Brain morphology in antipsychotic-naïve schizophrenia: A study of multiple brain structures

Alterations in the volume and shape of the basal ganglia and thalamus in schizophrenia with auditory hallucinations

Different lines of evidence indicate that the structure and physiology of the basal ganglia and the thalamus is disturbed in schizophrenia. However, it is unknown whether the volume and shape of these subcortical structures are affected in schizophrenia with auditory hallucinations (AH), a core positive symptom of the disorder. We took structural MRI from 63 patients with schizophrenia, including 36 patients with AH and 27 patients who had never experienced AH (NAH), and 51 matched healthy controls. We extracted volumes for the left and right thalamus, globus pallidus, putamen, caudate and nucleus accumbens. Shape analysis was also carried out. When comparing to controls, the volume of the right globus pallidus, thalamus, and putamen, was only affected in AH patients. The volume of the left putamen was also increased in individuals with AH, whereas the left globus pallidus was affected in both groups of patients. The shapes of right and left putamen and thalamus were also affected in both groups. The shape of the left globus pallidus was only altered in patients lacking AH, both in comparison to controls and to cases with AH. Lastly, the general PANSS subscale was correlated with the volume of the right thalamus, and the right and left putamen, in patients with AH. We have found volume and shape alterations of many basal ganglia and thalamus in patients with and without AH, suggesting in some cases a possible relationship between this positive symptom and these morphometric alterations.

The neurobiology of duration of untreated psychosis: a comprehensive review

Duration of untreated psychosis (DUP) is defined as the time from the onset of psychotic symptoms until the first treatment. Studies have shown that longer DUP is associated with poorer response rates to antipsychotic medications and impaired cognition, yet the neurobiologic correlates of DUP are poorly understood. Moreover, it has been hypothesized that untreated psychosis may be neurotoxic. Here, we conducted a comprehensive review of studies that have examined the neurobiology of DUP. Specifically, we included studies that evaluated DUP using a range of neurobiologic and imaging techniques and identified 83 articles that met inclusion and exclusion criteria. Overall, 27 out of the total 83 studies (32.5%) reported a significant neurobiological correlate with DUP. These results provide evidence against the notion of psychosis as structurally or functionally neurotoxic on a global scale and suggest that specific regions of the brain, such as temporal regions, may be more vulnerable to the effects of DUP. It is also possible that current methodologies lack the resolution needed to more accurately examine the effects of DUP on the brain, such as effects on synaptic density. Newer methodologies, such as MR scanners with stronger magnets, PET imaging with newer ligands capable of measuring subcellular structures (e.g., the PET ligand [11C]UCB-J) may be better able to capture these limited neuropathologic processes. Lastly, to ensure robust and replicable results, future studies of DUP should be adequately powered and specifically designed to test for the effects of DUP on localized brain structure and function with careful attention paid to potential confounds and methodological issues.

Advanced Brain-Age in Psychotic Psychopathology: Evidence for Transdiagnostic Neurodevelopmental Origins

Schizophrenia is characterized by abnormal brain structure such as global reductions in gray matter volume. Machine learning models trained to estimate the age of brains from structural neuroimaging data consistently show advanced brain-age to be associated with schizophrenia. Yet, it is unclear whether advanced brain-age is specific to schizophrenia compared to other psychotic disorders, and whether evidence that brain structure is "older" than chronological age actually reflects neurodevelopmental rather than atrophic processes. It is also unknown whether advanced brain-age is associated with genetic liability for psychosis carried by biological relatives of people with schizophrenia. We used the Brain-Age Regression Analysis and Computation Utility Software (BARACUS) prediction model and calculated the residualized brain-age gap of 332 adults (163 individuals with psychotic disorders: 105 schizophrenia, 17 schizoaffective disorder, 41 bipolar I disorder with psychotic features; 103 first-degree biological relatives; 66 controls). The model estimated advanced brain-ages for people with psychosis in comparison to controls and relatives, with no differences among psychotic disorders or between relatives and controls. Specifically, the model revealed an enlarged brain-age gap for schizophrenia and bipolar disorder with psychotic features. Advanced brain-age was associated with lower cognitive and general functioning in the full sample. Among relatives, cognitive performance and schizotypal symptoms were related to brain-age gap, suggesting that advanced brain-age is associated with the subtle expressions associated with psychosis. Exploratory longitudinal analyses suggested that brain aging was not accelerated in individuals with a psychotic disorder. In sum, we found that people with psychotic disorders, irrespective of specific diagnosis or illness severity, show indications of non-progressive, advanced brain-age. These findings support a transdiagnostic, neurodevelopmental formulation of structural brain abnormalities in psychotic psychopathology.

Strategies to solve the reverse inference fallacy in future MRI studies of schizophrenia: a review

Few advances in schizophrenia research have been translated into clinical practice, despite 60 years of serum biomarkers studies and 50 years of genetic studies. During the last 30 years, neuroimaging studies on schizophrenia have gradually increased, partly due to the beautiful prospect that the pathophysiology of schizophrenia could be explained entirely by the Human Connectome Project (HCP). However, the fallacy of reverse inference has been a critical problem of the HCP. For this reason, there is a dire need for new strategies or research "bridges" to further schizophrenia at the biological level. To understand the importance of research "bridges," it is vital to examine the strengths and weaknesses of the recent literature. Hence, in this review, our team has summarized the recent literature (1995-2018) about magnetic resonance imaging (MRI) of schizophrenia in terms of regional and global structural and functional alterations. We have also provided a new proposal that may supplement the HCP for studying schizophrenia. As postulated, despite the vast number of MRI studies in schizophrenia, the lack of homogeneity between the studies, along with the relatedness of schizophrenia with other neurological disorders, has hindered the study of schizophrenia. In addition, the reverse inference cannot be used to diagnose schizophrenia, further limiting the clinical impact of findings from medical imaging studies. We believe that multidisciplinary technologies may be used to develop research "bridges" to further investigate schizophrenia at the single neuron or neuron cluster levels. We have postulated about future strategies for overcoming the current limitations and establishing the research "bridges," with an emphasis on multimodality imaging, molecular imaging, neuron cluster signals, single transmitter biomarkers, and nanotechnology. These research "bridges" may help solve the reverse inference fallacy and improve our understanding of schizophrenia for future studies.

Parahippocampal area three gray matter is reduced in first-episode schizophrenia spectrum: Discovery and replication samples

Early course schizophrenia is associated with reduced gray matter. The specific structures affected first and how deficits impact symptoms and cognition remain unresolved. We used the Human Connectome Project multimodal parcellation (HCP‐MMP) to precisely identify cortical areas and investigate thickness abnormalities in discovery and replication samples of first‐episode schizophrenia spectrum individuals (FESz). In the discovery sample, T1w scans were acquired from 31 FESz and 31 matched healthy controls (HC). Thickness was calculated for 360 regions in Freesurfer. In the replication sample, high‐resolution T1w, T2w, and BOLD‐rest scans were acquired from 23 FESz and 32 HC and processed with HCP protocols. Thickness was calculated for regions significant in the discovery sample. After FDR correction (q < .05), left and right parahippocampal area 3 (PHA3) were significantly thinner in FESz. In the replication sample, bilateral PHA3 were again thinner in FESz (q < .05). Exploratory correlation analyses revealed left PHA3 was positively associated with hallucinations and right PHA3 was positively associated with processing speed, working memory, and verbal learning. The novel use of the HCP‐MMP in two independent FESz samples revealed thinner bilateral PHA3, suggesting this byway between cortical and limbic processing is a critical site of pathology near the emergence of psychosis.

