An MRI study of adolescent patients with either schizophrenia or bipolar disorder as compared to healthy control subjects

Brain morphology does not clearly map to cognition in individuals on the bipolar-schizophrenia-spectrum: a cross-diagnostic study of cognitive subgroups

BACKGROUND

Characterisation of brain morphological features common to cognitively similar individuals with bipolar disorder (BD) and schizophrenia spectrum disorders (SSD) may be key to understanding their shared neurobiological deficits. In the current study we examined whether three previously characterised cross-diagnostic cognitive subgroups differed among themselves and in comparison to healthy controls across measures of brain morphology.

METHOD

T1-weighted structural magnetic resonance imaging scans were obtained for 143 individuals; 65 healthy controls and 78 patients (SSD, n = 40; BD I, n = 38) classified into three cross-diagnostic cognitive subgroups: Globally Impaired (n = 24), Selectively Impaired (n = 32), and Superior/Near-Normal (n = 22). Cognitive subgroups were compared to each other and healthy controls on three separate analyses investigating (1) global, (2) regional, and (3) vertex-wise comparisons of brain volume, thickness, and surface area.

RESULTS

No significant subgroup differences were evident in global measures of brain morphology. In region of interest analyses, the Selectively Impaired subgroup had greater right accumbens volume than those Superior/Near-Normal subgroup and healthy controls, and the Superior/Near-Normal subgroup had reduced volume of the left entorhinal region compared to all other groups. In vertex-wise comparisons, the Globally Impaired subgroup had greater right precentral volume than the Selectively Impaired subgroup, and thicker cortex in the postcentral region relative to the Superior/Near-Normal subgroup.

LIMITATIONS

Exploration of medication effects was limited in our data.

CONCLUSIONS

Although some differences were evident in this sample, generally cross-diagnostic cognitive subgroups of individuals with SSD and BD did not appear to be clearly distinguished by patterns in brain morphology.

Alterations of Cognition and Cerebral Ventricle Volume in Manic and Euthymic Pediatric Bipolar Disorder

Introduction: It remains unknown whether volumetric alterations of ventricles are similar or not in pediatric bipolar disorder (PBD) among different mood states. The present study aims to estimate ventricular volumetric alteration of PBD patients in manic and euthymic status, as well as the relationship between this alteration and cognitive changes. Methods: T1 magnetic resonance images were obtained from 20 manic PBD patients, 21 euthymic PBD patients, and 19 healthy controls (HCs). Ventricular volumes were automatically obtained via FreeSurfer 6.0 software. Ventricular volumes and cognitive indices were compared among the three groups, and the relationship between ventricular volumes and cognitive/clinical indices was analyzed. Results: In contrast to HCs, manic and euthymic PBD patients exhibited decreased cognitive scores of the Stroop color-word test and the digit span subtest. Manic PBD subjects presented enlarged volumes in the bilateral ventricles, third ventricle, and whole ventricles, and euthymic PBD participants displayed increased volumes in the third ventricle, fourth ventricle, and whole ventricles. No significant differences in cognitive performance and ventricular volumes were found between PBD groups. No significant correlation was discovered between ventricular volumes and cognitive/clinical indices in both manic and euthymic PBD patients. Conclusions: No significant differences in cognitive performance and ventricle volume were observed between euthymic and manic PBD groups, which may imply that the alterations are not specific to mood state. It may indicate structural and functional damage of corresponding brain circuits in euthymic PBD patients similar with that of manic PBD, which may provide clues to the diagnosis and treatment of euthymic PBD.

Transdiagnostic neuroimaging in psychiatry: A review

Transdiagnostic approach has a long history in neuroimaging, predating its recent ascendance as a paradigm for new psychiatric nosology. Various psychiatric disorders have been compared for commonalities and differences in neuroanatomical features and activation patterns, with different aims and rationales. This review covers both structural and functional neuroimaging publications with direct comparison of different psychiatric disorders, including schizophrenia, bipolar disorder, major depressive disorder, autism spectrum disorder, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, conduct disorder, anorexia nervosa, and bulimia nervosa. Major findings are systematically presented along with specific rationales for each comparison.

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.

White matter abnormalities in the fornix are linked to cognitive performance in SZ but not in BD disorder: An exploratory analysis with DTI deterministic tractography

BACKGROUND

In psychosis, white matter (WM) microstructural changes have been detected previously; however, direct comparisons of findings between bipolar (BD) and schizophrenia (SZ) patients are scarce. In this study, we employed deterministic tractography to reconstruct WM tracts in BD and SZ patients.

METHODS

Diffusion tensor imaging (DTI) data was carried out with n=32 euthymic BD type I patients, n=26 SZ patients and 30 matched healthy controls. Deterministic tractography using multiple indices of diffusion (fractional anisotropy (FA), tract volume (Vol), tract length (Le) and number of tracts (NofT)) were obtained from the fornix, the cingulum, the anterior thalamic radiation, and the corpus callosum bilaterally.

RESULTS

We showed widespread WM microstructural changes in SZ, and changes in the corpus callosum, the left cingulum and the fornix in BD. Fornix fiber tracking scores were associated with cognitive performance in SZ, and with age and age at disease onset in the BD patient group.

LIMITATIONS

Although the influence of psychopharmacological drugs as biasing variables on morphological alterations has been discussed for SZ and BD, we did not observe a clear influence of drug exposure on our findings.

CONCLUSIONS

These results confirm the assumption that SZ patients have more severe WM changes than BD patients. The findings also suggest a major role of WM changes in the fornix as important fronto-limbic connections in the etiology of cognitive symptoms in SZ, but not in BD.

Shared and distinct gray matter abnormalities in schizophrenia, schizophrenia relatives and bipolar disorder in association with cognitive impairment

Cognitive impairments have been linked to structural and functional alterations in frontal and subcortical brain regions, ultimately leading to fronto-thalamic connectivity disturbances. We hypothesized that such neuronal disruptions in frontal and subcortical structures may account for neuropsychological deficits in schizophrenia (SZ), schizophrenia relatives and bipolar disorder (BD). We acquired T1-weighted anatomical MRI sequences in 209 participants: 57 SZ patients, 47 first-degree relatives of SZ patients, 48 BD I patients and 57 healthy controls. We computed group comparisons of gray matter (GM) volume in frontal and basal ganglia regions-of-interest, followed by correlation analysis between psychomotor speed, executive functioning and learning and GM volumes in candidate regions. Several frontal GM volume reductions as well as GM increases in the thalamus and the putamen were exhibited in SZ patients as compared to controls. The same finding was observed - less pronounced - when comparing SZ relatives and controls. BD patients presented GM volume increases in the basal ganglia in comparison to controls. In SZ patients, increases in bilateral thalamus GM volume and decreases in left middle and superior frontal gyrus volume were significantly associated with worse cognitive performance. In summary, our results indicate distinct imbalances across frontal-subcortical circuits in BD, SZ relatives and SZ. The functional relevance of the findings were mainly limited to the SZ patients group: in this group, abnormalities were directly associated with cognitive performance. This result is in line with the finding that the volume alterations were strongest in SZ patients and followed by BD patients and SZ relatives.

