Why do schizophrenic patients hallucinate?

Phillips & Silverstein argue that schizophrenia is a result of a deficit of the contextual coordination of neuronal responses. The authors propose that NMDA-receptors control these modulatory effects. However, hallucinations, which are among the principle symptoms of schizophrenia, imply a flaw in the interactions between neurons that is more fundamental than just a general weakness of contextual modulation.

Schizophrenic cognition: Taken out of context?

This commentary addresses: (a) the problems of definition which have been prominent in the use of the term context in schizophrenia research; (b) potentially useful distinctions and links with other theories of schizophrenic cognition; and (c) possible pathways to schizophrenic symptoms. It is suggested that at least two major aspects of the operation of context may be distinguished and that both may be impaired in schizophrenia.

NMDA synapses can bias competition between object representations and mediate attentional selection

Phillips & Silverstein emphasize the gain-control properties of NMDA synapses in cognitive coordination. We endorse their view and suggest that NMDA synapses play a crucial role in biased attentional competition and (visual) working memory. Our simulations show that NMDA synapses can control the storage rate of visual objects. We discuss specific predictions of our model about cognitive effects of NMDA-antagonists and schizophrenia.

Combating fuzziness with computational modeling

Phillips & Silverstein's ambitious link between receptor abnormalities and the symptoms of schizophrenia involves a certain amount of fuzziness: No detailed mechanism is suggested through which the proposed abnormality would lead to psychological traits. We propose that detailed simulation of brain regions, using model neural networks, can aid in understanding the relation between biological abnormality and psychological dysfunction in schizophrenia.

High numbers of circulating activated T cells and raised levels of serum IL-2 receptor in bipolar disorder

BACKGROUND

Previously, we found an increased prevalence of thyroid autoantibodies in patients with bipolar disorder. In the present study, we investigated other signs of immune activation in bipolar patients, in particular an activation of the T cell system.

METHODS

Fluorescence activated cell scanning (FACS) analysis was performed on lymphocytes of 64 outpatients with DSM-IV bipolar disorder using the T cell marker CD3 in combination with the activation markers MHC-class II, CD25, CD69 or CD71. In 34 patients, these assays were repeated after an interval of 2 years. In addition, T cell activation was determined by measuring serum soluble IL-2 receptor (sIL-2R) in 172 bipolar outpatients. Outcomes were compared with a healthy control group.

RESULTS

Significantly higher numbers of circulating activated T cells and raised sIL-2R levels were found in euthymic, manic, and depressed bipolar patients when compared with healthy controls. In general, these abnormalities were stable over time. Manic patients showed significantly higher levels of sIL-2R in comparison with depressed patients.

CONCLUSION

The T cell system was found to be activated in both symptomatic and euthymic patients with bipolar disorder. The pathophysiological significance of these findings remains to be explored.

Low CSF somatostatin associated with response to nimodipine in patents with affective illness

BACKGROUND

In patients with depression, treatment with nimodipine has been shown to increase cerebrospinal fluid (CSF) somatostatin (SRIF) and ameliorate baseline global cerebral hypometabolism. This study was conducted to assess whether a low baseline level of CSF SRIF was associated with response to nimodipine treatment.

METHODS

Twenty-one depressed patients underwent lumbar puncture for analysis of CSF somatostatin-like immunoreactivity (SRIF-LI) during a medication-free period and after at least 6 weeks of nimodipine monotherapy. Twenty-five healthy control subjects were utilized as a comparison group. Clinical improvement was assessed using the Clinical Global Impression Scale for Bipolar Illness.

RESULTS

As predicted, baseline CSF SRIF-LI was significantly lower in eventual nimodipine responders (33.1 +/- 2.8 pg/mol) compared to eventual nonresponders [41.9 +/- 2.6 pg/mL; t(19) = 1.98, p =.03, one-tailed].

CONCLUSIONS

Low baseline CSF somatostatin in depression may be associated with response to nimodipine, which in turn may be related to the ability of nimodipine to increase CSF somatostatin.

The World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for the Biological Treatment of Bipolar Disorders, Part II: Treatment of Mania

Identical to the preceding guidelines of this series, these practice guidelines for the biological, mainly pharmacological treatment of acute bipolar mania 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 acute mania. The data used for these guidelines have been extracted from a MEDLINE and EMBASE search, from recent proceedings of key conferences, and from 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 finally not only graded, but has also been commented by the experts of the task force to ensure practicability. Key words: bipolar disorder, mania, acute treatment, evidence-based guidelines, pharmacotherapy, antipsychotics, mood stabiliser, electroconvulsive therapy.

