Effect of antipsychotics on regional cerebral blood flow measured with positron emission tomography

Cytokine levels reflect tic symptoms more prominently during mild phases

Tic disorder is a neuropsychiatric condition that affects 3% of all children and can have a significant impact on their quality of life. Cytokines, interferons, interleukins, lymphokines, and tumor necrosis factors are involved in the neuroinflammatory circuitry of tic disorders. This study aimed to identify the cytokines involved in the pathogenesis of tic disorders. We enrolled 44 patients with tic disorder and 38 healthy controls. Patients were free of psychotropic medications for at least 3 weeks. Whole blood samples were analyzed using a Luminex® human cytokine multiplex assay kit. Patients were divided into groups with "mild tics" and "above moderate tics" based on Yale Global Tic Severity Scale (YGTSS) scores for comparison. The final analysis included 35 patients (28 male and 7 female) and 31 controls (20 male and 11 female). In the mild tic group, interleukin (IL)-12 p70 negatively correlated with motor tic scores. Granulocyte-macrophage colony-stimulating factor, IL-4, IL-8, and tumor necrosis factor (TNF)-α were positively correlated to phonic tic scores. IL-12 p40 and TNF-α were positively correlated to total tic scores. IL-12 p70 and IL-17a negatively correlated to impairment scores and total YGTSS scores. Tic disorder patients and healthy controls exhibit different cytokine profiles. Only patients with mild symptoms exhibit significant correlations, suggesting that the correlations between cytokine levels and tic symptoms are more relevant during the mild or remission phases. Our results present the importance of IL-1β and TNF-α, among others, but the identification of key cytokines are still necessary.

Reduced cortical cerebral blood flow in antipsychotic-free first-episode psychosis and relationship to treatment response

BACKGROUND

Altered cerebral blood flow (CBF) has been found in people at risk for psychosis, with first-episode psychosis (FEP) and with chronic schizophrenia (SCZ). Studies using arterial spin labelling (ASL) have shown reduction of cortical CBF and increased subcortical CBF in SCZ. Previous studies have investigated CBF using ASL in FEP, reporting increased CBF in striatum and reduced CBF in frontal cortex. However, as these people were taking antipsychotics, it is unclear whether these changes are related to the disorder or antipsychotic treatment and how they relate to treatment response.

METHODS

We examined CBF in FEP free from antipsychotic medication (N = 21), compared to healthy controls (N = 22). Both absolute and relative-to-global CBF were assessed. We also investigated the association between baseline CBF and treatment response in a partially nested follow-up study (N = 14).

RESULTS

There was significantly lower absolute CBF in frontal cortex (Cohen's d = 0.84, p = 0.009) and no differences in striatum or hippocampus. Whole brain voxel-wise analysis revealed widespread cortical reductions in absolute CBF in large cortical clusters that encompassed occipital, parietal and frontal cortices (Threshold-Free Cluster Enhancement (TFCE)-corrected <0.05). No differences were found in relative-to-global CBF in the selected region of interests and in voxel-wise analysis. Relative-to-global frontal CBF was correlated with percentage change in total Positive and Negative Syndrome Scale after antipsychotic treatment (r = 0.67, p = 0.008).

CONCLUSIONS

These results show lower cortical absolute perfusion in FEP prior to starting antipsychotic treatment and suggest relative-to-global frontal CBF as assessed with magnetic resonance imaging could potentially serve as a biomarker for antipsychotic response.

Cerebral blood flow in striatum is increased by partial dopamine agonism in initially antipsychotic-naïve patients with psychosis

BACKGROUND

Resting cerebral blood flow (rCBF) in striatum and thalamus is increased in medicated patients with psychosis, but whether this is caused by treatment or illness pathology is unclear. Specifically, effects of partial dopamine agonism, sex, and clinical correlates on rCBF are sparsely investigated. We therefore assessed rCBF in antipsychotic-naïve psychosis patients before and after aripiprazole monotherapy and related findings to sex and symptom improvement.

METHODS

We assessed rCBF with the pseudo-Continuous Arterial Spin Labeling (PCASL) sequence in 49 first-episode patients (22.6 ± 5.2 years, 58% females) and 50 healthy controls (HCs) (22.3 ± 4.4 years, 63% females) at baseline and in 29 patients and 49 HCs after six weeks. RCBF in striatum and thalamus was estimated with a region-of-interest (ROI) approach. Psychopathology was assessed with the positive and negative syndrome scale.

RESULTS

Baseline rCBF in striatum and thalamus was not altered in the combined patient group compared with HCs, but female patients had lower striatal rCBF compared with male patients (p = 0.009). Treatment with a partial dopamine agonist increased rCBF significantly in striatum (p = 0.006) in the whole patient group, but not significantly in thalamus. Baseline rCBF in nucleus accumbens was negatively associated with improvement in positive symptoms (p = 0.046), but baseline perfusion in whole striatum and thalamus was not related to treatment outcome.

CONCLUSIONS

The findings suggest that striatal perfusion is increased by partial dopamine agonism and decreased in female patients prior to first treatment. This underlines the importance of treatment effects and sex differences when investigating the neurobiology of psychosis.

The effect of first- and second-generation antipsychotics on brain morphology in schizophrenia: A systematic review of longitudinal magnetic resonance studies with a randomized allocation to treatment arms

Schizophrenia manifests as loss of brain volume in specific areas in a progressive nature and an important question concerns whether long-term treatment with medications contributes to this. The aim of the current PRISMA systematic review was to search for prospective studies involving randomization to treatment. PROSPERO ID: CRD42020197874. The MEDLINE/PUBMED was searched and it returned 2638 articles; 3 were fulfilling the inclusion criteria. A fourth was published later; they included 359 subjects, of whom 86 were healthy controls, while the rest were first-episode patients, with 91 under olanzapine, 93 under haloperidol, 48 under risperidone, 5 under paliperidone, 6 under ziprasidone, and 30 under placebo. Probably one-third of patients were suffering from a psychotic disorder other than schizophrenia. The consideration of their results suggested that there is no significant difference between these medications concerning their effects on brain structure and also in comparison to healthy subjects. There does not seem to be any strong support to the opinion that medications that treat psychosis cause loss of brain volume in patients with schizophrenia. On the contrary, the data might imply the possible presence of a protective effect for D2, 5-HT2, and NE alpha-2 antagonists (previously called SGAs). However, the literature is limited and focused research in large study samples is essential to clarify the issue, since important numerical differences do exist. The possibility of the results and their heterogeneity to be artifacts secondary to a modification of magnetic resonance imaging (MRI) signal by antipsychotics should not be easily rejected until relevant data are available.

Neurobiological substrates of the positive formal thought disorder in schizophrenia revealed by seed connectome-based predictive modeling

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Formal thought disorder (FTD) is a core symptom of schizophrenia, but its neurobiological substrates remain elusive.

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Resting-state functional connectivity (rsFC) of three meta-analytically defined seeds were correlated to positive and negative symptom dimensions of FTD.

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RsFC patterns allowed individual prediction of positive FTD symptom severity.

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These findings generalized to an independent data set.

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Our study has identified robust neurobiological correlates of positive FTD in schizophrenia.