Perspective on medication decisions following remission from first-episode psychosis

While antipsychotics (APs) could provide rapid relief of positive symptoms in psychotic disorders, their usage is often associated with side effects, stigma and inconveniences. For these and other reasons, many psychosis patients, particularly those of first-episode psychosis (FEP) in remission, wish to discontinue maintenance treatment. The current review aims to discuss the strategies of AP treatment following remission from FEP, with particular emphasis on the evaluation of outcomes following AP discontinuation. Upon review of relevant literature, three potential strategies are put forth for treatment-responsive, remitted FEP patients: a) life-long maintenance treatment, b) AP discontinuation during second year of treatment, or c) AP discontinuation after three years of treatment. In theory, the first strategy presents the safest option for maximal symptom control. However, a rigorous RCT indicates that if AP discontinuation is to be attempted, the third strategy best prevents poor long-term clinical outcomes. Further data is needed to address the costs and benefits of each treatment strategy, compare AP-free patients with those on different types of APs, as well as explore even longer-term outcomes.

Subcortical Brain Volume Abnormalities in Individuals With an At-risk Mental State

Previous structural magnetic resonance imaging studies of psychotic disorders have demonstrated volumetric alterations in subcortical (ie, the basal ganglia, thalamus) and temporolimbic structures, which are involved in high-order cognition and emotional regulation. However, it remains unclear whether individuals at high risk for psychotic disorders with minimal confounding effects of medication exhibit volumetric changes in these regions. This multicenter magnetic resonance imaging study assessed regional volumes of the thalamus, caudate, putamen, nucleus accumbens, globus pallidus, hippocampus, and amygdala, as well as lateral ventricular volume using FreeSurfer software in 107 individuals with an at-risk mental state (ARMS) (of whom 21 [19.6%] later developed psychosis during clinical follow-up [mean = 4.9 years, SD = 2.6 years]) and 104 age- and gender-matched healthy controls recruited at 4 different sites. ARMS individuals as a whole demonstrated significantly larger volumes for the left caudate and bilateral lateral ventricles as well as a smaller volume for the right accumbens compared with controls. In male subjects only, the left globus pallidus was significantly larger in ARMS individuals. The ARMS group was also characterized by left-greater-than-right asymmetries of the lateral ventricle and caudate nucleus. There was no significant difference in the regional volumes between ARMS groups with and without later psychosis onset. The present study suggested that significant volume expansion of the lateral ventricle, caudate, and globus pallidus, as well as volume reduction of the accumbens, in ARMS subjects, which could not be explained only by medication effects, might be related to general vulnerability to psychopathology.

Schizophrenia as a progressive brain disease

There is convincing evidence that schizophrenia is characterized by abnormalities in brain volume. At the Department of Psychiatry of the University Medical Centre Utrecht, Netherlands, we have been carrying out neuroimaging studies in schizophrenia since 1995. We focused our research on three main questions. First, are brain volume abnormalities static or progressive in nature? Secondly, can brain volume abnormalities in schizophrenia be explained (in part) by genetic influences? Finally, what environmental factors are associated with the brain volume abnormalities in schizophrenia?

Based on our findings we suggest that schizophrenia is a progressive brain disease. We showed different age-related trajectories of brain tissue loss suggesting that brain maturation that occurs in the third and fourth decade of life is abnormal in schizophrenia. Moreover, brain volume has been shown to be a useful phenotype for studying schizophrenia. Brain volume is highly heritable and twin and family studies show that unaffected relatives show abnormalities that are similar, but usually present to a lesser extent, to those found in the patients. However, also environmental factors play a role. Medication intake is indeed a confounding factor when interpreting brain volume (change) abnormalities, while independent of antipsychotic medication intake brain volume abnormalities appear influenced by the outcome of the illness.

In conclusion, schizophrenia can be considered as a progressive brain disease with brain volume abnormalities that are for a large part influenced by genetic factors. Whether the progressive volume change is also mediated by genes awaits the results of longitudinal twin analyses. One of the main challenges for the coming years, however, will be the search for gene-by-environment interactions on the progressive brain changes in schizophrenia.

Does Hippocampal Volume Predict Transition to Psychosis in a High-Risk Group? A Meta-Analysis

Schizophrenia has a prodromal phase of several years in most patients, making it possible to identify patients at clinical high risk (CHR) for developing the disorder. So far, these individuals are identified based on clinical criteria alone, and there is no reliable biomarker for predicting the transition to psychosis. It is well-established that reductions in brain volume, especially in the hippocampus, are associated with schizophrenia. Therefore, hippocampal volume may serve as a biomarker for psychosis. Several studies have already investigated hippocampal volume in CHR groups. Based on these studies, the present meta-analysis compares the baseline left and right hippocampal volume of CHR patients who developed a psychosis with that of CHR patients without such a transition. Our results show no statistically significant effect of the hippocampal volume on the transition risk for psychosis.

Variation in fourteen brain structure volumes in schizophrenia: A comprehensive meta-analysis of 246 studies

Despite hundreds of structural MRI studies documenting smaller brain volumes on average in schizophrenia compared to controls, little attention has been paid to group differences in the variability of brain volumes. Examination of variability may help interpret mean group differences in brain volumes and aid in better understanding the heterogeneity of schizophrenia. Variability in 246 MRI studies was meta-analyzed for 13 structures that have shown medium to large mean effect sizes (Cohen's d≥0.4): intracranial volume, total brain volume, lateral ventricles, third ventricle, total gray matter, frontal gray matter, prefrontal gray matter, temporal gray matter, superior temporal gyrus gray matter, planum temporale, hippocampus, fusiform gyrus, insula; and a control structure, caudate nucleus. No significant differences in variability in cortical/subcortical volumes were detected in schizophrenia relative to controls. In contrast, increased variability was found in schizophrenia compared to controls for intracranial and especially lateral and third ventricle volumes. These findings highlight the need for more attention to ventricles and detailed analyses of brain volume distributions to better elucidate the pathophysiology of schizophrenia.

Cerebellar volume and cerebellocerebral structural covariance in schizophrenia: a multisite mega-analysis of 983 patients and 1349 healthy controls

Although cerebellar involvement across a wide range of cognitive and neuropsychiatric phenotypes is increasingly being recognized, previous large-scale studies in schizophrenia (SZ) have primarily focused on supratentorial structures. Hence, the across-sample reproducibility, regional distribution, associations with cerebrocortical morphology and effect sizes of cerebellar relative to cerebral morphological differences in SZ are unknown. We addressed these questions in 983 patients with SZ spectrum disorders and 1349 healthy controls (HCs) from 14 international samples, using state-of-the-art image analysis pipelines optimized for both the cerebellum and the cerebrum. Results showed that total cerebellar grey matter volume was robustly reduced in SZ relative to HCs (Cohens's d=-0.35), with the strongest effects in cerebellar regions showing functional connectivity with frontoparietal cortices (d=-0.40). Effect sizes for cerebellar volumes were similar to the most consistently reported cerebral structural changes in SZ (e.g., hippocampus volume and frontotemporal cortical thickness), and were highly consistent across samples. Within groups, we further observed positive correlations between cerebellar volume and cerebral cortical thickness in frontotemporal regions (i.e., overlapping with areas that also showed reductions in SZ). This cerebellocerebral structural covariance was strongest in SZ, suggesting common underlying disease processes jointly affecting the cerebellum and the cerebrum. Finally, cerebellar volume reduction in SZ was highly consistent across the included age span (16-66 years) and present already in the youngest patients, a finding that is more consistent with neurodevelopmental than neurodegenerative etiology. Taken together, these novel findings establish the cerebellum as a key node in the distributed brain networks underlying SZ.