Progressive decrease of left superior temporal gyrus gray matter volume in patients with first-episode schizophrenia

OBJECTIVE

Smaller temporal lobe cortical gray matter volumes, including the left superior temporal gyrus, have been reported in magnetic resonance imaging (MRI) studies of patients with chronic schizophrenia and, more recently, in patients with first-episode schizophrenia. However, it remains unknown whether there are progressive decreases in temporal lobe cortical gray matter volumes in patients with first-episode schizophrenia and whether similarly progressive volume decreases are present in patients with affective psychosis.

METHOD

High-spatial-resolution MRI scans at initial hospitalization and 1.5 years later were obtained from 13 patients with first-episode schizophrenia, 15 patients with first-episode affective psychosis (mainly manic), and 14 healthy comparison subjects. MRI volumes were calculated for gray matter of superior temporal gyrus and for the amygdala-hippocampal complex.

RESULTS

Patients with first-episode schizophrenia showed significant decreases in gray matter volume over time in the left superior temporal gyrus compared with patients with first-episode affective psychosis or healthy comparison subjects. This progressive decrease was more pronounced in the posterior portion of the left superior temporal gyrus (mean=9.6%) than in the anterior portions (mean=8.4%). No group differences in the rate of change over time were present in other regions.

CONCLUSIONS

These findings demonstrate a progressive volume reduction of the left posterior superior temporal gyrus gray matter in patients with first-episode schizophrenia but not in patients with first-episode affective psychosis.

Role of the psychiatrist in the care of patients with hepatitis C and HIV/AIDS

Hepatitis C and HIV/AIDS are among the most significant infectious diseases of our time. Psychiatric patients are often part of the higher risk population to contract these diseases, and patients who have contracted these diseases experience a wide variety of psychiatric problems associated with the underlying infection and with its treatment. The authors provide an overview of these infectious diseases and then describe the varying roles psychiatrists have in caring for these patients in the various settings of their work. The complexity of these patients presents a unique challenge to, and opportunity for, psychiatrists to integrate and coordinate their interventions with those of other medical providers and thereby enhance the patient's cooperation with all aspects of care.

The evolution of antiepileptic drugs for mood stabilization and their main mechanisms of action

Although much progress has been made in successfully treating bipolar disorder, there is increasing awareness of the limitations of traditional treatment regimes, such as lithium or antipsychotics and the possible beneficial use of antiepileptic drugs. After the first generation of antiepileptic drugs such as phenytoin and clonazepam, the second generation is comprised of the frequently-used substances carbamazepine/oxcarbazepine and valproate. Lamotrigine, gabapentin, tiagabine, levetiracetam, zonisamide and topiramate will represent the third generation 5 years from now. Drugs such as retigabine might represent the next generation. However, the efficacy of antiepileptic drugs investigated in the treatment of bipolar disorder differs and most promising effects are seen in combination therapy with mood stabilizers. The authors review the main mechanisms of action of these drugs which may, in turn, improve our understanding of the pathophysiology of bipolar disorder.

Family history validation of the bipolar nature of depressive mixed states

BACKGROUND

Recent data indicate that depressive mixed states (DMX), major depressive episode (MDE) plus few concurrent hypomanic symptoms are common in clinical practice but omitted in DSM-IV. Our aims were to find the sensitivity and specificity of DMX for the diagnosis of bipolar II disorder, and validate it against familial bipolarity.

METHODS

377 consecutive private outpatients presenting with psychoactive drug-free MDE were interviewed with the Structured Clinical Interview for DSM-IV (Clinician Version). History of past hypomanic episodes and presence of hypomanic symptoms during the index MDE were systematically recorded. Of these, 226 were bipolar II and 151 unipolar. DMX3 was defined as an MDE plus three or more intra-episodic hypomanic symptoms.

RESULTS

DMX3 was present in 58.4% of bipolar II, and 23.1% of unipolar patients. It was significantly associated with variables distinguishing bipolar from strictly defined unipolar disorders (younger age at onset, more MDE recurrence, more atypical features, more bipolar II family history). Unipolar DMX3 (MDE with documented hypomania solely intra-episodically) was not significantly different from bipolar II MDE on age at onset, atypical features, and bipolar II family history.