Formal thought disorder (FTD) is a core symptom cluster of schizophrenia, but its neurobiological substrates remain poorly understood. Here we collected resting-state fMRI data from 276 subjects at seven sites and employed machine-learning to investigate the neurobiological correlates of FTD along positive and negative symptom dimensions in schizophrenia. Three a priori, meta-analytically defined FTD-related brain regions were used as seeds to generate whole-brain resting-state functional connectivity (rsFC) maps, which were then compared between schizophrenia patients and controls. A repeated cross-validation procedure was realized within the patient group to identify clusters whose rsFC patterns to the seeds were repeatedly observed as significantly associated with specific FTD dimensions. These repeatedly identified clusters (i.e., robust clusters) were functionally characterized and the rsFC patterns were used for predictive modeling to investigate predictive capacities for individual FTD dimensional-scores. Compared with controls, differential rsFC was found in patients in fronto-temporo-thalamic regions. Our cross-validation procedure revealed significant clusters only when assessing the seed-to-whole-brain rsFC patterns associated with positive-FTD. RsFC patterns of three fronto-temporal clusters, associated with higher-order cognitive processes (e.g., executive functions), specifically predicted individual positive-FTD scores (p = 0.005), but not other positive symptoms, and the PANSS general psychopathology subscale (p > 0.05). The prediction of positive-FTD was moreover generalized to an independent dataset (p = 0.013). Our study has identified neurobiological correlates of positive FTD in schizophrenia in a network associated with higher-order cognitive functions, suggesting a dysexecutive contribution to FTD in schizophrenia. We regard our findings as robust, as they allow a prediction of individual-level symptom severity.

Neuroimaging as a Window Into the Pathophysiological Mechanisms of Schizophrenia

Schizophrenia is a complex neuropsychiatric disorder with a diverse clinical phenotype that has a substantial personal and public health burden. To advance the mechanistic understanding of the illness, neuroimaging can be utilized to capture different aspects of brain pathology in vivo, including brain structural integrity deficits, functional dysconnectivity, and altered neurotransmitter systems. In this review, we consider a number of key scientific questions relevant in the context of neuroimaging studies aimed at unraveling the pathophysiology of schizophrenia and take the opportunity to reflect on our progress toward advancing the mechanistic understanding of the illness. Our data is congruent with the idea that the brain is fundamentally affected in the illness, where widespread structural gray and white matter involvement, functionally abnormal cortical and subcortical information processing, and neurometabolic dysregulation are present in patients. Importantly, certain brain circuits appear preferentially affected and subtle abnormalities are already evident in first episode psychosis patients. We also demonstrated that brain circuitry alterations are clinically relevant by showing that these pathological signatures can be leveraged for predicting subsequent response to antipsychotic treatment. Interestingly, dopamine D2 receptor blockers alleviate neural abnormalities to some extent. Taken together, it is highly unlikely that the pathogenesis of schizophrenia is uniform, it is more plausible that there may be multiple different etiologies that converge to the behavioral phenotype of schizophrenia. Our data underscore that mechanistically oriented neuroimaging studies must take non-specific factors such as antipsychotic drug exposure or illness chronicity into consideration when interpreting disease signatures, as a clear characterization of primary pathophysiological processes is an imperative prerequisite for rational drug development and for alleviating disease burden in our patients.

Normalizing the Abnormal: Do Antipsychotic Drugs Push the Cortex Into an Unsustainable Metabolic Envelope?

The use of antipsychotic medication to manage psychosis, principally in those with a diagnosis of schizophrenia or bipolar disorder, is well established. Antipsychotics are effective in normalizing positive symptoms of psychosis in the short term (delusions, hallucinations and disordered thought). Their long-term use is, however, associated with side effects, including several types of movement (extrapyramidal syndrome, dyskinesia, akathisia), metabolic and cardiac disorders. Furthermore, higher lifetime antipsychotic dose-years may be associated with poorer cognitive performance and blunted affect, although the mechanisms driving the latter associations are not well understood. In this article, we propose a novel model of the long-term effects of antipsychotic administration focusing on the changes in brain metabolic homeostasis induced by the medication. We propose here that the brain metabolic normalization, that occurs in parallel to the normalization of psychotic symptoms following antipsychotic treatment, may not ultimately be sustainable by the cerebral tissue of some patients; these patients may be characterized by already reduced oxidative metabolic capacity and this may push the brain into an unsustainable metabolic envelope resulting in tissue remodeling. To support this perspective, we will review the existing data on the brain metabolic trajectories of patients with a diagnosis of schizophrenia as indexed using available neuroimaging tools before and after use of medication. We will also consider data from pre-clinical studies to provide mechanistic support for our model.

Heritability of Cerebral Blood Flow and the Correlation to Schizophrenia Spectrum Disorders: A Pseudo-continuous Arterial Spin Labeling Twin Study

Whether aberrant cerebral blood flow (CBF) in schizophrenia is affected by genetic influences, and consequently a potential marker for genetic susceptibility, is unknown. Our aims were to determine the heritability of CBF in thalamic, frontal, and striatal areas, and to ascertain if associations with disease were under genetic influence. Monozygotic (MZ) twin pairs concordant (n = 2) or discordant (n = 20) for schizophrenia spectrum disorders (ICD-10 F2x.x), matched on sex and age with dizygotic (DZ; n = 20) and healthy control pairs (MZ: n = 27; DZ: n = 18; total: n = 181 individuals), were recruited via the National Danish Twin Register. CBF in thalamus, frontal lobes, and putamen was measured with pseudo-continuous arterial spin labeling on a 3 T magnetic resonance scanner. Twin statistics were performed with structural equation modeling. CBF in the frontal lobes was heritable (h2 = 0.44, 95% CI [0.22-0.60]) but not correlated to disease. CBF correlated to schizophrenia spectrum disorders in the left thalamus (r = 0.17, [0.03-0.31]; P = 0.02), as well as in the left putamen (r = 0.19, [0.05-0.32]; P = 0.007) and the right putamen (r = 0.18, [0.03-0.32]; P = 0.02). When restricting the sample to schizophrenia (F20.x) only, shared genetic influences between CBF in the left putamen and schizophrenia liability (phenotypic correlation = 0.44, [0.28-0.58], P < 0.001) were found. Our results provide heritability estimates of CBF in the frontal lobes, and we find CBF in thalamus and putamen to be altered in schizophrenia spectrum disorders. Furthermore, shared genetic factors influence schizophrenia liability and striatal perfusion. Specifically, higher perfusion in the left putamen may constitute a marker of genetic susceptibility for schizophrenia.

Evaluation of fronto-striatal networks during cognitive control in unmedicated patients with schizophrenia and the effect of antipsychotic medication

To understand the mechanism of cognitive control dysfunction in schizophrenia, it is critical to characterize brain function without the confounding effect of medication. It is also important to establish the extent to which antipsychotic medication restores brain function and whether those changes are related to psychosis improvement. Twenty-two patients with schizophrenia, initially unmedicated and after a 6-week course of risperidone, and 20 healthy controls (HC) studied twice, 6 weeks apart, performed an fMRI task. We examined group and longitudinal differences in anterior cingulate cortex (ACC), striatum, and midbrain functional activity during performance of a Stroop color task as well as activity patterns associated with improvement in psychosis symptoms. Unmedicated patients showed reduced functional activity in the ACC, striatum, and midbrain compared to HC. Post hoc contrasts from significant group-by-time interactions indicated that, in patients, drug administration was associated with both activity increases and decreases. In unmedicated patients, greater baseline functional activity in the striatum and midbrain predicted subsequent better treatment response. Greater changes in functional activity in ACC and ventral putamen over the course of 6 weeks positively correlated with better treatment response. Unmedicated patients show reduced activity in brain networks pivotal for cognitive control and medication is associated with functional changes in these regions. These results suggest a mechanism by which antipsychotic medication has a beneficial effect on cognition. Our results also support the notion that treatment response is determined by a combination of the baseline pattern of brain function and by the pharmacological modulation of these regions.

