Neurodevelopmental aspects of bipolar affective disorder

Genetic associations between bipolar disorder and brain structural phenotypes

Patients with bipolar disorder (BD) and their first-degree relatives exhibit alterations in brain volume and cortical structure, whereas the underlying genetic mechanisms remain unclear. In this study, based on the published genome-wide association studies (GWAS), the extent of polygenic overlap between BD and 15 brain structural phenotypes was investigated using linkage disequilibrium score regression and MiXeR tool, and the shared genomic loci were discovered by conjunctional false discovery rate (conjFDR) and expression quantitative trait loci (eQTL) analyses. MiXeR estimated the overall measure of polygenic overlap between BD and brain structural phenotypes as 4-53% on a 0-100% scale (as quantified by the Dice coefficient). Subsequent conjFDR analyses identified 54 independent loci (71 risk single-nucleotide polymorphisms) jointly associated with BD and brain structural phenotypes with a conjFDR < 0.05, among which 33 were novel that had not been reported in the previous BD GWAS. Follow-up eQTL analyses in respective brain regions both confirmed well-known risk genes (e.g. CACNA1C, NEK4, GNL3, MAPK3) and discovered novel risk genes (e.g. LIMK2 and CAMK2N2). This study indicates a substantial shared genetic basis between BD and brain structural phenotypes, and provides novel insights into the developmental origin of BD and related biological mechanisms.

Low α-N-acetylgalactosaminidase plasma concentration correlates with the presence and severity of the bipolar affective disorder

OBJECTIVES

Believing that a neurodevelopmental pathology may cause bipolar affective disorder (BAD), we aimed to measure the concentrations of α-N-acetylgalactosaminidase (α-NAGAL), a lysosomal enzyme.

METHODS

The study included 32 patients with BAD and 32 healthy controls. The Young Mania Rating Scale was used to measure the severity of the disease. Serum α-N-acetylgalactosaminidase concentrations were measured in all blood samples using the human α-N-acetylgalactosaminidase ELISA Kit.

RESULTS

A statistically significant difference was found in the α-NAGAL values between the groups. The mean α-NAGAL values of BAD patients are lower than the mean α-NAGAL values of the control group. A strong negative and statistically significant relationship was found between the α-NAGAL values of patients with BAD and their Young Mania Rating Scale scores. And a positive strong correlation was found between the age of onset of the disease and α-NAGAL levels.

CONCLUSIONS

Low α-N-acetylgalactosaminidase concentrations may cause the accumulation of some glycoproteins in the lysosomes in the brain during the gestational period, producing the clinical symptoms of BAD. α-N-acetylgalactosaminidase deficiency may not be the only cause of BAD, but it may be an important factor in the aetiology of this disease.

Phenotypes, mechanisms and therapeutics: insights from bipolar disorder GWAS findings

Genome-wide association studies (GWAS) have reported substantial genomic loci significantly associated with clinical risk of bipolar disorder (BD), and studies combining techniques of genetics, neuroscience, neuroimaging, and pharmacology are believed to help tackle clinical problems (e.g., identifying novel therapeutic targets). However, translating findings of psychiatric genetics into biological mechanisms underlying BD pathogenesis remains less successful. Biological impacts of majority of BD GWAS risk loci are obscure, and the involvement of many GWAS risk genes in this illness is yet to be investigated. It is thus necessary to review the progress of applying BD GWAS risk genes in the research and intervention of the disorder. A comprehensive literature search found that a number of such risk genes had been investigated in cellular or animal models, even before they were highlighted in BD GWAS. Intriguingly, manipulation of many BD risk genes (e.g., ANK3, CACNA1C, CACNA1B, HOMER1, KCNB1, MCHR1, NCAN, SHANK2 etc.) resulted in altered murine behaviors largely restoring BD clinical manifestations, including mania-like symptoms such as hyperactivity, anxiolytic-like behavior, as well as antidepressant-like behavior, and these abnormalities could be attenuated by mood stabilizers. In addition to recapitulating phenotypic characteristics of BD, some GWAS risk genes further provided clues for the neurobiology of this illness, such as aberrant activation and functional connectivity of brain areas in the limbic system, and modulated dendritic spine morphogenesis as well as synaptic plasticity and transmission. Therefore, BD GWAS risk genes are undoubtedly pivotal resources for modeling this illness, and might be translational therapeutic targets in the future clinical management of BD. We discuss both promising prospects and cautions in utilizing the bulk of useful resources generated by GWAS studies. Systematic integrations of findings from genetic and neuroscience studies are called for to promote our understanding and intervention of BD.

Schizophrenia and Bipolar Polygenic Risk Scores in Relation to Intracranial Volume

Schizophrenia and bipolar disorder are neurodevelopmental disorders with overlapping symptoms and a shared genetic background. Deviations in intracranial volume (ICV)—a marker for neurodevelopment—differ between schizophrenia and bipolar disorder. Here, we investigated whether genetic risk for schizophrenia and bipolar disorder is related to ICV in the general population by using the UK Biobank data (n = 20,196). Polygenic risk scores for schizophrenia (SZ-PRS) and bipolar disorder (BD-PRS) were computed for 12 genome wide association study P-value thresholds (PT) for each individual and correlations with ICV were investigated. Partial correlations were performed at each PT to investigate whether disease specific genetic risk variants for schizophrenia and bipolar disorder show different relationships with ICV. ICV showed a negative correlation with SZ-PRS at PT ≥ 0.005 (r < −0.02, p < 0.005). ICV was not associated with BD-PRS; however, a positive correlation between BD-PRS and ICV at PT = 0.2 and PT = 0.4 (r = +0.02, p < 0.005) appeared when the genetic overlap between schizophrenia and bipolar disorder was accounted for. Despite small effect sizes, a higher load of schizophrenia risk genes is associated with a smaller ICV in the general population, while risk genes specific for bipolar disorder are correlated with a larger ICV. These findings suggest that schizophrenia and bipolar disorder risk genes, when accounting for the genetic overlap between both disorders, have opposite effects on early brain development.

Altered neurochemistry in the anterior white matter of bipolar children and adolescents: a multivoxel 1H MRS study

Abnormalities within frontal lobe gray and white matter of bipolar disorder (BD) patients have been consistently reported in adult and pediatric studies, yet little is known about the neurochemistry of the anterior white matter (AWM) in pediatric BD and how medication status may affect it. The present cross-sectional 3T ¹H MRS study is the first to use a multivoxel approach to study the AWM of BD youth. Absolute metabolite levels from four bilateral AWM voxels were collected from 49 subjects between the ages of 8 and 18 (25 healthy controls (HC); 24 BD) and quantified. Our study found BD subjects to have lower levels of N-acetylaspartate (NAA) and glycerophosphocholine plus phosphocholine (GPC + PC), metabolites that are markers of neuronal viability and phospholipid metabolism and have also been implicated in adult BD. Further analysis indicated that the observed patterns were mostly driven by BD subjects who were medicated at the time of scanning and had an ADHD diagnosis. Although limited by possible confounding effects of mood state, medication, and other mood comorbidities, these findings serve as evidence of altered neurochemistry in BD youth that is sensitive to medication status and ADHD comorbidity.

