Plasma GABA in children and adolescents with mood, behavior, and comorbid mood and behavior disorders: a preliminary study

Neuromolecular Etiology of Bipolar Disorder: Possible Therapeutic Targets of Mood Stabilizers

Bipolar disorder is a mental illness that causes extreme mood swings and has a chronic course. However, the mechanism by which mood episodes with completely opposite characteristics appear repeatedly, or a mixture of symptoms appears, in patients with bipolar disorder remains unknown. Therefore, mood stabilizers are indicated only for single mood episodes, such as manic episodes and depressive episodes, and no true mood-stabilizing drugs effective for treating both manic and depressive episodes currently exist. Therefore, in this review, therapeutic targets that facilitate the development of mood stabilizers were examined by reviewing the current understanding of the neuromolecular etiology of bipolar disorder.

Effects of Integrated Amrita Meditation Technique on Anxiety, Depression, and Plasma Neurotransmitters on a Healthy Population: A Randomized Controlled Trial Followed by a Case-Control Study

Objective: We aimed to study the short-term effects of Integrated Amrita Meditation (IAM) technique in anxiety and depression states and to have a better understanding on the underlying physiological changes related to short-term and long-term IAM practice. Design: Short-term IAM practitioners (ST-IAM) and long-term IAM practitioners (LT-IAM) were compared to control groups of the same age and naïve to yoga and meditation (ST-control and LT-control, respectively). Settings/Location: Kerala, India. Subjects: People that did not suffer from any major medical condition. All participants were naïve to yoga and meditation practices, except for the 5 LT-IAM practitioners. Intervention: ST-IAM practitioners underwent 2 community IAM practices and 5 individual IAM practices. LT-IAM practitioners (performing IAM regularly for more than 4 years) underwent a community IAM practice before the study. Outcome measures: Anxiety and depression states and physiological parameters from ST-IAM and ST-control groups were assed in two different visits (before and after the week of IAM practice or control condition). LT-IAM and LT-control subjects' physiological measurements were taken in only one visit. Results: Short-term IAM practice significantly decreased anxiety and depression states; two way ANOVA indicated differences on anxiety and depression scores across visits between ST-IAM and ST-control groups (Group effect: F_{(1, 25)} = 6.083, p = 0.0209; F_{(1, 25)} = 4.449, p = 0.0451). However, no changes were observed on their physiological parameters (heart rate, blood pressure, oxygen saturation, and dopamine and GABA plasma levels). Interestingly, LT-IAM practitioners showed increased GABA plasma levels than the LT-control group (p = 0.0358, t = 2.521, df = 8). Conclusions: Our study indicates the possible role of IAM technique on modulations of the plasma GABAergic levels and shows that one week of IAM practice is accompanied by a significant decrease of anxiety and depression states in the healthy population.

Effects of taurine on striatal dopamine transporter expression and dopamine uptake in SHR rats

Dopaminergic deficits in the prefrontal cortex and striatum have been attributed to the pathogenesis of attention-deficit hyperactivity disorder (ADHD). Our recent study revealed that high-dose taurine improves hyperactive behavior and brain-functional signals in SHR rats. This study investigates the effect of taurine on the SHR striatum by detecting the spontaneous alternation, DA transporter (DAT) level, dopamine uptake and brain-derived neurotrophic factor (BDNF) expression. A significant increase in the total arm entries was detected in both WKY and SHR rats fed with low-dose taurine but not in those fed with high-dose taurine. Notably, significantly increased spontaneous alternation was observed in SHR rats fed with high-dose taurine. Significantly higher striatal DAT level was detected in WKY rats fed with low-dose taurine but not in SHR rats, whereas significantly reduced striatal DAT level was detected in SHR rats fed with high-dose taurine but not in WKY rats. Significantly increased dopamine uptake was detected in the striatal synaptosomes of both WKY and SHR rats fed with low-dose taurine. Conversely, significantly reduced dopamine uptake was detected in the striatal synaptosomes of SHR rats fed with high-dose taurine. Accordingly, a negative correlation was detected between striatal dopamine uptake and spontaneous alternation in SHR rats fed with low or high-dose taurine. Significantly increased BDNF was detected in the striatum of both WKY and SHR rats fed with low or high-dose taurine. These findings indicate that different dosages of taurine have opposite effects on striatal DAT expression and dopamine uptake, suggesting high-dose taurine as a possible candidate for ADHD treatment.