Presynaptic Dopamine Synthesis Capacity in Schizophrenia and Striatal Blood Flow Change During Antipsychotic Treatment and Medication-Free Conditions

Standard-of-care biological treatment of schizophrenia remains dependent upon antipsychotic medications, which demonstrate D₂ receptor affinity and elicit variable, partial clinical responses via neural mechanisms that are not entirely understood. In the striatum, where D₂ receptors are abundant, antipsychotic medications may affect neural function in studies of animals, healthy volunteers, and patients, yet the relevance of this to pharmacotherapeutic actions remains unresolved. In this same brain region, some individuals with schizophrenia may demonstrate phenotypes consistent with exaggerated dopaminergic signaling, including alterations in dopamine synthesis capacity; however, the hypothesis that dopamine system characteristics underlie variance in medication-induced regional blood flow changes has not been directly tested. We therefore studied a cohort of 30 individuals with schizophrenia using longitudinal, multi-session [¹⁵O]-water and [¹⁸F]-FDOPA positron emission tomography to determine striatal blood flow during active atypical antipsychotic medication treatment and after at least 3 weeks of placebo treatment, along with presynaptic dopamine synthesis capacity (ie, DOPA decarboxylase activity). Regional striatal blood flow was significantly higher during active treatment than during the placebo condition. Furthermore, medication-related increases in ventral striatal blood flow were associated with more robust amelioration of excited factor symptoms during active medication and with higher dopamine synthesis capacity. These data indicate that atypical medications enact measureable physiological alterations in limbic striatal circuitry that vary as a function of dopaminergic tone and may have relevance to aspects of therapeutic responses.

Proteome and pathway effects of chronic haloperidol treatment in mouse hippocampus

Proteomic exploration of the effects of psychotropic drugs on specific brain areas in rodents has the potential to uncover novel molecular networks and pathways affected by psychotropic medications, and may inform etiologic hypotheses on mental disorders. Haloperidol, a widely used first-generation antipsychotic, has been shown to produce structural and functional changes of the hippocampus, a brain region also implicated in the neuropathology of disorders such as schizophrenia and bipolar disorder. Seven adult male C57BL/6 mice were injected daily intraperitoneally with 0.5 mg/kg of haloperidol, for 28 days. A control group of six animals was injected with vehicle only (saline). Protein levels of postmortem hippocampus homogenate were determined using label-free LC/MS/MS. In the treatment group, 216 differentially expressed hippocampal proteins were identified as compared to controls. Ingenuity pathway analysis implicated oxidative phosphorylation and mitochondrial function as top canonical pathways, and local networks involved in tubulin-mediated cytoskeleton dynamics, clathrin-mediated endocytosis, and extracellular signal-regulated kinase and c-Jun N-terminal kinase signaling. The findings of this study could stimulate further research into the cellular mechanisms associated with haloperidol treatment and the pathophysiology of psychotic disorders, assisting treatment biomarker discovery. All MS data have been deposited in the ProteomeXchange with identifier PXD002250 (http://proteomecentral.proteomexchange.org/dataset/PXD002250).

Scene unseen: Disrupted neuronal adaptation in melancholia during emotional film viewing

Impairments in attention and concentration are distinctive features of melancholic depression, and may diminish the ability to shift focus away from internal dysphoric states. Disrupted brain networks may underlie the inability to effectively disengage from interoceptive signals in this disorder. This study investigates changes in effective connectivity between cortical systems supporting attention, interoception, and perception in those with melancholic depression when shifting attention from rest to viewing dynamic film stimuli. We hypothesised that those with melancholia would show impaired attentional shifting from rest to emotional film viewing, captured in neuronal states that differed little across conditions. Functional magnetic resonance imaging (fMRI) data were acquired from 48 participants (16 melancholic depressed, 16 non-melancholic depressed, and 16 healthy controls) at rest and whilst viewing emotionally salient movies. Using independent component analysis, we identified 8 cortical modes (default mode, executive control, left/right frontoparietal attention, left/right insula, visual and auditory) and studied their dynamics using dynamic causal modelling. Engagement with dynamic emotional material diminished in melancholia and was associated with network-wide increases in effective connectivity. Melancholia was also characterised by an increase in effective connectivity amongst cortical regions involved in attention and interoception when shifting from rest to negative film viewing, with the converse pattern in control participants. The observed involvement of attention- and insula-based cortical systems highlights a potential neurobiological mechanism for disrupted attentional resource allocation, particularly in switching between interoceptive and exteroceptive signals, in melancholia.

The Effect of Antipsychotic Treatment on Cortical Gray Matter Changes in Schizophrenia: Does the Class Matter? A Meta-analysis and Meta-regression of Longitudinal Magnetic Resonance Imaging Studies

BACKGROUND

Deficits in cortical gray matter (GM) have been found in patients with schizophrenia, with evidence of progression over time. The aim of this study was to determine the role of potential moderators of such changes, in particular of the amount and type of antipsychotic medication intake.

METHODS

Longitudinal magnetic resonance imaging studies comparing changes in the volume of cortical GM over time between patients with schizophrenia and healthy control subjects published between January 1, 1983, and March 31, 2014, were analyzed. Hedges' g was calculated for each study and volume changes from baseline to follow-up were analyzed. Meta-regression statistics were applied to investigate the role of potential moderators of the effect sizes.

RESULTS

Eighteen studies involving 1155 patients with schizophrenia and 911 healthy control subjects were included. Over time, patients with schizophrenia showed a significantly higher loss of total cortical GM volume. This was related to cumulative antipsychotic intake during the interval between scans in the whole study sample. Subgroup meta-analyses of studies on patients treated with second-generation antipsychotics and first-generation antipsychotics revealed a different and contrasting moderating role of medication intake on cortical GM changes: more progressive GM loss correlated with higher mean daily antipsychotic intake in patients treated with at least one first-generation antipsychotic and less progressive GM loss with higher mean daily antipsychotic intake in patients treated only with second-generation antipsychotics.

CONCLUSIONS

These findings add useful information to the controversial debate on the brain structural effects of antipsychotic medication and may have both clinical relevance and theoretical implications.

Increased hippocampal blood volume and normal blood flow in schizophrenia

Neuroimaging studies have provided compelling evidence for abnormal hippocampal activity in schizophrenia. Most studies made inferences about baseline hippocampal activity using a single hemodynamic parameter (e.g., blood volume or blood flow). Here we studied several hemodynamic measures in the same cohort to test the hypothesis of increased hippocampal activity in schizophrenia. We used dynamic susceptibility contrast- (DSC-) magnetic resonance imaging (MRI) to assess blood volume, blood flow, and mean transit time in the hippocampus of 15 patients with chronic schizophrenia and 15 healthy controls. Left and right hippocampal measurements were combined for absolute measures of cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT). We found significantly increased hippocampal CBV, but normal CBF and MTT, in schizophrenia. The uncoupling of CBV and CBF could be due to several factors, including antipsychotic medication, loss of cerebral perfusion pressure, or angiogenesis. Further studies need to incorporate several complementary imaging modalities to better characterize hippocampal dysfunction in schizophrenia.

Cognitive and neural strategies during control of the anterior cingulate cortex by fMRI neurofeedback in patients with schizophrenia

Cognitive functioning is impaired in patients with schizophrenia, leading to significant disabilities in everyday functioning. Its improvement is an important treatment target. Neurofeedback (NF) seems a promising method to address the neural dysfunctions underlying those cognitive impairments. The anterior cingulate cortex (ACC), a central hub for cognitive processing, is one of the brain regions known to be dysfunctional in schizophrenia. Here we conducted NF training based on real-time functional magnetic resonance imaging (fMRI) in patients with schizophrenia to enable them to control their ACC activity. Training was performed over 3 days in a group of 11 patients with schizophrenia and 11 healthy controls. Social feedback was provided in accordance with the evoked activity in the selected region of interest (ROI). Neural and cognitive strategies were examined off-line. Both groups learned to control the activity of their ACC but used different neural strategies: patients activated the dorsal and healthy controls the rostral subdivision. Patients mainly used imagination of music to elicit activity and the control group imagination of sports. In a stepwise regression analysis, the difference in neural control did not result from the differences in cognitive strategies but from diagnosis alone. Based on social reinforcers, patients with schizophrenia can learn to regulate localized brain activity. However, cognitive strategies and neural network location differ from healthy controls. These data emphasize that for therapeutic interventions in patients with schizophrenia compensatory strategies may emerge. Specific cognitive skills or specific dysfunctional networks should be addressed to train impaired skills. Social NF based on fMRI may be one method to accomplish precise learning targets.