Clinical correlates of hippocampus volume and shape in antipsychotic-naïve schizophrenia

While volume deficit of hippocampus is an established finding in schizophrenia, very few studies have examined large sample of patients without the confounding effect of antipsychotic treatment. Concurrent evaluation of hippocampus shape will offer additional information on the hippocampal aberrations in schizophrenia. In this study, we analyzed the volume and shape of hippocampus in antipsychotic-naïve schizophrenia patients (N=71) in comparison to healthy controls (N=82). Using 3-T MRI data, gray matter (GM) volume (anterior and posterior sub-divisions) and shape of the hippocampus were analyzed. Schizophrenia patients had significant hippocampal GM volume deficits (specifically the anterior sub-division) in comparison to healthy controls. There were significant positive correlations between anterior hippocampus volume and psychopathology scores of positive syndrome. Shape analyses revealed significant inward deformation of bilateral hippocampal surface in patients. In conclusion, our study findings add robust support for volume deficit in hippocampus in antipsychotic-naïve schizophrenia. Hippocampal shape deficits in schizophrenia observed in this study map to anterior CA1 sub-region. The differential relationship of anterior hippocampus (but not posterior hippocampus) with clinical symptoms is in tune with the findings in animal models. Further systematic studies are needed to evaluate the relationship between these hippocampal gray matter deficits with white matter and functional connectivity to facilitate understanding the hippocampal network abnormalities in schizophrenia.

Progressive disability and prefrontal shrinkage in schizophrenia patients with poor outcome: A 3-year longitudinal study

INTRODUCTION

Schizophrenia is a severe disabling disorder with heterogeneous illness courses. In this longitudinal study we characterized schizophrenia patients with poor and good outcome (POS, GOS), using functional and imaging metrics. Patients were defined in accordance to Keefe's criteria (i.e. Kraepelinian and non-Kraepelinian patients).

METHODS

35 POS patients, 35 GOS patients and 76 healthy controls (H) underwent clinical, functioning and magnetic resonance imaging (MRI) assessments twice over three years of follow-up. Information on psychopathology, treatment, disability (using the World Health Organization Disability Assessment Scale II, WHO-DAS-2) and prefrontal morphology was collected. Dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) were manually traced.

RESULTS

At baseline, subjects with POS showed significantly decreased right dorsolateral prefrontal cortex (DLPFC) white matter volumes (WM) compared to healthy controls and GOS patients (POS VS HC, p<0.001; POS vs GOS, p=0.03), with shrinkage of left DLPFC WM volumes at follow up (t=2.66, p=0.01). Also, POS patients had higher disability in respect to GOS subjects both at baseline and after 3years at the WHO-DAS-2 (p<0.05).

DISCUSSION

Our study supports the hypothesis that POS is characterized by progressive deficits in brain structure and in "real-life" functioning. These are particularly notable in the DLPFC.

Brain stem audiometry may supply markers for diagnostic and therapeutic control in psychiatry

The purpose of the present study is to try an alternative way of analyzing the ABR (Auditory Brainstem Response). The stimuli were complex sounds (c-ABR) as used in earlier studies. It was further aimed at corroborating earlier findings that this method can discriminate several neuropsychiatric states. Forty healthy control subjects, 26 subjects with the diagnosis schizophrenia (Sz) and 33 with ADHD (Attention deficit hyperactivity disorder) were recruited for the study. The ABRs were recorded. The analysis was based on calculation of areas of significantly group different time spans in the waves. Both latency and amplitude were thereby influential. The spans of differences were quantified for each subject in relation to the total area of the curve which made comparisons balanced. The results showed highly significant differences between the study groups. The results are important for future work on identifying markers for neuropsychiatric clinical use. To reach that goal calls for more extensive studies than this preliminary one.

New Insights into the Nature of Cerebellar-Dependent Eyeblink Conditioning Deficits in Schizophrenia: A Hierarchical Linear Modeling Approach

Evidence of cerebellar dysfunction in schizophrenia has mounted over the past several decades, emerging from neuroimaging, neuropathological, and behavioral studies. Consistent with these findings, cerebellar-dependent delay eyeblink conditioning (dEBC) deficits have been identified in schizophrenia. While repeated-measures analysis of variance is traditionally used to analyze dEBC data, hierarchical linear modeling (HLM) more reliably describes change over time by accounting for the dependence in repeated-measures data. This analysis approach is well suited to dEBC data analysis because it has less restrictive assumptions and allows unequal variances. The current study examined dEBC measured with electromyography in a single-cue tone paradigm in an age-matched sample of schizophrenia participants and healthy controls (N = 56 per group) using HLM. Subjects participated in 90 trials (10 blocks) of dEBC, during which a 400 ms tone co-terminated with a 50 ms air puff delivered to the left eye. Each block also contained 1 tone-alone trial. The resulting block averages of dEBC data were fitted to a three-parameter logistic model in HLM, revealing significant differences between schizophrenia and control groups on asymptote and inflection point, but not slope. These findings suggest that while the learning rate is not significantly different compared to controls, associative learning begins to level off later and a lower ultimate level of associative learning is achieved in schizophrenia. Given the large sample size in the present study, HLM may provide a more nuanced and definitive analysis of differences between schizophrenia and controls on dEBC.

Dorsal striatal volumes in never-treated patients with first-episode schizophrenia before and during acute treatment

BACKGROUND

Studies of pre-and post-treatment striatal volume in schizophrenia have reported conflicting results.

MATERIALS AND METHODS

We assessed dorsal striatal (caudate and putamen) volumes bilaterally in 22 never-treated, non-substance-abusing patients with first-episode schizophrenia or schizophreniform disorder and 23 healthy controls matched for age, sex and educational status. Patients received either risperidone or flupenthixol long acting injection and were compared by structural MRI with controls at weeks 0, 4 and 13. T1-weighted data on a 3T MRI scanner were obtained and images were reconstructed using FreeSurfer. Treatment outcome was assessed by changes in psychopathology, insight, functionality, cognitive performance and motor symptoms.

RESULTS

Caudate, but not putamen volumes was significantly larger in patients bilaterally at baseline (P=0.01). Linear mixed effects repeated measures found no significant group × time interactions for any of the regions. Caudate volume was not significantly associated with improvements in psychotic symptoms. Also, the findings of a regression model were inconsistent insofar as larger caudate volume was associated with less improvement in depression scores, greater improvement in functionality and greater improvement in verbal learning but less improvement in reasoning and problem solving (left caudate) and composite cognitive score (right caudate).

CONCLUSIONS

The increased caudate volumes prior to treatment are contrary to previous reports in never-treated patients with first-episode schizophrenia, and together with our failure to demonstrate volume changes related to acute treatment, call into question previous proposals that enlarged caudate volume is a consequence of antipsychotic treatment.

Dermatoglyphic correlates of hippocampus volume: Evaluation of aberrant neurodevelopmental markers in antipsychotic-naïve schizophrenia

Schizophrenia is a disorder of aberrant neurodevelopment is marked by abnormalities in brain structure and dermatoglyphic traits. However, the link between these two (i.e. dermatoglyphic parameters and brain structure) which share ectodermal origin and common developmental window has not been explored extensively. The current study examined dermatoglyphic correlates of hippocampal volume in antipsychotic-naïve schizophrenia patients in comparison with matched healthy controls. Ridge counts and asymmetry measures for palmar inter-digital areas (a-b, b-c, c-d) were obtained using high resolution digital scans of palms from 89 schizophrenia patients [M:F=48:41] and 48 healthy controls [M:F=30:18]. Brain scans were obtained for subset of subjects including 26 antipsychotic-naïve patients [M:F=13:13] and 29 healthy controls [M:F=19:10] using 3 T-MRI. Hippocampal volume and palmar ridge counts were measured by blinded raters with good inter-rater reliability using valid methods. Directional asymmetry (DA) of b-c and bilateral hippocampal volume were significantly lower in patients than controls. Significant positive correlation was found between DA and ridge count of b-c with bilateral anterior hippocampal volume. Study demonstrates the utility of dermatoglyphic markers in identifying structural changes in the brain which may form the basis for neurodevelopmental pathogenesis in schizophrenia.