CONCLUSIONS

Results support the inclusion of DMX3 (bipolar II and 'unipolar') into the bipolar spectrum. Adding the 23% of the UP-DMX3 to the roster of less-than-manic outpatient depressives will boost the rate of bipolarity in this outpatient depressive population to a respectable 70%, the highest rate yet reported for the bipolar spectrum below the threshold of mania.

The dual factor structure of self-rated MDQ hypomania: energized-activity versus irritable-thought racing

BACKGROUND

Bipolar II is diagnosed in a clinically depressed patient by documenting history of hypomania. Therefore, it is of great significance for both clinical and research purposes to characterize the factor structure of hypomania.

METHODS

Among consecutive depressive outpatients-126 major depressives and 187 bipolar II-diagnosed by the Structured Clinical Interview for DSM-IV (Clinician Version), 181 who had clinically recovered from depression were administered the Mood Disorder Questionnaire (MDQ of. Am. J. Psychiatry 157, 1873). The MDQ is a newly developed, psychometrically validated self-report screening instrument for bipolar spectrum disorders. It screens for lifetime history of manic/hypomanic symptoms by including yes/no items covering all DSM-IV symptoms of mania/hypomania. The MDQ symptom interrelationships were studied by principal component analysis with varimax rotation.

RESULTS

Hypomanic symptoms occurring in >50% were racing thoughts, increased energy and social activity, and irritability. Factor analysis revealed two factors: 'Energized-Activity' (eigenvalue=3.1) and 'Irritability-Racing Thoughts' (eigenvalue=1.5).

LIMITATIONS

Cross-sectional assessment.

CONCLUSIONS

Self-assessment of past hypomanic symptoms by patients, during clinical remission from depression, revealed two independent hypomanic factors, neither of which comprised euphoria. Hypomanic behavior appears to be more fundamental for the diagnosis of hypomania than elated mood accorded priority in DSM-IV; of hypomanic moods, irritability had greater significance than elation. It would appear that self-report of euphoria is less likely when hypomanias are brief (>or=2 vs. >or=4 days). The main implication for busy clinical practice is that energized activity and irritable mood associated with racing thoughts represent the modal experiences of hypomania among bipolar II outpatients; euphoria is neither sensitive, nor pathognomonic, in the diagnosis of these patients. These conclusions accord with recommendations made many years ago for the diagnosis of hypomania among cyclothymic patients [. Am. J. Psychiatry 134, 1227].

Valproate for acute mood episodes in bipolar disorder

BACKGROUND

Bipolar disorder is a common debilitating illness, characterised by acute affective episodes with full or partial inter-episode remission. Effective and acceptable treatment of acute episodes is required. Valproate has become a leading adjunctive and alternative mood stabilising treatment to lithium in bipolar disorder.

OBJECTIVES

To determine the efficacy and acceptability of valproate in the treatment of acute episodes of bipolar disorder.

SEARCH STRATEGY

The search included the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Registrar (CCDANCTR), the Cochrane Controlled Clinical Trials Register (CCTR), reference lists of relevant papers and books, and contact with authors of trials, experts and pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials comparing valproate with placebo, other mood stabilisers and antipsychotic medication in the treatment of any bipolar affective episode. Participants were of both sexes, of all ages, with a diagnosis of bipolar affective disorder approximating to ICD 10 Code F31 and DSM IV 296.

DATA COLLECTION AND ANALYSIS

Methodological quality was assessed independently by two reviewers blind to the authorship and source of papers. Ten randomised controlled trials were found comparing valproate with other interventions in mania. None was found examining its use in depression or mixed affective episodes. Data were extracted on the main outcome 'failure to respond by the end of the study' assessed by a less than 50% reduction in the Young Mania Rating Scale or the SADS-S mania scale. Three trials (316 participants) compared valproate with placebo. Three trials (158 participants) compared valproate with lithium. Two trials (363 participants) compared valproate with olanzapine. One trial (36 participants) compared valproate with haloperidol. Two trials (59 patients) compared valproate with carbamazepine. Acceptability of treatment was estimated using the outcome measure 'total number of subjects withdrawing from the study'. Three trials (321 patients) contributed to the comparison between valproate and placebo, two studies (144 patients) contributed to the comparison with lithium. One study (30 patients) provided data on this outcome in the comparison between valproate and carbamazepine. Pooled relative risks (with 95% confidence intervals) were calculated using fixed effect approaches.