Minor Physical Anomalies in Bipolar Disorder-A Meta-Analysis

Introduction: Minor physical anomalies (MPAs) may reflect basic neurobiological features underlying bipolar disorders (BPD), as they are sensitive physical indicators of morphogenetic failure of the brain. Despite several researches about the presence of MPAs in BPD, the results are still controversial. Objectives: The aim of the present meta-analysis was to assess the standardized weighted mean effect sizes of MPAs in BPD and to examine if MPAs may be found predominantly in the head and/or facial regions in BPD patients compared to controls (HC). Methods: Four studies, involving 155 patients with BPD, and 187 HC, were involved in the analysis after searching the literature. For the investigation of MPAs in the peripheral (MPA-P) and in the head and facial regions (MPA-CF), two studies involving 121 BPD patients, and 133 HC passed the inclusion criteria. Results: The number of the MPAs in the BPD group was significantly higher compared to HC. Another important finding of the present study is that BPD patients' MPA-P scores do not significantly differ from those of the HC. In contrast, BPD patients' MPA-CF scores were found to be significantly higher compared to HC subjects. It is important to note that there was a low number of eligible publications included, which caused higher heterogeneity. Conclusions: Low quality of evidence suggests that MPAs are more common in patients with BPD than in HC and the higher rate of MPAs is found predominantly in the head and facial regions.

The Association Between Familial Risk and Brain Abnormalities Is Disease Specific: An ENIGMA-Relatives Study of Schizophrenia and Bipolar Disorder

BACKGROUND

Schizophrenia and bipolar disorder share genetic liability, and some structural brain abnormalities are common to both conditions. First-degree relatives of patients with schizophrenia (FDRs-SZ) show similar brain abnormalities to patients, albeit with smaller effect sizes. Imaging findings in first-degree relatives of patients with bipolar disorder (FDRs-BD) have been inconsistent in the past, but recent studies report regionally greater volumes compared with control subjects.

METHODS

We performed a meta-analysis of global and subcortical brain measures of 6008 individuals (1228 FDRs-SZ, 852 FDRs-BD, 2246 control subjects, 1016 patients with schizophrenia, 666 patients with bipolar disorder) from 34 schizophrenia and/or bipolar disorder family cohorts with standardized methods. Analyses were repeated with a correction for intracranial volume (ICV) and for the presence of any psychopathology in the relatives and control subjects.

RESULTS

FDRs-BD had significantly larger ICV (d = +0.16, q < .05 corrected), whereas FDRs-SZ showed smaller thalamic volumes than control subjects (d = -0.12, q < .05 corrected). ICV explained the enlargements in the brain measures in FDRs-BD. In FDRs-SZ, after correction for ICV, total brain, cortical gray matter, cerebral white matter, cerebellar gray and white matter, and thalamus volumes were significantly smaller; the cortex was thinner (d < -0.09, q < .05 corrected); and third ventricle was larger (d = +0.15, q < .05 corrected). The findings were not explained by psychopathology in the relatives or control subjects.

CONCLUSIONS

Despite shared genetic liability, FDRs-SZ and FDRs-BD show a differential pattern of structural brain abnormalities, specifically a divergent effect in ICV. This may imply that the neurodevelopmental trajectories leading to brain anomalies in schizophrenia or bipolar disorder are distinct.

The protocadherin 17 gene affects cognition, personality, amygdala structure and function, synapse development and risk of major mood disorders

Major mood disorders, which primarily include bipolar disorder and major depressive disorder, are the leading cause of disability worldwide and pose a major challenge in identifying robust risk genes. Here, we present data from independent large-scale clinical data sets (including 29 557 cases and 32 056 controls) revealing brain expressed protocadherin 17 (PCDH17) as a susceptibility gene for major mood disorders. Single-nucleotide polymorphisms (SNPs) spanning the PCDH17 region are significantly associated with major mood disorders; subjects carrying the risk allele showed impaired cognitive abilities, increased vulnerable personality features, decreased amygdala volume and altered amygdala function as compared with non-carriers. The risk allele predicted higher transcriptional levels of PCDH17 mRNA in postmortem brain samples, which is consistent with increased gene expression in patients with bipolar disorder compared with healthy subjects. Further, overexpression of PCDH17 in primary cortical neurons revealed significantly decreased spine density and abnormal dendritic morphology compared with control groups, which again is consistent with the clinical observations of reduced numbers of dendritic spines in the brains of patients with major mood disorders. Given that synaptic spines are dynamic structures which regulate neuronal plasticity and have crucial roles in myriad brain functions, this study reveals a potential underlying biological mechanism of a novel risk gene for major mood disorders involved in synaptic function and related intermediate phenotypes.

Quantitative analysis of the amygdala, thalamus and hippocampus on magnetic resonance images in paediatric bipolar disorders and compared with the children of bipolar parents and healthy control

MR imaging studies in paediatric bipolar disorder have particularly focused on the amygdala and hippocampus, subcortical structures, and to a lesser extent on the thalamus. The purpose of this study was to perform structural analysis of the regions of interest (ROI) associated with mood regulation. In this study 18 children (between the ages of 12-18) were matched according to their age and sex and were divided into three groups. These were: a paediatric bipolar disorder group, risk group and a healthy control group. The structured diagnostic interviews were performed with children and their parents. T1 weighted MR images in the sagittal plane with a thickness of 1mm were taken from the subjects. Automatic structural brain analysis was performed, and the volume and volume fraction (VF) of the ROIs were obtained. Brain size in the patients with paediatric bipolar disorder (742.4 ± 110.1cm³) was significantly smaller than the healthy control group (880.7 ± 73.8cm³) (p≤0.05). MRI analysis between the paediatric bipolar disorder, risk group and healthy control group revealed no difference between them in terms of amygdala, thalamus or hippocampal volumes. In this study, there was no difference between the volumes of amygdala, thalamus or hippocampus.

Clinical, Cognitive, and Neuroimaging Evidence of a Neurodevelopmental Continuum in Offspring of Probands With Schizophrenia and Bipolar Disorder

BACKGROUND

Studies in child and adolescent offspring of patients with schizophrenia or bipolar disorders may help understand the influence of neurodevelopmental factors on the premorbid phenotype of these disorders.

AIMS

To assess whether a combination of neurodevelopmental factors discriminates between young offspring of patients with schizophrenia (SzO) or bipolar disorder (BpO) and community controls (CcO). To assess the association between these factors and rates of psychiatric diagnoses in high risk (HR) youth.

METHODS

One hundred thirty-three HR offspring (47 SzO and 86 BpO) and 84 CcO, aged 6-17, underwent cross-sectional clinical, neurocognitive, and structural neuroimaging assessment. Information on perinatal events and early childhood development was also obtained. General linear mixed models were performed to assess group discrimination and association with lifetime axis I psychiatric disorders.

RESULTS

Multivariate analyses revealed that greater neurological soft signs (NSS), less total grey matter volume (GMV) and a higher frequency of obstetric complications discriminated HR offspring from CcO. When comparing each group individually, greater NSS and a higher frequency of obstetric complications discriminated SzO from CcO, and BpO from CcO, while lower intelligence also discriminated SzO from CcO and from BpO. Within HR offspring, lower intelligence and less total GMV were associated with lifetime incidence of psychiatric disorders.

CONCLUSIONS

Both SzO and BpO showed evidence of neurodevelopmental insult, although this may have a greater impact in SzO. Lower intelligence and less total GMV hold potential as biomarkers of risk for psychiatric disorders in HR youth.