ERBB4 polymorphism and family history of psychiatric disorders on age-related cortical changes in healthy children

Genetic variations in ERBB4 were associated with increased susceptibility for schizophrenia (SCZ) and bipolar disorders (BPD). Structural imaging studies showed cortical abnormalities in adolescents and adults with SCZ or BPD. However, less is known about subclinical cortical changes or the influence of ERBB4 on cortical development. 971 healthy children (ages 3-20 years old; 462 girls and 509 boys) were genotyped for the ERBB4-rs7598440 variants, had structural MRI, and cognitive evaluation (NIH Toolbox ®). We investigated the effects of ERBB4 variants and family history of SCZ and/or BPD (FH) on cortical measures and cognitive performances across ages 3-20 years using a general additive model. Variations in ERBB4 and FH impact differentially the age-related cortical changes in regions often affected by SCZ and BPD. The ERBB4-TT-risk genotype children with no FH had subtle cortical changes across the age span, primarily located in the left temporal lobe and superior parietal cortex. In contrast, the TT-risk genotype children with FH had more pronounced age-related changes, mainly in the frontal lobes compared to the non-risk genotype children. Interactive effects of age, FH and ERBB4 variations were also found on episodic memory and working memory, which are often impaired in SCZ and BPD. Healthy children carrying the risk-genotype in ERBB4 and/or with FH had cortical measures resembling those reported in SCZ or BPD. These subclinical cortical variations may provide early indicators for increased risk of psychiatric disorders and improve our understanding of the effect of the NRG1-ERBB4 pathway on brain development.

Cortical Volume Alterations in Conduct Disordered Adolescents with and without Bipolar Disorder

Background: There is increasing evidence that bipolar disorder (BD) and conduct disorder (CD) are co-occurring disorders. Magnetic resonance imaging has revealed differences in the structure and function of the frontal cortex in these disorders when studied separately; however, the impact of BD comorbidity on brain structure in adolescents with CD has not yet been examined. Method: We conducted an optimized voxel based morphometry (VBM) study of juvenile offenders with the following diagnoses: conduct disorder with comorbid bipolar disorder (CD-BD; n = 24), conduct disorder without bipolar disorder (CD; n = 24) and healthy controls (HC, n = 24). Participants were 13–17 years of age, in a residential treatment facility for repeat offenders. The three groups in this study were similar in age, gender, socioeconomic status and ethnicity. Results: We found CD-BD subjects had decreased volume relative to controls at the voxel level in the right medial prefrontal cortex (PFC). Using a Threshold-Free Cluster Enhancement (TFCE) technique, the CD-BD subjects had significantly decreased volumes of the right medial prefrontal cortex and portions of the superior and inferior frontal gyrus, anterior cingulate and temporal gyrus. The CD subjects did not have differences in brain volume compared to control subjects or CD-BD subjects. Conclusions: Our findings suggest the comorbidity between CD and BD is associated with neurobiological impact namely volumetric differences from healthy controls. Furthermore subjects with this comorbidity had poorer lifetime functioning, more mood and attentional dysfunction, and more medication exposure than subjects with CD who were not BD.

Differential neurodevelopmental trajectories in patients with early-onset bipolar and schizophrenia disorders

Schizophrenia and bipolar disorders share not only clinical features but also some risk factors such as genetic markers and childhood adversity, while other risk factors such as urbanicity and obstetric complications seem to be specific to schizophrenia. An intriguing question is whether the well-established abnormal neurodevelopment present in many children and adolescents who eventually develop schizophrenia is also present in bipolar patients. The literature on adult bipolar patients is controversial. We report data on a subgroup of patients with pediatric-onset psychotic bipolar disorder who seem to share some developmental trajectories with patients with early-onset schizophrenia. These early-onset psychotic bipolar patients have low intelligence quotient, more neurological signs, reduced frontal gray matter at the time of their first psychotic episode, and greater brain changes than healthy controls in a pattern similar to early-onset schizophrenia cases. However, patients with early-onset schizophrenia seem to have more social impairment, developmental abnormalities (eg, language problems), and lower academic achievement in childhood than early-onset bipolar patients. We suggest that some of these abnormal developmental trajectories are more related to the phenotypic features (eg, early-onset psychotic symptoms) of these 2 syndromes than to categorically defined Diagnostic and Statistical Manual of Mental Disorders disorders.

Review of magnetic resonance imaging and spectroscopy studies in children with bipolar disorder

Pediatric bipolar disorder is a serious condition that affects a child's ability to function normally during important developmental stages. Pediatric bipolar disorder often presents with a different symptom complex than adult-onset bipolar disorder, including higher rates of irritability and rapid cycling. Due to these differences, it is important to understand the neural substrates of the disease as it presents in children, especially when compared with adults. Understanding the brain abnormalities associated with pediatric bipolar disorder may provide much needed markers useful in diagnosing childhood-onset bipolar disorder, give insight into the neurobiological etiology of the disorder and lead to more effective treatments. Currently, there has been little neuroimaging research into pediatric bipolar disorder, specifically with regards to brain function. This review summarizes the neurobiological research that has been conducted on childhood- and adolescent-onset bipolar disorder using magnetic resonance technology. Future directions of research needed in this area also are discussed in the context of the existing literature.

Brain gray matter phenotypes across the psychosis dimension

This study sought to examine whole brain and regional gray matter (GM) phenotypes across the schizophrenia (SZ)-bipolar disorder psychosis dimension using voxel-based morphometry (VBM 8.0 with DARTEL segmentation/normalization) and semi-automated regional parcellation, FreeSurfer (FS 4.3.1/64 bit). 3T T1 MPRAGE images were acquired from 19 volunteers with schizophrenia (SZ), 16 with schizoaffective disorder (SAD), 17 with psychotic bipolar I disorder (BD-P) and 10 healthy controls (HC). Contrasted with HC, SZ showed extensive cortical GM reductions, most pronounced in fronto-temporal regions; SAD had GM reductions overlapping with SZ, albeit less extensive; and BD-P demonstrated no GM differences from HC. Within the psychosis dimension, BD-P showed larger volumes in fronto-temporal and other cortical/subcortical regions compared with SZ, whereas SAD showed intermediate GM volumes. The two volumetric methodologies, VBM and FS, revealed highly overlapping results for cortical GM, but partially divergent results for subcortical volumes (basal ganglia, amygdala). Overall, these findings suggest that individuals across the psychosis dimension show both overlapping and unique GM phenotypes: decreased GM, predominantly in fronto-temporal regions, is characteristic of SZ but not of psychotic BD-P, whereas SAD display GM deficits overlapping with SZ, albeit less extensive.

Enhancing synaptic plasticity and cellular resilience to develop novel, improved treatments for mood disorders

There is mounting evidence that recurrent mood disorders - once considered “good prognosis diseases”- are, in fact, often very severe and life-threatening illnesses. Furthermore, although mood disorders have traditionally been conceptualized as neurochemical disorders, there is now evidence from a variety of sources demonstrating regional reductions in central nervous system (CNS) volume, as well as reductions in the numbers and/or sizes ofglia and neurons in discrete brain areas. Although the precise cellular mechanisms underlying these morphometric changes remain to be fully elucidated, the data suggest that mood disorders are associated with impairments of synaptic plasticity and cellular resilience. In this context, it is noteworthy that there is increasing preclinical evidence that antidepressants regulate the function of the glutamatergic system. Moreover, although clearly preliminary, the available clinical data suggest that attenuation of N-methyl-D-aspartate (NMDA) function has antidepressant effects. Recent preclinical and clinical studies have shown that signaling pathways involved in regulating cell survival and cell death are long-term targets for the actions of antidepressant agents. Antidepressants and mood stabilizers indirectly regulate a number of factors involved in cell survival pathways, including cyclic adenosine monophosphate (cAMP) response element binding protein (CREB), brain-derived neurotrophic factor (BDNF), the antiapoptotic protein bcl-2, and mitogen-activated protein (MAP) kinases, and may thus bring about some of their delayed long-term beneficial effects via underappreciated neurotrophic effects. There is much promise for the future development of treatments that more directly target molecules in critical CNS signaling pathways regulating synaptic plasticity and cellular resilience. These will represent improved long-term treatments for mood disorders.