MAIN RESULTS

Valproate was more efficacious than placebo (RRR 38%; RR 0.62; 95% C.I. 0.51 to 0.77) in the treatment of mania. There was no significant difference between valproate and lithium (RRI 5%; RR 1.05; 95% C.I. 0.74-1.50) or between valproate and carbamazepine (RRR 34%; RR 0.66; 95% C.I. 0.38 to 1.16). Valproate was less effective than olanzapine (failure to achieve clinical response; RRI 25%; RR 1.25, 95% C.I. 1.01 to 1.54; average of 2.8 point less change on the Mania Rating Scale (95% CI 0.83 to 4.79). There were no significant differences in acceptability as measured by total number of subjects withdrawing from the study. There were significant differences in the side effect profiles of valproate and olanzapine, with more sedation and weight gain on olanzapine.

REVIEWER'S CONCLUSIONS

There is consistent, if limited, evidence to suggest that valproate is an efficacious treatment for acute mania. Valproate may be less effective than olanzapine but may cause less sedation and weight gain. More well designed, randomised controlled trials investigating the relative efficacy and acceptability of valproate in the treatment of the full range of acute affective episodes occurring in bipolar disorder are required.

Lamotrigine in mood disorders

Lamotrigine is an anticonvulsant drug with good efficacy and safety in the treatment of epilepsy. There is now substantial evidence that lamotrigine is also useful in treating resistant depression, rapid cycling bipolar affective disorder, depressive episodes in bipolar affective disorder and in the maintenance phase or prophylaxis of bipolar affective disorder. There are possible roles in managing mood changes in borderline personality disorder, reducing chronic pain and treating schizoaffective disorder. The general range of doses found effective in affective disorders is from 50 to 300 mg daily. Clinical use seems to involve a titration of dose upwards over several weeks until the desired effect is obtained. However, further definitive double-blind, randomised controlled trials against gold standard treatments are required. Lamotrigine has a preferable side-effect profile compared to standard agents for bipolar affective disorder such as lithium or carbamazepine. Further research is certainly warranted and, given its tolerability, could point to lamotrigine as the treatment of choice for some affective disorders.

An epigenetic mouse model for molecular and behavioral neuropathologies related to schizophrenia vulnerability

Reelin and glutamic acid decarboxylase (GAD)67 expressed by cortical gamma-aminobutyric acid-ergic interneurons are down-regulated in schizophrenia. Because epidemiological studies of schizophrenia fail to support candidate gene haploinsufficiency of Mendelian origin, we hypothesize that epigenetic mechanisms (i.e., cytosine hypermethylation of CpG islands present in the promoter of these genes) may be responsible for this down-regulation. Protracted l-methionine (6.6 mmolkg for 15 days, twice a day) treatment in mice elicited in brain an increase of S-adenosyl-homocysteine, the processing product of the methyl donor S-adenosyl-methionine, and a marked decrease of reelin and GAD67 mRNAs in both WT and heterozygous reeler mice. This effect of l-methionine was associated with an increase in the number of methylated cytosines in the CpG island of the reelin promoter region. This effect was not observed for GAD65 or neuronal-specific enolase and was not replicated by glycine doses 2-fold greater than those of l-methionine. Prepulse inhibition of startle declined at a faster rate as the prepulsestartle interval increased in mice receiving l-methionine. Valproic acid (2 mmolkg for 15 days, twice a day) reverted l-methionine-induced down-regulation of reelin and GAD67 in both WT and heterozygous reeler mice, suggesting an epigenetic action through the inhibition of histone deacetylases. The same dose of valproate increased acetylation of histone H3 in mouse brain nearly 4-fold. This epigenetic mouse model may be useful in evaluating drug efficacy on schizophrenia vulnerability. Hence the inhibition of histone deacetylases could represent a pharmacological intervention mitigating epigenetically induced vulnerability to schizophrenia in individuals at risk.

Review of the use of topiramate for treatment of bipolar disorders

Lithium alone or in combination with other psychotherapeutic drugs has long been the gold standard of management for bipolar disorder (BD). Recognition of its limitations in the acute and chronic management of BD has led to the development of alternative therapies. One such approach involves the use of antiepileptic drugs (AEDs). The AED topiramate is currently being studied in the efficacy and management of BD. Topiramate has mechanisms in common with other AEDs, including sodium channel-blocking activity and enhancement of cerebral GABA concentrations. Open-label trials have evaluated topiramate at mean daily doses of 100 to 300 mg in various BD subtypes, including acute mania, depression, rapid-cycling, mixed states, and BD refractory to other medications. Results from these trials suggest topiramate may be efficacious in BD subtypes, particularly in rapid-cycling patients and those refractory to conventional treatment. Its side effect profile appears benign when used as monotherapy or in combination with other mood stabilizers. Placebo-controlled, double-blind studies are warranted to evaluate topiramate further in BD.

