Reduced thalamic volume in first-episode non-affective psychosis: correlations with clinical variables, symptomatology and cognitive functioning

Functional and structural alterations in different durations of untreated illness in the frontal and parietal lobe in major depressive disorder

Major depressive disorder (MDD) is one of the most disabling illnesses that profoundly restricts psychosocial functions and impairs quality of life. However, the treatment rate of MDD is surprisingly low because the availability and acceptability of appropriate treatments are limited. Therefore, identifying whether and how treatment delay affects the brain and the initial time point of the alterations is imperative, but these changes have not been thoroughly explored. We investigated the functional and structural alterations of MDD for different durations of untreated illness (DUI) using regional homogeneity (ReHo) and voxel-based morphometry (VBM) with a sample of 125 treatment-naïve MDD patients and 100 healthy controls (HCs). The MDD patients were subgrouped based on the DUI, namely, DUI ≤ 1 M, 1 < DUI ≤ 6 M, 6 < DUI ≤ 12 M, and 12 < DUI ≤ 48 M. Subgroup comparison (MDD with different DUIs) was applied to compare ReHo and grey matter volume (GMV) extracted from clusters of regions with significant differences (the pooled MDD patients relative to HCs). Correlations and mediation effects were analysed to estimate the relationships between the functional and structural neuroimaging changes and clinical characteristics. MDD patients exhibited decreased ReHo in the left postcentral gyrus and precentral gyrus and reduced GMV in the left middle frontal gyrus and superior frontal gyrus relative to HCs. The initial functional abnormalities were detected after being untreated for 1 month, whereas this duration was 3 months for GMV reduction. Nevertheless, a transient increase in ReHo was observed after being untreated for 3 months. No significant differences were discovered between HCs and MDD patients with a DUI less than 1 month or among MDD patients with different DUIs in either ReHo or GMV. Longer DUI was related to reduced ReHo with GMV as mediator in MDD patients. We identified disassociated functional and anatomical alterations in treatment-naïve MDD patients at different time points in distinct brain regions at the early stage of the disease. Additionally, we also discovered that GMV mediated the relationship between a longer DUI and diminished ReHo in MDD patients, disclosing the latent deleterious and neuro-progressive implications of DUI on both the structure and function of the brain and indicating the necessity of early treatment of MDD.

A voxel- and source-based morphometry analysis of grey matter volume differences in very-late-onset schizophrenia-like psychosis

BACKGROUND

Very-late-onset schizophrenia-like psychosis (VLOSLP) is associated with significant burden. Its clinical importance is increasing as the global population of older adults rises, yet owing to limited research in this population, the neurobiological underpinnings of VLOSP remain insufficiently clarified. Here we address this knowledge gap using novel morphometry techniques to investigate grey matter volume (GMV) differences between VLOSLP and healthy older adults, and their correlations with neuropsychological scores.

METHODS

In this cross-sectional study, we investigated whole-brain GMV differences between 35 individuals with VLOSLP (mean age 76.7, 26 female) and 36 healthy controls (mean age 75.7, 27 female) using whole-brain voxel-based morphometry (VBM) and supplementary source-based morphometry (SBM) on high resolution 3D T1-weighted MRI images. Additionally, we investigated relationships between GMV differences and cognitive function assessed with an extensive neuropsychological battery.

RESULTS

VBM showed lower GMV in the thalamus, left inferior frontal gyrus and left insula in patients with VLOSLP compared to healthy controls. SBM revealed lower thalamo-temporal GMV in patients with VLOSLP. Processing speed, selective attention, mental flexibility, working memory, verbal memory, semantic fluency and confrontation naming were impaired in patients with VLOSLP. Correlations between thalamic volumes and memory function were significant within the group of individuals with VLOSLP, whereas no significant associations remained in the healthy controls.

CONCLUSIONS

Lower GMV in the thalamus and fronto-temporal regions may be part of the underlying neurobiology of VLOSLP, with lower thalamic GMV contributing to memory impairment in the disorder.

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.

Cortico-thalamic dysconnection in early-stage schizophrenia: a functional connectivity magnetic resonance imaging study

Studies have indicated thalamus-related network dysfunction in schizophrenia and psychotic disorders. However, whether thalamus-related functional connectivity (FC) contributes to the psychopathology and cognitive deficits of early-stage schizophrenia requires further investigation. A total of 34 patients with early-stage schizophrenia (illness duration = 1.62 ± 1.16 years; age = 26.00 ± 6.34 years) and 34 age- and sex-matched healthy controls were enrolled in our study and underwent comprehensive assessments of the clinical symptoms of schizophrenia, working memory tasks, and resting-state FC magnetic resonance imaging. The patients with early-stage schizophrenia had increased FC of the thalamus with the bilateral postcentral and temporal gyri, inferior occipital cortex, and temporal pole and decreased FC of the thalamus with the vestibulocerebellum and frontal pole compared with the controls. Furthermore, increased FC between the thalamus and temporal pole was positively correlated with positive scores of the Positive and Negative Syndrome Scale for Schizophrenia (PANSS) and negatively correlated with performance on working memory tasks in early-stage schizophrenia. Increased FC of the thalamus with the inferior occipital cortex was positively associated with negative PANSS scores and negatively correlated with Personal and Social Performance Scale scores in early-stage schizophrenia. Our results supported the vital role of thalamus-related network dysfunction in the psychopathology and cognitive deficits of early-stage schizophrenia.

Self-Awareness of Psychopathology and Brain Volume in Patients With First Episode Psychosis

Memory impairment, excessive rumination, and increased interpersonal sensitivity are major characteristics of high psychosis risk or first episode psychosis (FEP). Herein, we investigated the relationship between brain volume and self-awareness of psychopathology in patients with FEP. All participants (FEP: 34 and HCs: 34) completed clinical assessments and the following self-reported psychopathology evaluations: prospective and retrospective memory questionnaire (PRMQ), ruminative response scale (RRS), and interpersonal sensitivity measure (IPSM). Structural magnetic resonance imaging was then conducted. The PRMQ, RRS, and IPSM scores were significantly higher in the FEP group than in the healthy controls (HCs). The volumes of the amygdala, hippocampus, and superior temporal gyrus (STG) were significantly lower in the FEP group than in the HCs. There was a significant group-dependent moderation effect between self-awareness of psychopathology (PRMQ, RRS, and IPSM scores) and right STG (rSTG) volume. In the FEP group, self-awareness of psychopathology was positively associated with rSTG volume, while in the HCs, this correlation was negative. Our results indicate that self-awareness of psychopathology impacts rSTG volume in the opposite direction between patients with FEP and HCs. In patients with FEP, awareness of impairment may induce increases in rSTG brain volume. However, HCs showed decreased rSTG volume when they were aware of impairment.

Neurological soft signs (NSS) and cognitive impairment in chronic schizophrenia

Recent studies indicate that neurological soft signs (NSS) in schizophrenia are associated with generalized cognitive impairments rather than changes in specific neuropsychological domains. However, the majority of studies solely included first-episode patients or patients with a remitting course and did not consider age, course, education or severity of global cognitive deficits as potential confounding variables. Therefore, we examined NSS with respect to cognitive deficits in chronic schizophrenia, i.e. patients who are particularly vulnerable to both, NSS and cognitive impairments.

Eighty patients with chronic schizophrenia (43.36 ± 15a) and 60 healthy controls (47.52 ± 14.8a) matched for age, sex and years of education were examined on the Heidelberg NSS scale and a broad neuropsychological battery including short term, working, logical and autobiographic memory (AM), theory of mind (ToM), psychomotor speed and cognitive flexibility.