Comparison of cerebral blood flow in oral somatic delusion in patients with and without a history of depression: a comparative case series

BACKGROUND

A significant number of patients visit dental clinics because of unusual oral sensations for which no physical cause can be found. Such patients are recognized as having oral somatic delusion (OSD). OSD may be either primary (monosymptomatic) or secondary to another disease, such as depression or cerebral infarction. Although the presenting complaints of patients with primary and secondary OSD are nearly indistinguishable, symptoms in patients with secondary OSD seem to be resistant to treatment compared with those in patients with primary OSD. Moreover, right dominant cerebral blood flow (CBF) has been reported in patients with primary OSD, but the difference in CBF between patients with primary and secondary OSD remains unclear. The aim of this study was to assess the differences in clinical characteristics and CBF distribution between patients with monosymptomatic OSD (non-depression group) and OSD in conjunction with remitted depression (depression group).

METHODS

Participants were 27 patients of a psychosomatic dentistry clinic, all diagnosed with OSD. They were categorized into either the non-depression group (17 patients) or the depression group (10 patients) on the basis of assessments by their personal medical providers. CBF was examined using single-photon emission computed tomography.

RESULTS

There was no difference in clinical presentation between the two groups. A significant right dominant asymmetry in the temporal and posterior cerebral regions was observed in both groups. In the central region, a right dominance was seen in the non-depression group, while a left dominance was seen in the depression group. Moreover, the mean regional CBF values for patients in the depression group were significantly lower in several regions (including bilateral callosomarginal, precentral, angular, temporal, posterior cerebral, pericallosal, lenticular nucleus, thalamus, and hippocampus; and right central and cerebellum) than for patients in the non-depression group.

CONCLUSION

These results suggest that the temporal and posterior cerebral regions are involved in in the pathophysiology of OSD, regardless of depression history, and that widespread CBF reduction is a characteristic of remitted depression.

A multimodal analysis of antipsychotic effects on brain structure and function in first-episode schizophrenia

IMPORTANCE

Recent data suggest that treatment with antipsychotics is associated with reductions in cortical gray matter in patients with schizophrenia. These findings have led to concerns about the effect of antipsychotic treatment on brain structure and function; however, no studies to date have measured cortical function directly in individuals with schizophrenia and shown antipsychotic-related reductions of gray matter.

OBJECTIVE

To examine the effects of antipsychotics on brain structure and function in patients with first-episode schizophrenia, using cortical thickness measurements and administration of the AX version of the Continuous Performance Task (AX-CPT) during event-related functional magnetic resonance imaging.

DESIGN, SETTING, AND PARTICIPANTS

This case-control cross-sectional study was conducted at the Imaging Research Center of the University of California, Davis, from November 2004 through July 2012. Participants were recruited on admission into the Early Diagnosis and Preventive Treatment Clinic, an outpatient clinic specializing in first-episode psychosis. Patients with first-episode schizophrenia who received atypical antipsychotics (medicated patient group) (n = 23) and those who received no antipsychotics (unmedicated patient group) (n = 22) and healthy control participants (n = 37) underwent functional magnetic resonance imaging using a 1.5-T scanner.

MAIN OUTCOMES AND MEASURES

Behavioral performance was measured by trial accuracy, reaction time, and d'-context score. Voxelwise statistical parametric maps tested differences in functional activity during the AX-CPT, and vertexwise maps of cortical thickness tested differences in cortical thickness across the whole brain.

RESULTS

Significant cortical thinning was identified in the medicated patient group relative to the control group in prefrontal (mean reduction [MR], 0.27 mm; P < .001), temporal (MR, 0.34 mm; P = .02), parietal (MR, 0.21 mm; P = .001), and occipital (MR, 0.24 mm; P = .001) cortices. The unmedicated patient group showed no significant cortical thickness differences from the control group after clusterwise correction. The medicated patient group showed thinner cortex compared with the unmedicated patient group in the dorsolateral prefrontal cortex (DLPFC) (MR, 0.26 mm; P = .001) and temporal cortex (MR, 0.33 mm; P = .047). During the AX-CPT, both patient groups showed reduced DLPFC activity compared with the control group (P = .02 compared with the medicated group and P < .001 compared with the unmedicated group). However, the medicated patient group demonstrated higher DLPFC activation (P = .02) and better behavioral performance (P = .02) than the unmedicated patient group.

CONCLUSIONS AND RELEVANCE

These findings highlight the complex relationship between antipsychotic treatment and the structural, functional, and behavioral deficits repeatedly identified in schizophrenia. Although short-term treatment with antipsychotics was associated with prefrontal cortical thinning, treatment was also associated with better cognitive control and increased prefrontal functional activity. This study adds important context to the growing literature on the effects of antipsychotics on the brain and suggests caution in interpreting neuroanatomical changes as being related to a potentially adverse effect on brain function.

Impaired subjective well-being in schizophrenia is associated with reduced anterior cingulate activity during reward processing

BACKGROUND

Patients with schizophrenia have substantially reduced subjective well-being (SW) compared to healthy individuals. It has been suggested that diminished SW may be related to deficits in the neural processing of reward but this has not been shown directly. We hypothesized that, in schizophrenia, lower SW would be associated with attenuated reward-related activation in the reward network.

METHOD

Twenty patients with schizophrenia with a range of SW underwent a functional magnetic resonance imaging (fMRI) reward task. The brain activity underlying reward anticipation and outcome in schizophrenia was examined and compared to that of 12 healthy participants using a full factorial analysis. Region of interest (ROI) analyses of areas within the reward network and whole-brain analyses were conducted to reveal neural correlates of SW.

RESULTS

Reward-related neural activity in schizophrenia was not significantly different from that of healthy participants; however, the patients with schizophrenia showed significantly diminished SW. Both ROI and whole-brain analyses confirmed that SW scores in the patients correlated significantly with activity, specifically in the dorsal anterior cingulate cortex (dACC), during both reward anticipation and reward outcome. This association was not seen in the healthy participants.

CONCLUSIONS

In patients with schizophrenia, reduced activation of the dACC during multiple aspects of reward processing is associated with lower SW. As the dACC has been widely linked to coupling of reward and action, and the link to SW is apparent over anticipation and outcome, these findings suggest that SW deficits in schizophrenia may be attributable to reduced integration of environmental rewarding cues, motivated behaviour and reward outcome.

Use of magnetic resonance imaging in pharmacogenomics

Because of the large variation in the response to psychoactive medication, many studies have attempted to uncover genetic factors that determine response. While considerable knowledge exists on the large effects of genetic polymorphisms on pharmacokinetics and plasma concentrations of drugs, effects of the concentration at the target site and pharmacodynamic effects on brain functions in disease are much less known. This article reviews the role of magnetic resonance imaging (MRI) to visualize response to medication in brain behaviour circuits in vivo in humans and assess the influence of pharmacogenetic factors. Two types of studies have been used to characterize effects of medication and genetic variation. In task-related activation studies the focus is on changes in the activity of a neural circuit associated with a specific psychological process. The second type of study investigates resting state perfusion. These studies provide an assessment of vascular changes associated with bioavailability of drugs in the brain, but may also assess changes in neural activity after binding of centrally active agents. Task-related pharmacogenetic studies of cognitive function have characterized the effects in the prefrontal cortex of genetic polymorphisms of dopamine receptors (DRD2), metabolic enzymes (COMT) and in the post-synaptic signalling cascade under the administration of dopamine agonists and antagonists. In contrast, pharmacogenetic imaging with resting state perfusion is still in its infancy. However, the quantitative nature of perfusion imaging, its non-invasive character and its repeatability might be crucial assets in visualizing the effects of medication in vivo in man during therapy.