Meta-analysis of central and peripheral γ-aminobutyric acid levels in patients with unipolar and bipolar depression

BACKGROUND

Many studies have measured central and peripheral γ-aminobutyric acid (GABA) levels in patients with depression. We performed a meta-analysis to provide an objective overview of GABA changes in those with unipolar or bipolar depression.

METHODS

After a systematic database search, original data were extracted with the help of seminal authors to calculate standardized mean differences. We compared GABA levels between patients with current major depressive episodes and controls, between euthymic patients and controls, and in patients before and after treatment. We performed meta-regressions to explore the influence of demographic and clinical variables on GABA significant mean differences.

RESULTS

For unipolar depression, central and peripheral GABA levels were diminished in currently depressed patients, but normal in euthymic patients, compared with the healthy controls. For bipolar disorder, GABA levels were diminished in medication-free patients, but seemed to be normalized in medicated patients, compared with the healthy controls. We found no significant association with demographic or clinical variables.

LIMITATIONS

There was a great heterogeneity across studies, probably because of the substantial variation of clinical characteristics in the included samples. Many subanalyses were performed to assess how the diagnosis, medications, or the type of measurements of peripheral or central GABA levels may affect the main results.

CONCLUSION

The GABA levels evolved differentially in patients with unipolar and bipolar disorders. Our results suggest that GABA levels could represent a biomarker of symptomatic states in patients with unipolar disorder and would be normalized by mood stabilizers in those with bipolar disorder.

Embryonic GABA(B) receptor blockade alters cell migration, adult hypothalamic structure, and anxiety- and depression-like behaviors sex specifically in mice

Neurons of the paraventricular nucleus of the hypothalamus (PVN) regulate the hypothalamic- pituitary-adrenal (HPA) axis and the autonomic nervous system. Females lacking functional GABA_B receptors because of a genetic disruption of the R1 subunit have altered cellular characteristics in and around the PVN at birth. The genetic disruption precluded appropriate assessments of physiology or behavior in adulthood. The current study was conducted to test the long term impact of a temporally restricting pharmacological blockade of the GABA_B receptor to a 7-day critical period (E11–E17) during embryonic development. Experiments tested the role of GABA_B receptor signaling in fetal development of the PVN and later adult capacities for adult stress related behaviors and physiology. In organotypic slices containing fetal PVN, there was a female specific, 52% increase in cell movement speeds with GABA_B receptor antagonist treatment that was consistent with a sex-dependent lateral displacement of cells in vivo following 7 days of fetal exposure to GABA_B receptor antagonist. Anxiety-like and depression-like behaviors, open-field activity, and HPA mediated responses to restraint stress were measured in adult offspring of mothers treated with GABA_B receptor antagonist. Embryonic exposure to GABA_B receptor antagonist resulted in reduced HPA axis activation following restraint stress and reduced depression-like behaviors. There was also increased anxiety-like behavior selectively in females and hyperactivity in males. A sex dependent response to disruptions of GABA_B receptor signaling was identified for PVN formation and key aspects of physiology and behavior. These changes correspond to sex specific prevalence in similar human disorders, namely anxiety disorders and hyperactivity.

A randomized targeted amino acid therapy with behaviourally at-risk adopted children

BACKGROUND

Increasing numbers of children are at-risk for behavioural and emotional disorders, a phenomenon contributing to increased use of pharmacological interventions for paediatric clients. Adverse side effects and other risks associated with pharmacological approaches have helped fuel interest in nutritional interventions for behaviourally at-risk children.

METHODS

The current randomized clinical trial evaluates the efficacy of a neurochemical intervention involving the glutamine and glutamate analogue L-theanine and 5-hydroxytryptophan, the precursor for serotonin, with children adopted from traumatic backgrounds.

RESULTS

Results include significant increases in urinary levels of the biomarkers for serotonin and gamma-aminobutyric acid, coupled with significant decreases in parent reports of the children's behaviour problems.

CONCLUSIONS

While further research is needed, these initial findings are encouraging and are consistent with a growing number of studies indicating the efficacy of nutritional approaches to help behaviourally at-risk children.