When contrasted with the controls, patients showed significantly higher NSS scores and impairments in all neuropsychological domains but short-term memory. NSS were significantly associated with all neuropsychological domains considered but short-term memory and semantic AM. Except for episodic AM (which was significantly correlated with NSS in patients only) these correlations applied to both groups and were confirmed when age, years of education and severity of global cognitive deficits (Mini Mental State Examination) were controlled for.

Results demonstrate that NSS reflect a rather wide range of cognitive impairments in schizophrenia, which also involves episodic AM and ToM. These associations were not accounted for by age, education or severity of global cognitive deficits and facilitate the clinical usage of NSS as a screening instrument.

Recognition of Schizophrenia with Regularized Support Vector Machine and Sequential Region of Interest Selection using Structural Magnetic Resonance Imaging

Structural brain abnormalities in schizophrenia have been well characterized with the application of univariate methods to magnetic resonance imaging (MRI) data. However, these traditional techniques lack sensitivity and predictive value at the individual level. Machine-learning approaches have emerged as potential diagnostic and prognostic tools. We used an anatomically and spatially regularized support vector machine (SVM) framework to categorize schizophrenia and healthy individuals based on whole-brain gray matter densities estimated using voxel-based morphometry from structural MRI scans. The regularized SVM model yielded recognition accuracy of 86.6% in the training set of 127 individuals and validation accuracy of 83.5% in an independent set of 85 individuals. A sequential region-of-interest (ROI) selection step was adopted for feature selection, improving recognition accuracy to 92.0% in the training set and 89.4% in the validation set. The combined model achieved 96.6% sensitivity and 74.1% specificity. Seven ROIs were identified as the optimal discriminatory subset: the occipital fusiform gyrus, middle frontal gyrus, pars opercularis of the inferior frontal gyrus, anterior superior temporal gyrus, superior frontal gyrus, left thalamus and left lateral ventricle. These findings demonstrate the utility of spatial and anatomical priors in SVM for neuroimaging analyses in conjunction with sequential ROI selection in the recognition of schizophrenia.

Associations between psychosis endophenotypes across brain functional, structural, and cognitive domains

BACKGROUND

A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related.

METHODS

This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes.

RESULTS

The P300 amplitude and latency were not associated (regression coef. -0.06, 95% CI -0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10-0.28, p 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships.

CONCLUSIONS

The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.

Duration of active psychosis and functional outcomes in first-episode non-affective psychosis

BACKGROUND

The duration of untreated psychosis (DUP) has been associated with negative outcomes in psychosis; however, few studies have focused on the duration of active psychotic symptoms after commencing treatment (DAT). In this study, we aimed to evaluate the effect of DUP and DAT on functional long-term outcomes (3 years) in patients with early psychosis.

METHODS

We evaluated the Scale for the Assessment of Positive Symptoms (SAPS) at frequent intervals for 3 years after presentation to determine the DAT for 307 individuals with first-episode psychosis together with DUP and clinical variables. The functional outcomes were assessed using the Disability Assessment Scale (DAS) at three years, and functional recovery was defined as minimal impairment and return to activity. Associated variables, DAT and DUP were included in logistic regression models to predict functional outcomes. Receiver operating characteristic curves and Youden's index were applied to assess the best cut-off values.

RESULTS

DAT, (Wald: 13.974; ExpB: 1.097; p < 0.001), premorbid adjustment, initial BPRS score, gender, age of onset and schizophrenia diagnosis were significant predictors of social functioning, whereas only premorbid adjustment (Wald: 11.383; ExpB:1.009), DAT (Wald: 4.850; ExpB: 1.058; p = 0.028) and education were significant predictors of recovery. The optimal cut-off of DAT for predicting social functioning was 3.17 months for DAT (sensitivity: 0.68; specificity: 0.64; Youden's index: 0.314).

CONCLUSIONS

DAT is strongly related to functional outcomes independent of the DUP period or other variables. As a modifiable variable, the reduction of the DAT should be considered a main focus of intervention from the onset of the illness to improve long-term outcomes.

Cognitive Functions and Neurodevelopmental Disorders Involving the Prefrontal Cortex and Mediodorsal Thalamus

The mediodorsal nucleus of the thalamus (MD) has been implicated in executive functions (such as planning, cognitive control, working memory, and decision-making) because of its significant interconnectivity with the prefrontal cortex (PFC). Yet, whilst the roles of the PFC have been extensively studied, how the MD contributes to these cognitive functions remains relatively unclear. Recently, causal evidence in monkeys has demonstrated that in everyday tasks involving rapid updating (e.g., while learning something new, making decisions, or planning the next move), the MD and frontal cortex are working in close partnership. Furthermore, researchers studying the MD in rodents have been able to probe the underlying mechanisms of this relationship to give greater insights into how the frontal cortex and MD might interact during the performance of these essential tasks. This review summarizes the circuitry and known neuromodulators of the MD, and considers the most recent behavioral, cognitive, and neurophysiological studies conducted in monkeys and rodents; in total, this evidence demonstrates that MD makes a critical contribution to cognitive functions. We propose that communication occurs between the MD and the frontal cortex in an ongoing, fluid manner during rapid cognitive operations, via the means of efference copies of messages passed through transthalamic routes; the conductance of these messages may be modulated by other brain structures interconnected to the MD. This is similar to the way in which other thalamic structures have been suggested to carry out forward modeling associated with rapid motor responding and visual processing. Given this, and the marked thalamic pathophysiology now identified in many neuropsychiatric disorders, we suggest that changes in the different subdivisions of the MD and their interconnections with the cortex could plausibly give rise to a number of the otherwise disparate symptoms (including changes to olfaction and cognitive functioning) that are associated with many different neuropsychiatric disorders. In particular, we will focus here on the cognitive symptoms of schizophrenia and suggest testable hypotheses about how changes to MD-frontal cortex interactions may affect cognitive processes in this disorder.

A polygenic risk score analysis of psychosis endophenotypes across brain functional, structural, and cognitive domains

This large multi-center study investigates the relationships between genetic risk for schizophrenia and bipolar disorder, and multi-modal endophenotypes for psychosis. The sample included 4,242 individuals; 1,087 patients with psychosis, 822 unaffected first-degree relatives of patients, and 2,333 controls. Endophenotypes included the P300 event-related potential (N = 515), lateral ventricular volume (N = 798), and the cognitive measures block design (N = 3,089), digit span (N = 1,437), and the Ray Auditory Verbal Learning Task (N = 2,406). Data were collected across 11 sites in Europe and Australia; all genotyping and genetic analyses were done at the same laboratory in the United Kingdom. We calculated polygenic risk scores for schizophrenia and bipolar disorder separately, and used linear regression to test whether polygenic scores influenced the endophenotypes. Results showed that higher polygenic scores for schizophrenia were associated with poorer performance on the block design task and explained 0.2% (p = 0.009) of the variance. Associations in the same direction were found for bipolar disorder scores, but this was not statistically significant at the 1% level (p = 0.02). The schizophrenia score explained 0.4% of variance in lateral ventricular volumes, the largest across all phenotypes examined, although this was not significant (p = 0.063). None of the remaining associations reached significance after correction for multiple testing (with alpha at 1%). These results indicate that common genetic variants associated with schizophrenia predict performance in spatial visualization, providing additional evidence that this measure is an endophenotype for the disorder with shared genetic risk variants. The use of endophenotypes such as this will help to characterize the effects of common genetic variation in psychosis.