Grey matter morphological anomalies in the caudate head in first-episode psychosis patients with delusions of reference

Delusions of reference (DOR) are theoretically linked with aberrant salience and associative learning. Previous studies have shown that the caudate nucleus plays a critical role in the cognitive circuits of coding prediction errors and associative learning. The current study aimed at testing the hypothesis that abnormalities in the caudate nucleus may be involved in the neuroanatomical substrate of DOR. Structural magnetic resonance imaging of the brain was performed in 44 first-episode psychosis patients (with diagnoses of schizophrenia or schizophreniform disorder) and 25 healthy controls. Patients were divided into three groups according to symptoms: patients with DOR as prominent positive symptom; patients with prominent positive symptoms other than DOR; and patients with minimal positive symptoms. All groups were age-, gender-, and education-matched, and patient groups were matched for diagnosis, duration of illness, and antipsychotic treatment. Voxel-based morphometric analysis was performed to identify group differences in grey matter density. Relationships were explored between grey matter density and DOR. Patients with DOR were found to have reduced grey matter density in the caudate compared with patients without DOR and healthy controls. Grey matter density values of the left and right caudate head were negatively correlated with DOR severity. Decreased grey matter density in the caudate nucleus may underlie DOR in early psychosis.

Minimal evidence that untreated psychosis damages brain structures: a systematic review

INTRODUCTION

A longer duration of untreated psychosis (DUP) is associated with poor outcomes in first-episode psychosis (FEP); however, it is unclear whether this is due to the effects of psychosis on brain structure. We systematically reviewed the literature on the association between the length of untreated psychosis and brain structure in first-episode psychosis.

METHODS

We searched three electronic databases and conducted forward and backward citation searching to identify relevant papers. Studies were included if they: (1) included patients with a psychotic disorder who were treatment naïve or minimally treated; and (2) had correlated measures of DUP or duration of untreated illness (DUI) with structural measures.

RESULTS

We identified 48 studies that met the inclusion criteria. Forty-three examined the correlation between DUP and brain structure, and 19 examined the correlation between DUI and brain structure. There was evidence of significant associations in brain regions considered important in psychosis; however, the proportion of significant associations was low and the findings were inconsistent across studies. The majority of included studies were not primarily designed to examine whether DUP/DUI is correlated with brain structure, and there were methodological limitations in many studies that prevent drawing a strong conclusion.

CONCLUSION

To date, there is minimal evidence of an association between untreated psychosis and brain structure in FEP. Although the body of literature is substantial, there are few hypothesis-driven studies with a primary objective to answer this question. Future studies should be specifically designed to examine whether untreated psychosis has a deleterious effect on brain structure.

Regional white matter abnormalities in drug-naive, first-episode schizophrenia patients and their healthy unaffected siblings

OBJECTIVE

Shared neuropathological features between schizophrenia patients and their siblings may represent intermediate phenotypes of schizophrenia and can be used to investigate genetic susceptibility to the illness. This study aimed to discover regional white matter abnormalities in first-episode schizophrenia (FES) patients and their unaffected siblings compared to healthy subjects in the Chinese Han population using optimized Voxel-Based Morphometry (VBM).

METHOD

A total of 51 drug-naive, FES patients, 45 of their unaffected siblings and 59 healthy comparisons were studied with magnetic resonance imaging (MRI).

RESULTS

FES patients exhibited significant regional white matter deficits in the left inferior frontal gyrus and left joint of external capsule and internal capsule compared with healthy subjects (corrected FDR, p<0.005). The sibling group also showed significant white matter deficits in these two regions compared with the healthy comparison group (uncorrected, p<0.001). White matter deficits with a less stringent threshold for significance in the left cerebellum anterior lobe, left middle frontal gyrus, left hippocampus, right anterior cingulate and right internal capsule were observed in patients compared to their siblings.

CONCLUSIONS

Our findings extend those from previous VBM analyses showing that FES patients and their unaffected siblings may share white matter deficits in the left inferior frontal gyrus and the left joint of external capsule and internal capsule. These regional white matter deficits may be related to genetic factors related to schizophrenia susceptibility.

Cerebellar volume in schizophrenia and bipolar I disorder with and without psychotic features

OBJECTIVE

There is growing evidence that cerebellum plays a crucial role in cognition and emotional regulation. Cerebellum is likely to be involved in the physiopathology of both bipolar disorder and schizophrenia. The objective of our study was to compare cerebellar size between patients with bipolar disorder, patients with schizophrenia, and healthy controls in a multicenter sample. In addition, we studied the influence of psychotic features on cerebellar size in patients with bipolar disorder.

METHOD

One hundred and fifteen patients with bipolar I disorder, 32 patients with schizophrenia, and 52 healthy controls underwent 3 Tesla MRI. Automated segmentation of cerebellum was performed using FreeSurfer software. Volumes of cerebellar cortex and white matter were extracted. Analyses of covariance were conducted, and age, sex, and intracranial volume were considered as covariates.

RESULTS

Bilateral cerebellar cortical volumes were smaller in patients with schizophrenia compared with patients with bipolar I disorder and healthy controls. We found no significant difference of cerebellar volume between bipolar patients with and without psychotic features. No change was evidenced in white matter.

CONCLUSION

Our results suggest that reduction in cerebellar cortical volume is specific to schizophrenia. Cerebellar dysfunction in bipolar disorder, if present, appears to be more subtle than a reduction in cerebellar volume.

Eyeblink Conditioning in Schizophrenia: A Critical Review

There is accruing evidence of cerebellar abnormalities in schizophrenia. The theory of cognitive dysmetria considers cerebellar dysfunction a key component of schizophrenia. Delay eyeblink conditioning (EBC), a cerebellar-dependent translational probe, is a behavioral index of cerebellar integrity. The circuitry underlying EBC has been well characterized by non-human animal research, revealing the cerebellum as the essential circuitry for the associative learning instantiated by this task. However, there have been persistent inconsistencies in EBC findings in schizophrenia. This article thoroughly reviews published studies investigating EBC in schizophrenia, with an emphasis on possible effects of antipsychotic medication and stimulus and analysis parameters on reports of EBC performance in schizophrenia. Results indicate a consistent finding of impaired EBC performance in schizophrenia, as measured by decreased rates of conditioning, and that medication or study design confounds do not account for this impairment. Results are discussed within the context of theoretical and neurochemical models of schizophrenia.

Impaired cerebellar-dependent eyeblink conditioning in first-degree relatives of individuals with schizophrenia

Consistent with reports of cerebellar structural, functional, and neurochemical anomalies in schizophrenia, robust cerebellar-dependent delay eyeblink conditioning (dEBC) deficits have been observed in the disorder. Impaired dEBC is also present in schizotypal personality disorder, an intermediate phenotype of schizophrenia. The present work sought to determine whether dEBC deficits exist in nonpsychotic first-degree relatives of individuals with schizophrenia. A single-cue tone dEBC paradigm consisting of 10 blocks with 10 trials each (9 paired and 1 unpaired trials) was used to examine the functional integrity of cerebellar circuitry in schizophrenia participants, individuals with a first-degree relative diagnosed with schizophrenia, and healthy controls with no first-degree relatives diagnosed with schizophrenia. The conditioned stimulus (a 400ms tone) coterminated with the unconditioned stimulus (a 50ms air puff to the left eye) on paired trials. One relative and 2 healthy controls were removed from further analysis due to declining conditioned response rates, leaving 18 schizophrenia participants, 17 first-degree relatives, and 16 healthy controls. Electromyographic data were subsequently analyzed using growth curve models in hierarchical linear regression. Acquisition of dEBC conditioned responses was significantly impaired in schizophrenia and first-degree relative groups compared with controls. This finding that cerebellar-mediated associative learning deficits are present in first-degree relatives of individuals with schizophrenia provides evidence that dEBC abnormalities in schizophrenia may not be due to medication or course of illness effects. Instead, the present results are consistent with models of schizophrenia positing cerebellar-cortical circuit abnormalities and suggest that cerebellar abnormalities represent a risk marker for the disorder.