Application of induced pluripotent stem cells to understand neurobiological basis of bipolar disorder and schizophrenia

The etiology of neuropsychiatric disorders, such as schizophrenia and bipolar disorder, usually involves complex combinations of genetic defects/variations and environmental impacts, which hindered, for a long time, research efforts based on animal models and patients' non-neuronal cells or post-mortem tissues. However, the development of human induced pluripotent stem cell (iPSC) technology by the Yamanaka group was immediately applied to establish cell research models for neuronal disorders. Since then, techniques to achieve highly efficient differentiation of different types of neural cells following iPSC modeling have made much progress. The fast-growing iPSC and neural differentiation techniques have brought valuable insights into the pathology and neurobiology of neuropsychiatric disorders. In this article, we first review the application of iPSC technology in modeling neuronal disorders and discuss the progress in the accompanying neural differentiation. Then, we summarize the progress in iPSC-based research that has been accomplished so far regarding schizophrenia and bipolar disorder.

Maternal serum cytokine levels and risk of bipolar disorder

Prenatal exposure to influenza has previously been associated with increased risk of bipolar disorder (BD), an association that may be mediated by maternal cytokines. The objective of this study was to determine the association between maternal levels of cytokines measured during each trimester of pregnancy and the risk of BD in offspring. We conducted a case-control study nested in the Child Health and Development Study, a birth cohort that enrolled pregnant women in 1959-1966. Potential cases with DSM-IV-TR bipolar I disorder, bipolar II disorder, BD not otherwise specified, and BD with psychotic features were ascertained through electronic medical records, a public agency database, and a mailing to the cohort. Diagnoses were confirmed by clinical interview. Nine cytokines (IL-1β, IL-4, IL-5, IL-6, IL-8, IL-10, IFN-γ, TNF-α and GM-CSF) were measured simultaneously by Luminex assays in archived prenatal maternal serum samples from 85 cases and 170 matched controls. Data were analyzed using conditional logistic regression. In the overall study sample, there were no significant associations between prenatal maternal cytokine levels and BD after adjustment for confounders. The risk of BD without psychotic features was decreased among subjects with higher maternal levels of first trimester log-transformed IL-4 (OR (95% CI)=0.76 (0.58, 0.98); p=0.04) and third trimester log-transformed IL-6 (OR (95% CI)=0.64 (0.42, 0.98); p=0.04). In conclusion, higher levels of prenatal maternal cytokines were not associated with increased risk for BD. Further studies with larger samples are necessary to confirm the finding.

Minor physical anomalies in bipolar I and bipolar II disorders - Results with the Méhes Scale

Minor physical anomalies (MPAs) are external markers of abnormal brain development, so the more common appearence of these signs among bipolar I and bipolar II patients can confirm the possibility of a neurodevelopmental deficit in these illnesses. The aim of the present study was to investigate the rate and topological profile of minor physical anomalies in patients with bipolar I and - first in literature - with bipolar II disorders compared to matched healthy control subjects. Using a list of 57 minor physical anomalies (the Méhes Scale), 30 bipolar I and 30 bipolar II patients, while as a comparison 30 matched healthy control subjects were examined. Significant differences were detected between the three groups comparing the total number of minor physical anomalies, minor malformations and phenogenetic variants and in the cases of the ear and the mouth regions. The individual analyses of the 57 minor physical anomalies by simultaneous comparison of the three groups showed, that in the cases of furrowed tongue and high arched palate were significant differences between the three groups. The results can promote the concept, that a neurodevelopmental deficit may play a role in the etiology of both bipolar I and bipolar II disorders.

Neurodevelopmental origins of bipolar disorder: iPSC models

Bipolar disorder (BP) is a chronic neuropsychiatric condition characterized by pathological fluctuations in mood from mania to depression. Adoption, twin and family studies have consistently identified a significant hereditary component to BP, yet there is no clear genetic event or consistent neuropathology. BP has been suggested to have a developmental origin, although this hypothesis has been difficult to test since there are no viable neurons or glial cells to analyze, and research has relied largely on postmortem brain, behavioral and imaging studies, or has examined proxy tissues including saliva, olfactory epithelium and blood cells. Neurodevelopmental factors, particularly pathways related to nervous system development, cell migration, extracellular matrix, H3K4 methylation, and calcium signaling have been identified in large gene expression and GWAS studies as altered in BP. Recent advances in stem cell biology, particularly the ability to reprogram adult somatic tissues to a pluripotent state, now make it possible to interrogate these pathways in viable cell models. A number of induced pluripotent stem cell (iPSC) lines from BP patient and healthy control (C) individuals have been derived in several laboratories, and their ability to form cortical neurons examined. Early studies suggest differences in activity, calcium signaling, blocks to neuronal differentiation, and changes in neuronal, and possibly glial, lineage specification. Initial observations suggest that differentiation of BP patient-derived neurons to dorsal telencephalic derivatives may be impaired, possibly due to alterations in WNT, Hedgehog or Nodal pathway signaling. These investigations strongly support a developmental contribution to BP and identify novel pathways, mechanisms and opportunities for improved treatments.

Minor physical anomalies in schizophrenia and bipolar I disorder and the neurodevelopmental continuum of psychosis

OBJECTIVES

Minor physical anomalies (MPAs) have been investigated by numerous studies in patients with schizophrenia in support of the neurodevelopmental hypothesis of the disorder, but have rarely been examined in patients with bipolar disorder or in direct comparisons between the two conditions. The main objective of the present study was to compare the prevalence of MPAs in psychiatrically healthy controls, patients with bipolar I disorder, and patients with schizophrenia.

METHODS

A slightly modified version of the Waldrop Physical Anomaly Scale was used to assess MPAs in psychiatrically healthy controls (n = 103), patients with bipolar I disorder (n = 61), and patients with schizophrenia (n = 128).

RESULTS

In five out of six topographic regions (mouth, feet, head, eyes, and ears) there was a pattern of lowest regional MPA scores in controls, intermediate in bipolar I disorder, and highest in schizophrenia. The cephalofacial composite score and the total MPA score showed the same pattern, with all between-group differences being statistically significant. Seven individual MPAs in the discriminant analysis model contributed independently to the prediction of the triple-dependent status of 'psychiatrically healthy control, bipolar I disorder patient, schizophrenia patient': high/arched palate, fine electric hair, large gap between first and second toes, third toe ≥ second toe, epicanthus, malformed ears, and furrowed tongue.

CONCLUSIONS

Our findings support the existence of a continuum of neurodevelopmental adversity within the clinical spectrum of psychosis, with bipolar I disorder occupying an intermediate position between psychiatric health and schizophrenia.

Association of the 3' region of the neuregulin 1 gene with bipolar I disorder in the Chinese Han population

BACKGROUND

Based on the function of neuregulin 1 (NRG1) in neurodevelopment, susceptibility to bipolar disorder presumably involves this gene. The 3' region of NRG1 contains the majority of the coding exons, and transcripts from this region encode 8 of the 9 known NRG1 isoforms; therefore, this region is likely to be predominant versus the 5' region in terms of their relative contributions to NRG1 function. We investigated the association between the 3' region of the NRG1 gene and bipolar I disorder (BPI) in the Chinese Han population and performed further analyses depending on the presence or absence of psychotic features.

METHODS

A total of 385 BPI patients and 475 healthy controls were recruited for this study. Thirty tag single nucleotide polymorphisms (SNPs) across the 3' region of the NRG1 gene were genotyped for allelic and haplotypic associations with BPI and subgroups with psychotic features (BPI-P) or without psychotic features (BPI-NP).

RESULTS

Individual marker analysis showed that 2 SNPs (rs12547858 and rs6468121) in this region were significantly associated with BPI. Moreover, subgroup analyses showed significant but marginal associations of rs6468121 with BPI-P and rs3757933 with BPI-NP. Haplotype analyses showed that 6 haplotypes were associated with BPI only.