Microstructures in striato-thalamo-orbitofrontal circuit in methamphetamine users

Background Striato-thalamo-orbitofrontal (STO) circuit plays a key role in the development of drug addiction. Few studies have investigated its microstructural abnormalities in methamphetamine (MA) users. Purpose To evaluate the microstructural changes and relevant clinical relevance of the STO circuit in MA users using diffusion tensor imaging (DTI). Material and Methods Twenty-eight MA users and 28 age-matched normal volunteers were enrolled. 3T magnetic resonance imaging (MRI) was employed to obtain structural T1-weighted (T1W) imaging and diffusion-tensor imaging (DTI) data. Freesurfer software was used for automated segmentation of the bilateral nucleus accumbens (NAc), thalami, and orbitofrontal cortex (OFC). Four DTI measures maps, fractional anisotropy (FA), mean diffusivity (MD), axial diffusion (AD), and radial diffusion (RD) were generated and non-linearly co-registered to structural space. Comparisons of DTI measures of the STO circuit were carried out between MA and controls using repeated measures analysis of variance. Correlation analyses were performed between STO circuit DTI measures and clinical characteristics. Results The MA group had significant FA reduction in the bilateral NAc, OFC, and right thalamus ( P < 0.05). Lower left OFC FA and right NAc FA/AD were associated with longer duration of MA use. Lower right OFC FA was associated with younger age at first MA use. Higher FA and lower MD/RD in the thalamus, as well as higher left OFC RD, were associated with increased psychiatric symptoms. Conclusion The STO circuit has reduced microstructural integrity in MA users. Microstructural changes in the thalamus may compensate for dysfunction in functionally connected cortices, which needs further investigation.

Duration of untreated psychosis/illness and brain volume changes in early psychosis

The time period during which patients manifest psychotic or unspecific symptoms prior to treatment (duration of untreated psychosis, DUP, and the duration of untreated illness, DUI) has been found to be moderately associated with poor clinical and social outcome. Equivocal evidence exists of an association between DUP/DUI and structural brain abnormalities, such as reduced hippocampus volume (HV), pituitary volume (PV) and grey matter volume (GMV). Thus, the goal of the present work was to examine if DUP and DUI are associated with abnormalities in HV, PV and GMV. Using a region of interest (ROI) based approach, we present data of 39 patients from the Basel FePsy (Früherkennung von Psychosen, early detection of psychosis) study for which information about DUP, DUI and HV, PV and GMV data could be obtained. Twenty-three of them were first episode psychosis (FEP) and 16 at-risk mental state (ARMS) patients who later made the transition to frank psychosis. In unadjusted analyses, we found a significant positive correlation between DUP and PV in FEP patients. However, when adjusted for covariates, we found no significant correlation between DUP or DUI and HV, PV or GMV anymore. There only was a trend for decreasing GMV with increasing DUI in FEP. Our results do not comprehensively support the hypothesis of a "toxic" effect of the pathogenic mechanism underlying untreated psychosis on brain structure. If there is any effect, it might rather occur very early in the disease process, during which patients experience only unspecific symptoms.

Amygdala volume is reduced in early course schizophrenia

Subcortical structural alterations have been implicated in the neuropathology of schizophrenia. Yet, the extent of anatomical alterations for subcortical structures across illness phases remains unknown. To assess this, magnetic resonance imaging (MRI) was used to examine volume differences of major subcortical structures: thalamus, nucleus accumbens, caudate, putamen, globus pallidus, amygdala and hippocampus. These differences were examined across four groups: (i) healthy comparison subjects (HCS, n=96); (ii) individuals at high risk (HR, n=21) for schizophrenia; (iii) early-course schizophrenia patients (EC-SCZ, n=28); and (iv) chronic schizophrenia patients (C-SCZ, n=20). Raw gray matter volumes and volumetric ratios (volume of specific structure/total gray matter volume) were extracted using automated segmentation tools. EC-SCZ group exhibited smaller bilateral amygdala volumetric ratios, compared to HCS and HR subjects. Findings did not change when corrected for age, level of education and medication use. Amygdala raw volumes did not differ among groups once adjusted for multiple comparisons, but the smaller amygdala volumetric ratio in EC-SCZ survived Bonferroni correction. Other structures were not different across the groups following Bonferroni correction. Smaller amygdala volumes during early illness course may reflect pathophysiologic changes specific to illness development, including disrupted salience processing and acute stress responses.

Duration of Untreated Psychosis and Brain Function during Verbal Fluency Testing in First-Episode Schizophrenia: A Near-Infrared Spectroscopy Study

A longer duration of untreated psychosis (DUP) has been associated with poor clinical outcomes in patients with schizophrenia (SZ); however, it remains unclear whether this is due to neurotoxic effects of psychosis. The purpose of this study was to use near-infrared spectroscopy (NIRS) to investigate the influence of DUP on brain function using two verbal fluency tests (VFTs) in patients with first-episode SZ (FES). A total of 28 FES patients and 29 healthy controls (HC) underwent NIRS during VFTs. Group comparisons of cortical activity were made using two-tailed t-tests and the false discovery rate method. We then examined the associations between DUP and hemodynamic changes in each channel to identify any effects of DUP on brain cortical activity. During the letter VFT, the HC group exhibited significantly greater cortical activations over bilateral frontotemporal regions compared to FES patients. However, this distinction was not observed while performing a category version of the VFT. In addition, no associations between DUP and brain cortical activity were observed in the FES group during either VFT. In conclusion, we did not find an association between DUP and frontotemporal cortical activities. This might be because neurodevelopmental disturbances result in neurocognitive deficits long before psychotic symptoms onset.

Grey matter volume differences in non-affective psychosis and the effects of age of onset on grey matter volumes: A voxelwise study

Previous evidence indicates that structural brain alterations are already present in the early phases of psychosis. In this study we aim to investigate the relationships among the different diagnoses in the spectrum of non-affective psychosis. A hundred-and-one first-episode psychosis patients (FEP) and 69 healthy volunteers, matched for age, gender, handedness and educational level were analyzed by structural MRI and high-dimensional voxel-based morphometry as implemented in SPM8 software. We obtained three main results: (1) FEP patients showed reduction of grey matter volume (GMV) in the frontal, temporal and occipital lobes, left insula and cerebellum. (2) Age of disease onset was an important factor revealing a gradual decrease of GMV (healthy controls>late onset>intermediate onset>early onset) in the frontal, temporal and occipital lobes, insula and cerebellum. (3) A gradual reduction of GMV related to diagnosis spectrum in the frontal, temporal, parietal and occipital lobes of schizophrenia patients being the most affected. These results suggest that an earlier onset of psychosis is linked to an earlier disease-related disruption of structural brain development, which may be most pronounced in schizophrenia compared to other psychoses.

Progressive Structural Brain Changes and NRG1 Gene Variants in First-Episode Nonaffective Psychosis

BACKGROUND

Structural brain abnormalities are already present during the early phases of psychosis, but factors underlying brain volume changes are still not well understood. The neuregulin 1 gene (NRG1), influencing neurodevelopment and neuroplasticity, has been associated with schizophrenia. Our aim was to examine whether variations in the NRG1 gene (SNP8NRG221132, SNP8NRG6221533 and SNP8NRG243177 polymorphisms) influence longitudinal changes in the brain during a first episode of psychosis (FEP).