A plausible model of schizophrenia must incorporate psychological and social, as well as neuro developmental, risk factors

Subtle alterations in brain development caused by genes or early environmental hazards, such as obstetric complications, play a role in projecting some individuals on a trajectory toward schizophrenia. High-risk and cohort studies demonstrate that children destined to develop schizophrenia tend to have delayed milestones and subtle neuromotor and cognitive impairments (particularly in coordination and language). These neurocognitive problems lead to difficulties in interpersonal relations, and their progressive alienation makes these at-risk children more likely to harbor odd or paranoid ideas. This cascade of increasingly deviant development may then be compounded by brain maturational changes during adolescence with a resultant lability of the dopaminergic response to stress. As a result, the individual is more susceptible to the effects of the abuse of dopamine-releasing drugs, and to other risk factors such as migration or stressful life events; social isolation may be a common pathway underlying several of the social risk factors.

Comprehensive segmentation of subcortical brain volumes in early onset schizophrenia reveals limited structural abnormalities

Structural brain abnormalities are well documented in adult schizophrenia, but there are few studies of brain structures in early onset schizophrenia (EOS) and findings are inconsistent. Most previous EOS studies have been limited to global morphometric measures, such as whole gray matter (GM) or cerebrospinal fluid (CSF), or to single brain structures. The purpose of this study was to compare specific volumes and hemispheric lateralization in a large number of subcortical brain structures, between EOS patients and a healthy control group. High-resolution structural magnetic resonance images (MRI) and automatic brain volume segmentation were performed on 18 EOS patients and 33 healthy controls (11-18 years). A total of 29 brain structures were studied. The patients showed marked bilateral enlargements of the lateral ventricles and of the fourth ventricle, and bilateral enlargement of the caudate nuclei compared to the controls. For all other subcortical brain structures, there were no significant differences between the EOS group and the healthy control group, contrary to findings from the majority of morphometric studies of childhood or adult onset schizophrenia.

Neuroprogression in bipolar disorder

OBJECTIVE

Recent theories regarding the neuropathology of bipolar disorder suggest that both neurodevelopmental and neurodegenerative processes may play a role. While magnetic resonance imaging has provided significant insight into the structural, functional, and connectivity abnormalities associated with bipolar disorder, research assessing longitudinal changes has been more limited. However, such research is essential to elucidate the pathophysiology of the disorder. The aim of our review is to examine the extant literature for developmental and progressive structural and functional changes in individuals with and at risk for bipolar disorder.

METHODS

We conducted a literature review using MEDLINE and the following search terms: bipolar disorder, risk, child, adolescent, bipolar offspring, MRI, fMRI, DTI, PET, SPECT, cross-sectional, longitudinal, progressive, and developmental. Further relevant articles were identified by cross-referencing with identified manuscripts.

CONCLUSIONS

There is some evidence for developmental and progressive neurophysiological alterations in bipolar disorder, but the interpretation of correlations between neuroimaging findings and measures of illness exposure or age in cross-sectional studies must be performed with care. Prospective longitudinal studies placed in the context of normative developmental and atrophic changes in neural structures and pathways thought to be involved in bipolar disorder are needed to improve our understanding of the neurodevelopmental underpinnings and progressive changes associated with bipolar disorder.

Gyrification and neural connectivity in schizophrenia

There is emerging evidence for a connection between the surface morphology of the brain and its underlying connectivity. The foundation for this relationship is thought to be established during brain development through the shaping influences of tension exerted by viscoelastic nerve fibers. The tension-based morphogenesis results in compact wiring that enhances efficient neural processing. Individuals with schizophrenia present with multiple symptoms that can include impaired thought, action, perception, and cognition. The global nature of these symptoms has led researchers to explore a more global disruption of neuronal connectivity as a theory to explain the vast array of clinical and cognitive symptoms in schizophrenia. If cerebral function and form are linked through the organization of neural connectivity, then a disruption in neural connectivity may also alter the surface morphology of the brain. This paper reviews developmental theories of gyrification and the potential interaction between gyrification and neuronal connectivity. Studies of gyrification abnormalities in children, adolescents, and adults with schizophrenia demonstrate a relationship between disrupted function and altered morphology in the surface patterns of the cerebral cortex. This altered form may provide helpful clues in understanding the neurobiological abnormalities associated with schizophrenia.

Are Bipolar Disorder and Schizophrenia Neuroanatomically Distinct? An Anatomical Likelihood Meta-analysis

Objective: There is renewed debate on whether modern diagnostic classification should adopt a dichotomous or dimensional approach to schizophrenia and bipolar disorder. This study synthesizes data from voxel-based studies of schizophrenia and bipolar disorder to estimate the extent to which these conditions have a common neuroanatomical phenotype. Methods: A post-hoc meta-analytic estimation of the extent to which bipolar disorder, schizophrenia, or both conditions contribute to brain gray matter differences compared to controls was achieved using a novel application of the conventional anatomical likelihood estimation (ALE) method. 19 schizophrenia studies (651 patients and 693 controls) were matched as closely as possible to 19 bipolar studies (540 patients and 745 controls). Result: Substantial overlaps in the regions affected by schizophrenia and bipolar disorder included regions in prefrontal cortex, thalamus, left caudate, left medial temporal lobe, and right insula. Bipolar disorder and schizophrenia jointly contributed to clusters in the right hemisphere, but schizophrenia was almost exclusively associated with additional gray matter deficits (left insula and amygdala) in the left hemisphere. Limitation: The current meta-analytic method has a number of constraints. Importantly, only studies identifying differences between controls and patient groups could be included in this analysis. Conclusion: Bipolar disorder shares many of the same brain regions as schizophrenia. However, relative to neurotypical controls, lower gray matter volume in schizophrenia is more extensive and includes the amygdala. This fresh application of ALE accommodates multiple studies in a relatively unbiased comparison. Common biological mechanisms may explain the neuroanatomical overlap between these major disorders, but explaining why brain differences are more extensive in schizophrenia remains challenging.

Brain size and brain/intracranial volume ratio in major mental illness

BACKGROUND

This paper summarizes the findings of a long term study addressing the question of how several brain volume measure are related to three major mental illnesses in a Colorado subject group. It reports results obtained from a large N, collected and analyzed by the same laboratory over a multiyear period, with visually guided MRI segmentation being the primary initial analytic tool.

METHODS

Intracerebral volume (ICV), total brain volume (TBV), ventricular volume (VV), ventricular/brain ratio (VBR), and TBV/ICV ratios were calculated from a total of 224 subject MRIs collected over a period of 13 years. Subject groups included controls (C, N = 89), and patients with schizophrenia (SZ, N = 58), bipolar disorder (BD, N = 51), and schizoaffective disorder (SAD, N = 26).

RESULTS

ICV, TBV, and VV measures compared favorably with values obtained by other research groups, but in this study did not differ significantly between groups. TBV/ICV ratios were significantly decreased, and VBR increased, in the SZ and BD groups compared to the C group. The SAD group did not differ from C on any measure.

CONCLUSIONS

In this study TBV/ICV and VBR ratios separated SZ and BD patients from controls. Of interest however, SAD patients did not differ from controls on these measures. The findings suggest that the gross measure of TBV may not reliably differ in the major mental illnesses to a degree useful in diagnosis, likely due to the intrinsic variability of the measures in question; the differences in VBR appear more robust across studies. Differences in some of these findings compared to earlier reports from several laboratories finding significant differences between groups in VV and TBV may relate to phenomenological drift, differences in analytic techniques, and possibly the "file drawer problem".