Toxic effect of blood components on perinatal rat subventricular zone cells and oligodendrocyte precursor cell proliferation, differentiation and migration in culture

The germinal matrix of human brain gives rise to oligodendrocytes and astrocytes after mid-gestation. Hemorrhage in the germinal matrix of premature infants is associated with suppressed cell proliferation. We hypothesize that soluble blood constituents have an adverse effect on the proliferation of cultured rat subventricular zone (SVZ) cells and the proliferation, migration, and differentiation of oligodendrocyte progenitor cells (OPC). Using caspase 3 activation and lactate dehydrogenase release assays, rat plasma, serum, thrombin, and kallikrein killed SVZ cells when grown in the presence (but not absence) of platelet derived growth factor. Plasma and serum killed OPC at 1:1 to 1:100 dilutions. Using a bromodeoxyuridine incorporation assay OPC proliferation was reduced by plasma, serum, thrombin and plasmin. Blood proteins also suppressed OPC migration in a concentration dependent manner. However, differentiation of OPC into myelin basic protein expressing cells was suppressed only by thrombin. We conclude that soluble blood components, particularly thrombin, have an adverse effect on maturing SVZ cells and OPC derived from newborn rat brain.

Divalproex sodium reduces overall aggression in youth at high risk for bipolar disorder

INTRODUCTION

The psychopharmacology of aggression in youth is relatively unexplored, even though such maladaptive aggression manifests across many different diagnoses.

METHODS

This study was a 12-week, open-label trial with divalproex sodium (DVPX) in 24 bipolar offspring 6-18 years of age (mean age = 11.3 years; 17 boys) with mixed diagnoses of major depression, cyclothymia, attention-deficit/hyperactivity disorder (ADHD), and oppositional defiant disorder (ODD). The Overt Aggression Scale (OAS) was used to measure aggression in 4-week intervals. We measured serum gamma-butyric acid (GABA) and glutamate levels at baseline and week 12.

RESULTS

Seventy-one percent of evaluable subjects were considered responders to DVPX treatment by the OAS. There was a significant correlation between the Young Mania Rating Scale (YMRS) and OAS scores at week 0 (p = 0.036) and week 12 (p = 0.025). Serum DVPX level did not correlate with treatment response.

CONCLUSIONS

These youths who are at high risk for bipolar disorder experienced an overall decrease in aggressive behavior in response to DVPX. Age or gender did not predict a positive response to DVPX. This study is the first report of treatment efficacy of a mood stabilizer for aggression in youth at high risk for bipolar disorder.

Cross-cultural Similarities in ADHD-Like Behaviour Amongst South African Primary School Children

This study investigates whether the Disruptive Behaviour Disorders (DBDs) rating scale measures the same constructs in South African as in Western cultures, and explores the differences in scale scores as a function of language, gender and age. Teacher ratings between 1997 and 1999 of the 18 DSM-IV symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD) in 6 094 primary school children of six language groups in the Limpopo Province of South Africa were collected and analysed. For all language groups, the results were consistent with a two-factor model of ADHD with correlated factors. There were gender and age effects on both scales. The prevalence rates for ADHD sub-types were in line with rates in the United States of America (US) and Europe. Similarities across language groups, as well as to results reported in the US and Europe, were striking. Despite the limitations discussed, teacher ratings of ADHD symptoms on the DBD scale can be used as a screening instrument in South Africa. Separate norms for different language groups are not indicated.

GABAergic dysfunction in mood disorders

The authors review the available literature on the preclinical and clinical studies involving GABAergic neurotransmission in mood disorders. Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter present almost exclusively in the central nervous system (CNS), distributed across almost all brain regions, and expressed in interneurons modulating local circuits. The role of GABAergic dysfunction in mood disorders was first proposed 20 years ago. Preclinical studies have suggested that GABA levels may be decreased in animal models of depression, and clinical studies reported low plasma and CSF GABA levels in mood disorder patients. Also, antidepressants, mood stabilizers, electroconvulsive therapy, and GABA agonists have been shown to reverse the depression-like behavior in animal models and to be effective in unipolar and bipolar patients by increasing brain GABAergic activity. The hypothesis of reduced GABAergic activity in mood disorders may complement the monoaminergic and serotonergic theories, proposing that the balance between multiple neurotransmitter systems may be altered in these disorders. However, low GABAergic cortical function may probably be a feature of a subset of mood disorder patients, representing a genetic susceptibility. In this paper, we discuss the status of GABAergic hypothesis of mood disorders and suggest possible directions for future preclinical and clinical research in this area.

The comorbidity of bipolar and anxiety disorders: prevalence, psychobiology, and treatment issues

BACKGROUND

Although symptoms of anxiety as well as anxiety disorders commonly occur in patients with bipolar disorder, the pathophysiologic, theoretical, and clinical significance of their co-occurrence has not been well studied.

METHODS

The epidemiological and clinical studies that have assessed the overlap of bipolar and anxiety disorders are reviewed, with focus on panic disorder and obsessive-compulsive disorder (OCD), and to a lesser extent, social phobia and post-traumatic stress disorder. Potential neural mechanism and treatment response data are also reviewed.