A proposal for reframing schizophrenia research

The current schizophrenia concept is built on experts' agreement on the matter, and it is basically rooted in the epidemiological and clinical evidence. However, the numerous and intensive attempts to find the biological underpinnings of this syndrome face almost constantly a low degree of replication of the results. We have reviewed previously published work to contribute to identify some reasons underlying that failure. The difficulty in replicating biological findings in schizophrenia may relate to the intrinsic heterogeneity among patient samples, acquired through the current diagnostic criteria. As a result, the necessary replication for any finding to be accepted as characteristic data for schizophrenia would be impeded. Therefore, a new frame based on identification of correlates of the most replicated biological anomalies in schizophrenia to date may contribute to overcome those difficulties.

Disease and genetic contributions toward local tissue volume disturbances in schizophrenia: a tensor-based morphometry study

Structural brain deficits, especially frontotemporal volume reduction and ventricular enlargement, have been repeatedly reported in patients with schizophrenia. However, it remains unclear whether brain structural deformations may be attributable to disease-related or genetic factors. In this study, the structural magnetic resonance imaging data of 48 adult-onset schizophrenia patients, 65 first-degree nonpsychotic relatives of schizophrenia patients, 27 community comparison (CC) probands, and 73 CC relatives were examined using tensor-based morphometry (TBM) to isolate global and localized differences in tissue volume across the entire brain between groups. We found brain tissue contractions most prominently in frontal and temporal regions and expansions in the putamen/pallidum, and lateral and third ventricles in schizophrenia patients when compared with unrelated CC probands. Results were similar, though less prominent when patients were compared with their nonpsychotic relatives. Structural deformations observed in unaffected patient relatives compared to age-similar CC relatives were suggestive of schizophrenia-related genetic liability and were pronounced in the putamen/pallidum and medial temporal regions. Schizophrenia and genetic liability effects for the putamen/pallidum were confirmed by regions-of-interest analysis. In conclusion, TBM findings complement reports of frontal, temporal, and ventricular dysmorphology in schizophrenia and further indicate that putamen/pallidum enlargements, originally linked mainly with medication exposure in early studies, also reflect a genetic predisposition for schizophrenia. Thus, brain deformation profiles revealed in this study may help to clarify the role of specific genetic or environmental risk factors toward altered brain morphology in schizophrenia.

Brain volume reductions in medication-naive patients with schizophrenia in relation to intelligence quotient

BACKGROUND

Global brain abnormalities such as brain volume loss and grey- and white-matter deficits are consistently reported in first-episode schizophrenia patients and may already be detectable in the very early stages of the illness. Whether these changes are dependent on medication use or related to intelligence quotient (IQ) is still debated.

METHOD

Magnetic resonance imaging scans were obtained for 20 medication-naive patients with first-episode schizophrenia and 26 matched healthy subjects. Volume measures of total brain grey and white matter, third and lateral ventricles and cortical thickness/surface were obtained. Differences between the groups were investigated, taking into account the effect of intelligence.

RESULTS

Medication-naive patients showed statistically significant reductions in whole-brain volume and cerebral grey- and white-matter volume together with lateral ventricle enlargement compared to healthy subjects. IQ was significantly lower in patients compared to controls and was positively associated with brain and white-matter volume in the whole group. No significant differences in cortical thickness were found between the groups but medication-naive patients had a significantly smaller surface in the left superior temporal pole, Heschl's gyrus and insula compared to controls.

CONCLUSIONS

Our findings suggest that brain volume loss is present at illness onset, and can be explained by the reduced surface of the temporal and insular cortex. These abnormalities are not related to medication, but IQ.

Cerebellar-dependent eyeblink conditioning deficits in schizophrenia spectrum disorders

Accumulating evidence suggests that abnormalities in neural circuitry and timing associated with the cerebellum may play a role in the pathophysiology of schizophrenia. Schizotypal personality disorder (SPD) may be genetically linked to schizophrenia, but individuals with SPD are freer from potential research confounds and may therefore offer insight into psychophysiological correlates of schizophrenia. The present study employed a delay eyeblink conditioning (EBC) procedure to examine cerebellar-dependent learning in schizophrenia, SPD, and healthy control subjects (n = 18 per group) who were matched for age and gender. The conditioned stimulus was a 400-ms tone that coterminated with a 50 ms unconditioned stimulus air puff. Cognitive performance on the Picture Completion, Digit Symbol Coding, Similarities, and Digit Span subscales of the Wechsler Adult Intelligence Scale--Third Edition was also investigated. The schizophrenia and SPD groups demonstrated robust EBC impairment relative to the control subjects; they had significantly fewer conditioned responses (CRs), as well as smaller CR amplitudes. Schizophrenia subjects showed cognitive impairment across subscales compared with SPD and control subjects; SPD subjects showed intermediate performance to schizophrenia and control subjects and performed significantly worse than controls on Picture Completion. Impaired EBC was significantly related to decreased processing speed in schizophrenia spectrum subjects. These findings support the role of altered cortico-cerebellar-thalamic-cortical circuitry in the pathophysiology of schizophrenia spectrum disorders.

Imputation techniques for the detection of microstructural changes in schizophrenia, with an application to magnetization transfer imaging

Neuroimaging techniques such as magnetization transfer imaging allow the detection of microstructural alterations of tissue, and for this reason have been applied to the study of disorders such as schizophrenia. However, they are also sensitive to partial volume effects arising from mixed compartments, such as those comprising cerebral spinal fluid, which makes separate evaluation of volumetric and structural alterations difficult. Ensuing regional differences in the distribution of data and signal-to-noise ratio add further potential bias to their assessment. In the present study we simultaneously applied tissue segmentation, statistical imputation, and nonparametric inference to address these issues and improve the validity of statistical inference. In a case study of N=32 schizophrenic patients matched to the same number of controls, we compared a standard voxel-based analysis with one supplemented by the imputation technique. We were able to replicate significant results in the imputed analysis and even extend them in the areas not excluded by excessive partial volume effects. Application of segmentation algorithms in this dataset also suggested that partial volume effects from spinal fluid potentially affect inference in most cortical gray matter, unless remedial steps are undertaken. Refined imputation methods may be particularly attractive in future research settings characterized by large samples and the availability of adequate computational resources.

Different gray matter patterns in chronic schizophrenia and chronic bipolar disorder patients identified using voxel-based morphometry

Gray matter (GM) volume deficits have been described in patients with schizophrenia (Sz) and bipolar disorder (BD), but to date, few studies have directly compared GM volumes between these syndromes with methods allowing for whole-brain comparisons. We have used structural magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) to compare GM volumes between 38 Sz and 19 BD chronic patients. We also included 24 healthy controls. The results revealed a widespread cortical (dorsolateral and medial prefrontal and precentral) and cerebellar deficit as well as GM deficits in putamen and thalamus in Sz when compared to BD patients. Besides, a subcortical GM deficit was shown by Sz and BD groups when compared to the healthy controls, although a putaminal reduction was only evident in the Sz patients. In this comparison, the BD patients showed a limited cortical and subcortical GM deficit. These results support a partly different pattern of GM deficits associated to chronic Sz and chronic BD, with some degree of overlapping.