A systematic review and meta-analysis of the effects of antipsychotic medications on regional cerebral blood flow (rCBF) in schizophrenia: association with response to treatment

Evaluating the short- and long-term effects of antipsychotics on brain physiology is a key factor in advancing our understanding of neurophysiological changes in psychosis and improving prediction of treatment response. Understanding the nature of such changes is crucial to the interpretation of neuroimaging findings in patients with schizophrenia and psychoses in general. This review has systematically appraised existing evidence on resting cerebral blood flow (rCBF) in schizophrenia, before and after antipsychotic treatment, relating the findings to symptom severity. The review shows that antipsychotics exert regional effects on rCBF, particularly in frontal and basal ganglia regions, and that different antipsychotic generations have differential effects on rCBF. These findings are supported by an exploratory meta-analysis of a subset of studies. The review also highlights the relative lack of studies that use a priori definitions of treatment response, which is an important step in identifying testable hypotheses and ensuring clinical relevance of remission criteria. Finally, the review highlights important considerations for future psychopharmacological studies investigating the potential for rCBF to predict symptomatic improvement, which could inform the management of treatment in schizophrenia.

Effects of amisulpride on human resting cerebral perfusion

RATIONALE

Quantitative neuroimaging studies show that different neuroleptics have similar effects on resting metabolism/perfusion in the basal ganglia, but vary in their effect on the cortex, especially in the prefrontal and temporal lobes. These differences may represent signatures of the action of medication on distinctive receptor combinations.

OBJECTIVES

This study seeks to determine the effect on cerebral perfusion at rest of low-dose amisulpride, a neuroleptic with a receptor profile relatively selective to dopaminergic D2-receptors and both antidepressant and antipsychotic efficacy.

METHODS

Continuous arterial spin labelling in a placebo-controlled, double blind, crossover study at steady state of N = 20 healthy male adults.

RESULTS

Relative to placebo, amisulpride was associated with extensive and significant cortical decrements in resting perfusion levels, particularly in the prefrontal lobes (p = 0.01, corrected). Decrements spared the basal ganglia, where perfusion was slightly increased.

CONCLUSIONS

In contrast to earlier reports on other neuroleptics, amisulpride was associated with intense cortical perfusion decrements at rest. These results are consistent with an existing model in which dopaminergic blockade is associated not only with metabolism/perfusion increases in the basal ganglia, but also with decreases in the cerebral cortex that in most neuroleptics are compensated by action on other receptor systems. The selective receptor profile of amisulpride may explain the extensive cortical decrements.

A volumetric MRI study of limbic, associative and sensorimotor striatal subregions in schizophrenia

INTRODUCTION

Cognitive and emotional functioning is mediated by frontal-subcortical feedback loops. The striatum, a component of this circuitry, thus is a possible neural substrate of schizophrenia. Striatum volume, however, is believed to be differentially influenced by neuroleptic treatment due to an anterior-posterior D2 receptor density gradient. We thus rigorously parcellated it into subregions in order to assess whether neuroleptic effect on group differences is regionally specific.

METHODS

29 chronic, male, schizophrenia patients and 28 male, normal controls (NCs), group-matched for handedness, age, and parental SES, underwent structural brain imaging on a 1.5 Tesla GE system. We manually measured the volume, normalized for intracranial contents, of the striatum parcellated into anatomic subregions and their corresponding limbic, associative and sensorimotor functional subregions and performed clinical correlations.

RESULTS

First, we found a localized bilateral enlargement of the posterior putamen in medicated chronic schizophrenia. Second, we showed associative striatal subregion volumes correlated with executive function in schizophrenia subjects and, to a lesser extent, in NCs. Third, we showed associative striatal subregions inversely correlated with negative symptoms but conversely, the ventral/limbic striatum did not correlate with positive or negative clinical symptoms.

DISCUSSION

Our novel parcellation strategy, based on rigorous delineation of the ventral striatum, allowed for the demonstration of localized volumetric differences between schizophrenia and NCs. Furthermore, by parcellating the striatum into functional subregions we demonstrated significant positive correlations between the volume of the associative striatum and executive functioning in schizophrenia, adding further support to the importance of its role in the pathophysiology of schizophrenia.

Progressive loss of cortical gray matter in schizophrenia: a meta-analysis and meta-regression of longitudinal MRI studies

Cortical gray matter deficits have been found in patients with schizophrenia, with evidence of progression over time. The aim of this study was to determine the extent of progressive cortical gray matter volume changes over time in schizophrenia, their site and time of occurrence, and the role of potential moderators of brain changes. English language articles published between 1 January 1983 and 31 March 2012 in the MEDLINE and EMBASE databases were searched. Longitudinal magnetic resonance imaging studies comparing changes in cortical gray matter volume over time between patients with schizophrenia and healthy controls were included. Hedges g was calculated for each study. Analyses were performed using fixed- and random-effects models. A subgroup analysis was run to explore the pattern of brain changes in patients with first-episode schizophrenia. A meta-regression statistic was adopted to investigate the role of potential moderators of the effect sizes (ESs). A total of 19 studies, analyzing 813 patients with schizophrenia and 718 healthy controls, were included. Over time, patients with schizophrenia showed a significantly higher volume loss of total cortical gray matter, left superior temporal gyrus (STG), left anterior STG, left Heschl gyrus, left planum temporale and posterior STG bilaterally. Meta-analysis of first-episode schizophrenic patients showed a more significant pattern of progressive loss of whole cerebral gray matter volume involving the frontal, temporal and parietal lobes, and left Heschl gyrus compared with healthy controls. Clinical, pharmacologic and neuroradiological variables were found to be significant moderators of brain volume changes in patients with schizophrenia. The meta-analysis demonstrates that progressive cortical gray matter changes in schizophrenia occur with regional and temporal specificity. The underlying pathological process appears to be especially active in the first stages of the disease, affects the left hemisphere and the superior temporal structures more and is at least partly moderated by the type of pharmacological treatment received.

Hippocampal shape and volume changes with antipsychotics in early stage psychotic illness

Progression of hippocampal shape and volume abnormalities has been described in psychotic disorders such as schizophrenia. However it is unclear how specific antipsychotic medications influence the development of hippocampal structure. We conducted a longitudinal, randomized, controlled, multisite, double-blind study involving 14 academic medical centers (United States 11, Canada 1, Netherlands 1, and England 1). One hundred thirty-four first-episode psychosis patients (receiving either haloperidol [HAL] or olanzapine [OLZ]) and 51 healthy controls were followed for up to 104 weeks using magnetic resonance imaging and large-deformation high-dimensional brain mapping of the hippocampus. Changes in hippocampal volume and shape metrics (i.e., percentage of negative surface vertex slopes, and surface deformation) were evaluated. Mixed-models analysis did not show a significant group-by-time interaction for hippocampal volume. However, the cumulative distribution function of hippocampal surface vertex slopes showed a notable left shift with HAL treatment compared to OLZ treatment and to controls. OLZ treatment was associated with a significantly lower percentage of "large magnitude" negative surface vertex slopes compared to HAL treatment (p = 0.004). Surface deformation maps however did not localize any hippocampal regions that differentially contracted over time with OLZ treatment, after FDR correction. These results indicate that surface analysis provides supplementary information to volumetry in detecting differential treatment effects of the hippocampus. Our results suggest that OLZ is associated with less longitudinal hippocampal surface deformation than HAL, however the hippocampal regions affected appear to be variable across patients.

Gray matter volume deficits are associated with motor and attentional impairments in adolescents with schizophrenia

Cognitive deficits have been well described in adolescents with schizophrenia, but little is known about the neuroanatomical basis of these abnormalities. The authors examined whether neuropsychological deficits observed in adolescents with schizophrenia were associated with cortical gray matter volume deficits. Volumes of the superior frontal gyrus, anterior cingulate gyrus and orbital frontal lobe were outlined manually from contiguous MR images and automatically segmented into gray and white matter in 52 patients and 48 healthy volunteers. Subjects received a comprehensive neuropsychological test battery, assessing five different functional domains: executive, attention, verbal memory, motor and sensory motor. Children and adolescents with schizophrenia were found to have lower total cortical and lower superior frontal gyrus gray matter volumes and lower test scores across all functional domains compared to healthy volunteers. Among patients, the lower total cortical gray matter volume was associated with worse functioning on the attention and motor domains. Our findings point to widespread, perhaps multifocal, pathology as contributing to cognitive dysfunction in adolescents with schizophrenia.