Genetics and intermediate phenotypes of the schizophrenia--bipolar disorder boundary

Categorization of psychotic illnesses into schizophrenic and affective psychoses remains an ongoing controversy. Although Kraepelinian subtyping of psychosis was historically beneficial, modern genetic and neurophysiological studies do not support dichotomous conceptualization of psychosis. Evidence suggests that schizophrenia and bipolar disorder rather present a clinical continuum with partially overlapping symptom dimensions, neurophysiology, genetics and treatment responses. Recent large scale genetic studies have produced inconsistent findings and exposed an urgent need for re-thinking phenomenology-based approach in psychiatric research. Epidemiological, linkage and molecular genetic studies, as well as studies in intermediate phenotypes (neurocognitive, neurophysiological and anatomical imaging) in schizophrenia and bipolar disorders are reviewed in order to support a dimensional conceptualization of psychosis. Overlapping and unique genetic and intermediate phenotypic signatures of the two psychoses are comprehensively recapitulated. Alternative strategies which may be implicated into genetic research are discussed.

Research applications of magnetic resonance spectroscopy to investigate psychiatric disorders

Advances in magnetic resonance spectroscopy (MRS) methodology and related analytic strategies allow sophisticated testing of neurobiological models of disease pathology in psychiatric disorders. An overview of principles underlying MRS, methodological considerations, and investigative approaches is presented. A review of recent research is presented that highlights innovative approaches applying MRS, in particular, hydrogen MRS, to systematically investigate specific psychiatric disorders, including autism spectrum disorders, schizophrenia, panic disorder, major depression, and bipolar disorder.

Magnetic resonance imaging studies in early onset bipolar disorder: an updated review

Over the past 5-10 years, advances in neuroimaging methods and study designs have begun to appear in the literature of early-onset bipolar disorder (onset before 18 years of age). This article contains an updated review of the literature regarding neuroimaging in youths with bipolar disorder (BPD), highlighting important new study designs and techniques. Overall, structural, functional (fMRI) and magnetic resonance spectroscopy (MRS) report consistent abnormalities in regions of the frontal lobe and limbic structures. Functional MRI and MRS studies also frequently report striatal and thalamic abnormalities in early-onset BPD. Future neuroimaging studies in youths with BPD should include longitudinal studies incorporating multimodal neuroimaging techniques.

Galantamine-ER for cognitive dysfunction in bipolar disorder and correlation with hippocampal neuronal viability: a proof-of-concept study

BACKGROUND

Many subjects with bipolar disorder experience significant cognitive dysfunction, even when euthymic, but few studies assess biological correlates of or treatment strategies for cognitive dysfunction.

METHOD

Nineteen subjects with bipolar disorder in remission, who reported subjective cognitive deficits, were treated with open-label galantamine-ER 8-24 mg/day for 4 months. Ten healthy volunteers matched for age and gender were also assessed. Mood and subjective cognitive questionnaires were administered monthly. At the beginning and the end of the trial all subjects were administered neuropsychological tests, including tests of attention (Conners CPT) and episodic memory (CVLT). Bipolar subjects underwent proton magnetic resonance spectroscopy (1H-MRS) measurements before and after treatment, healthy volunteers completed baseline 1H-MRS. We acquired 1H-MRS data at 4.0 T from voxels centered on the left and right hippocampus to measure hippocampal N-acetyl aspartate (NAA, a measure of neuronal viability) and choline containing compounds (Cho, a marker of lipid metabolism and membrane turn-over).

RESULTS

Compared to healthy volunteers, bipolar subjects had higher baseline subjective cognitive deficits and lower scores on objective tests of attention (Conner's CPT) and verbal episodic memory (CVLT). After treatment, bipolar subjects experienced significant improvement of subjective cognitive scores and on objective tests of attention (Conner's CPT) and verbal episodic memory (CVLT). In the left hippocampus NAA increased and choline (Cho) decreased in bipolar subjects during treatment.

CONCLUSION

Bipolar subjects had cognitive dysfunction; treatment with Galantamine-ER was associated with improved cognition and with increases in neuronal viability and normalization of lipid membrane metabolism in the left hippocampus. This study was registered on ClinicalTrials.gov (NCT00181636).

Progression of brain volume changes in adolescent-onset psychosis

Little is known about the changes that take place in the adolescent brain over the first few years following the onset of psychosis. The present longitudinal study builds on an earlier cross-sectional report demonstrating brain abnormalities in adolescent-onset psychosis patients with a recent-onset first episode of psychosis. Magnetic resonance imaging studies were obtained at baseline and 2 years later from 21 adolescents with psychosis and 34 healthy controls matched for age, gender, and years of education. Whole-brain volumes and gray matter (GM) and cerebrospinal fluid (CSF) volumes of the frontal, parietal, temporal, and occipital lobes were measured at baseline and at 2-year follow-up. In the frontal lobe, the rate of GM volume loss was significantly higher in male patients (2.9% and 2.0%, respectively, for left and right) than in controls (1.2% and 0.7%, respectively, for left and right). In the left frontal lobe, male patients showed a significantly higher rate of CSF volume increase than controls (8.6% vs 6.4%). These differences in rates of volume change were observed in male and female patients, although only males showed significant time x diagnosis interactions. This negative finding in females should be interpreted with caution as the study was underpowered to detect change in women due to limited sample size. An exploratory analysis revealed that schizophrenia and nonschizophrenia psychotic disorders showed similar volume change patterns relative to controls. Change in clinical status was not correlated with longitudinal brain changes. Our results support progression of frontal lobe changes in males with adolescent-onset psychosis.

Neural bases of emotional processing in pediatric bipolar disorder

Pediatric bipolar disorder (PBD) presents with severe affect dysregulation characterized by elated mood, irritability and depressive symptoms, often in the form of a mixed episode. Early recognition of the external clinical features and the underlying emotional processing circuitry will help us understand the neurobiological underpinnings of this disorder and offer innovative ideas for early intervention.

METHODS

A 5-year review was conducted in structural and functional imaging studies in PBD that are potentially relevant to the emotional processing in PBD.

RESULTS

The ventral frontolimbic circuitry and the dorsal frontostriatal circuitry appear to be involved in affect regulation, with the ventral circuitry being more directly involved in emotion processing. The associated and interlinked circuits include the facial emotion-processing circuit and the association circuit between the occipital and the limbic regions responsible for automatic processing of emotions.

CONCLUSION

While we are at a preliminary stage in understanding the neural circuitry behind emotional processing, there appears to be a top-down regulation of affect with prefrontal systems modulating subcortical structures such as the amygdala and the ventral striatum. Structural and connectivity studies support the functional studies findings, providing a cogent model for understanding emotion-processing circuits involving corticosubcortical neural systems. Functional studies with PBD patients are beginning to demonstrate the dysfunction in the affective and cognitive circuits that work in concert.

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.

Neuroanatomical characterization of child offspring of bipolar parents

OBJECTIVE

To examine structural differences in selected anterior limbic brain regions between at-risk children of parents with bipolar I disorder and children with healthy parents. We hypothesized that at-risk (AR) children would exhibit abnormalities in brain regions that are involved in mood regulation.

METHOD

Children (8-12 years old) of parents with bipolar I disorder (AR children, n = 21) and of parents without any DSM-IV Axis I disorder (healthy controls, n = 24) were evaluated using diagnostic assessments and brain magnetic resonance imaging. Morphometric analyses were used to examine group differences in the prefrontal cortical, thalamic, striatal, and amygdalar volumes.

RESULTS

Nine (43%) of the AR children met DSM-IV-TR criteria for a nonbipolar mood disorder at the time of assessment. AR and healthy control children did not demonstrate statistically significant differences across regions of interest (Wilks lambda =.86, F4,39 = 1.64, p = .18; effect size, f = 0.19). Post hoc analyses of covariance showed the largest relative effect size was contributed by the prefrontal cortex (f = 0.26).