METHODS

A 3-year follow-up magnetic resonance imaging (MRI) study was performed. Fifty-nine minimally medicated patients who were experiencing FEP and 14 healthy control individuals underwent genotyping and structural brain MRI at baseline and at 1- and 3-year follow-up. A comparison of brain volumes, gray matter, white matter (WM), lateral ventricles (LV), cortical cerebrospinal fluid, and thalamus and caudate was made between the groups according to their genotype.

RESULTS

In patients, the SNP8NRG6221533 risk C allele was significantly associated with increased LV volume across time. C allele carriers had significantly less WM compared with subjects homozygous for the T allele after the follow-up. No other significant differences were observed among subgroups. No significant changes according to the genotypes were found in healthy individuals.

CONCLUSION

Our findings suggest that variations of neurodevelopment-related genes, such as the NRG1 gene, can contribute to brain abnormalities described in early phases of schizophrenia and progressive changes during the initial years of the illness. To our knowledge, it is the first time that a relation between NRG1 polymorphisms and longitudinal brain changes is reported. © 2015 S. Karger AG, Basel.

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.

Time perception networks and cognition in schizophrenia: a review and a proposal

Timing is an essential function for the survival of many living organisms. Despite its significance, it is relatively under-researched, particularly in schizophrenia. We examined neurophysiological, neuropathological, imaging and genetic studies of both healthy subjects and subjects suffering from schizophrenia in relation to time perception as measured by interval timing. We found that the data from studies in healthy populations indicate that time perception may be inter-linked with numerous other cognitive functions and share common brain networks. The same networks are implicated in the pathophysiology of schizophrenia. There is also evidence that several neurotransmitter systems, particularly the dopaminergic D2 system, are involved in interval timing. Patients with schizophrenia have been shown to suffer from a distorted sense of time, which has an impact on their cognitive function and results in both positive and negative symptoms. Therefore, genes involved in interval timing can be considered candidate genes for distorted cognition in schizophrenia. We discuss the hypothesis that time perception dysfunction is a primary cognitive dysfunction in schizophrenia.

The role of untreated psychosis in neurodegeneration: a review of hypothesized mechanisms of neurotoxicity in first-episode psychosis

For over 20 years, studies have tried to measure the association between the duration of untreated psychosis (DUP) and changes in brain morphology. A hypothesis that untreated psychosis is neurotoxic has been postulated, but the mechanisms of that toxicity have not been described. We re-analyzed papers collected for a systematic review to extract data on the hypotheses that have been generated on the potential mechanisms by which DUP could impact brain morphology in first-episode psychosis. Dopaminergic hyperactivity, prolonged hypothalamic-pituitary-adrenal activation, and persistent activity of catecholamines have been hypothesized as mechanisms to explain these associations. However, the question remains as to whether the observed structural changes are permanent or may be reversed via antipsychotic treatment.

The GABRB1 gene is associated with thalamus volume and modulates the association between thalamus volume and intelligence

The GABRB1 gene encodes the beta 1 subunit of the gamma-aminobutyric acid A receptor (GABA A receptor), which is responsible for mediating inhibitory neurotransmission in the thalamus. Potential relationships between the GABRB1 gene, thalamus volume, and intelligence have been suggested by previous clinical studies, but have not been directly examined among nonclinical samples. The current study collected structural MRI, genetic, and behavioral data from 316 healthy Chinese adults (including 187 females and 129 males), and examined associations between GABRB1 variants, thalamus volume, and intelligence (measured by the Wechsler Adult Intelligence Scale Revised). After controlling for intracranial volume, sex, and age, GABRB1 genetic polymorphism at the SNP rs7435958 had the strongest association with thalamus volume (p = 0.002 and 0.00008 for left and right thalamus volumes, respectively), with GG homozygotes having smaller bilateral thalamus volumes than the other genotypes. Furthermore, there were positive correlations between bilateral thalamus volumes and intelligence, especially for GABRB1 rs7435958 GG female homozygotes (r's = 0.31 and 0.29, p < 0.01, for the correlations of intelligence with left and right thalamus volumes, respectively). This study provides the first evidence for the involvement of the GABRB1 gene in the thalamus structure and their interactive effects on intelligence. Future studies of the thalamus-intelligence associations should consider genetic factors as potential moderators.

Three-year longitudinal population-based volumetric MRI study in first-episode schizophrenia spectrum patients

BACKGROUND

Schizophrenia is a chronic brain disorder associated with structural brain abnormalities already present at the onset of the illness. Whether these brain abnormalities might progress over time is still under debate.

METHOD

The aim of this study was to investigate likely progressive brain volume changes in schizophrenia during the first 3 years after initiating antipsychotic treatment. The study included 109 patients with a schizophrenia spectrum disorder and a control group of 76 healthy subjects. Subjects received detailed clinical and cognitive assessment and structural magnetic resonance imaging (MRI) at regular time points during a 3-year follow-up period. The effects of brain changes on cognitive and clinical variables were examined along with the impact of potential confounding factors.

RESULTS

Overall, patients and healthy controls exhibited a similar pattern of brain volume changes. However, patients showed a significant lower progressive decrease in the volume of the caudate nucleus than control subjects (F 1,307.2 = 2.12, p = 0.035), with healthy subjects showing a greater reduction than patients during the follow-up period. Clinical and cognitive outcomes were not associated with progressive brain volume changes during the early years of the illness.

CONCLUSIONS

Brain volume abnormalities that have been consistently observed at the onset of non-affective psychosis may not inevitably progress, at least over the first years of the illness. Taking together with clinical and cognitive longitudinal data, our findings, showing a lack of brain deterioration in a substantial number of individuals, suggest a less pessimistic and more reassuring perception of the illness.

Distinct effects of duration of untreated psychosis on brain cortical activities in different treatment phases of schizophrenia: a multi-channel near-infrared spectroscopy study

BACKGROUND

Duration of untreated psychosis (DUP) has been shown to be associated with both poor short-term and long-term outcomes in schizophrenia. Even so, few studies have used functional neuroimaging to investigate DUP in schizophrenia. In the present study, we used near-infrared spectroscopy (NIRS) to investigate the influence of DUP on brain functions during a verbal fluency test (VFT) in patients with schizophrenia.

METHODS

A total of 62 patients with schizophrenia were included. They were categorized into either short treatment (≤6months, n=33) or long treatment (>6months, n=29) groups based on their duration of treatment. Hemodynamic changes over the frontotemporal regions during a VFT were measured using multi-channel NIRS. We examined the associations between DUP and hemodynamic changes in each group to explore if there were different effects of DUP on brain cortical activity at different treatment durations.

RESULTS

In the long treatment group, we found significant associations between a longer DUP and decreased cortical activity approximately at the left inferior frontal gyrus, left middle frontal gyrus, left postcentral gyrus, right precentral gyrus, bilateral superior temporal gyrus, and bilateral middle temporal gyrus, whereas no associations between DUP and brain cortical activity were observed in the short treatment group.

CONCLUSIONS

Our results indicated that longer DUP may be associated with decreased level of cortical activities over the frontotemporal regions in the long-term. Early detection and intervention of psychosis that shortens DUP might help to improve the long-term outcomes in patients with schizophrenia.

Neuroanatomical Differences between First-Episode Psychosis Patients with and without Neurocognitive Deficit: A 3-Year Longitudinal Study

BACKGROUND

The course of cognitive function in first-episode psychosis (FEP) patients suggests that some individuals are normal or near normal whereas some cases present a marked decline. The goal of the present longitudinal study was to identify neuroanatomical differences between deficit and non-deficit patients.