RESULTS

A growing number of epidemiological studies have found that bipolar disorder significantly co-occurs with anxiety disorders at rates that are higher than those in the general population. Clinical studies have also demonstrated high comorbidity between bipolar disorder and panic disorder, OCD, social phobia, and post-traumatic stress disorder. Psychobiological mechanisms that may account for these high comorbidity rates likely involve a complicated interplay among various neurotransmitter systems, particularly norepinephrine, dopamine, gamma-aminobutyric acid (GABA), and serotonin. The second-messenger system constituent, inositol, may also be involved. Little controlled data are available regarding the treatment of bipolar disorder complicated by an anxiety disorder. However, adequate mood stabilization should be achieved before antidepressants are used to treat residual anxiety symptoms so as to minimize antidepressant-induced mania or cycling. Moreover, preliminary data suggesting that certain antimanic agents may have anxiolytic properties (e.g. valproate and possibly antipsychotics), and that some anxiolytics may not induce mania (e.g. gabapentin and benzodiazepines other than alprazolam) indicate that these agents may be particularly useful for anxious bipolar patients.

CONCLUSIONS

Comorbid anxiety symptoms and disorders must be considered when diagnosing and treating patients with bipolar disorder. Conversely, patients presenting with anxiety disorders must be assessed for comorbid mood disorders, including bipolar disorder. Pathophysiological, theoretical, and clinical implications of the overlap of bipolar and anxiety disorders are discussed.

Antiepileptic drugs: affective use in autism spectrum disorders

Antiepileptic drugs are widely administered to individuals with autistic spectrum disorders. There are several reasons for the use of antiepileptic drugs in autistic spectrum disorders, including the high incidence of epilepsy in these individuals, the anecdotal reports suggesting an improvement of communication and behavior in autistic subjects with epileptic discharges, and the increased awareness that some disruptive behaviors may be manifestations of an associated affective disorder. In this study, data on the current use of antiepileptic drugs in the treatment of autism, and on the association of affective disorders with epilepsy and autism, are reviewed. The evidence supporting the hypothesis that there may be a subgroup of autistic children with epilepsy and affective disorders that preferentially respond to antiepileptic drugs is still very preliminary, and further investigations with double-blind controlled studies are needed. Although the role of antiepileptic drugs at the present time is not established, there is evidence that autism, epilepsy, and affective disorders commonly co-occur, and that they may share a common neurochemical substrate, which is the common target of the psychotropic mechanism of action of different antiepileptic drugs.

Are child-, adolescent-, and adult-onset depression one and the same disorder?

This paper reviews prior research studies examining neurobiological correlates and treatment response of depression in children, adolescents, and adults. Although there are some similarities in research findings observed across the life cycle, both children and adolescents have been found to differ from depressed adults on measures of basal cortisol secretion, corticotropin stimulation post-corticotropin releasing hormone (CRH) infusion, response to several serotonergic probes, immunity indices, and efficacy of tricyclic medications. These differences are proposed to be due to 1) developmental factors, 2) stage of illness factors (e.g., number of episodes, total duration of illness), or 3) heterogeneity in clinical outcome (e.g., recurrent unipolar course vs. new-onset bipolar disorder). Relevant clinical and preclinical studies that provide support for these alternate explanations of the discrepant findings are reviewed, and directions for future research are discussed. To determine whether child-, adolescent-, and adult-onset depression represent the same condition, it is recommended that researchers 1) use the same neuroimaging paradigms in child, adolescent, and adult depressed cohorts; 2) carefully characterize subjects' stage of illness; and 3) conduct longitudinal clinical and repeat neurobiological assessments of patients of different ages at various stages of illness. In addition, careful attention to familial subtypes (e.g., depressive spectrum disorders vs. familial pure depressive disorders) and environmental factors (e.g., trauma history) are suggested for future investigations.

Bipolar disorder in children and adolescents

Bipolar disorder is an affective or mood disorder that affects children and adolescents as well as adults. Originally thought to be rare in childhood, this disorder is now diagnosed even in the prepubertal age group. With pediatricians providing health care for the majority of children and adolescents, these physicians will see the children early in their presentation with affective disorder. This review focuses on the early recognition of children with bipolar disorder or children who are at increased risk of developing mania. Early recognition can lead to early treatment and reduce both short- and long-term morbidity and mortality. This review covers the definition, epidemiology, presentation and differential diagnosis, comorbid diagnoses, precipitants, risk factors, treatment, and outcome.