Long-term antipsychotic treatment and brain volumes: a longitudinal study of first-episode schizophrenia

CONTEXT

Progressive brain volume changes in schizophrenia are thought to be due principally to the disease. However, recent animal studies indicate that antipsychotics, the mainstay of treatment for schizophrenia patients, may also contribute to brain tissue volume decrement. Because antipsychotics are prescribed for long periods for schizophrenia patients and have increasingly widespread use in other psychiatric disorders, it is imperative to determine their long-term effects on the human brain.

OBJECTIVE

To evaluate relative contributions of 4 potential predictors (illness duration, antipsychotic treatment, illness severity, and substance abuse) of brain volume change.

DESIGN

Predictors of brain volume changes were assessed prospectively based on multiple informants.

SETTING

Data from the Iowa Longitudinal Study.

PATIENTS

Two hundred eleven patients with schizophrenia who underwent repeated neuroimaging beginning soon after illness onset, yielding a total of 674 high-resolution magnetic resonance scans. On average, each patient had 3 scans (≥2 and as many as 5) over 7.2 years (up to 14 years).

MAIN OUTCOME MEASURE

Brain volumes.

RESULTS

During longitudinal follow-up, antipsychotic treatment reflected national prescribing practices in 1991 through 2009. Longer follow-up correlated with smaller brain tissue volumes and larger cerebrospinal fluid volumes. Greater intensity of antipsychotic treatment was associated with indicators of generalized and specific brain tissue reduction after controlling for effects of the other 3 predictors. More antipsychotic treatment was associated with smaller gray matter volumes. Progressive decrement in white matter volume was most evident among patients who received more antipsychotic treatment. Illness severity had relatively modest correlations with tissue volume reduction, and alcohol/illicit drug misuse had no significant associations when effects of the other variables were adjusted.

CONCLUSIONS

Viewed together with data from animal studies, our study suggests that antipsychotics have a subtle but measurable influence on brain tissue loss over time, suggesting the importance of careful risk-benefit review of dosage and duration of treatment as well as their off-label use.

Regional brain activation/deactivation during word generation in schizophrenia: fMRI study

BACKGROUND

Examination of the brain regions that show aberrant activations and/or deactivations during semantic word generation could pave the way for a better understanding of the neurobiology of cognitive dysfunction in schizophrenia.

AIMS

To examine the pattern of functional magnetic resonance imaging blood oxygen level dependent activations and deactivations during semantic word generation in schizophrenia.

METHOD

Functional magnetic resonance imaging was performed on 24 participants with schizophrenia and 24 matched healthy controls during an overt, paced, 'semantic category word generation' condition and a baseline 'word repetition' condition that modelled all the lead-in/associated processes involved in the performance of the generation task.

RESULTS

The brain regions activated during word generation in healthy individuals were replicated with minimal redundancies in participants with schizophrenia. The individuals with schizophrenia showed additional activations of temporo-parieto-occipital cortical regions as well as subcortical regions, despite significantly poorer behavioural performance than the healthy participants. Importantly, the extensive deactivations in other brain regions during word generation in healthy individuals could not be replicated in those with schizophrenia.

CONCLUSIONS

More widespread activations and deficient deactivations in the poorly performing participants with schizophrenia may reflect an inability to inhibit competing cognitive processes, which in turn could constitute the core information-processing deficit underlying impaired word generation in schizophrenia.

Modulation of limbic circuitry predicts treatment response to antipsychotic medication: a functional imaging study in schizophrenia

The regional neuronal changes taking place in the early and late stages of antipsychotic treatment are still not well characterized in humans. In addition, it is not known whether these regional changes are predictive of or are correlated with treatment response. Using PET with 15O, we evaluated the time course of regional cerebral blood flow (rCBF) patterns generated by a first (haloperidol) and a second (olanzapine) generation antipsychotic drug in patients with schizophrenia during a 6-week treatment trial. Patients were initially scanned after withdrawal of all psychotropic medication (2 weeks), and then blindly randomized to treatment with haloperidol (n=12) or olanzapine (n=17) for a period of 6 weeks. Patients were scanned again after 1 and 6 weeks of treatment. All assessments, including scanning sessions, were obtained in a double-blind manner. As hypothesized, we observed rCBF changes that were common to both the drugs, implicating cortico-subcortical and limbic neuronal networks in antipsychotic action. In addition, in these regions, some patterns seen at weeks 1 and 6 were distinctive, indexing neuronal changes related to an early (ventral striatum, hippocampus) and consolidated (anterior cingulate/medial frontal cortex) stage of drug response. Finally, both after 1 and 6 weeks of treatment, we observed differential patterns of rCBF activation between good and poor responders. After 1 week of treatment, greater rCBF increase in the ventral striatum and greater decrease in the hippocampus were associated with good response.

Do antipsychotic drugs affect brain structure? A systematic and critical review of MRI findings

BACKGROUND

The potential effects of antipsychotic drugs on brain structure represent a key factor in understanding neuroanatomical changes in psychosis. This review addresses two issues: (1) do antipsychotic medications induce changes in total or regional human brain volumes and (2) do such effects depend on antipsychotic type?

METHOD

A systematic review of studies reporting structural brain magnetic resonance imaging (MRI) measures: (1) directly in association with antipsychotic use; and (2) in patients receiving lifetime treatment with antipsychotics in comparison with drug-naive patients or healthy controls. We searched Medline and EMBASE databases using the medical subject heading terms: 'antipsychotics' AND 'brain' AND (MRI NOT functional). The search included studies published up to 31 January 2007. Wherever possible, we reported the effect size of the difference observed.

RESULTS

Thirty-three studies met our inclusion criteria. The results suggest that antipsychotics act regionally rather than globally on the brain. These volumetric changes are of a greater magnitude in association with typical than with atypical antipsychotic use. Indeed, there is evidence of a specific effect of antipsychotic type on the basal ganglia, with typicals specifically increasing the volume of these structures. Differential effects of antipsychotic type may also be present on the thalamus and the cortex, but data on these and other brain areas are more equivocal.

CONCLUSIONS

Antipsychotic treatment potentially contributes to the brain structural changes observed in psychosis. Future research should take into account these potential effects, and use adequate sample sizes, to allow improved interpretation of neuroimaging findings in these disorders.

Diminished neural sensitivity to irregular facial expression in first-episode schizophrenia

INTRODUCTION

Blunted, inappropriate affective-social behavior is a hallmark of early schizophrenia, possibly corresponding to reduced ability to recognize and express emotions. It is yet unknown if this affective deficiency relates to disturbed neural sensitivity to facial expressions or to overall face processing. In a previous imaging study, healthy subjects showed less suppression of the fusiform gyrus (FG) to repeated presentation of the same transfigured-bizarre face relative to regular face. We assumed that the FG in schizophrenia will show reduced repetition related sensitivity to transfigured-bizarre faces, while having overall normal response to faces.

METHODS

Ten first-episode patients with schizophrenia and 10 controls rated the bizarreness of upright and inverted faces. In an fMRI study, another group of 17 first-episode patients with schizophrenia and 12 controls viewed regular and transfigured-bizarre faces in blocks. Each block contained regular- or transfigured-bizarre faces of either different or same individual, presented in an upright or inverted orientation.

RESULTS

Patients in comparison with controls rated irregular faces as less bizarre. The FG, in patients and controls exhibited similar response to inverted faces, suggesting normal face processing. In contrast, the FG only in patients, showed similar suppression to repeated transfigured-bizarre and regular faces. Finally, the FG in patients compared with controls showed reduced functional connectivity with the amygdala and prefrontal cortex.