CONCLUSIONS

Eight- to 12-year-old children with a familial risk for mania do not exhibit any statistically significant volumetric differences in the prefrontal cortex, thalamus, striatum, or amygdala as compared with age-matched children of parents without any psychopathology. Longitudinal studies examining whether structural changes over time may be associated with vulnerability for developing subsequent bipolar disorder are needed to clarify the underlying pathophysiology of this disorder.

Pediatric bipolar disorder: validity, phenomenology, and recommendations for diagnosis

OBJECTIVE

To find, review, and critically evaluate evidence pertaining to the phenomenology of pediatric bipolar disorder and its validity as a diagnosis.

METHODS

The present qualitative review summarizes and synthesizes available evidence about the phenomenology of bipolar disorder (BD) in youths, including description of the diagnostic sensitivity and specificity of symptoms, clarification about rates of cycling and mixed states, and discussion about chronic versus episodic presentations of mood dysregulation. The validity of the diagnosis of BD in youths is also evaluated based on traditional criteria including associated demographic characteristics, family environmental features, genetic bases, longitudinal studies of youths at risk of developing BD as well as youths already manifesting symptoms on the bipolar spectrum, treatment studies and pharmacologic dissection, neurobiological findings (including morphological and functional data), and other related laboratory findings. Additional sections review impairment and quality of life, personality and temperamental correlates, the clinical utility of a bipolar diagnosis in youths, and the dimensional versus categorical distinction as it applies to mood disorder in youths.

RESULTS

A schema for diagnosis of BD in youths is developed, including a review of different operational definitions of 'bipolar not otherwise specified.' Principal areas of disagreement appear to include the relative role of elated versus irritable mood in assessment, and also the limits of the extent of the bipolar spectrum--when do definitions become so broad that they are no longer describing 'bipolar' cases?

CONCLUSIONS

In spite of these areas of disagreement, considerable evidence has amassed supporting the validity of the bipolar diagnosis in children and adolescents.

Limbic structures and networks in children and adolescents with schizophrenia

Studies of adults with schizophrenia provide converging evidence for abnormalities in the limbic system. Limbic structures that show consistent patient/control differences in both postmortem and neuroimaging studies include the anterior cingulate and hippocampus, although differences in the amygdala, parahippocampal gyrus, and fornix have also been observed. Studies of white matter in children and adolescents with schizophrenia tend to show findings that are more focal than those seen in adults. Interestingly, these focal abnormalities in early-onset schizophrenia tend to be more localized to limbic regions. While it is unclear if these early limbic abnormalities are primary in the etiology of schizophrenia, there is evidence that supports a developmental progression with early limbic abnormalities evolving over time to match the neuroimaging profiles seen in adults with schizophrenia. Alternatively, the aberrations in limbic structures may be secondary to a more widespread or global pathological processes occurring with the brain that disrupt neural transmission. The goal of this article is to provide a review of the limbic system and limbic network abnormalities reported in children and adolescents with schizophrenia. These findings are compared with the adult literature and placed within a developmental context. These observations from neuroimaging studies enrich our current understanding of the neurodevelopmental model of schizophrenia and raise further questions about primary vs secondary processes. Additional research within a developmental framework is necessary to determine the putative etiologic roles for limbic and other brain abnormalities in early-onset schizophrenia.

Findings of proton magnetic resonance spectometry in the dorsolateral prefrontal cortex in adolescents with first episodes of psychosis

Knowledge of the neurobiology of early onset psychosis is limited. We used proton magnetic resonance spectroscopy to investigate the possible existence of dorsolateral prefrontal brain biochemical abnormalities in adolescents with psychosis and to determine possible differential effects related to specific psychotic diagnoses. We measured the ratios of N-acetyl-aspartate (NAA), choline (Cho), and creatine (Cr) to water in two groups of adolescents with a first episode of psychosis (schizophrenia n=8; non-schizophrenia n=15) and in 32 healthy controls matched for age, gender, and years of education. Proton magnetic resonance spectroscopy at 1.5 T was used to study two 6.75-cc voxels placed in the left and right dorsolateral prefrontal region. The schizophrenia patients presented statistically significant reductions in NAA/water levels in the left dorsolateral prefrontal voxel as compared with non-schizophrenia patients and healthy controls. No significant differences were detected between groups for NAA/water in the right dorsolateral prefrontal voxel or for Cho/water and Cr/water levels in any hemisphere. A reduction of the NAA/water level in the left dorsolateral prefrontal region may be selectively present at the onset of psychosis during adolescence in patients who later progress to schizophrenia, but not in those who later progress to other psychotic disorders.

Dynamic mapping of cortical development before and after the onset of pediatric bipolar illness

BACKGROUND

There are, to date, no pre-post onset longitudinal imaging studies of bipolar disorder at any age. We report the first prospective study of cortical brain development in pediatric bipolar illness for 9 male children, visualized before and after illness onset.

METHOD

We contrast this pattern with that observed in a matched group of healthy children as well as in a matched group of 8 children with 'atypical psychosis' who had similar initial presentation marked by mood dysregulation and transient psychosis (labeled as 'multi-dimensionally impaired' (MDI)) as in the bipolar group, but have not, to date, developed bipolar illness.

RESULTS

Dynamic maps, reconstructed by applying novel cortical pattern matching algorithms, for the children who became bipolar I showed subtle, regionally specific, bilaterally asymmetrical cortical changes. Cortical GM increased over the left temporal cortex and decreased bilaterally in the anterior (and sub genual) cingulate cortex. This was seen most strikingly after the illness onset, and showed a pattern distinct from that seen in childhood onset schizophrenia. The bipolar neurodevelopmental trajectory was generally shared by the children who remained with MDI diagnosis without converting to bipolar I, suggesting that this pattern of cortical development may reflect affective dysregulation (lability) in general.

CONCLUSIONS

These dynamic trajectories of cortical development may explain age-related disparate findings from cross-sectional studies of bipolar illness, and suggest the importance of mood disordered non-bipolar control group in future studies.

Increased rates of bipolar disorder diagnoses among U.S. child, adolescent, and adult inpatients, 1996-2004

BACKGROUND

Volatile, aggressive behavior is the chief complaint that brings children to inpatient psychiatric care. These difficulties are increasingly conceptualized as bipolar disorder (BD). The impact of doing so on clinical diagnoses in clinical care is uncertain.

METHODS

We extracted records from the annual National Hospital Discharge Survey (NHDS) for which a psychiatric diagnosis was primary and examined trends in the rates of hospitalization for BD.

RESULTS

Population-adjusted rates of hospital discharges of children with a primary diagnosis of BD increased linearly over survey years. The rate in 1996 was 1.3 per 10,000 U.S. children and climbed to 7.3 per 10,000 U.S. children in 2004. Bipolar disorder related discharges also increased fourfold among adolescents. Adults showed a more modest, though still marked, rise of 56%. Bipolar disorder related hospitalization was more prevalent among female adolescents and adults, while male children had larger risk than female children. Children's BD diagnoses tended not to specify a prevailing mood state, while depression and psychotic features were the most common codes for adults. Black individuals, especially men, had lower rates of BD diagnoses in early survey years, but more recently their rate of BD related hospitalizations has exceeded other NHDS race groups.

CONCLUSIONS

Higher rates of inpatient admissions among youth associated with BD may reflect greater appreciation of the importance of affective dysregulation in this patient group or "upcoding" to putatively more severe conditions for reimbursement or administrative reasons. Further study is warranted to examine this shift's causes and implications for treatments and outcomes.