Pharmacotherapy of bipolar disorder: the role of atypical antipsychotics and experimental strategies

Bipolar disorder, despite being a common and debilitating illness, has remarkably few pharmacological therapeutic options, the majority of which, with the exception of lithium, have been borrowed from other medical indications. Furthermore the quantity and quality of controlled clinical data are considerably smaller than in conditions of comparable severity and frequency. Not surprisingly, the clinical outcome of bipolar disorder is frequently suboptimal. Fortunately there are a growing number of novel therapeutic options for its treatment such as atypical antipsychotics, calcium channel blockers and omega-3 fatty acids. This paper summarizes some of the data regarding these "experimental" therapeutic options, focusing principally on atypical antipsychotics as these are now widely prescribed in the management of bipolar disorder.

The Maudsley bipolar disorder project. A survey of psychotropic prescribing patterns in bipolar I disorder

OBJECTIVES

The outcome of Bipolar 1 Disorder (BD1) is greatly dependent on the adequacy and appropriateness of its treatment. As the treatment choices in BD1 disorder are increasing the aim of this study was to examine the current use of the pharmacological agents in BD1 patients and its association with clinical characteristics.

METHODS

Case note review of the pharmacotherapy of a sample of BD1 patients from a specified South London sector of a National Health Service Trust.

RESULTS

Half of the patients were on mood-stabilizers (usually lithium) and their use was associated with female gender and multiple admissions. Antipsychotics were more commonly used in patients with psychotic features and multiple manic episodes. Antidepressants were rarely prescribed alone and were not associated with increased number of manic episodes. Combination treatments were mostly used in patients in acute episodes and with multiple hospitalizations.

CONCLUSIONS

In ordinary care, the treatment of BD1 is often driven by symptoms and falls short of the existing practice guidelines.

Magnesium and affective disorders

There are several findings on the action of magnesium ions supporting their possible therapeutic potential in affective disorders. Examinations of the sleep-electroencephalogram (EEG) and of endocrine systems point to the involvement of the limbic-hypothalamus-pituitary-adrenocortical axis as magnesium affects all elements of this system. Magnesium has the property to suppress hippocampal kindling, to reduce the release of adrenocorticotrophic hormone (ACTH) and to affect adrenocortical sensitivity to ACTH. The role of magnesium in the central nervous system could be mediated via the N-methyl-D-aspartate-antagonistic, gamma-aminobutyric acidA-agonistic or a angiotensin II-antagonistic property of this ion. A direct impact of magnesium on the function of the transport protein p-glycoprotein at the level of the blood-brain barrier has also been demonstrated, possibly influencing the access of corticosteroids to the brain. Furthermore, magnesium dampens the calciumion-proteinkinase C related neurotransmission and stimulates the Na-K-ATPase. All these systems have been reported to be involved in the pathophysiology of depression. Despite the antagonism of lithium to magnesium in some cell-based experimental systems, similarities exist on the functional level, i.e. with respect to kindling, sleep-EEG and endocrine effects. Controlled clinical trials examining the effect of Mg in affective disorder are warranted.

Relevance of new and newly rediscovered anticonvulsants for atypical forms of bipolar disorder

The so-called atypical forms of bipolar disorder are not a rarity, but instead are rather the rule. Particularly in specialized settings such as the bipolar disorder clinic, the majority of patients are characterized by atypical manifestations (). Mixed states, psychotic mania and a rapid cycling course of bipolar disorder are a challenge both to pharmacological and non-pharmacological treatment. The benefit of classical mood stabilizers such as lithium and carbamazepine is limited in monotherapy, although valproate has a broader spectrum of activity in atypical bipolar disorders and is often used in combination with other agents. Thus, new treatment alternatives are needed urgently for optimizing the treatment of atypical bipolar disorder. During the last decade, several new antiepileptic drugs have been released, e.g. lamotrigine, gabapentin, tiagabine, topiramate and levetiracetam. Others have been available for some time, but only recently have become the focus of bipolar disorder research; for example, phenytoin, and especially, oxcarbazepine. This review will consider our current knowledge of the benefit of these new and newly rediscovered anticonvulsants in treating bipolar disorders, with a special focus on their value in treating atypical manifestations.