CONCLUSION

Patients with schizophrenia already at first-episode, showed reduced behavioral and neural sensitivity to bizarre facial expressions. Possibly, this deficiency is related to disturbed modulations of emotion-related face processing in the FG by the amygdala and prefrontal cortex.

Effect of antipsychotic drugs on brain morphometry. A randomized controlled one-year follow-up study of haloperidol, risperidone and olanzapine

BACKGROUND

The effect of antipsychotic drugs on brain morphology is under debate. Here we investigate the effects of risperidone, olanzapine and low doses of haloperidol on cortical and subcortical morphometry in first episode drug naïve patients with non-affective psychosis.

METHODS

Morphological variables were measured in three treatment groups (haloperidol=18; risperidone=16; olanzapine=18) and in healthy subjects (N=38) at baseline and after one year. The relationship between brain morphometric changes and changes in clinical scores was also assessed.

RESULTS

At one year, the three antipsychotics had had an equal effect on the gray matter cortical structure, overall and lobes (all p's>0.121.). A significant time-by-group interaction was found in lateral ventricle volume (F2,47=5.65; p=0.006). Post-hoc comparisons revealed a significant increase in lateral ventricles in patients treated with risperidone (p=0.009). Patients exposed to atypicals (olanzapine and risperidone) exhibited a decrease in caudate nucleus volume (p=0.001). In general, brain changes did not account in any significant manner for clinical changes over time in any treatment group.

CONCLUSIONS

We conclude that low doses of haloperidol, risperidone and olanzapine seem to have an equal effect on the gray matter cortical structure after 1 year of treatment. In contrast to typical antipsychotics, atypicals have differential effects on lateral ventricle and caudate nucleus volumes.

Effect of retrieval effort and switching demand on fMRI activation during semantic word generation in schizophrenia

Verbal fluency deficits in schizophrenia are difficult to interpret because the tasks are multi-factorial and groups differ in total words generated. We manipulated retrieval and switching demands by requiring alternation between over-learned sequences in which retrieval is relatively automatic (OS) and semantic categories requiring increased retrieval effort (SC). Controlled processing was also manipulated by including switching and non-switching conditions, and formal thought disorder (FTD) was assessed with the communication disorders index (CDI). The OS/SC semantic fluency paradigm was administered during fMRI to 13 patients with schizophrenia and 14 matched controls. Images were acquired on a 3 Tesla Siemens scanner using compressed image acquisition to allow for cued overt word production. Subjects alternated between OS, SC, OS-switch, SC-switch, and baseline blocks. Images were pre-processed in SPM-2, and a two-stage random effects analysis tested within and between group contrasts. There were no group performance differences. fMRI analysis did not reveal any group differences during the OS non-switching condition. Both groups produced expected activation in bilateral prefrontal and inferior parietal regions. However, during the SC condition patients had greater activation than controls in left prefrontal, right anterior cingulate, right superior temporal, bilateral thalamus, and left parietal regions. There was also evidence of patient over-activation in prefrontal, superior temporal, superior parietal, and visual association areas when a switching component was added. FTD was negatively correlated with BOLD response in the right anterior cingulate, cuneus and superior frontal gyrus during increased retrieval demand, and positively correlated with fMRI activation in the left lingual gyrus, right fusiform gyrus and left superior parietal lobule during increased switching demand. These results indicate that patients are able to successfully perform effortful semantic fluency tasks during non-speeded conditions. When retrieval is relatively automatic there does not appear to be an effect of schizophrenia on fMRI response. However, when retrieval and controlled processing demands increase, patients have greater activation than controls despite unimpaired task performance. This inefficient BOLD response may explain why patients are slower and less accurate on standard self-paced fluency tasks.

The effects of antipsychotic treatment on cerebral structure and function in schizophrenia

This paper analyses the effects of antipsychotic drug treatment on cerebral structure and function in schizophrenia reviewing qualitatively some of the relevant literature on the issue. Magnetic resonance imaging (MRI) studies of brain morphology in patients at different stages of illness and after varying times of neuroleptic exposure and longitudinal studies show possible different effects of first and second generation antipsychotics. This is true also for functional parameters, such as regional cerebral blood flow and metabolism, analysed, both in resting condition and after specific activation paradigms, with such diverse techniques as positron emission tomography (PET), single photon emission computed tomography (SPECT), functional MRI and MR spectroscopy. The possible molecular mechanisms underlying such differences and whether they represent direct drug effects or indirect consequences of their different and specific interactions with the 'natural' pathophysiological trajectory of brain abnormalities in schizophrenia are matter of present research and debate.

Reduced amygdala volumes in first-episode bipolar disorder and correlation with cerebral white matter

BACKGROUND

Previous magnetic resonance imaging (MRI) findings on amygdala volume abnormalities in bipolar disorder have been inconsistent, which may partly reflect clinical heterogeneity. It is unclear whether amygdala abnormalities are present early in the course of illness and/or are the consequence of disease progression.

METHODS

Twenty patients with first-episode bipolar disorder and 23 matched healthy comparison subjects were included. Magnetic resonance images were used to measure amygdala volumes, as well as whole brain measures of gray and white matter volume.

RESULTS

First-episode bipolar patients had significant reductions in amygdala volume relative to healthy subjects in an analysis of covariance that accounted for the effects of age, sex, and whole brain volume. First-episode patients also showed a trend reduction in cerebral white matter volume, and there was a significant correlation between cerebral white matter volume and total amygdala volume in patients but not control subjects.

CONCLUSIONS

These findings indicate that amygdala volume deficits are present early in the course of bipolar disorder and may occur within a neuroanatomical context of reduced cerebral white matter. Additional research should examine whether the nature of regional white matter deficits, particularly in frontal-temporal tracts, may help parse the pathophysiology of amygdala volume abnormalities in bipolar disorder.

Tuning the engine of cognition: A focus on NMDA/D1 receptor interactions in prefrontal cortex

The prefrontal cortex of the primate frontal lobes provides the capacity for judgment which can constantly adapt behavior in order to optimize its outcome. Adjudicating between long-term memory programs and prepotent responses, this capacity reviews all incoming information and provides an interpretation dependent on the events that have just occurred, the events that are predicted to happen, and the alternative response strategies that are available in the given situation. It has been theorized that this function requires two essential integrated components, a central executive which guides selective attention based on mechanisms of associative memory, as well as the second component, working memory buffers, in which information is held online, abstracted, and translated on a mental sketchpad of work in progress. In this review, we critically outline the evidence that the integration of these processes and, in particular, the induction and maintenance of persistent activity in prefrontal cortex and related networks, is dependent upon the interaction of dopamine D1 and glutamate NMDA receptor signaling at critical nodes within local circuits and distributed networks. We argue that this interaction is not only essential for representational memory, but also core to mechanisms of neuroadaptation and learning. Understanding its functional significance promises to reveal major new insights into prefrontal dysfunction in schizophrenia and, hence, to target a new generation of drugs designed to ameliorate the debilitating working memory deficits in this disorder.

D2 antidopaminergic modulation of frontal lobe function in healthy human subjects

BACKGROUND

Although the major principles of dopamine (DA) signaling have been well described previously, its precise modulatory impact on the prefrontal cortex (PFC) in humans is poorly understood. Two major neurophysiological models propose segregated functional circuits on the systems level as well as D(1) and D(2) receptor-dependent processing states on the cellular level (two-state model).

METHODS

We examined the predictive validity of these models in 10 healthy male volunteers with a haloperidol challenge (HLP). Cortico-striatal-thalamo-cortical (CSTC) motor loop functions were examined during functional magnetic resonance imaging (fMRI) with a sequential finger opposition task. Neuropsychological implications of the two-state model were evaluated with a test battery of D(1)- or D(2)-sensitive prefrontal measures.