Bipolar disorder: how far are we from a rigorous definition and effective management?

Bipolar disorder is a pathological disturbance of mood, characterized by waxing and waning manic, depressive and, sometimes distinctly mixed states. A diagnosis of bipolar disorder can only be made with certainty when the manic syndrome declares itself. Most individuals who are diagnosed with this disorder will experience both poles of the illness recurrently, but depressive episodes are the commonest cause of morbidity and, indeed, of death by suicide. Twin, adoption and epidemiological studies suggest a strongly genetic aetiology. It is a genetically and phenotypically complex disorder. Thus, the genes contributing are likely to be numerous and of small effect. Individuals with bipolar disorder also display deficits on a range of neuropsychological tasks in both the acute and euthymic phases of illness and correlations between number of affective episodes experienced and task performance are commonly reported. Current self-report and observer-rated scales are optimized for unipolar depression and hence limited in their ability to accurately assess bipolar depression. The development of a specific depression rating scale will improve the assessment of bipolar depression in both research and clinical settings. It will improve the development of better treatments and interventions. Guidelines support the use of antidepressants for bipolar depression. With regard to the adverse effects of antidepressants for bipolar depression, double-blind, placebo-controlled data suggest that antidepressant monotherapy or the addition of a tricyclic antidepressant may worsen the course of bipolar disorder. Importantly, adjunctive psychotherapies add significantly (both statistically and clinically) to the efficacy of pharmacological treatment regimens. The successful management of bipolar disorder clearly demands improved recognition of bipolar disorder and effective long-term treatment for bipolar depression as well as mania.

The occurrence of cavum septi pellucidi enlargement is increased in bipolar disorder patients

OBJECTIVES

This study was conducted to evaluate the prevalence of cavum septi pellucidi (CSP) enlargement in patients with bipolar disorder (BD) and healthy comparison subjects.

METHODS

The occurrence of enlarged CSP in patients with BD (n = 41, age 35.4 +/- 10.8 years) and healthy volunteers (n = 41, age 35.3 +/- 10.0 years) was studied using magnetic resonance imaging. The length of the CSP was measured by counting the number of consecutive resliced coronal 0.5-mm images in which the CSP was present. A CSP length > or = 6 mm was a priori defined as abnormal enlargement of the CSP.

RESULTS

Bipolar subjects exhibited a significantly higher prevalence of abnormal CSP enlargement (8 of 41 subjects, 19.5%) than healthy comparison subjects (1 of 41 subjects, 2.4%) (logistic regression analysis: Wald statistic = 5.07, df = 1, p = 0.024). The prevalence of abnormally enlarged CSP was not significantly different between drug-naïve and drug-exposed bipolar subjects or when comparing bipolar I and II sub-diagnoses. Bipolar subjects with abnormal CSP enlargement had a significantly earlier onset of BD than those without (14.3 +/- 3.6 versus 20.1 +/- 7.4 years, respectively).

CONCLUSIONS

The current study is the first to report an increased prevalence of abnormally enlarged CSP in a well-characterized bipolar population. Our finding that an abnormal enlargement of CSP, a neurodevelopmental abnormality, is associated with early onset of illness implicates early maturational processes as contributing to BD.

Hippocampal CA1 pyramidal cell size is reduced in bipolar disorder

1. Schizophrenia and bipolar disorder are neurodevelopmental disorders with significant genetic vulnerabilities. Several trophic genes and/or proteins have been implicated in the causation for both disorders.2. We hypothesized that these genes and/or proteins may impact neuronal growth in both disorders.3. Hippocampal tissue sections from CA1 area of schizophrenic, bipolar, depressed, and controls subjects, matched for age, sex, PMI, drug exposure, and brain pH were prepared for cell size determination using the Stanley Medical Research Foundation postmortem brain collection.4. Quantification of hippocampal CA1 pyramidal neuron size showed a significant 12% reduction in cell size (p < 0.05) in bipolar subjects vs. controls. There were nonsignificant trends for reduction in cell size in both schizophrenic and depressed subjects vs. controls.5. These results indicate for the first time that pyramidal cell atrophy is present in hippocampus of subjects with bipolar disorder.

A cognitive vulnerability-stress perspective on bipolar spectrum disorders in a normative adolescent brain, cognitive, and emotional development context

Why is adolescence an "age of risk" for onset of bipolar spectrum disorders? We discuss three clinical phenomena of bipolar disorder associated with adolescence (adolescent age of onset, gender differences, and specific symptom presentation) that provide the point of departure for this article. We present the cognitive vulnerability-transactional stress model of unipolar depression, evidence for this model, and its extension to bipolar spectrum disorders. Next, we review evidence that life events, cognitive vulnerability, the cognitive vulnerability-stress combination, and certain developmental experiences (poor parenting and maltreatment) featured in the cognitive vulnerability-stress model play a role in the onset and course of bipolar disorders. We then discuss how an application of the cognitive vulnerability-stress model can explain the adolescent age of onset, gender differences, and adolescent phenomenology of bipolar disorder. Finally, we further elaborate the cognitive vulnerability-stress model by embedding it in the contexts of normative adolescent cognitive (executive functioning) and brain development, normative adolescent development of the stress-emotion system, and genetic vulnerability. We suggest that increased brain maturation and accompanying increases in executive functioning along with augmented neural and behavioral stress-sensitivity during adolescence combine with the cognitive vulnerability-stress model to explain the high-risk period for onset of bipolar disorder, gender differences, and unique features of symptom presentation during adolescence.

Structural brain abnormalities in early onset first-episode psychosis

BACKGROUND

Brain morphometry in children and adolescents with first-episode psychosis offer a unique opportunity for pathogenetic investigations.

METHODS

We compared high-resolution 3D T1-weighted magnetic resonance images of the brain in 29 patients (schizophrenia, schizotypal disorder, delusional disorder or other non-organic psychosis), aged 10-18 to those of 29 matched controls, using optimized voxel-based morphometry.

RESULTS

Psychotic patients had frontal white matter abnormalities, but expected (regional) gray matter reductions were not observed. Post hoc analyses revealed that schizophrenia patients (n = 15) had significantly larger lateral ventricles as compared to controls. Duration and dose of antipsychotics correlated negatively with global gray matter volume in minimally medicated patients (n = 18).

CONCLUSION

Findings of white matter changes and enlarged lateral ventricles already at illness onset in young schizophrenia spectrum patients, suggests aberrant neurodevelopmental processes in the pathogenesis of these disorders. Gray matter volume changes, however, appear not to be a key feature in early onset first-episode psychosis.

Classification of adolescent psychotic disorders using linear discriminant analysis

BACKGROUND

The differential diagnosis between schizophrenia and bipolar disorder during adolescence presents a major clinical problem. Can these two diagnoses be differentiated objectively early in the courses of illness?

METHODS

We used linear discrimination analysis (LDA) to classify 28 adolescent subjects into one of three diagnostic categories (healthy, N=8; schizophrenia, N=10; bipolar, N=10) using subsets from a pool of 45 variables as potential predictors (22 neuropsychological test scores and 23 quantitative structural brain measurements). The predictor variables were adjusted for age, gender, race, and psychotropic medication. All possible subsets composed of k=2-12 variables, from the set of 45 variables available, were evaluated using the robust leaving-one-subject-out method.

RESULTS

The highest correct classification (96%) of the 3 diagnostic categories was yielded by 9 sets of k=12 predictors, comprising both neuropsychological and brain structural measures. Although each one of these sets misclassified one case, each set correctly classified (100%) at least one group, such that a fully correct diagnosis could be reached by a tree-type decision procedure.