LIMITATIONS

The sample size was relatively small. The investigated tag SNPs only represented 83% of the information on the targeted region. There might be a retrospective bias in the subgroup analyses.

CONCLUSION

The results suggest that the 3' region of the NRG1 gene plays a role in BPI susceptibility in the Chinese Han population. In addition, the preliminary results show that BPI with psychotic features and BPI without psychotic features may constitute different sub-phenotypes; however, this finding should be confirmed in a larger population sample.

Transcripts involved in calcium signaling and telencephalic neuronal fate are altered in induced pluripotent stem cells from bipolar disorder patients

Bipolar disorder (BP) is a chronic psychiatric condition characterized by dynamic, pathological mood fluctuations from mania to depression. To date, a major challenge in studying human neuropsychiatric conditions such as BP has been limited access to viable central nervous system tissue to examine disease progression. Patient-derived induced pluripotent stem cells (iPSCs) now offer an opportunity to analyze the full compliment of neural tissues and the prospect of identifying novel disease mechanisms. We have examined changes in gene expression as iPSC derived from well-characterized patients differentiate into neurons; there was little difference in the transcriptome of iPSC, but BP neurons were significantly different than controls in their transcriptional profile. Expression of transcripts for membrane bound receptors and ion channels was significantly increased in BP-derived neurons compared with controls, and we found that lithium pretreatment of BP neurons significantly altered their calcium transient and wave amplitude. The expression of transcription factors involved in the specification of telencephalic neuronal identity was also altered. Control neurons expressed transcripts that confer dorsal telencephalic fate, whereas BP neurons expressed genes involved in the differentiation of ventral (medial ganglionic eminence) regions. Cells were responsive to dorsal/ventral patterning cues, as addition of the Hedgehog (ventral) pathway activator purmorphamine or a dorsalizing agent (lithium) stimulated expression of NKX2-1 (ventral identity) or EMX2 (dorsal) in both groups. Cell-based models should have a significant impact on our understanding of the genesis and therefore treatment of BP; the iPSC cell lines themselves provide an important resource for comparison with other neurodevelopmental disorders.

Are obstetrical, perinatal, and infantile difficulties associated with pediatric bipolar disorder?

OBJECTIVES

Despite increasing acknowledgement of bipolar disorder (BD) in childhood, there is a paucity of literature that has investigated obstetrical, perinatal, and infantile difficulties and their potential link with BD. To this end, we examined difficulties during delivery, immediate post-birth, and infancy and the association with BD in childhood.

METHODS

From two similarly designed, ongoing, longitudinal, case-control family studies of pediatric BD (N = 327 families), we analyzed 338 children and adolescents [mean (± standard deviation) age: 12.00 ± 3.37 years]. We stratified them into three groups: healthy controls (N = 98), BD probands (N = 120), and their non-affected siblings (N = 120). All families were comprehensively assessed with a structured psychiatric diagnostic interview for psychopathology and substance use. Mothers were directly questioned regarding the pregnancy, delivery, and infancy difficulties that occurred with each child using a module from the Diagnostic Interview for Children and Adolescents-Parent Version (DICA-P).

RESULTS

Mothers of BD subjects were more likely to report difficulties during infancy than mothers of controls [odds ratio (95% confidence interval) = 6.6 (3.0, 14.6)]. Specifically, children with BD were more likely to have been reported as a stiffened infant [7.2 (1.1, 47.1)] and more likely to have experienced 'other' infantile difficulties [including acting colicky; 4.9 (1.3, 18.8)] compared to controls. We found no significant differences between groups in regards to obstetrical or perinatal difficulties (all p values > 0.05).

CONCLUSIONS

While our results add to previous literature on obstetrical and perinatal difficulties and BD, they also highlight characteristics in infancy that may be prognostic indicators for pediatric BD.

Minor physical anomalies in patients with bipolar I disorder and normal controls

BACKGROUND

The neurodevelopmental hypothesis is well established in schizophrenia but has received modest empirical support in bipolar disorder. In schizophrenia it is partly based on the higher prevalence of minor physical anomalies (MPAs), established by many well controlled studies. No studies with comparable designs have been performed in bipolar disorder. The present study aims to establish the rate and topographic distribution of MPAs in bipolar I patients.

METHODS

The subjects were 61 patients (25 men, 36 women) with bipolar I disorder and 103 normal subjects (49 men, 54 women) who were examined for MPAs using a modified version of the Waldrop Physical Anomaly Scale.

RESULTS

The bipolar I patients showed significantly higher regional MPA scores in 3 distinct regions - mouth, feet and head, as well as in the overall scores for the craniofacial complex, the periphery and the total MPA score. Differences were statistically significant for 3 anomalies - high/steepled palate, big gap between I and II toes and furrowed tongue that made significant contribution to the prediction of the patient-control status in a discriminant analysis model.

CONCLUSIONS

Our data suggest that aberrant processes of neurodevelopment may contribute to the etiology of bipolar I disorder. The field is open for further research using modern instruments and designs in order to identify potential biological markers for bipolar disorder.

Towards a whole-body systems [multi-organ] lipidomics in Alzheimer's disease

Preclinical and clinical evidence suggests that docosahexaenoic acid (DHA), an omega-3 fatty acid derived from diet or synthesized in the liver, decreases the risk of developing Alzheimer's disease (AD). DHA levels are reduced in the brain of subjects with AD, but it is still unclear whether human dementias are associated with dysregulations of DHA metabolism. A systems biological view of omega-3 fatty acid metabolism offered unexpected insights on the regulation of DHA homeostasis in AD [1]. Results of multi-organ lipidomic analyses were integrated with clinical and gene-expression data sets to develop testable hypotheses on the functional significance of lipid abnormalities observed and on their possible mechanistic bases. One surprising outcome of this integrative approach was the discovery that the liver of AD patients has a limited capacity to convert shorter chain omega-3 fatty acids into DHA due to a deficit in the peroxisomal d-bifunctional protein. This deficit may contribute to the decrease in brain DHA levels and contribute to cognitive impairment.

Phospholipid profile in the postmortem hippocampus of patients with schizophrenia and bipolar disorder: no changes in docosahexaenoic acid species

Previous studies with postmortem brain tissues showed abnormalities not only in n-3 long-chain polyunsaturated fatty acids (PUFA) but also in phospholipid metabolism in the cortex of individuals with schizophrenia and mood disorder. In this study we investigated whether there is similar abnormality in n-3 long-chain PUFAs and/or in phospholipid profile in the hippocampus of schizophrenia and bipolar disorder patients compared to unaffected controls. Using high-performance liquid chromatography/electrospray ionization-mass spectrometry (LC/MS), the phospholipid contents in the postmortem hippocampus from 35 individuals with schizophrenia, 34 individuals with bipolar disorder and 35 controls were evaluated. Unlike the previous findings form orbitofrontal cortex, we found no significant differences in either n-3 long-chain PUFA or total phosphatidylserine (PS), phosphatidylethanolamine (PE) and phosphatidylcholine (PC). However, docosapentaenoic acid (n-6, 22:5n-6)-PS and 22:5n-6-PC were significantly lower in individuals with schizophrenia or bipolar disorder than the controls. When fatty acid contents were estimated from PS, PE and PC, 22:5n-6 was significantly lower in both patient groups compared to the controls. From these results we concluded that DHA loss associated with these psychiatric disorders may be specific to certain regions of the brain. The selective decrease in 22:5n-6 without affecting DHA contents suggests altered lipid metabolism, particularly n-6 PUFA rather than n-3 PUFA, in the hippocampus of individuals with schizophrenia or bipolar disorder.

