell IPSP must last longer than the i-cell IPSP, i.e., the interneuron --> pyramidal cell conductance must be sufficiently large and the interneuron --> interneuron conductance sufficiently small (local effect). 2) We define a "long-interval doublet" as a pair of interneuron action potentials-separated by approximately "delay milliseconds"-in which a) the first spike is induced by tonic inputs and/or excitation from nearby e-cells, while b) the second spike is induced by (delayed) excitation from distant e-cells. "Long-interval population doublets" (long-interval doublets of the i-cell population) are necessary for synchronized firing in our networks. Failure to produce them leads to almost anti-phase activity at gamma frequency. 3) An (almost) anti-phase oscillation is the most stable oscillation pattern of two assemblies that are separated by axonal conduction delays of approximately one-half a gamma period (delays from 8 to 17 ms in our simulations) and that are firing at gamma frequency. 4) Two assemblies separated by large conduction delays can synchronize their activity with the help of interneuron plasticity. They can also synchronize without pyramidal cell --> pyramidal cell connections being present. The presence of pyramidal cell --> pyramidal cell connections allows, however, for synchronization if other parameters are at inappropriate values for synchronization to occur. 5) Synchronization of two assemblies separated by large conduction delays with the help of interneuron plasticity is not simply due to slowing down of the oscillation frequency. It is reached with the help of a "synchronizing-weak-beat," which induces sudden changes in the oscillation period length of the two assemblies.

A pilot study of loading versus titration of valproate in the treatment of acute mania

OBJECTIVE

This double-blind pilot study compares the effectiveness and incidence of adverse effects of oral loading versus titration schedules of valproate in acute mania.

METHOD

Consecutive new admissions for an acute manic episode were prescribed either an oral loading dose (20 mg/kg/day; n = 5; mean age = 33.4) or slower titration dose (10 mg/kg/day, n = 6. mean age = 30.6) of valproate for 7 days without other psychotropic agents. with the exception of benzodiazepines. Daily outcome measures included: serum valproic acid levels, the Young Mania Rating Scale (YMRS), the Brief Psychiatry Rating Scale (BPRS), the Clinical Global Impression Scale (CGI) and the Adverse Effect Rating Scale.

RESULTS

The mean serum valproic acid levels were significantly higher in the loading group when compared with the titration group after 1 and 2 days following the initiation of treatment (p < 0.05). After 3 days of treatment there was a trend for the group that received the loading regimen to have slightly more improvement in YMRS scores compared with the titration group. Side-effects were minor for both treatments, however, a higher incidence of side-effects was reported in the titration group, with 50% of patients reporting sedation most likely because of increased use of benzodiazepines.

CONCLUSION

This suggests that a loading dose of valproate is likely safe and may provide an earlier onset of antimanic effects in patients with bipolar disorder. Future studies with larger sample sizes are indicated.

The neurobehavioural effects of kava

OBJECTIVE

This review considers the context in which kava is used, together with its underlying psychopharmacological mechanisms, to investigate the neurobehavioural effects associated with kava use.

METHOD

We conducted a systematic search using the computerized databases MEDLINE, OVID and PsychLIT for all articles containing any of the following words: kava, kavain, kawa and Piper methysticum. In the opinion of the authors, all articles from this collection containing data that could inform the neurological and cognitive sequelae of kava use were included for the purpose of this review.

RESULTS

The use of kava occurs among indigenous populations in the South Pacific and in northern Australia, while also being used throughout the western world as a herbal medicine. Animal studies show that kava lactones alter neuronal excitation through direct interactions with voltage-dependent ion channels, giving rise to kava's muscle relaxant, anaesthetic, anxiolytic and anticonvulsive properties. Several isolated cases of psychotic and severe dystonic reactions following kava use suggest that kava also has psychoactive properties, yet there is no conclusive evidence that kava interferes with normal cognitive processes.

CONCLUSIONS

Kava is effective in the treatment of tension and anxiety. There may be risk-factors for severe motor and psychiatric responses to kava use, although these are not well-understood. Given the increasingly widespread use of kava, further investigation is necessary to gain an understanding of its immediate neuropsychiatric effects and long-term cognitive effects.

Topiramate: a case series study in migraine prophylaxis

We reviewed the electronic records of 74 migraine patients treated with topiramate for more than 6 weeks. Twenty-four patients had episodic migraine and 50 had chronic (transformed) migraine. Most (81%) started treatment at 25 mg per day and reached a dose of 100 mg twice a day (mean dose on the last follow-up visit was 208 mg). The mean headache frequency decreased from 20.6 days to 13.6 days per month (P<0.0001) for all headaches (9.9-5.1 (P<0.0001) and 25.7-17.7 (P<0.001) for episodic migraine and chronic migraine, respectively). The percentage of patients whose headache frequency was reduced by > or =50% was 44.6% for all patients; 58.3 for episodic migraine and 38.0 for chronic migraine. For all patients mean headache severity (10-point scale) was reduced from 6.2 to 4.8 (P<0.0001). Patients on monotherapy (20%) and polytherapy (80%) had similar reductions in headache frequency. Adverse events were usually mild to moderate and were seen in 58.1% (paresthesias in 25%, cognitive difficulties 14.9%). Mean weight loss was 3.1 +/- 4 kg (3.8% of total body weight).

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.