Systemic immune parameters and sleep after ultra-low dose administration of IL-2 in healthy men

A somnogenic function is suspected for various cytokines. Foregoing experiments in humans indicated a selective increase in the production of interleukin-2 (IL-2) during sleep as compared with nocturnal wakefulness. Here, we examined whether conversely, IL-2 exerts a promoting influence on sleep. Also, the effects of IL-2 administered at ultra-low doses on systemic immune and endocrine parameters were assessed. Eighteen healthy men participated in three night sessions, receiving subcutaneously at 19:00 h either placebo or recombinant human IL-2 at doses of 1000 and 10,000 IU/kg bw. Polysomnographical recordings were obtained between 23:00 and 07:00 h. Blood was collected repeatedly to determine (i) white blood cell (WBC) counts including the enumeration of monocytes, natural killer (NK) cells, and lymphocyte subsets, (ii) serum concentrations of IL-2, soluble IL-2 receptor (sIL-2r), IL-4, IL-6, and interferon-gamma (IFN-gamma), and (iii) concentrations of adrenocorticotropin (ACTH), cortisol, thyreotropin (TSH), and growth hormone (GH). Changes after 1000 IU/kg bw IL-2 generally remained non-significant. However, distinct effects occurred after 10,000 IU/kg bw IL-2, inducing serum IL-2 concentrations selectively activating the high affinity IL-2 receptor. At this dose, IL-2 reduced the number of circulating lymphocytes (including all major subtypes) and NK cells, while counts of monocytes and neutrophils were increased. IL-4 release was stimulated and IFN-gamma concentration reduced after IL-2. Also, IL-2 increased the TSH concentration. There were no hints at a sleep promoting effect of IL-2. Immune changes suggest that nocturnal IL-2 administration induces a shift towards Th2 mediated defense.

Effectiveness of adjunctive gabapentin in resistant bipolar disorder: is it due to anxious-alcohol abuse comorbidity?

We evaluated effectiveness and predictors of response of gabapentin (GBP) as adjunctive treatment in a sample of 43 subjects with DSM-III-R bipolar disorder who were resistant to standard mood stabilizers. Diagnostic evaluation was performed by means of the Semistructured Interview for Mood Disorder. Clinical evaluation was performed at the beginning and end of the observation period by means of the Hamilton Rating Scale for Depression (HAM-D), the Young Mania Rating Scale, and the Clinical Global Impression Scale. GBP was administered as an adjunctive treatment for an 8-week period in combination with other mood stabilizers, benzodiazepines, antidepressants, and neuroleptics. Mean dosage +/- SD at week 8 was 1270 +/- 561.4 mg (range, 600-2400 mg). Adjunctive treatment with GBP was well tolerated by almost all the subjects; only three patients had to interrupt treatment before week 8, two because of inefficacy and one because of the appearance of side effects (ataxia and irritability); in other patients, the most frequent side effects were sedation, irritability, tremor, ataxia or motor instability, and nausea. Eighteen (41.9%) of 43 patients who began treatment were considered responders. Mean total HAM-D score showed a significant reduction during the 8 weeks of treatment. Analysis of the various HAM-D dimensions showed that the anxiety-somatization factor was the one with the greatest change. Seventeen of the 18 responder patients remained in remission for a period ranging from 4 to 12 months without clinically significant side effects or adverse events. One patient had to interrupt GBP treatment and be administered neuroleptics because of the reappearance of manic symptoms. Regarding response predictors, logistical regression analysis showed that the presence of panic disorder and alcohol abuse was associated with positive response. The results of the present study replicate prior studies indicating that GBP is an effective and well tolerated treatment in a large proportion of bipolar patients who are resistant to traditional mood stabilizers. More specifically, this drug appears to have antidepressant and anxiolytic properties. What is new in the present report is the suggestion that the utility of GBP in resistant bipolar disorder resides in its effectiveness against comorbid panic disorder and alcohol abuse.