Generation and characterization of conditional heparin-binding EGF-like growth factor knockout mice

Recently, neurotrophic factors and cytokines have been shown to be associated in psychiatric disorders, such as schizophrenia, bipolar disorder, and depression. Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the EGF family, serves as a neurotrophic molecular and plays a significant role in the brain. We generated mice in which HB-EGF activity is disrupted specifically in the ventral forebrain. These knockout mice showed (a) behavioral abnormalities similar to those described in psychiatric disorders, which were ameliorated by typical or atypical antipsychotics, (b) altered dopamine and serotonin levels in the brain, (c) decreases in spine density in neurons of the prefrontal cortex, (d) reductions in the protein levels of the NR1 subunit of the N-methyl-D-aspartate (NMDA) receptor and post-synaptic protein-95 (PSD-95), (e) decreases in the EGF receptor, and in the calcium/calmodulin-dependent protein kinase II (CaMK II) signal cascade. These results suggest the alterations affecting HB-EGF signaling could comprise a contributing factor in psychiatric disorder.

Neurodevelopmental basis of bipolar disorder: a critical appraisal

Neurodevelopmental factors have been implicated in the pathophysiology of mental disorders. However, the evidence regarding their role in bipolar disorder is controversial. We reviewed the pertinent literature searching for evidence regarding a neurodevelopmental origin of bipolar disorder. Findings from clinical, epidemiological, neuroimaging, and post-mortem studies are discussed, as well as the implications of the available data for a better understanding of the mechanisms involved in the genesis of bipolar disorder. While some evidence exists for developmental risk factors in bipolar disorder, further research is needed to determine the precise extent of their contribution to pathogenesis. The timing and course of such developmentally mediated neurobiological alterations also need to be determined. Of particular importance for further study is the possibility that bipolar disorder may be mediated by an abnormal maturation of brain structures involved in affect regulation.

Obstetrical complications in children at high risk for bipolar disorder

OBJECTIVE

To examine obstetrical complications as a risk factor for developing bipolar disorder (BPD). We hypothesized that children with a bipolar parent would be at greater risk for obstetrical complications than demographically matched children of healthy adults. Additionally, within this "at-risk" (AR) sample, we hypothesized that obstetrical complications would be associated with the development of psychiatric disorders.

METHODS

The Washington University in St. Louis Kiddie-Schedule for Affective Disorders and Schizophrenia (WASH-U KSADS) was administered to children (AR) who had at least one parent with BPD (N=36) and children of healthy parents (HC) (N=27), by raters who were blind to diagnostic category. To assess obstetrical risk history, the Rochester Research Obstetrical Scale (ROS) was administered to parents of AR and HC children.

RESULTS

Children at familial risk for BPD had greater total (p=0.02) and prenatal (p=0.006) obstetrical complication scores than children of healthy parents. However, obstetrical complications were not associated with the development of affective, anxiety, or disruptive behavioral disorders within the at-risk group.

CONCLUSION

Our data suggest that compared with children of families without BPD, children of parents with BPD may be at greater risk for obstetrical complications, particularly those that occur during the prenatal period; however, at this early follow-up period factors other than obstetrical complications appear to contribute to the differences in rates of psychiatric disorders between these groups.

Impaired working memory monitoring in euthymic bipolar patients

OBJECTIVES

Converging evidence suggests that patients with remitted bipolar disorder (BD) have a persistent cognitive deficit in the executive control of working memory (WM). However, the component operations that contribute to this deficit remain unclear. The aim of the present study was to further profile the nature and specificity of WM impairment in euthymic BD.

METHODS

Fifty DSM-IV-confirmed patients with euthymic BD and demographically matched controls completed a modified version of the Self-Ordered Pointing Task (SOPT) and the Cambridge Neuropsychological Test Automated Battery Pattern Recognition Test along with traditional executive and WM tasks [Stroop, initial letter Verbal Fluency (FAS), Trail-Making, Digits Forwards and Backwards]. Prospective clinical ratings over one month prior to testing confirmed that patients were euthymic at test. Absence of basal hypercortisolaemia was confirmed by serial saliva sampling.

RESULTS

Error analysis revealed that whilst patients made more errors on the SOPT overall, they were no more likely to perseverate than controls. Patients' erroneous responses did not proliferate across trials, suggesting that proactive interference did not contribute to their poor performance, but serial position effects were evident where patients' errors clustered towards the end of a trial. No differences were found on the recognition memory test, in WM capacity, or on two of the three traditional executive procedures (FAS and Trail-Making). However, patients' Digits Backwards was impaired.

CONCLUSIONS

These data suggest that patients with BD have a deficit in their ability to monitor the contents of WM. This deficit is not an epiphenomenon of mood, but may be due to enduring brain dysfunction, integral to bipolar illness.

Exposure to obstetric complications and subsequent development of bipolar disorder: Systematic review

BACKGROUND

Research has suggested an association between obstetric complications and bipolar disorder. However, no quantitative evaluation has been made of the pooled data from existing studies.

AIMS

To systematically review studies comparing exposure to obstetric complications in cases of bipolar disorder v. non-psychiatric controls, and in cases of bipolar disorder v. cases of other mental disorders.

METHOD

Publications were identified by computer searches of seven databases, by hand searches of reference lists and from raw data received from researchers.

RESULTS

Forty-six studies were identified, of which 22 met the inclusion criteria. The pooled odds ratio for exposure to obstetric complications and subsequent development of bipolar disorder was 1.01 (95% CI 0.76-1.35) compared with healthy controls, 1.13 (95% CI 0.64-1.99) compared with cases of unipolar disorder and 0.61 (95% CI 0.39-0.95) compared with those who developed schizophrenia.

CONCLUSIONS

There is no robust evidence that exposure to obstetric complications increases the risk of developing bipolar disorder. However, the range of events regarded as obstetric complications and methodological inadequacies make definitive conclusions difficult.

Magnetic resonance imaging studies in early-onset bipolar disorder: a critical review

BACKGROUND

Neuroimaging studies of early-onset bipolar disorder (BD) are important in order to establish a fuller understanding of the underlying pathophysiology of the illness. The advantages of studying BD in children and adolescents include the relative absence of some confounds present in adult-onset research, such as lengthy duration of illness and exposure to treatments, greater number of mood episodes, and the presence of substance abuse or dependence. Finally, studying youths with the disorder may enhance our knowledge about the neural mechanisms of affective dysregulation and may specifically elucidate whether there are abnormalities that are unique to the early-onset form of the illness.

METHODS

PubMed was used to identify peer-reviewed publications from the past 15 years (January 1990 to January 2005) that used brain-imaging techniques (anatomic, functional, and biochemical) to research early-onset BD.

RESULTS

Eleven studies using anatomic magnetic resonance imaging (MRI), seven using magnetic resonance spectroscopy (MRS), and two using functional MRI (fMRI) were identified. Structural abnormalities were reported in total cerebral, white matter, superior temporal gyrus, putamen, thalamus, amygdala, and hippocampal volumes. Deficits in cortical gray matter were also reported. Using MRS, abnormalities were reported in the dorsolateral prefrontal cortex, anterior cingulate, and basal ganglia. One fMRI study found increased activation in the putamen and thalamus of BD youths compared to controls, and a second found abnormal prefrontal-subcortical activation in familial pediatric BD.