METHODS

Fifty nine FEP patients with neuroimage and neurocognitive information were studied at baseline and 3 year after illness onset. A global cognitive function score was used to classify deficit and non-deficit patients at baseline. Analysis of covariances and repeated-measures analysis were performed to evaluate differences in brain volumes. Age, premorbid IQ, and intracranial volume were used as covariates. We examined only volumes of whole brain, whole brain gray and white matter, cortical CSF and lateral ventricles, lobular volumes of gray and white matter, and subcortical (caudate nucleus and thalamus) regions.

RESULTS

At illness onset 50.8% of patients presented global cognitive deficit. There were no significant differences between neuropsychological subgroups in any of the brain regions studied at baseline [all F(1, 54) ≤ 3.42; all p ≥ 0.07] and follow-up [all F(1, 54) ≤ 3.43; all p ≥ 0.07] time points. There was a significant time by group interaction for the parietal tissue volume [F(1, 54) = 4.97, p = 0.030] and the total gray matter volume [F(1, 54) = 4.31, p = 0.042], with the deficit group showing a greater volume decrease.

CONCLUSION

Our results did not confirm the presence of significant morphometric differences in the brain regions evaluated between cognitively impaired and cognitively preserved schizophrenia patients at the early stages of the illness. However, there were significant time by group interactions for the parietal tissue volume and the total gray matter volume during the 3-year follow-up period, which might indicate that cognitive deficit in schizophrenia would be associated with progressive brain volume loss.

BDNF Val66Met variants and brain volume changes in non-affective psychosis patients and healthy controls: a 3 year follow-up study

INTRODUCTION

Functional gene polymorphisms modulating neuroplasticity might mediate brain longitudinal structural changes in schizophrenia. The present study aimed to explore possible effects of BDNF Val66Met polymorphism variations on progressive structural brain changes after 3 years from the first episode of psychosis.

METHOD

Patients were part of a large epidemiological and longitudinal intervention program of first-episode psychosis, carried out at the University Hospital Marqués de Valdecilla, Cantabria, Spain. Eighty first-episode patients and 54 healthy controls were included in the final analyses. Brain magnetic resonance imaging (baseline and 3-year follow-up) and BDNF genotype, and clinical and functional outcome were investigated.

RESULTS

We did not detect significant association between brain changes and BDNF Val66Met polymorphism variations in patients and controls (all p>0.060). At baseline, there were no significant associations between brain anomalies and BDNF genotype. Functional deficits were similar in Met-carrier and Val homozygote patients after 3-year follow-up (X(2) = 0.66; p = 0.564); there was no relationship between significant volume change across time and functional outcome. Otherwise, Met-carrier controls had significant high rates of alcohol-consumption (p = 0.019) compared to Val homozygote controls.

CONCLUSION

Our findings do not support the notion that BDNF genotype variations may mediate brain macroscopic morphological changes across time.

Lack of gender influence on cortical and subcortical gray matter development in childhood-onset schizophrenia

BACKGROUND

Progressive cortical gray matter (GM) abnormalities are an established feature of schizophrenia and are more pronounced in rare, severe, and treatment refractory childhood-onset schizophrenia (COS) cases. The effect of sex on brain development in schizophrenia is poorly understood and studies to date have produced inconsistent results.

METHODS

Using the largest to date longitudinal sample of COS cases (n = 104, scans = 249, Male/Female [M/F] = 57/47), we compared COS sex differences with sex differences in a sample of matched typically developing children (n = 104, scans = 244, M/F = 57/47), to determine whether or not sex had differential effects on cortical and subcortical brain development in COS.

RESULTS

Our results showed no significant differential sex effects in COS for either GM cortical thickness or subcortical volume development (sex × diagnosis × age interaction; false discovery rate q = 0.05).

CONCLUSION

Sex appears to play a similar role in cortical and subcortical GM development in COS as it does in normally developing children.

One year longitudinal study of the straight gyrus morphometry in first-episode schizophrenia-spectrum patients

The aim of this study was to use a region-of-interest approach with magnetic resonance imaging to examine the volume of the straight gyrus volume change in first-episode schizophrenia-spectrum patients compared with healthy subjects over a 1-year follow-up period. We did not find a differential pattern of volumetric change between the two groups.

Impact of cannabis use on thalamic volume in people at familial high risk of schizophrenia

BACKGROUND

No longitudinal study has yet examined the association between substance use and brain volume changes in a population at high risk of schizophrenia.

AIMS

To examine the effects of cannabis on longitudinal thalamus and amygdala-hippocampal complex volumes within a population at high risk of schizophrenia.

METHOD

Magnetic resonance imaging scans were obtained from individuals at high genetic risk of schizophrenia at the point of entry to the Edinburgh High-Risk Study (EHRS) and approximately 2 years later. Differential thalamic and amygdala-hippocampal complex volume change in high-risk individuals exposed (n = 25) and not exposed (n = 32) to cannabis in the intervening period was investigated using repeated-measures analysis of variance.

RESULTS

Cannabis exposure was associated with bilateral thalamic volume loss. This effect was significant on the left (F = 4.47, P = 0.04) and highly significant on the right (F= 7.66, P= 0.008). These results remained significant when individuals using other illicit drugs were removed from the analysis.

CONCLUSIONS

These are the first longitudinal data to demonstrate an association between thalamic volume loss and exposure to cannabis in currently unaffected people at familial high risk of developing schizophrenia. This observation may be important in understanding the link between cannabis exposure and the subsequent development of schizophrenia.

Duration of untreated illness in schizophrenia is not associated with 5-year brain volume change

OBJECTIVES

Evidence for an association between duration of untreated illness (DUI) with clinical and functional outcome or brain volume (change) in schizophrenia patients is inconclusive. We aimed to investigate the relationship between DUI, outcome and brain volume at illness onset or brain volume change during the first five years of the illness in first-episode patients.

METHODS

Magnetic resonance images were acquired at baseline (T0) and after 5-year (T5) of 57 schizophrenia patients. Correlations were calculated in patients between brain volume (change), DUI and outcome variables.

RESULTS

We found no significant correlation between DUI and brain volume (change) in schizophrenia patients. A longer DUI was significantly correlated with higher PANSS scores at T0 and T5, and with higher scores on the Camberwell Assessment of Need scale at T5. Baseline volume of the cerebrum and lateral ventricles, and cerebellum volume (change) were associated with PANSS scores at T0 and T5.

CONCLUSION

Although clinical outcome is associated with both brain volume (change) and DUI, we found no evidence for a relationship between DUI and brain volume (change). DUI and baseline brain volume or 5-year brain volume (change) seem to explain different parts of the variation in clinical outcome.

Sleep correlates of cognition in early course psychotic disorders

BACKGROUND

Slow waves and sleep spindles, the main oscillations during non-rapid eye movement sleep, have been thought to be related to cognitive processes, and are impaired in psychotic disorders. Cognitive impairments, seen early in the course of psychotic disorders, may be related to alterations in these oscillations, but few studies have examined this relationship.

METHOD

Twenty seven untreated patients with a recently diagnosed psychotic disorder had polysomnographic sleep studies and neuro-cognitive testing.

RESULTS

Reduced power in the sigma range, which reflects spindle density, was associated with impaired attention, and reasoning, but not intelligence quotient (IQ). Slow wave sleep measures were not significantly associated with any cognitive measures.