CONCLUSIONS

We conclude that LDA with 12 predictor variables can provide correct and robust classification of subjects into the three diagnostic categories above. This robust classification relies upon both neuropsychological and brain structural information. Our results demonstrate that, despite overlapping clinical symptoms, schizophrenia and bipolar disorder can be differentiated early in the course of disease. This finding has two important implications. Firstly, schizophrenia and bipolar disorder are different illnesses. If schizophrenia and bipolar are dissimilar clinical manifestations of the same disease, we would not be able to use non-clinical information to classify ('diagnose') schizophrenia and bipolar disorder. Secondly, if this study's findings are replicated, brain structure (MRI) and brain function (neuropsychological) used together may be useful in the diagnosis of new patients.

The neurophysiology of childhood and adolescent bipolar disorder

INTRODUCTION

Children and adolescents with bipolar disorder often present with higher rates of mixed episodes, rapid cycling, and co-occurring attention-deficit/hyperactivity disorder than adults with bipolar disorder. It is unclear whether the differences in clinical presentation between youth and adults with bipolar disorder are due to differences in underlying etiologies or developmental differences in symptom manifestation. Neuroimaging studies of children and adolescents with bipolar disorder may clarify whether neurobiological abnormalities associated with early- and adult-onset bipolar disorder are distinct. Moreover, children and adolescents with bipolar disorder are typically closer to their illness onset than bipolar adults, providing a window of opportunity for identifying core neurobiological characteristics of the illness (ie, disease biomarkers) that are independent of repeated affective episodes and other confounding factors associated with illness course.

METHODS

Peer-reviewed publications of neuroimaging studies of bipolar children and adolescents were reviewed.

RESULTS

Structural, neurochemical, and neurofunctional abnormalities in prefrontal and medical temporal and subcortical limbic structures, including the striatum, amygdala, and possibly hippocampus, are present in children and adolescents with bipolar disorder.

CONCLUSION

Differences between neurobiological abnormalities in bipolar youth and adults as well as recommendations for future research directions are discussed.

Age, rapid-cycling, and pharmacotherapy effects on ventral prefrontal cortex in bipolar disorder: a cross-sectional study

BACKGROUND

Neuroimaging data suggest that deficits in ventral prefrontal cortex (VPFC) function in bipolar disorder (BD) progress during adolescence and young adulthood. However, the developmental trajectory of VPFC morphological abnormalities in BD is unknown. This study investigated potential age-dependent volume abnormalities in VPFC in BD.

METHODS

Thirty-seven individuals diagnosed with BD I (14 adolescents, 10 young adults and 13 older adults) and 56 healthy comparison subjects (HC) participated in imaging. Gray and white matter volumes of VPFC were measured using high-resolution structural magnetic resonance imaging (MRI). We used a mixed model, repeated measures analysis to examine VPFC volumes across age groups while co-varying for total brain volume. Potential effects of illness features including rapid-cycling and medication were explored.

RESULTS

VPFC volumes declined with age (p < .001). The diagnosis-by-age group interaction was significant (p = .01). Relative to HC subjects, VPFC gray and white matter volumes were significantly smaller in BD patients only in young adulthood (p = .04). In participants with BD, VPFC volumes were significantly smaller in participants with rapid-cycling than participants without rapid-cycling (p = .02). Conversely, current use of medication was associated with larger VPFC gray matter volumes (p = .005), independent of age.

CONCLUSIONS

These preliminary findings suggest the presence of a more rapid initial decline in VPFC volumes with age in adolescents and young adults with BD than HC. These findings also suggest that the rapid-cycling subtype of BD is associated with larger VPFC volume deficits than the non-rapid-cycling subtype, and that pharmacotherapy may have trophic or protective effects on VPFC volumes in BD patients.

Cortical gray matter differences identified by structural magnetic resonance imaging in pediatric bipolar disorder

OBJECTIVE

Few magnetic resonance imaging (MRI) studies of bipolar disorder (BPD) have investigated the entire cerebral cortex. Cortical gray matter (GM) volume deficits have been reported in some studies of adults with BPD; this study assessed the presence of such deficits in children with BPD.

METHODS

Thirty-two youths with DSM-IV BPD (mean age 11.2 +/- 2.8 years) and 15 healthy controls (HC) (11.2 +/- 3.0 years) had structured and clinical interviews, neurological examinations, neurocognitive testing, and MRI scanning on a 1.5 T GE Scanner. Image parcellation divided the neocortex into 48 gyral-based units per hemisphere, and these units were combined into frontal (FL), temporal (TL), parietal (PL), and occipital (OL) lobe volumes. Volumetric differences were examined using univariate linear regression models with alpha = 0.05.

RESULTS

Relative to controls, the BPD youth had significantly smaller bilateral PL, and left TL. Analysis of PL and TL gyri showed significantly smaller volume in bilateral postcentral gyrus, and in left superior temporal and fusiform gyri, while the parahippocampal gyri were bilaterally increased in the BPD group. Although the FL overall did not differ between groups, an exploratory analysis showed that the right middle frontal gyrus was also significantly smaller in the BPD group.

CONCLUSIONS

Children with BPD showed deficits in PL and TL cortical GM. Further analyses of the PL and TL found differences in areas involved in attentional control, facial recognition, and verbal and declarative memory. These cortical deficits may reflect early age of illness onset.

Structural neuroimaging in adolescents with a first psychotic episode

OBJECTIVE

The objective of the present study is to replicate findings in first-episode psychosis reporting a smaller volume in brain structures in a population with adolescent onset.

METHOD

Magnetic resonance imaging studies were performed on 23 psychotic adolescents (12-18 years old, 17 males, 6 females) consecutively admitted to an adolescent inpatient unit and on 37 normal controls (13-18 years, 23 males, 14 females) matched for age, sex, and years of education. Diagnosis was made at baseline on the basis of the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version and confirmed after 12 months of follow-up. Total brain volume and gray matter, white matter, and cerebrospinal fluid (CSF) volumes of the frontal, parietal, temporal, and occipital lobes were measured bilaterally using a segmentation method based on the Talairach grid system.

RESULTS

Male patients showed significantly larger volumes than did male controls in overall CSF and left frontal and right parietal sulci CSF. Male patients also showed significantly lower volumes of gray matter in the right and left frontal lobes. No significant volumetric differences were found in females. There were no differences between individuals with a diagnosis of schizophrenia at follow-up and the rest of the patients.

CONCLUSIONS

This study suggests that larger CSF and lower gray matter volumes in the frontal lobes may be a nonspecific vulnerability marker for psychosis in male adolescents.

Neuroanatomical abnormalities as risk factors for bipolar disorder

OBJECTIVE

Neuroimaging studies show structural brain abnormalities in bipolar patients. Some of the abnormalities may represent biological risk factors conveying vulnerability for the disease. This paper aims to identify neuroanatomical risk factors for bipolar disorder (BD).

METHODS

We reviewed magnetic resonance imaging (MRI) findings in populations in which the effects of the disease or treatment are minimal or where the chances of finding genetically coded risk factors shared within the families are increased. Such populations include unaffected relatives of bipolar patients, first-episode patients, children or adolescents with BD and patients with familial BD.

RESULTS

MEDLINE search revealed 30 relevant scientific papers. Abnormalities in the volume of the striatum, left hemispheric white matter, thalamus and anterior cingulate as well as quantitative MRI signal hyperintensities were identified already in unaffected relatives of bipolar patients. Subjects in the early stages of the disease showed volume changes of the ventricles, white matter, caudate, putamen, amygdala, hippocampus and the subgenual prefrontal cortex. Reduction in the subgenual prefrontal cortex volume was replicated in three of four studies in patients with familial BD.