Brain volume changes after withdrawal of atypical antipsychotics in patients with first-episode schizophrenia

The influence of antipsychotic medication on brain morphology in schizophrenia may confound interpretation of brain changes over time. We aimed to assess the effect of discontinuation of atypical antipsychotic medication on change in brain volume in patients. Sixteen remitted, stable patients with first-episode schizophrenia, schizoaffective or schizophreniform disorder and 20 healthy controls were included. Two magnetic resonance imaging brain scans were obtained from all subjects with a 1-year interval. The patients either discontinued (n = 8) their atypical antipsychotic medication (olanzapine, risperidone, or quetiapine) or did not (n = 8) discontinue during the follow-up period. Intracranial volume and volumes of total brain, cerebral gray and white matter, cerebellum, third and lateral ventricle, nucleus caudatus, nucleus accumbens, and putamen were obtained. Multiple linear regression analyses were used to assess main effects for group (patient-control) and discontinuation (yes-no) for brain volume (change) while correcting for age, sex, and intracranial volume. Decrease in cerebral gray matter and caudate nucleus volume over time was significantly more pronounced in patients relative to controls. Our data suggest decreases in the nucleus accumbens and putamen volumes during the interval in patients who discontinued antipsychotic medication, whereas increases were found in patients who continued their antipsychotics. We confirmed earlier findings of excessive gray matter volume decrements in patients with schizophrenia compared with normal controls. We found evidence suggestive of decreasing volumes of the putamen and nucleus accumbens over time after discontinuation of medication. This might suggest that discontinuation reverses effects of atypical medication.

Progressive striatal and hippocampal volume loss in initially antipsychotic-naive, first-episode schizophrenia patients treated with quetiapine: relationship to dose and symptoms

First-generation antipsychotics have been associated with striatal volume increases. The effects of second-generation antipsychotics (SGAs) on the striatum are unclear. Moreover, SGAs may have neuroprotective effects on the hippocampus. Dose-dependent volumetric effects of individual SGAs have scarcely been investigated. Here we investigated structural brain changes in antipsychotic-naive, first-episode schizophrenia patients after 6 months treatment with the SGA, quetiapine. We have recently reported on baseline volume reductions in the caudate nucleus and hippocampus. Baseline and follow-up T1-weighted images (3 T) from 22 patients and 28 matched healthy controls were analysed using tensor-based morphometry. Non-parametric voxel-wise group comparisons were performed. Small volume correction was employed for striatum, hippocampus and ventricles. Dose-dependent medication effects and associations with psychopathology were assessed. Patients had significant bilateral striatal and hippocampal loss over the 6-month treatment period. When compared to controls the striatal volume loss was most pronounced with low quetiapine doses and less apparent with high doses. Post-hoc analyses revealed that the striatal volume loss was most pronounced in the caudate and putamen, but not in accumbens. Conversely, hippocampal volume loss appeared more pronounced with high quetiapine doses than with low doses. Clinically, higher baseline positive symptoms were associated with more striatal and hippocampal loss over time. Although patients' ventricles did not change significantly, ventricular increases correlated with less improvement of negative symptoms. Progressive regional volume loss in quetiapine-treated, first-episode schizophrenia patients may be dose-dependent and clinically relevant. The mechanisms underlying progressive brain changes, specific antipsychotic compounds and clinical symptoms warrant further research.

Gray matter in first-episode schizophrenia before and after antipsychotic drug treatment. Anatomical likelihood estimation meta-analyses with sample size weighting

BACKGROUND

Cerebral morphological abnormalities in schizophrenia may be modulated by treatment, chronicity, and duration of illness. Comparing brain imaging studies of individuals with first-episode schizophrenia and neuroleptic naive (NN-FES) with that of their neuroleptic-treated counterparts (NT-FES) can help to dissect out the effect of these potential confounders.

METHODS

We used the anatomical likelihood estimation method to compare voxel-based morphometric studies of NN-FES (n = 162 patients) and NT-FES (n = 336 patients) studies. The analysis included a sample size weighting step based on the Liptak-Stouffer method to reflect the greater power of larger studies.

RESULTS

Patient samples were matched for age, gender, and duration of illness. An extensive network of gray matter deficits in frontal, temporal, insular, striatal, posterior cingulate, and cerebellar regions was detected in the NN-FES samples as compared with healthy controls. Major deficits were detected in the frontal, superior temporal, insular, and parahippocampal regions for the NT-FES group compared with the NN-FES group. In addition, the NT-FES group showed minor deficits in the caudate, cingulate, and inferior temporal regions compared with the NN-FES group. There were no regions with gray matter volumetric excess in the NT-FES group.

CONCLUSION

Frontal, striato-limbic, and temporal morphological abnormalities are present in the early stage of schizophrenia and are unrelated to the effects of neuroleptic treatment, chronicity, and duration of illness. There may be dynamic effects of treatment on striato-limbic and temporal, but not frontal, regional gray matter volumes of the brain.

The contributions of disease and genetic factors towards regional cortical thinning in schizophrenia: the UCLA family study

OBJECTIVE

Cortical thickness reductions in prefrontal and temporal cortices have been repeatedly observed in patients with schizophrenia. However, it remains unclear whether regional variations in cortical thickness may be attributable to disease-related or genetic-liability factors.

METHOD

The structural magnetic resonance imaging data of 48 adult-onset schizophrenia patients, 66 first-degree non-psychotic relatives of schizophrenia patients, 27 community comparison (CC) probands and 77 CC relatives were examined using cortical pattern matching methods to map and compare highly localized changes in cortical gray matter thickness between groups defined by biological risk for schizophrenia.

RESULTS

Schizophrenia patients showed marked cortical thinning primarily in frontal and temporal cortices when compared to unrelated CC probands. Results were similar, though less pronounced when patients were compared with their non-psychotic relatives. Cortical thickness reductions observed in unaffected relatives compared to age-similar CC relatives suggestive of schizophrenia-related genetic liability were marginal, surviving correction for the left parahippocampal gyrus and inferior occipital cortex only.

CONCLUSIONS

Observations of pronounced fronto/temporal cortical thinning in schizophrenia patients replicate prior findings. The lack of marked cortical thickness alterations in non-psychotic relatives of patients, suggests that disease processes are primary contributors toward cortical thickness reductions in the disorder. However, genetic factors may have a larger influence on abnormalities in the medial temporal lobe.

A systematic review of the effects of antipsychotic drugs on brain volume

BACKGROUND

People with schizophrenia are often found to have smaller brains and larger brain ventricles than normal, but the role of antipsychotic medication remains unclear.

METHOD

We conducted a systematic review of magnetic resonance imaging (MRI) studies. We included longitudinal studies of brain changes in patients taking antipsychotic drugs and we examined studies of antipsychotic-naive patients for comparison purposes.

RESULTS

Fourteen out of 26 longitudinal studies showed a decline in global brain or grey-matter volume or an increase in ventricular or cerebrospinal fluid (CSF) volume during the course of drug treatment, including the largest studies conducted. The frontal lobe was most consistently affected, but overall changes were diffuse. One large study found different degrees of volume loss with different antipsychotics, and another found that volume changes were associated with taking medication compared with taking none. Analyses of linear associations between drug exposure and brain volume changes produced mixed results. Five out of 21 studies of patients who were drug naive, or had only minimal prior treatment, showed some differences from controls in volumes of interest. No global differences were reported in three studies of drug-naive patients with long-term illness. Studies of high-risk groups have not demonstrated differences from controls in global or lobar brain volumes.