CONCLUSIONS

Impairments in sleep spindles may be associated with cognitive deficits in the early course of psychotic disorders. These observations may help clarify neuro-biologic mechanisms of cognitive deficits in psychotic disorders such as schizophrenia.

Putative structural neuroimaging endophenotypes in schizophrenia: a comprehensive review of the current evidence

The genetic contribution to schizophrenia etiopathogenesis is underscored by the fact that the best predictor of developing schizophrenia is having an affected first-degree relative, which increases lifetime risk by tenfold, as well as the observation that when both parents are affected, the risk of schizophrenia increases to approximately 50%, compared with 1% in the general population. The search to elucidate the complex genetic architecture of schizophrenia has employed various approaches, including twin and family studies to examine co-aggregation of brain abnormalities, studies on genetic linkage and studies using genome-wide association to identify genetic variations associated with schizophrenia. ‘Endophenotypes’, or ‘intermediate phenotypes’, are potentially narrower constructs of genetic risk. Hypothetically, they are intermediate in the pathway between genetic variation and clinical phenotypes and can supposedly be implemented to assist in the identification of genetic diathesis for schizophrenia and, possibly, in redefining clinical phenomenology.

Multivariate patterns of brain-cognition associations relating to vulnerability and clinical outcome in the at-risk mental states for psychosis

BACKGROUND

Neuropsychological deficits are a core feature of established psychosis and have been previously linked to fronto-temporo-limbic brain alterations. Both neurocognitive and neuroanatomical abnormalities characterize clinical at-risk mental states (ARMS) for psychosis. However, structure-cognition relationships in the ARMS have not been directly explored using multivariate neuroimaging techniques.

METHODS

Voxel-based morphometry and partial least squares were employed to study system-level covariance patterns between whole-brain morphological data and processing speed, working memory, verbal learning/IQ, and executive functions in 40 ARMS subjects and 30 healthy controls (HC). The detected structure-cognition covariance patterns were tested for significance and reliability using non-parametric permutation and bootstrap resampling.

RESULTS

We identified ARMS-specific covariance patterns that described a generalized association of neurocognitive measures with predominantly prefronto-temporo-limbic and subcortical structures as well as the interconnecting white matter. In the conversion group, this generalized profile particularly involved working memory and verbal IQ and was positively correlated with limbic, insular and subcortical volumes as well as negatively related to prefrontal, temporal, parietal, and occipital cortices. Conversely, the neurocognitive profiles in the HC group were confined to working memory, learning and IQ, which were diffusely associated with cortical and subcortical brain regions.

CONCLUSIONS

These findings suggest that the ARMS and prodromal phase of psychosis are characterized by a convergent mapping from multi-domain neurocognitive measures to a set of prefronto-temporo-limbic and subcortical structures. Furthermore, a neuroanatomical separation between positive and negative brain-cognition correlations may not only point to a biological process determining the clinical risk for disease transition, but also to possible compensatory or dysmaturational neural processes.

Global and regional cortical thinning in first-episode psychosis patients: relationships with clinical and cognitive features

BACKGROUND

The thickness of the cortical mantle is a sensitive measure for identifying alterations in cortical structure. We aimed to explore whether first episode schizophrenia patients already show a significant cortical thinning and whether cortical thickness anomalies may significantly influence clinical and cognitive features.

METHOD

We investigated regional changes in cortical thickness in a large and heterogeneous sample of schizophrenia spectrum patients (n=142) at their first break of the illness and healthy controls (n=83). Magnetic resonance imaging brain scans (1.5 T) were obtained and images were analyzed by using brains2. The contribution of sociodemographic, cognitive and clinical characterictics was investigated.

RESULTS

Patients showed a significant total cortical thinning (F=17.55, d=-0.62, p<0.001) and there was a diffuse pattern of reduced thickness (encompassing frontal, temporal and parietal cortices) (all p's<0.001, d's>0.53). No significant group×gender interactions were observed (all p's>0.15). There were no significant associations between the clinical and pre-morbid variables and cortical thickness measurements (all r's<0.12). A weak significant negative correlation between attention and total (r=-0.24, p=0.021) and parietal cortical thickness (r=-0.27, p=0.009) was found in patients (thicker cortex was associated with lower attention). Our data revealed a similar pattern of cortical thickness changes related to age in patients and controls.

CONCLUSIONS

Cortical thinning is independent of gender, age, age of onset and duration of the illness and does not seem to significantly influence clinical and functional symptomatology. These findings support a primary neurodevelopment disorder affecting the normal cerebral cortex development in schizophrenia.

Subcortical brain volumes relate to neurocognition in schizophrenia and bipolar disorder and healthy controls

BACKGROUND

Similar patterns of subcortical brain abnormalities and neurocognitive dysfunction have been demonstrated in schizophrenia and bipolar disorder, with more extensive findings in schizophrenia. It is unknown whether relationships between subcortical volumes and neurocognitive performance are similar or different between schizophrenia and bipolar disorder.

METHODS

MRI scans and neuropsychological test performance were obtained from 117 schizophrenia or 121 bipolar spectrum disorder patients and 192 healthy control subjects. Using the FreeSurfer software, volumes of 18 selected subcortical structures were automatically segmented and analyzed for relationships with results from 7 neurocognitive tests.

RESULTS

In schizophrenia, larger left ventricular volumes were related to poorer motor speed, and bilateral putamen volumes were related to poorer verbal learning, executive functioning and working memory performance. In bipolar disorder, larger left ventricular volumes were related to poorer motor speed and executive functioning. The relationship between left putamen volume and working memory was specific to schizophrenia. The relationships between left inferior lateral ventricles and motor speed and between right putamen volumes and executive functioning were similar in schizophrenia and bipolar disorder, and different from healthy controls. The results remained significant after corrections for use of antipsychotic medication. Significant structure-function relationships were also found when all subjects were combined into one group.

CONCLUSION

The present findings suggest that there are differences as well as similarities in subcortical structure/function relationships between patients with schizophrenia or bipolar disorder and healthy individuals. The observed differences further suggest that ventricular and putamen volume sizes may reflect severity of cognitive dysfunction in these disorders.

Correlations of cerebello-thalamo-prefrontal structure and neurological soft signs in patients with first-episode psychosis

OBJECTIVE

This study aimed at determining brain structural imaging correlates of neurological soft signs (NSS) in patients suffering from a first-episode psychosis.

METHOD

Fifty-two patients with a DSMIV diagnosis of first-episode psychosis (schizophrenia or schizophrenia spectrum disorder) were consecutively included. Subjects were assessed using a standardized neurological examination for motor coordination, motor integration and sensory integration. Anatomical magnetic resonance images (MRI) were analysed in the whole brain using optimized voxel-based morphometry.

RESULTS

Neurological soft signs (NSS) total score (P-corrected = 0.013) and motor integration subscore (P-corrected = 0.035) were found to negatively correlate with grey matter structure of the dorsolateral prefrontal cortices. Motor coordination subscore was positively correlated with grey matter structure of the thalami (P-corrected = 0.002) and negatively with white matter structure of the cerebellum (P-corrected = 0.034). The addition of age and gender as covariate yielded similar results. We did not find any correlation between neither sensory integration subscore and grey matter structure nor NSS total score, motor integration subscore and voxel-based morphometry (VBM) white matter structure.

CONCLUSION

Structural alteration in the cerebello-thalamo-prefrontal network is associated with neurological soft signs in schizophrenia, a candidate network for 'cognitive dysmetria'.