Somatostatin depresses long-term potentiation and Ca2+ signaling in mouse dentate gyrus

The selective loss of somatostatin (SST)-containing interneurons from the hilus of the dentate gyrus is a hallmark of epileptic hippocampus. The functional consequence of this loss, including its contribution to postseizure hyperexcitability, remains unclear. We address this issue by characterizing the actions of SST in mouse dentate gyrus using electrophysiological techniques. Although the majority of dentate SST receptors are located in the outer molecular layer adjacent to lateral perforant path (LPP) synapses, we found no consistent action of SST on standard synaptic responses generated at these synapses. However, when SST was present during application of high-frequency trains that normally generate long-term potentiation (LTP), the induction of LTP was impaired. SST did not alter the maintenance of LTP when applied after its induction. To examine the mechanism by which SST inhibits LTP, we recorded from dentate granule cells and examined the actions of this neuropeptide on synaptic transmission and postsynaptic currents. Unlike findings in the CA1 hippocampus, we observed no postsynaptic actions on K(+) currents. Instead, SST inhibited Ca(2+)/Ba(2+) spikes evoked by depolarization. This inhibition was dependent on N-type Ca(2+)currents. Blocking these currents also blocked LTP, suggesting a mechanism through which SST may inhibit LTP. Our results indicate that SST reduction of dendritic Ca(2+) through N-type Ca(2+) channels may contribute to modulation of synaptic plasticity at LPP synapses. Therefore the loss of SST function postseizure could result in abnormal synaptic potentiation that contributes to epileptogenesis.

Voltage-gated sodium channels in epilepsy

Animal experiments, and particularly functional investigations on human chronically epileptic tissue as well as genetic studies in epilepsy patients and their families strongly suggest that some forms of epilepsy may share a pathogenetic mechanism: an alteration of voltage-gated sodium channels. This review summarizes recent data on changes of sodium channel expression, molecular structure and function associated with epilepsy, as well as on the interaction of new and established antiepileptic drugs with sodium currents. Although it remains to be determined precisely how and to what extent altered sodium-channel functions play a role in different epilepsy syndromes, future promising therapy approaches may include drugs modulating sodium currents, and particularly substances changing their inactivation characteristics.

Kava-kava and anxiety: growing knowledge about the efficacy and safety

Kava-kava (Piper methysticum G. Forster) has been used in social and ceremonial life in the Pacific islands from ancient times for the soporific and narcotic effects. Today several extracts standardized in the biologically active constituents kavalactones are marketed both as herbal medicinal products for anxiety disorders and as dietary supplements to improve stress disorders, nervous tension and restlessness. Unlike other substances used for these purposes, kava-kava has been shown to have minimal negative effects, and possibly positive effects, on reaction time and cognitive processing. Furthermore, it decreases anxiety without the loss of mental acuity. Although kava-kava has been found to be very effective, well tolerated, and non-addictive at therapeutic dosages, potential side effects can occur when very high doses are taken for extended periods. In addition, in the last two years unexpected high liver toxicity has been reported in two patients. Until now no studies support the liver toxicity of kavalactones and it is unknown which compound could have provoked the liver disease. On the other hand, it should be possible that unknown or unexpected constituents are the responsible or contributed to the liver toxicity.

Newer antiepileptic drugs in bipolar disorder: rationale for use and role in therapy

Antiepileptic drugs (AEDS) are used regularly in the treatment of patients with bipolar disorders. Carbamazepine and valproic acid (sodium valproate) are effective as antimanic treatments, and the success of these medications has prompted investigation of other AEDs as possible treatments in patients with mood disorders. Lamotrigine appears to be the most promising of the newer AEDs with respect to effects in mood disorders. Current evidence suggests efficacy of this drug both as monotherapy and as an adjunctive agent in bipolar depression, and studies are underway to clarify its efficacy in mood stabilisation and rapid cycling, as currently available data are equivocal. Use of gabapentin is not as well supported in the literature, although data from open trials using it as an adjunctive agent suggest that it may be helpful in patients with bipolar depression. There have been some open trials and case reports supporting the use of topiramate as an adjunctive agent for the treatment of mania; however, data from controlled trials are not yet available. Further controlled trials of lamotrigine, gabapentin or topiramate as monotherapy and adjunctive treatment are needed to clarify their potential roles in the treatment of patients with mood disorders.

Tiagabine in treatment refractory bipolar disorder: a clinical case series

OBJECTIVES

Anticonvulsants have provided major treatment advances for patients with bipolar disorder. Many of these drugs, including several with proven efficacy in bipolar mania or depression, enhance the activity of the gamma-amino butyric acid (GABA) neurotransmitter system. A new anticonvulsant, tiagabine, has selective GABAergic activity and is approved for patients with partial epilepsy. Few reports of its potential effectiveness in bipolar disorder, however, have been published. We sought to evaluate the effectiveness of tiagabine added to ongoing medication regimens in patients with bipolar disorder inadequately responsive to or intolerant of usual treatments.