CONCLUSION

Published MRI studies of early-onset BD are few. Nonetheless, extant data implicate abnormalities in brain regions thought to regulate mood and cognition. Synthesis of the findings into an overall model of anatomic and functional disruption is difficult due to the methodological variations among studies and the limitations of individual studies, such as the use of small sample sizes, the heterogeneity of sample characteristics, and the wide range of brain structures selected for analysis. Recommendations are offered to guide future research. It will be important for future studies to reproduce prior findings and determine which findings are unique to early-onset BD, relative to adult-onset illness. In addition, studies will need to establish the extent to which early-onset BD may overlap with comorbid disruptive, mood, anxiety, or psychotic disorders.

Cavum septi pellucidi in first-episode schizophrenia and first-episode affective psychosis: an MRI study

A high prevalence of abnormal cavum septi pellucidi (CSP) in schizophrenia may reflect neurodevelopmental abnormalities in midline structures of the brain. The relationship, however, between abnormal CSP and clinical symptoms, and with abnormalities in other limbic structures remains unclear, as does the question of whether a similar abnormality is present in affective psychosis. Seventy-four patients at their first hospitalization, 33 with schizophrenia and 41 with affective (mainly manic) psychosis, and 56 healthy control subjects underwent high-spatial-resolution magnetic resonance imaging (MRI). CSP on six slices or more on 0.9375-mm resampled coronal images was categorized as abnormal. The prevalence of abnormal CSP in both schizophrenic patients (26.1%) and affective psychosis patients (18.2%) was significantly higher than was observed in control subjects (8.2%). In schizophrenic patients only, larger CSP was significantly associated with more severe thinking disturbance and smaller left parahippocampal gyrus gray matter volumes. While the relationships between CSP ratings and clinical symptoms did not significantly differ between the two psychosis groups as assessed by the comparison of regression slopes, the association with limbic volumes appeared to be specific to schizophrenic patients. These results suggest that psychosis associated with schizophrenia and affective disorder share, at least to some extent, neurodevelopmental abnormalities involving midline structures and associated psychopathological consequences. However, the association between abnormal CSP and limbic systems may be more specific to schizophrenia.

The neuropsychology and neuroanatomy of bipolar affective disorder: a critical review

Bearden CE, Hoffman KM, Cannon TD. The neuropsychology and neuroanatomy of bipolar affective disorder: a critical review. Bipolar Disord 2001: 3: 106 150. C Munksgaard, 2001

OBJECTIVES

To present a comprehensive review of the existing neuropsychological and neuroimaging literature on bipolar affective disorder. This review critically evaluates two common conceptions regarding the neuropsychology of bipolar disorder: 1) that, in contrast to schizophrenia, bipolar affective disorder is not associated with general cognitive impairment independent of illness episodes, and 2) relative right hemisphere (RH) dysfunction is implicated in bipolar illness patients, supported by reports of relatively greater impairment in visuospatial functioning, lateralization abnormalities, and mania secondary to RH lesions.

METHODS

The major computerized databases (Medline and PSYCInfo) were consulted in order to conduct a comprehensive, integrated review of the literature on the neuropsychology and neuroanatomy of bipolar disorder. Articles meeting specified criteria were included in this review.

RESULTS

In a critical evaluation of the above notions, this paper determines that: 1) while there is little evidence for selective RH dysfunction, significant cognitive impairment may be present in bipolar illness, particularly in a subgroup of chronic, elderly or multiple-episode patients, suggesting a possible toxic disease process, and 2) the underlying functional correlate of these cognitive deficits may be white matter lesions ('signal hyperintensities') in the frontal lobes and basal ganglia, regions critical for executive function, attention, speeded information processing, learning and memory, and affect regulation. While this hypothesized neural correlate of cognitive impairment in bipolar disorder is speculative, preliminary functional neuroimaging evidence supports the notion of frontal and subcortical hypometabolism in bipolar illness.

CONCLUSIONS

The etiology of the structural brain abnormalities commonly seen in bipolar illness, and their corresponding functional deficits, remains unknown. It is possible that neurodevelopmental anomalies may play a role, and it remains to be determined whether there is also some pathophysiological progression that occurs with repeated illness episodes. More research is needed on first-episode patients, relatives of bipolar probands, and within prospective longitudinal paradigms in order to isolate disease-specific impairments and genetic markers of neurocognitive function in bipolar disorder.

Obstetric complications in patients with depression--a population-based case-control study

BACKGROUND

To examine whether sufferers of affective disorders are more likely to be subject to obstetric complications than normal healthy people.

METHOD

Data based on prospectively recorded birth case-notes for patients with a diagnosis of depression (or related disorders) with early onset were compared to those of normal healthy controls, individually matched by gender, time and parity of birth, maternal age and marital status.

RESULTS

Forty-one case-controls pairs born between 1964 and 1978 were compared. No differences between cases and controls in gestational age or birthweight were significant, though depressive patients on average weighed 200 g less than controls at birth. Patients were more likely than controls to be small for their gestational age (22 vs. 1: chi(2)=4.34, P=0.03). They were significantly more likely than controls to have suffered at least one obstetric complication: 35 (85%) vs. 25 (60%), chi(2)=5.03, P=0.02; or more than one (two on average, as opposed to one on average among controls). No obstetric complication was seen significantly more among cases than controls, apart from bleeding during gestation, which was observed for four cases and no controls. The prevalence of complications with a clear brain damaging potential did not differ significantly between cases and controls: 11 (26%) vs. 8 (19%).

CONCLUSIONS

A developmental deficit, as indicated by lower birthweight and gestational age, may contribute to the risk of depressive breakdowns and affective disorders in later life. Severe, brain damaging obstetric complications are unlikely to be a significant risk factor for affective disorders, though some early onset cases may be accounted for by prenatal brain lesions.

LIMITATIONS

Sample size limits statistical power for isolation of a rare, single risk factor.

Meta-analysis of brain size in bipolar disorder

A recent meta-analysis concluded that patients with schizophrenia have reduced cerebral volume, and this finding has been used to implicate neurodevelopmental events in the etiology of this disorder. Since bipolar-disorder patients and schizophrenia patients have some similar brain abnormalities, it was of interest to meta-analytically review the literature on brain size in bipolar disorder. Only seven studies met the inclusion/exclusion criteria for our meta-analysis, but none reported the brain size differences between the bipolar patients and the controls to be statistically significant. The composite effect size was a negligible 0.04 (95% CI: -0.17 to 0.25) and statistically not significantly different from 0.0 (no effect). Thus, it appears that bipolar disorder is not associated with the same cerebral volume reductions noted in schizophrenia. Implications for hypotheses regarding the etiology of the two disorders are discussed.

Hyperintense lesions on magnetic resonance images in bipolar disorder

BACKGROUND

To examine the magnetic resonance (MR) images of bipolar patients across a wide age range for the presence of hyperintense lesions compared to age- and gender-matched control subjects.

METHODS

Consecutive admissions to a mood disorders unit over a 2-year period were evaluated retrospectively for the presence of bipolar disorder by DSM-III-R criteria and whether they received an MR scan. Bipolar patients (n = 70, mean age = 49.9 +/- 19.7 years) were age- and gender-matched to control subjects (n = 70, mean age = 53.2 +/- 18.1 years) and the MR scans were rated to assess for the presence of hyperintensites.

RESULTS

Compared to control subjects, the bipolar patients demonstrated hyperintense lesions in the subependymal region, subcortical gray nuclei, and the deep white matter.