CONCLUSIONS

Possible candidates for neuroanatomical risk factors for BD are volumetric abnormalities of the subgenual prefrontal cortex, striatum, white matter, and probably also the hippocampus and amygdala. Qualitative finding of white matter hyperintensities was already utilized as an endophenotype.

Fronto-limbic brain abnormalities in juvenile onset bipolar disorder

BACKGROUND

Advances in brain imaging techniques and cognitive neuropsychology have brought new possibilities for the in vivo study of the pathophysiology of neuropsychiatric disorders, including bipolar disorder (BD). Recently, such studies have been extended to the pediatric age range. Here we review the neuroimaging and neuropsychological studies conducted in BD children and adolescents.

METHODS

A review of the peer-reviewed published literature was conducted in Medline for the period of 1966 to April 2005.

RESULTS

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) studies suggest abnormalities in fronto-limbic structures in pediatric BD patients, similar to those found in adults. A notable exception in pediatric BD patients is smaller amygdala volumes compared to healthy controls, contrary to what has been reported in most adult studies.

CONCLUSIONS

Further research evaluating children and adolescents is needed to study the normal neurodevelopmental process and to answer how and when the illness processes that result in bipolar disorder exert their effects on the developing brain.

Pediatric bipolar disorder: a review of the past 10 years

OBJECTIVE

To review the literature of the past decade covering the epidemiology, clinical characteristics, assessment, longitudinal course, biological and psychosocial correlates, and treatment and prevention of pediatric bipolar disorder (BD).

METHOD

A computerized search for articles published during the past 10 years was made and selected studies are presented.

RESULTS

Pediatric BD is increasingly recognized, and there are several prevailing views on core features of this disorder. The incidence and prevalence of the disorder and the associated comorbidities vary according to study setting and criteria used. This disorder is highly recurrent and accompanied by substantial psychiatric and psychosocial morbidity. Familial studies, including "top down" (offspring of parents with BD) and "bottom up" (relatives of youths with BD) studies indicate that pediatric BD is aggregated in families with adult or later-onset BD and suggest the existence of genetic predisposition. Greater understanding of the risk factors for early onset BD and recognition of the phenomenology of prodromal symptoms offers hope for early identification and prevention. Neuroimaging studies indicate frontotemporal and frontostriatal pathology, but none of these findings seems to be disorder specific. Combination pharmacotherapies appear promising, and the field awaits further short- and long-term randomized, placebo-controlled trials. Preliminary studies of various psychotherapies, including psychoeducation strategies tailored specifically for BD in youths, look encouraging.

CONCLUSIONS

Considerable advances have been made in our knowledge of pediatric BD; however, differing viewpoints on the clinical presentation of BD in children are the rule. Phenomenological and longitudinal studies and biological validation using genetic, neurochemical, neurophysiological, and neuroimaging methods may strengthen our understanding of the phenocopy. Randomized, controlled treatment studies for the acute and maintenance treatment of BD disorder are warranted.

Cortical magnetic resonance imaging findings in familial pediatric bipolar disorder

BACKGROUND

Morphometric magnetic resonance imaging (MRI) studies of pediatric bipolar disorder (BD) have not reported on gray matter volumes but have reported increased lateral ventricular size and presence of white matter hyperintensities (WMH). We studied gray matter volume, ventricular-to-brain ratios (VBR), and number of WMH in patients with familial, pediatric BD compared with control subjects.

METHODS

Twenty subjects with BD (aged 14.6 +/- 2.8 years; 4 female) according to the Washington University in St. Louis Kiddie Schedule for Affective Disorders and Schizophrenia, each with a parent with BD, and 20 age-, gender-, and intelligence quotient-matched healthy control subjects (aged 14.1 +/- 2.8 years; 4 female) were scanned at 3 T. Most subjects were taking psychotropic medications. A high-resolution T1-weighted spoiled gradient echo three-dimensional MRI sequence was analyzed by BrainImage for volumetric measurements, and T2-weighted images were read by a neuroradiologist to determine presence of WMH.

RESULTS

After covarying for age and total brain volume, there were no significant differences between subjects with BD and control subjects in volume of cerebral (p = .09) or prefrontal gray matter (p = .34). Subjects with BD did not have elevated numbers of WMH or greater VBR when compared with control subjects.

CONCLUSIONS

Children and adolescents with familial BD do not seem to have decreased cerebral grey matter or increased numbers of WMH, dissimilar to findings in adults with BD. Gray matter decreases and development of WMH might be later sequelae of BD or unique to adult-onset BD.

Neuropsychological dysfunction in bipolar affective disorder: a critical opinion

Data from the imaging literature have led to suggestions that permanent structural brain changes may be associated with bipolar disorder. Individuals diagnosed with bipolar disorder display deficits on a range of neuropsychological tasks in both the acute and euthymic phases of illness, and correlations between experienced number of affective episodes and task performance are commonly reported. These findings have renewed interest in the neuropsychological profile of individuals with bipolar disorder, with deficits of attention, learning and memory, and executive function, asserted to be present. This paper critically reviews five different potential causes of neurocognitive dysfunction in bipolar disorder: (i) iatrogenic, (ii) acute functional changes associated with depression or mania, (iii) permanent structural lesions of a neurodegenerative origin, (iv) permanent structural lesions that are neurodevelopmental in origin, and (v) permanent functional changes that are most likely genetic in origin. Although the potential cognitive effects of residual symptomatology and long-term medication use cannot be entirely excluded, we conclude that functional changes associated with genetically driven population variation in critical neural networks underpin both the neurocognitive and affective symptoms of bipolar disorder. The philosophical implications of this conclusion for neuropsychology are briefly discussed.

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.

When euthymia is just not good enough: the neuropsychology of bipolar disorder

Bipolar disorder (BD) is a debilitating psychiatric illness that is uniquely characterized by switching between psychopathologically contrasting phases of mania and depression, often with intervening periods of euthymia. However, these periods of apparent clinical recovery (euthymia) are marked by subtle social, occupational, and cognitive impairments, profiled by recent neuropsychological investigations. Determining the cognitive changes across these three phases may help differentiate the disruptions that are mood state-dependent from those associated with underlying pathology. This article therefore critically reviews the reported neuropsychological impairments in BD and the methodological limitations facing such research. Integration of the available evidence, principally from the field of neuropsychology, when synthesized, implicates the prefrontal cortex in the etiopathogenesis of BD and posits cortical-subcortical-limbic disruption in recovered euthymic patients that manifests as cognitive dysfunction.

Regional volume deviations of brain structure in schizophrenia and psychotic bipolar disorder: computational morphometry study

BACKGROUND

It is unclear whether schizophrenia and psychotic bipolar disorder are associated with similar deviations of brain morphometry.

AIMS

To assess volumetric abnormalities of grey and white matter throughout the entire brain in individuals with schizophrenia or with bipolar disorder compared with the same control group.

METHOD

Brain scans were obtained by magnetic resonance imaging from 25 people with schizophrenia, 37 with bipolar disorder who had experienced psychotic symptoms and 52 healthy volunteers. Regional deviation in grey and white matter volume was assessed using computational morphometry.

RESULTS

Individuals with schizophrenia had distributed grey matter deficit predominantly involving the fronto-temporal neocortex, medial temporal lobe, insula, thalamus and cerebellum, whereas those with bipolar disorder had no significant regions of grey matter abnormality. Both groups had anatomically overlapping white matter deficits in regions normally occupied by major longitudinal and interhemispheric tracts.

CONCLUSIONS

Schizophrenia and psychotic bipolar disorder are associated with distinct grey matter deficits but anatomically coincident white matter abnormalities.