METHODS

Seventeen treatment-refractory patients participating in the Stanley Foundation Bipolar Network (SFBN) long-term follow-up study were offered open treatment with add-on tiagabine after discussion of the risks, benefits, other treatment options and giving informed consent. Patients' clinical symptoms and somatic complaints were closely monitored with SFBN longitudinal and cross-sectional ratings. Four patients discontinued low-dose tiagabine prior to the second visit and were excluded from data analysis.

RESULTS

Thirteen patients received a mean of 38 days of treatment at a mean dose of 8.7 mg/day of tiagabine. On the Clinical Global Impression Scale for Bipolar Disorder Overall category, three (23%) patients showed much or very much improvement and 10 (77%) patients showed no change or worsening. Three significant adverse events were noted, including two presumptive seizures.

CONCLUSIONS

Open add-on tiagabine for treatment-refractory patients with bipolar disorder demonstrated limited efficacy with the majority of patients showing no change or worsening of clinical symptoms. In addition, patients experienced serious side-effects attributed as likely due to the medication, which resolved without lasting consequence when tiagabine was discontinued.

Which could be a clinically useful definition of depressive mixed state?

Depressive mixed state (DMX) (major depressive episode [MDE] with few superimposed hypomanic symptoms) was reported to be common among depressed outpatients. Study aim was to find if the best clinically useful definition of DMX was one based on a minimum number of hypomanic symptoms, or instead one based on the combination of specific hypomanic symptoms.

METHODS

Consecutive 138 bipolar II and 83 unipolar MDE outpatients were interviewed with DSM-IV Structured Clinical Interview. DMX definitions tested were: MDE with three or more hypomanic symptoms (DMX3) and MDE with hypomanic symptoms irritability, distractibility and racing thoughts.

RESULTS

DMX3, and the combination of racing thoughts, irritability and distractibility, had the same significant and nonsignificant associations with study variables. DMX3, and the combination of the specific hypomanic symptoms, significantly predicted bipolar II diagnosis. For predicting bipolar II diagnosis, DMX3 had higher specificity (86.7% vs. 50.6%), while the combination of the specific hypomanic symptoms had higher sensitivity (76.8% vs. 51.4%).

CONCLUSIONS

A DMX definition with higher specificity (DMX3) for predicting bipolar II diagnosis may be more clinically useful because it may reduce misdiagnosis.

Depressive mixed state frequency: age/gender effects

Depressive mixed state (DMX), a major depressive episode (MDE) combined with few manic/hypomanic symptoms, is understudied. Age and gender are important variables in mood disorders. The aim of the present study was to determine whether age and gender had any effect on the frequency of DMX. Consecutive unipolar (n = 144) and bipolar II (n = 218) drug-free MDE out-patients were interviewed with the Structured Clinical Interview for DSM-IV when presenting for MDE treatment. The presence of hypomanic symptoms during the index MDE was assessed systematically. Depressive mixed state was defined as a MDE with three or more concurrent hypomanic symptoms (DMX3), following previous reports. Associations were tested by logistic regression. The results showed that the DMX3 frequency was 43.9% and that it affected more females than males. Frequency decreased with age. The lower frequency with age was related to the lower frequency of bipolar II disorder with age. Bipolar disorder family history of DMX3 patients did not change with age. In conclusion, the frequency of DMX3 was high and related to age. The high frequency of DMX3 supports the clinical usefulness of the definition, as well as observations that antidepressants may worsen its hypomanic symptoms, whereas antipsychotics and mood stabilisers may treat them. A bipolar vulnerability seems to be required for the appearance of DMX3 also in later life.

The use of newer anticonvulsants in neuropsychiatric disorders

Anticonvulsants are becoming increasingly popular for the management of psychiatric and neuropsychiatric syndromes. This may be related to antikindling properties of these agents in addition to modulation of gamma-aminobutyric acid, serotonin, and other neurotransmitters. Treatment selection is complicated by the inconsistent availability of randomized controlled data among the growing range of choices. Moreover, generalization of psychiatric to neuropsychiatric applications of anticonvulsant treatments is not universally applicable. This paper reviews the use of newer anticonvulsants in the management of neuropsychiatric disorders, particularly aggression and agitation. The largest body of treatment data is available for valproic acid, which appears to be efficacious and well-tolerated in a wide range of neuropsychiatric disorders. Less consistent data are available for other medications. Further prospective studies are warranted to examine the use of these medications in neuropsychiatric populations.

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.

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.

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.

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.