CONCLUSIONS

Hyperintense lesions in bipolar patients are found in both the subcortical white matter and gray nuclei and may play an important role in the etiology of bipolar illness.

Pre- and perinatal complications and risk for bipolar disorder: a retrospective study

BACKGROUND

Many studies have reported that obstetric complications are risk factors for schizophrenia, but few studies have examined whether complications increase risk for bipolar disorder.

METHODS

Bipolar-disorder probands and their adult siblings were diagnosed using DSM-III-R criteria. Obstetrical data from maternal reports were scored, blind to diagnosis, applying published scales that take into account number and severity of complications.

RESULTS

Obstetric complication scores were significantly worse in probands than siblings without mood disorders.

LIMITATIONS

Probands had relatively severe symptoms; research using more heterogeneous samples is needed.

CONCLUSION

Results suggest obstetric complications are etiologically significant in bipolar disorder.

MRI study of cavum septi pellucidi in schizophrenia, affective disorder, and schizotypal personality disorder

OBJECTIVE

A cavum between the septi pellucidi may reflect neurodevelopmental anomalies in midline structures of the brain. The authors examined cavum septi pellucidi in subjects with schizophrenia, affective disorder, and schizotypal personality disorder and in normal subjects.

METHOD

Thirty schizophrenic patients (15 chronic, 15 first-episode), 16 patients with affective disorder (first-episode), 21 patients with schizotypal personality disorder, and 46 normal subjects were evaluated with magnetic resonance imaging. Cavum septi pellucidi was assessed by counting the number of 1.5-mm slices containing cavum septi pellucidi.

RESULTS

The presence or absence of cavum septi pellucidi did not differentiate among groups. However, the prevalence of abnormal cavum septi pellucidi (i.e., cavum septi pellucidi contained on four or more slices) was 30.4% for schizophrenic patients (36.4% for chronic, 25.0% for first-episode), 20.0% for patients with affective disorder, 18.8% for patients with schizotypal personality disorder, and 10.3% for normal subjects. When the authors used the Nopoulos et al. criteria for rating cavum septi pellucidi, which omitted borderline cases with cavum septi pellucidi on three slices, the prevalence of abnormal cavum septi pellucidi increased to 35.0% for schizophrenia (40.0% for chronic, 30.0% for first-episode), 25.0% for affective disorder, 27.3% for schizotypal personality disorder, and 13.0% for normal subjects. There was a statistically significant difference in ratings between schizophrenic and normal subjects.

CONCLUSIONS

The results suggest that alterations in midline structures during the course of neurodevelopment may play a role in the pathogenesis of schizophrenia.

The clinical stigmata of aberrant neurodevelopment in schizophrenia

The neurodevelopmental hypothesis of schizophrenia is currently a primary etiopathological model for schizophrenia. Its tenets derive from observations of epidemiological, postmortem, and brain imaging evidence of neurodevelopmental deviance. Clinical stigmata of neurodevelopmental arrest include the presence of obstetric complications, minor physical anomalies, abnormal dermatoglyphics, and childhood neuromotor precursors of adult schizophrenic illness. The relative importance of these stigmata and their relationship to brain imaging findings in schizophrenia are discussed.

Structural changes in the brain of patients with bipolar affective disorder by MRI: a review of the literature

1. Current literature was searched to evaluate the use of magnetic resonance imaging in patients with bipolar disorder. 2. The presence of white matter hyperintensities, differences in temporal lobe and hippocampal structures, and ventricular enlargement in patients with bipolar disorder was assessed. 3. Further use of MRI in patients with bipolar disorder is reviewed.

Schizophrenia: a disorder of neurodevelopment?

For the first time, there is a pathogenic hypothesis of schizophrenia based upon reasonable empirical data. The hypothesis is that schizophrenia is a disorder arising from aberrant brain development. The neurodevelopmental view of schizophrenia is supported by neuropathological, epidemiological and clinical findings. Here, the evidence in favour of the model is summarized, together with a consideration of its weaknesses.

The anatomy of mood disorders--review of structural neuroimaging studies

The structural neuroimaging findings in mood disorders were reviewed, to evaluate evidence for a neuroanatomic model of pathophysiology, involving the prefrontal cortex, the basal ganglia, the amygdala-hippocampus complex, thalamus, and connections among these structures. Global atrophy is not consistently found. The best replicated finding is an increased rate of white matter and periventricular hyperintensities. A smaller frontal lobe, cerebellum, caudate, and putamen appear present in unipolar depression. A larger third ventricle, and smaller cerebellum and perhaps temporal lobe appear present in bipolar disorder. These localized structural changes involve regions that may be critical in the pathogenesis of mood disorders. Generalized and localized anatomic alterations may be related to age or vascular disease. The clinical and biological correlates of these changes need to be investigated to allow development of a more complete model of pathophysiology of mood disorders.

Increased prefrontal sulcal prominence in relatively young patients with unipolar major depression

Although several studies have reported ventricular enlargement and sulcal prominence in mixed samples of patients with affective disorders (unipolar and bipolar subtypes), it is not established if these findings extend to a homogeneous sample of relatively young patients with unipolar major depression ventricular:brain ratio (VBR) and prefrontal sulcal prominence (PSP). In the present study, measures of ventricle-brain ratio (VBR) and prefrontal sulcal prominence (PSP) were compared in patients with affective disorders (n = 24, mean age = 39), medical control subjects (n = 40), patients with schizophrenia (n = 101) on ventricular : brain ratio (VBR) and prefrontal sulcal prominence (PSP). No statistically significant differences were noted in VBR in the three groups. Both patient groups had significantly greater PSP than the medical control subjects but did not differ significantly from each other. The results of the present study extend the finding of prefrontal sulcal prominence, but not ventricular enlargement, to relatively young patients with unipolar depression. Furthermore, the results of the present study suggest that patients with schizophrenia and patients with affective disorders differ only slightly or not at all in brain morphology, at the level of resolution studied.

Treatment-resistant depression in children and adolescents

Treatment resistance in depressed children and adolescents cannot yet be defined fully because of the paucity of controlled studies that demonstrate efficacy. Therefore, this article addresses several of the age-specific, developmental considerations that may impinge upon treatment response. Areas covered include familial-genetic, psychosocial, and neuroimaging studies in addition to a review of controlled studies to date.

Prevalence of cavum septum pellucidum detected by MRI in patients with bipolar disorder, major depression and schizophrenia

The incidence of cavum septum pellucidum (CSP), which has been widely regarded as a developmental anomaly of little clinical importance in neuropathology, was examined in 113 patients with affective disorders (69 with bipolar disorder and 44 with major depression), 40 schizophrenic patients, and 92 control subjects by magnetic resonance imaging (MRI). Significantly higher incidence of Grade 3-4 CSP (moderate to large) compared with the controls was found only in the schizophrenics. When a broader interpretation of CSP, including indeterminant (Grade 1) and small (Grade 2) CSP was used, three additional patients with bipolar disorder were found to have Grade 1-2 CSP, and the total prevalence of Grade 1-4 CSP in the patients with bipolar disorder was significantly higher than that in the control subjects but slightly lower than that in the schizophrenic patients. CSP was not observed in any patient with major depression. There were no differences between the patients with and without CSP in age, sex, education, or the duration of illness. These findings are consistent with the hypothesis that neurodevelopmental abnormality may be present in schizophrenia, and such an abnormality may also be present in some patients with bipolar disorder.