Straight gyrus morphology in first-episode schizophrenia-spectrum patients

Previous studies on the straight gyrus have shown inconsistent results in first-episode schizophrenia. In the present study, straight gyrus morphometry in first-episode schizophrenia-spectrum patients was investigated by using a region-of-interest methodology. 141 schizophrenia-spectrum patients and 81 healthy subjects were studied. Magnetic resonance imaging brain scans (1.5 T) were obtained and images were analyzed by using BRAINS2. The main resulting measurements were straight gyrus gray matter volume and cortical surface area. Patients with schizophrenia-spectrum disorders did not significantly differ from controls in the straight gyrus morphometric variables evaluated (p>0.115). There was neither significant group-by-side (p>0.199) or group-by-gender interaction (p>0.096). Clinical variables were not significantly related with straight gyrus morphology. Our results, based on a large and representative sample, do not confirm the presence of significant straight gyrus morphometric anomalies in schizophrenia-spectrum disorders, after controlling for potential confounding variables.

Duration of untreated psychosis is associated with orbital-frontal grey matter volume reductions in first episode psychosis

BACKGROUND

Delay in treatment of psychosis is associated with poor clinical and social outcome and is measured as the duration of untreated psychosis (DUP) prior to treatment of the first episode. It has been suggested that this may be mediated through toxic effects of psychosis on the structure and function of the brain. Equivocal evidence exists regarding association between longer DUP and neuro-anatomical changes such as, reduced grey matter volume in specific regions in the brain and deficits in neurocognitive functions.

OBJECTIVE

To examine if duration of untreated psychosis (DUP) preceding treatment of a first episode of psychosis is associated with structural brain abnormalities and deficits in neurocognitive functions.

METHOD

We investigated the relationship between DUP and grey matter volume using voxel-based morphometry techniques and with multiple domains of cognition. Eighty patients with a first episode of psychosis were separated into two equal sized groups based on a median split (18 weeks) of their DUP.

RESULTS

Compared to the short-DUP group (mean DUP 7.9 weeks ± 5.6), the long-DUP group (mean 113.7 weeks ± 170 .4) showed significant grey matter volume reductions in orbital-frontal regions (bilateral medial frontal gyrus and bilateral rectal gyrus, BA 11) and parietal regions (postcentral gyrus and superior parietal lobule) as well as a significant reduction in whole brain grey matter volume (p<0.04). For schizophrenia spectrum cases only these findings were confined to left rectal gyrus. There were no differences in white matter or cerebral spinal fluid volumes or on cognitive functions. Results are controlled for antipsychotic medication exposure.

LIMITATIONS

The inherent difficulty in separating slow and insidious onset from long-DUP may limit the interpretation of our results and there may be an overlap between DUP and duration of illness (including the prodrome).

CONCLUSION

Patients with a longer delay in treatment of psychosis show a significant reduction in overall grey matter volume with specific reductions in the inferior-orbital region. These results provide some support to a possible neurotoxic effect of prolonged untreated psychosis.

Hippocampi, thalami, and accumbens microstructural damage in schizophrenia: a volumetry, diffusivity, and neuropsychological study

Volumetric abnormalities in the subcortical structures have been described in schizophrenia. However, it still has to be clarified if subtle microstructural damage is also present. Thus, we aimed to detect subcortical volume and mean diffusivity (MD) alterations in 45 patients with diagnosis of schizophrenia compared with 45 age-, gender-, and educational attainment-matched healthy comparison (HC) participants, by using a combined volumetry and diffusion tensor imaging (DTI) method. A secondary aim was to identify the neuropsychological correlates of subcortical abnormalities in the schizophrenic group. We found thalami and hippocampi bilaterally and left accumbens to show MD increase in the schizophrenic group. No volumetric decrease was found. Moreover, significant correlations between the MD values in subcortical structures (right thalamus and hippocampus and left accumbens) and working memory performance were found. Thus, subcortical microstructural alterations are present in schizophrenia even in absence of volumetric abnormalities. Furthermore, microstructural damage in subcortical areas is linked to working memory, suggesting the presence of a subtle microstructural subcortical dysfunction in the pathoetiological mechanism underlying high cognitive load performances in schizophrenia. Finally, our findings indicate that MD is a more sensitive marker of brain tissue deficits than signal intensity variations measured in T1-weighted imaging data, consistently with previous reports. Thus, DTI appears to be an invaluable tool to investigate subcortical pathology in schizophrenia, greatly enhancing the ability to detect subtle brain changes in this complex disorder.

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.

Temporal pole morphology in first-episode schizophrenia patients: clinical correlations

Studies of the temporal pole (TP) in schizophrenia patients are not consistent. The aim of this study was to investigate morphometric anomalies of the TP in first-episode schizophrenia patients. Patients did not significantly differ from controls in the TP morphometric variables evaluated. Clinical variables were not significantly related to the TP.

Association between duration of untreated psychosis and brain morphology in schizophrenia within the Northern Finland 1966 Birth Cohort

BACKGROUND

Duration of untreated psychosis (DUP) has been linked with poor prognosis and changes in the brain structure in schizophrenia at least at the beginning of the disease, but it is still unknown whether DUP relates to brain morphometry in the longer term. Our aim was to analyze the relation between DUP and the brain structure in schizophrenia in the general population, after several years of illness.

METHODS

Brains of subjects with psychosis from the Northern Finland 1966 Birth Cohort (NFBC 1966) were scanned with MRI during 1999-2001 after an 11-year follow-up. DUP was assessed from medical records and regressed against global and local tissue density measurements. The brain morphometric and the DUP information were available for 46 subjects with DSM-III-R schizophrenia.

RESULTS

The DUP did not correlate with volumes of the total gray or white matter or the cerebrospinal fluid. The length of DUP associated positively with reduced densities of the right limbic area and the right hippocampus.

CONCLUSIONS

Long DUP was slightly associated with reductions of gray matter densities in the limbic area and especially the hippocampus after several years follow-up, supporting the hypothesis that, compared to short DUP, long DUP might be a marker of different disease trajectories including subtle morphometric changes.

Deficit of inhibition motor control in untreated patients with schizophrenia: further support from visually guided saccade paradigms

In addition to classical delusional, negative, and cognitive deficit, schizophrenia has consistently been associated with impairments in saccadic eye movements, e.g., an increased error rate in the antisaccade task. We hypothesized that a deficit in inhibitory control is a core defect in untreated patients with schizophrenia leading to impairment in different oculomotor paradigms. Ten drug-free or drug-naïve patients with schizophrenia were matched in age and gender to 11 healthy controls with no psychoactive substance use or abuse. They were explored using reflexive saccades with unpredictable targets with or without the gap procedure, predictive saccades and a fixation/distracter paradigm. Patients with schizophrenia displayed shorter latency in reflexive and predictive saccades. In the GAP condition, patients made more anticipatory saccades, fewer regular saccades, and had a shorter latency of express saccades than controls. In addition, patients had an increased error rate in the fixation/distracters task. Altogether, these results provide new evidence of reduced prefrontal inhibitory regulation of subcortical and brainstem systems involved in the control of saccades.

Updated meta-analyses reveal thalamus volume reduction in patients with first-episode and chronic schizophrenia

OBJECTIVES

Although several structural MRI studies report significant thalamus volume reduction in patients with schizophrenia, many other studies do not. Therefore, the present meta-analyses aimed to clarify whether a reduction in thalamic volume characterizes patients diagnosed with schizophrenia by considering first-episode and chronic phases of the illness and right and left thalamus separately.