CONCLUSIONS

Some evidence points towards the possibility that antipsychotic drugs reduce the volume of brain matter and increase ventricular or fluid volume. Antipsychotics may contribute to the genesis of some of the abnormalities usually attributed to schizophrenia.

Correlation analysis confirms differences in antioxidant defence in the blood of types I and II schizophrenic male patients treated with anti-psychotic medication

The activities of antioxidant defence enzymes were determined in erythrocytes isolated from types I and II schizophrenic male patients and from healthy controls. Significant differences in superoxide dismutase (SOD) activity (type I: 3284+/-577; type II: 2959+/-697 compared with controls: 3778+/-577; analysis of variance (ANOVA) P<0.001), catalase (CAT) activity (type I: 17.8+/-1.8 compared to type II: 19.2+/-1.5 and both compared with controls: 19.2+/-1.5; ANOVA P<0.05), glutathione peroxidase (GSH-Px) activity (controls: 17.8+/-2.3; type I: 13.9+/-2.9 and type II: 11.6+/-1.9; ANOVA P<0.001) as well as in glutathione reductase (GR) activity (controls: 5,0+/-0.8; type I: 4.3+/-0.9 and type II: 4.5+/-0.8; ANOVA P<0.01) were apparent. Correlation analysis of antioxidant defence enzymes showed significant negative correlation between GSH-Px and CAT activities (P<0.01) in type I patients. In type II patients, GSH-Px activity was significantly positively correlated with GR (P<0.01). Canonical discriminant analysis separated type I and type II patients from controls (and among each other) with a high degree of certainty according to the overall group composition of antioxidant defence enzymes. Our results indicate differences in the composition of antioxidant defence between controls and anti-psychotic treated type I and type II patients with a possible negative feedback influence on the pathological process, which could provide a rationale for applying antioxidants during schizophrenic therapy.

Maternal influenza infection during pregnancy impacts postnatal brain development in the rhesus monkey

BACKGROUND

Maternal infection with influenza and other pathogens during pregnancy has been associated with increased risk for schizophrenia and neurodevelopmental disorders. In rodent studies, maternal inflammatory responses to influenza affect fetal brain development. However, to verify the relevance of these findings to humans, research is needed in a primate species with more advanced prenatal corticogenesis.

METHODS

Twelve pregnant rhesus monkeys were infected with influenza, A/Sydney/5/97 (H3N2), 1 month before term (early third trimester) and compared with 7 control pregnancies. Nasal swabs and blood samples confirmed viral shedding and immune activation. Structural magnetic resonance imaging was conducted at 1 year; behavioral development and cortisol reactivity were also assessed.

RESULTS

Maternal infections were mild and self-limiting. At birth, maternally derived influenza-specific immunoglobulin G was present in the neonate, but there was no evidence of direct viral exposure. Birth weight and gestation length were not affected, nor were infant neuromotor, behavioral, and endocrine responses. However, magnetic resonance imaging analyses revealed significant reductions in cortical gray matter in flu-exposed animals. Regional analyses indicated the largest gray matter reductions occurred bilaterally in cingulate and parietal areas; white matter was also reduced significantly in the parietal lobe.

CONCLUSIONS

Influenza infection during pregnancy affects neural development in the monkey, reducing gray matter throughout most of the cortex and decreasing white matter in parietal cortex. These brain alterations are likely to be permanent, given that they were still present at the monkey-equivalent of older childhood and thus might increase the likelihood of later behavioral pathology.

Voxel-based morphometry comparison between first episodes of psychosis with and without evolution to schizophrenia

First episodes (FE) of psychosis may evolve or not to schizophrenia in ensuing years, but there is a lack of reliable predictors of which patients will have to face such an unfavorable outcome. Given the replicated structural alterations of the brain in schizophrenia, it seems advisable to assess whether the alterations of this kind that can be detected at the time of an initial psychotic episode are different depending on the outcome of the patients. To this end, here we applied voxel-based morphometry to assess whether the degree of cerebral abnormalities differ between 30 FE patients who evolved to schizophrenia in the ensuing 2years and another 14 FE patients who could not be diagnosed as such during that period. Forty-one controls were also included in the study. We found that the FE patients who evolved to schizophrenia had a significantly lower GM value than the controls bilaterally in the left dorsolateral prefrontal (BA 9) and in left anterior cingulate (BA 33) regions while the FE patients who did not develop schizophrenia showed a distinct, right-sided pattern of deviation (visual cortex, superior temporal gyrus and inferior frontal). The direct comparison between FE patients who evolved or not evolved to schizophrenia did not reveal significant differences. Taken together, our results support the notion that brain abnormalities may be different in psychotic FE patients depending on their evolution in the medium term.

Hippocampal and caudate volume reductions in antipsychotic-naive first-episode schizophrenia

BACKGROUND

Enlarged ventricles and reduced hippocampal volume are consistently found in patients with first-episode schizophrenia. Studies investigating brain structure in antipsychotic-naive patients have generally focused on the striatum. In this study, we examined whether ventricular enlargement and hippocampal and caudate volume reductions are morphological traits of antipsychotic-naive first-episode schizophrenia.

METHODS

We obtained high-resolution 3-dimensional T1-weighted magnetic resonance imaging scans for 38 antipsychotic-naive first-episode schizophrenia patients and 43 matched healthy controls by use of a 3-T scanner. We warped the brain images to each other by use of a high-dimensional intersubject registration algorithm. We performed voxel-wise group comparisons with permutation tests. We performed small volume correction for the hippocampus, caudate and ventricles by use of a false discovery rate correction (p < 0.05) to control for multiple comparisons. We derived and analyzed estimates of brain structure volumes. We grouped patients as those with (n = 9) or without (n = 29) any lifetime substance abuse to examine the possible effects of substance abuse.

RESULTS

We found that hippocampal and caudate volumes were decreased in patients with first-episode schizophrenia. We found no ventricular enlargement, differences in global volume or significant associations between tissue volume and duration of untreated illness or psychopathology. The hippocampal volume reductions appeared to be influenced by a history of substance abuse. Exploratory analyses indicated reduced volume of the nucleus accumbens in patients with first-episode schizophrenia.

LIMITATIONS

This study was not a priori designed to test for differences between schizophrenia patients with or without lifetime substance abuse, and this subgroup was small.

CONCLUSION

Reductions in hippocampal and caudate volume may constitute morphological traits in antipsychotic-naive first-episode schizophrenia patients. However, the clinical implications of these findings are unclear. Moreover, past substance abuse may accentuate hippocampal volume reduction. Magnetic resonance imaging studies addressing the potential effects of substance abuse in antipsychotic-naive first-episode schizophrenia patients are warranted.

A selective review of volumetric and morphometric imaging in schizophrenia

Brain imaging studies have long supported that schizophrenia is a disorder of the brain, involving many discrete and widely spread regions. Generally, studies have shown decreases in cortical gray matter (GM) volume. Here, we selectively review recent papers studying GM volume changes in schizophrenia subjects, both first-episode (FE) and chronic, in an attempt to quantify and better understand differences between healthy and patient groups. We focused on the cortical GM of the prefrontal cortex, limbic and paralimbic structures, temporal lobe, and one subcortical structure (the caudate nucleus). We performed a search of the electronic journal database PsycINFO using the keywords "schizophrenia" and "MRI," and selected for papers published between 2001 and 2008. We then screened for only those studies utilizing manual or manually edited tracing methodologies for determining regions of interest (ROIs). Each region of interest was indexed independently; thus, one paper might yield results for numerous brain regions. Our review found that in almost all ROIs, cortical GM volume was decreased in the patient populations. The only exception was the caudate nucleus - most studies reviewed showed no change, while one study showed an increase in volume; this region, however, is particularly sensitive to medication effects. The reductions were seen in both FE and chronic schizophrenia. These results clearly support that schizophrenia is an anatomical disorder of the brain, and specifically that schizophrenia patients tend to have decreased cortical GM in regions involved in higher cognition and emotional processing. That these reductions were found in both FE and chronic subjects supports that brain abnormalities are present at the onset of illness, and are not simply a consequence of chronicity. Additional studies assessing morphometry at different phases of the illness, including prodromal stages, together with longitudinal studies will elucidate further the role of progression in this disorder.