Developmental abnormalities and cortical sulcal enlargement in psychosis

Neurodevelopmental abnormalities and cortical sulcal enlargement both occur in schizophrenia. To test the hypothesis that these abnormalities were related, CT scans from 164 psychotic patients (80 with schizophrenia) were reviewed. Neurodevelopmental abnormalities were observed in 11%. Abnormalities were equally prevalent in schizophrenia and other psychotic disorders. Cortical sulcal enlargement was observed in 39% of patients with schizophrenia, and was not associated with developmental abnormalities. Different mechanisms may contribute to distinct structural abnormalities.

Preliminary study of magnetic resonance imaging characteristics in 8- to 16-year-olds with mania

OBJECTIVE

To examine magnetic resonance imaging (MRI) characteristics in children and adolescents with mania according to DSM-III-R criteria.

METHOD

A convenience sample of consecutively referred 8- to 16-year-old manic (n = 10) and normal (n = 5) subjects were assessed using the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present Episode Version, the Children's Global Assessment Scale, and the Family History-Research Diagnostic Criteria. MRI scans were obtained from unsedated subjects using a 1.5 T MR scanner to acquire T1-weighted coronal and sagittal images and T2-weighted axial images. Images were assessed by blind clinical interpretation, ratings of T2-weighted deep white matter hyperintensities and petalia, and computer-assisted volumetric analysis of ventricular and cerebral volumes.

RESULTS

Eight of 10 manic subjects and all 5 controls completed the scans. Scans of 4 manic subjects and 1 control subject showed ventricular or white matter abnormalities by clinical interpretation. Significant findings were positive correlations between increasing age and both right and left ventricular volumes. Two of the 8 manic subjects and no controls had confluent subcortical hyperintensities.

CONCLUSIONS

MRI brain scanning was feasible in 8- to 16-year-olds. Preliminary findings from clinical interpretations and structured ratings suggest structural differences between young manic and normal subjects. Investigations of larger samples are needed to better characterize the differences.

Phosphorus-31 magnetic resonance spectroscopy and ventricular enlargement in bipolar disorder

Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) was used to examine whether reduced levels of phosphomonoesters (PME) were correlated with ventricular enlargement in 40 patients with bipolar disorder and 60 age-matched normal control subjects. Ventricular enlargement was assessed by magnetic resonance imaging (1H-MRI) using the following three methods: Evans ratio (ER), Huckman number (HN), and minimum distance of caudate nuclei (MDCN). Although MDCN and ER were significantly larger in the patient group, no significant correlations were found between 31P-MRS and 1H-MRI. PME was negatively correlated with age in bipolar disorder. Decreased levels of PME were found only in bipolar I disorder. Intracellular pH was positively correlated with duration of lithium treatment. These results suggest that the observed PME reduction was not related to ventricular enlargement, but the issue should be further studied with volumetric MRI analysis.

Organic manic syndrome: causative factors, phenomenology and immediate outcome

A prospective study on organic manic syndromes led to identification of 30 cases over a period of 11 months, constituting 1.75% of all admissions and 4.67% of all patients with mania. They were compared with 60 sex- and age-matched bipolar controls. The mean age of onset of illness was not significantly different in the two groups. Family history of affective disorder was more often negative in organic manics. The overall mania rating score was similar in the two groups, but after 3 months organic manics improved less. Compared to the bipolar group, organic manics were more often irritable, made threats, had delusions, and showed cognitive dysfunctions. The implications of these findings on definition of the organic manic syndrome are discussed.

Neural development is regulated by classical neurotransmitters: dopamine D2 receptor stimulation enhances neurite outgrowth

The classical neurotransmitters serotonin and dopamine are thought to be involved in the etiology or treatment of a variety of psychiatric disorders. Recent studies suggest that these neurotransmitters may also have roles as neural morphogens during brain development. Previously, we have demonstrated that stimulation of serotonin 5-HT1A receptors selectively inhibited neurite branching in an in vitro system (Sikich et al 1990). In the present study, the developmental role of dopamine D2 receptors in the control of neurite outgrowth has been investigated by quantitating the morphological response of cortical neurons to agonist stimulation in vitro. Cultures of fetal rat frontal, cortical neurons were shown to express both alternatively spliced forms of D2 receptor messenger RNA (mRNA). The larger mRNA form predominated (D2A444:D2A415 ratio of about 6:1). In a small but significant percentage of these neurons, culture in the presence of the D2 receptor selective agonist, quinpirole, resulted in a three-to ten-fold increase in the length of neurites and in the number of branch points per neurite. These effects were blocked by the D2 receptor antagonists eticlopride and spiperone. Early abnormalities in the stimulation of dopamine or serotonin receptor subtypes could lead to the types of neuroanatomical changes observed in studies of schizophrenia, bipolar affective disorder, and autism. These morphogenic effects of classical transmitters could unite neurodevelopmental and neurotransmitter theories of the etiology of severe psychiatric disorders.

MRI abnormalities in adolescent bipolar affective disorder

There is increasing evidence for structural differences in the brains of patients with affective disorders. Recent magnetic resonance imaging (MRI) studies have reported focal signal hyperintensities in the deep white matter of bipolar patients. These previous reports had focused on adult patients with prior episodes of illness. In this case report, the authors discuss a young adolescent patient during her first episode of mania and the finding of subcortical focal signal hyperintensities on brain MRI. The etiology, pathophysiology, and clinical correlates of these lesions will be reviewed.

A review of evidence for GABergic predominance/glutamatergic deficit as a common etiological factor in both schizophrenia and affective psychoses: more support for a continuum hypothesis of "functional" psychosis

Virtually all antidepressant and antipsychotic drugs, including clozapine, rimcazole and lithium ion, are proconvulsants, and convulsive therapy, using metrazol, a known GABA-A antagonist, as well as electro-convulsive therapy, can be effective in treating both schizophrenia and affective psychoses. Many antidepressant and antipsychotic drugs, including clozapine, as well as some of their metabolites, reverse the inhibitory effect of GABA on 35S-TBPS binding, a reliable predictor of GABA-A receptor blockade. A review of relevant literature suggests that 1) "functional" psychoses constitute a continuum of disorders ranging from schizophrenia to affective psychoses with overlap of symptoms, heredity and treatments, 2) a weakening of GABergic inhibitory activity, or potentiation of counterbalancing glutamatergic neurotransmission, in the brain, may be involved in the therapeutic activities of both antidepressant and antipsychotic drugs, and 3) schizophrenia and the affective psychoses may be different expressions of the same underlying defect: GABergic preponderance/glutamatergic deficit. Schizophrenia and affective psychoses share the following: 1) several treatments are effective in both, 2) similar modes of inheritance, 3) congruent seasonal birth excesses, 4) enlarged cerebral ventricles and cerebellar vermian atrophy, 5) dexamethasone non-suppression. Both genetic and environmental factors are involved in both schizophrenia and affective psychoses, and several lines of evidence suggest that important environmental factors are neurotropic pathogens that selectively destroy glutamatergic neurons. One group of genes associated with psychoses may increase vulnerability to attack and destruction, by neurotropic pathogens, of excitatory glutamatergic neurons that counterbalance inhibitory GABergic neurons. A second group of genes may encode subunits of overactive GABA-A receptors, while a third group of genes may encode subunits of hypo-active glutamate receptors. Improved antipsychotic drugs may be found among selective blockers of GABA-A receptor subtypes and/or enhancers of glutamatergic neurotransmission. A mechanism similar to kindling, leading to long-lasting reduction of GABergic inhibition in the brain, may be involved in several treatments of psychoses.