METHODS

Using Pubmed databases, we made a detailed literature search for structural MRI studies on patients with schizophrenia that reported physical volumetric measures of the right and left thalamus. Thirteen structural MRI studies were considered eligible for meta-analysis of the entire sample of patients and of the healthy control subjects. Individual meta-analyses were also performed on 6 studies of first-episode patients only and on 7 studies of chronic patients only. These were followed by additional meta-analyses to investigate the role of the factors "illness phase" and "side" on thalamic volume reduction.

RESULTS

Overall, the patient group showed a significant bilateral thalamus volume reduction compared to healthy control subjects. This was found in both first-episode and chronic patients. Furthermore, left thalamus was smaller than right in both patients and healthy control subjects.

CONCLUSIONS

When only studies that used physical volumetric measures were considered, the present meta-analyses confirmed that thalamic volume reduction characterizes patients with schizophrenia, both at the first-episode and chronic phases of the illness.

Longitudinal rates of lobar atrophy in frontotemporal dementia, semantic dementia, and Alzheimer's disease

This study compared rates of regional atrophy in Alzheimer disease (AD), frontotemporal dementia (FTD), and semantic dementia (SD). Cross-sectional studies have shown that different dementia syndromes are associated with different patterns of regional brain tissue loss. Rates of atrophy over time may be useful for differential diagnosis, and could be used to monitor disease progression, serving as an outcome measure for clinical trials. We studied patients with AD (n=12), FTD (n=13), SD (n=20), and normal controls (n=23) longitudinally with structural magnetic resonance imaging, using BRAINS2 software to measure frontal, temporal, and parietal lobe volumes. In FTD the rate of frontal lobe atrophy over 1 year was greater than in any other group, whereas SD showed the highest rate in the temporal lobes. Atrophy in these regions progressed twice as quickly in FTD and SD compared with AD. Atrophy was not significantly faster for AD in any brain region compared with the other groups. Regional atrophy over time was significantly faster in FTD and SD compared with AD, and the regions of greatest atrophy were specific for each syndrome. Measuring specific regions of cerebral volume changes by serial neuroimaging may serve as a useful biomarker outcome measure for clinical trials in neurodegenerative diseases.

Gyrification brain abnormalities associated with adolescence and early-adulthood cannabis use

Although cannabis is the most widely used illicit drug in the world, the long-term effect of its use in the brain remains controversial. In order to determine whether adolescence and early-adulthood cannabis use is associated with gross volumetric and gyrification abnormalities in the brain, we set up a cross-sectional study using structural magnetic resonance imaging in a sample of general population subjects. Thirty cannabis-using subjects (mean age, 25.7 years; mean duration of regular use, 8.4 years, range: 3-21) with no history of polydrug use or neurologic/mental disorder and 44 non-using control subjects (mean age, 25.8 years) were included. Cannabis users showed bilaterally decreased concavity of the sulci and thinner sulci in the right frontal lobe. Among non-users, age was significantly correlated with decreased gyrification (i.e., less concave sulci and more convexe gyri) and decreased cortical thickness, supporting the notion of age-related gyrification changes. However, among cannabis users gyrification indices did not show significant dependency on age, age of regular cannabis use initiation, or cumulative exposure to cannabis. These results suggest that cannabis use in adolescence and early-adulthood might involve a premature alteration in cortical gyrification similar to what is normally observed at a later age, probably through disruption of normal neurodevelopment.

Thalamic pathology in schizophrenia

The thalamus plays a critical role in the coordination of information as it passes from region to region within the brain. A disruption of that information flow may give rise to some of the cardinal symptoms of schizophrenia. In support of this hypothesis, schizophrenia-like syndromes emerge when illnesses, such as stroke, selectively damage the thalamus while sparing the rest of the brain. Evidence from many sources has implicated thalamic dysfunction in schizophrenia. In postmortem studies, several subregions of the thalamus, including the mediodorsal nucleus and the pulvinar, have been shown to have fewer neurons in schizophrenia. Neurochemical disturbances are also seen, with changes in both the glutamate and dopamine systems; thalamic glutamate receptor expression is altered in schizophrenia, and dopamine appears to be elevated in thalamic subregions, while evidence exists of an imbalance between dopamine and other neurotransmitters. In vivo studies using magnetic resonance imaging have demonstrated smaller thalamic volumes in schizophrenia, as well as shape deformations suggesting changes in those thalamic regions that are most densely connected to the portions of the brain responsible for executive function and sensory integration. These changes seem to be correlated with clinical symptoms. The thalamus is a starting point for several parallel, overlapping networks that extend from thalamic nuclei to the cortex. Evidence is emerging that changes in the thalamic nodes of these networks are echoed by changes at other points along the chain; this suggests that schizophrenia might be a disease of disrupted thalamocortical neural networks. This model distributes the pathology throughout the network, but also concentrates attention on the thalamus as a critical structure, especially because of its role in coordinating the flow of information within and between neural networks.

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.

Additive effect of NRG1 and DISC1 genes on lateral ventricle enlargement in first episode schizophrenia

Neuregulin 1 (NRG1) and Disrupted-in-schizophrenia (DISC1) genes, which are candidate genes for schizophrenia, are implicated in brain development. We have previously reported an association between the T allele of the rs6994992 SNP within NRG1 gene and lateral ventricle (LV) enlargement in first-episode schizophrenia patients. Moreover, transgenic mice with mutant DISC1 have also been reported as showing LV enlargement. In this study, we examined the possible interactive effects of NRG1 and DISC1 on brain volumes in a sample of first-episode schizophrenia patients. Ninety-one patients experiencing their first episode of schizophrenia underwent genotyping of three SNPs within DISC1 and structural brain MRI. These results were combined with our previously reported genotypes on three SNPs within NRG1. The T/T genotype of rs2793092 SNP in DISC1 was significantly associated with increased LV volume. However, taking into account the rs6994992 SNP in the NRG1 gene, which was also associated with LV volume in a previous study, the DISC1 SNP only predicted LV enlargement among those patients carrying the T allele in the NRG1 SNP. Those patients with the "at risk" allelic combinations in both genes had LV volumes which were 48% greater than those with none of the allelic combinations. Our findings suggest that NRG1 and DISC1 genes may be associated with brain abnormalities in schizophrenia through their influence on related pathways of brain development.

Volumetric and shape analysis of the thalamus in first-episode schizophrenia

Thalamic abnormalities have been implicated in the pathogenesis of schizophrenia, although the majority of studies used chronic samples treated extensively with antipsychotics. Moreover, the clinical and neuropsychological correlates of these abnormalities remain largely unknown. Using high-resolution MR imaging and novel methods for shape analysis, we investigated thalamic subregions in 35 (25 M/10 F) first-episode schizophrenia patients compared with 33 (23 M/10 F) healthy volunteers. The right and left thalami were traced bilaterally on coronal brain slices and volumes were compared between groups. In addition, regional abnormalities were identified by comparing distances, measured from homologous thalamic surface points to the central core of each individual's surface model, between groups in 3D space. Patients had significantly less total thalamic volume compared with healthy volunteers. Statistical mapping demonstrated most pronounced shape abnormalities in the pulvinar; however, estimated false discovery rates in these regions were sizable. Smaller thalamus volume was significantly correlated with worse overall neuropsychological functioning and specific deficits were observed in the language, motor, and executive domains. There were no significant associations between thalamus volume and positive or negative symptoms. Our findings suggest that thalamic abnormalities are evident at the onset of a first episode of schizophrenia prior to extensive pharmacologic intervention and that these abnormalities have neuropsychological correlates.