Neuroanatomical correlates of psychopathology in antipsychotic-naïve schizophrenia

BACKGROUND

Previous Magnetic Resonance Imaging (MRI) studies using manual techniques reporting significant relationship between psychopathology and gray matter volume in schizophrenia are limited by various confounding factors. None used automated image analysis to examine gray matter volume correlates of psychopathology in antipsychotic-naïve schizophrenia patients.

AIM

This study aimed at examining the relationship between psychopathology and gray matter volume abnormalities in antipsychotic-naïve schizophrenia patients.

PATIENTS AND METHODS

MRI of 30 antipsychotic-naïve schizophrenia (DSM-IV) patients and 27 age-, sex- education- and handedness-matched healthy controls were compared for gray matter volume differences using Optimized Voxel-based Morphometry (VBM)-an automated, rapid and unbiased technique. Psychopathology was measured using Positive and Negative Syndrome Scale (PANSS) with good inter-rater reliability. The correlations between PANSS scores and gray matter volume were examined using VBM.

RESULTS

Schizophrenia patients had significant gray matter volume deficits in frontal, cingulate, temporal, insula and precuneus cortices; thalamus, caudate and cerebellum. Positive syndrome score had significant negative correlation with left superior temporal gyrus volume. Negative syndrome score had significant inverse correlation with frontal, cingulate and cerebellar gray matter volumes.

CONCLUSIONS

Cortical and cerebellar gray matter volume deficits and their significant negative correlations with psychopathology scores are supportive of 'Cognitive Dysmetria' in schizophrenia.

Specific brain structural abnormalities in first-episode schizophrenia. A comparative study with patients with schizophreniform disorder, non-schizophrenic non-affective psychoses and healthy volunteers

Evidence so far indicates the consistent association between brain structural abnormalities and schizophrenia already present at the early phases of the illness. This study investigates the specificity of brain structural abnormalities in schizophrenia by using region-of-interest method of volumetric analysis in a heterogeneous sample of schizophrenia spectrum patients at their first break of the illness. 225 subjects, comprising 82 schizophrenia patients, 36 schizophreniform disorder patients and 24 patients with non-schizophrenic non-affective psychoses, and 83 healthy individuals underwent a magnetic resonance imaging brain scan. Quantitative brain morphometric variables were assessed: cortical CSF, lateral ventricle, total brain tissue, white matter and cortical and subcortical gray matter volumes. The contribution of sociodemographic, cognitive and clinical characteristics was controlled. Compared with controls, schizophrenia (P=0.017) and schizophreniform disorder (P=0.023) patients showed an increase in cortical CSF volume. Schizophrenia patients had also markedly enlarged lateral ventricle volume compared to controls (P=0.026). The patients with non-schizophrenic non-affective psychoses did not significantly differ in lateral ventricle and cortical CSF volumes from controls. Compared with controls, schizophrenia and schizophreniform disorder patients demonstrated a significant decrease in total brain tissue (-1.30% and -1.12% respectively). Thalamic volume was reduced (-3.84%) in schizophrenia patients compared to controls (P=0.040). Clinical and cognitive variables were not significantly related with morphological changes. The brain changes found in patients with a first episode of schizophrenia spectrum disorders are robustly associated with the diagnoses of schizophrenia and schizophreniform disorder and are independent of relevant intervening variables.

Proton magnetic resonance spectroscopy in subjects with high genetic risk of schizophrenia: investigation of anterior cingulate, dorsolateral prefrontal cortex and thalamus

OBJECTIVE

Reduced N-acetylaspartate levels in regions of the frontal cortex, including the anterior cingulate cortex, dorsolateral prefrontal cortex, and thalamus, involved in the pathophysiology of schizophrenia suggest that brain metabolite abnormalities may be a marker of genetic vulnerability to schizophrenia. We used proton magnetic resonance spectroscopy (H-MRS) to acquire absolute concentrations of brain metabolites in subjects with a high genetic risk of schizophrenia to investigate the potential relationship between unexpressed genetic liability to schizophrenia and neuronal dysfunction.

METHOD

Included in the study were 22 subjects who had at least two relatives with schizophrenia (high genetic risk group) and 22 controls with no second-degree relatives with schizophrenia. Absolute concentrations of N-acetylaspartate, creatine, choline, glutamate/glutamine, and myo-inositol and the ratios of metabolites in the anterior cingulate cortex, left dorsolateral prefrontal cortex, and left thalamus were measured using H-MRS at 1.5 Tesla.

RESULTS

Relative to the controls, the high genetic risk group showed significant differences in absolute metabolite levels in the spectra of the regions of the left thalamus, including significant decreases in N-acetylaspartate, creatine, and choline concentrations.

CONCLUSIONS

The study points to neuronal dysfunction, and in particular thalamic dysfunction, as a key region of the vulnerability marker of schizophrenia. Further studies should examine the nature of the thalamus more intensively to further our understanding of thalamic dysfunction as a vulnerability marker.

The forthcoming revision of the diagnostic and classificatory system: perspectives based on the European psychiatric tradition

Europe has a rich tradition in psychopathology and psychiatric classification. This could be helpful developing new classification systems like ICD-11 and DSM-V. Some examples of this are described and further discussed, such as the categorical vs. the syndromatological approach, the relevance of hierarchical rules for the delineation of nosological entities, the antagonistic tradition of unitarian vs. splitting approaches and the relevance of a differentiated psychopathological description. Finally, the conclusion is that a too radical change of the classificatory system, e.g. in the direction of a purely symptomatical/dimensional systematic, or a totally new classification based on modern new biological findings, might be problematic and premature.

Is computed tomography still useful as a neuroimaging tool in psychiatry?

BACKGROUND

Computed tomography (CT) has played a pivotal role in psychiatry from its inception; however with the advent of other high-resolution noninvasive neuroimaging techniques such as MRI, the field has gone through a dramatic transformation.

OBJECTIVE

This article will explore the current role of CT in psychiatry.

METHODS

An extensive search of the published literature (1970 - 2008) was conducted, employing a number of databases and terms relevant to CT and imaging.

RESULTS/CONCLUSION

At present CT is primarily used as a screening tool to exclude intracranial pathology. This is partly because it is widely available and less expensive than other imaging modalities. CT is unable to provide region-specific information like MRI and this has restricted its use in disorders in which functional disturbances are suspected, however it remains the preferred mode of investigation where gross structural abnormalities are suspected.

Systematic of psychiatric disorders between categorical and dimensional approaches: Kraepelin's dichotomy and beyond

This paper describes basic principles of systematics for psychiatric disorders such as the categorical and dimensional approach. It summarises validity aspects of the traditional psychiatric nosology and syndromatology. The importance and limitations of the dichotomy of schizophrenia and affective disorders, first suggested by Kraepelin, is reviewed in the light of results from modern research in the field of classification, follow-up and neurobiological studies, especially neurochemical, neurogenetic and neuroimaging studies. Current developments towards DSM-V and ICD-11 are critically reflected. The conclusion is reached that there might be insufficient data to establish a new systematics of psychoses. Therefore it might be premature to leave the Kraepelinian dichotomy totally although it has to be modified in the light of new research.