RESULTS

Analysis of fMRI data revealed a significant HLP-induced blood oxygen level dependent-signal decrease in the sensorimotor striatum and a lateralized activation loss of ipsilateral higher order motor cortices and contralateral cerebellum. Neuropsychological evaluation demonstrated a preferential impairment of D(2)-sensitive functions, whereas D(1) or non-dopaminergic domains were unaffected.

CONCLUSIONS

Our data support the hypothesis that mesocortical D(1) and D(2) receptors exert differential influences in the PFC for cognitive function, but the nigrostriatal CSTC network model for the motor domain could not be confirmed.

Design and analysis of fMRI studies with neurologically impaired patients

Functional neuroimaging can be used to characterize two types of abnormality in patients with neurological deficits: abnormal functional segregation and abnormal functional integration. In this paper we consider the factors that influence the experimental design, analysis, and interpretation of such studies. With respect to experimental design, we emphasize that: 1) task selection is constrained to tasks the patient is able to perform correctly, and 2) the most sensitive designs entail presenting stimuli of the same type close together. In terms of data preprocessing, prior to statistical analysis, we note that structural pathology may call for constraints on nonlinear transformations, used by spatial normalization, to prevent distortion of intact tissue. This means that one may have to increase spatial smoothing to reduce the impact of inaccurate normalization. Important issues in statistical modeling concern the first level of analysis (estimation of activation within subject), which has to distinguish correct from incorrect responses. At the second level (between subjects), inference should be based on between-subjects variance. Provided that these and other constraints are met, deficits in functional segregation are indicated when activation in one or a set of regions is higher or lower in patients relative to control subjects. In contrast, deficits in functional integration are implied when the influence of one brain region on another is stronger or weaker in patients relative to control subjects.

Differential effects of haloperidol and olanzapine on levels of vascular endothelial growth factor and angiogenesis in rat hippocampus

Compared to first-generation antipsychotics (FGAs) such as haloperidol, second-generation antipsychotics (SGAs) such as olanzapine are found superior to improve cognitive performance and reduce negative symptoms with no extrapyramidal symptoms (EPS). These clinical effects of SGAs have been reported to be associated with the most replicated phenomenon, favorable changes in brain regional blood flow and volume. The changes in brain regional blood flow are shown to parallel changes in angiogenesis, which is primarily mediated by vascular endothelial growth factor (VEGF) through its receptor, Flk-1, on endothelial cells. Therefore, we studied the differential effects of time-dependent treatment (14 and 45 days) with haloperidol and olanzapine (2 and 10 mg/kg/day, respectively, in drinking water) on hippocampal levels of VEGF, its receptor Flk-1, and angiogenesis in adult rat. The levels of VEGF were determined by both Western blot analysis and ELISA, and Flk-1 levels were determined by Western blot analysis. Immunohistochemical analysis of rat endothelial cell antigen-1 (RECA-1) and laminin were used to evaluate the changes in angiogenesis. After 14 days of treatment with both haloperidol and olanzapine, the levels of VEGF and angiogenesis were significantly increased (p<0.001 vs vehicle for both), but 45 days of treatment with haloperidol reduced their levels back to levels in vehicle-treated rats. However, olanzapine treatment further increased VEGF levels (p<0.05 vs levels after 14 days of treatment). Changes in the levels of Flk-1 paralleled the changes in VEGF levels. Thus, the data indicate that haloperidol and olanzapine have distinct time-dependent patterns of regulation of VEGF and angiogenesis. These changes probably provide a new molecular mechanism to better explain their differential effects on the patterns of regional blood flow and associated changes in regional volume/neuroplasticity and psychopathology.

Differential effects of haloperidol and olanzapine on the expression of erythropoietin and its receptor in rat hippocampus and striatum

Compared with first-generation antipsychotics (FGAs), second-generation antipsychotics (SGAs) seem to be neuroprotective and trigger neuroplasticity. Because neuroplasticity is regulated by a variety of neurotrophic factors we studied differential effects of haloperidol (HAL, a FGA) and olanzapine (OLZ, a SGA) on temporal expression of erythropoietin (EPO), a potent neuroprotective factor and its receptor (EPOr) in rat brain. Rats (8-10/group) were treated with HAL or OLZ for 14 days (HAL-14 or OLZ-14) or 45 days (HAL-45 or OLZ-45). Animals were killed by decapitation or by perfusion to collect brains for immunoblotting and immunohistochemical analysis respectively. In hippocampus, the levels of both EPO and EPOr were significantly increased in HAL-14 (p < 0.001) and OLZ-14 (p < 0.001) groups. Their levels decreased in HAL-45 compared with levels in HAL-14 (EPO, p < 0.001; EPOr, p < 0.05), whereas the levels were further increased (EPO, p < 0.05) in OLZ-45 compared with OLZ-14. In striatum, the levels of both EPO and EPOr were unchanged in HAL-14 and EPO levels significantly decreased in HAL-45 (p < 0.05), whereas their levels were significantly increased in OLZ-14 and OLZ-45 compared with the vehicle-treated control (p < 0.001). Both EPO and EPOr were primarily expressed by neurons and endothelial cells. These data suggest that SGAs such as OLZ may have neuroprotective effects through expression of EPO that may be clinically relevant for long-term safe and beneficial management of psychotic patients.

Gray matter abnormalities associated with duration of untreated psychosis

PURPOSE

A long duration of untreated psychosis (DUP) is associated with relatively poor clinical and social outcomes. In order to identify whether an anatomically mediated mechanism may give rise to poorer outcomes, it is important to identify whether a long DUP is associated with greater brain structural abnormalities.

METHOD

81 patients with first-episode psychosis (schizophrenia, affective, and other psychoses) were scanned using high resolution Magnetic Resonance Imaging. DUP was defined as the number of days between first onset of psychotic symptoms and first contact with mental health services. High-resolution MRI images and voxel-based methods of image analysis were used to investigate brain structure in these patients.

RESULTS

Longer DUP was associated with gray matter reductions in left middle and inferior temporal, left occipital and left fusiform cortices, and with gray matter excess of the left basal ganglia. All findings remained significant when co-varying for exposure to antipsychotic treatment.

CONCLUSIONS

Temporal gray matter reductions are more marked in patients with a long DUP. This could reflect a progressive pathological process that is active prior to treatment. Alternatively, these abnormalities could be associated with a more insidious onset of illness and a later presentation to services.

Effects of antipsychotics on brain structure

PURPOSE OF REVIEW

This review highlights the recent findings of different effects of typical and atypical antipsychotics on brain structure.

RECENT FINDINGS

Studies examining the effect of treatment with typical antipsychotics on brain structure revealed a significant increase in basal ganglia volumes and decreased grey matter volume in different cortical regions. These volume changes were detectable even after a 12-week treatment. In contrast to these results, treatment with atypical antipsychotics does not seem to change basal ganglia volumes in neuroleptic-naïve patients. Moreover, switching from typical to atypical antipsychotic treatment reduces the increased basal ganglia volume to normal values compared with healthy controls. Only the volumes of thalamus and cortical grey matter increased after atypical antipsychotic treatment.

SUMMARY

Currently, there is growing evidence that atypical antipsychotics might ameliorate structural changes caused by the disease process underlying schizophrenia and effects of typical antipsychotics. Further studies have to investigate the mechanism leading to these varying effects on brain structure.

SPECT study of Chinese schizophrenic patients suggests that cerebral hypoperfusion and laterality exist in different ethnic groups

Hypofrontality is a common finding in schizophrenia in many countries. To date, there have been few studies on Chinese patients with schizophrenia. We thus wondered whether hypofrontality exists in Chinese patients with schizophrenia. We investigated 45 patients with schizophrenia and 21 healthy controls using brain perfusion single photon emission computed tomography (SPECT). Subjects were also administered the Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Positive Symptoms (SAPS), Scale for the Assessment of Negative Symptoms (SANS), Halstead-Reitan Neuropsychological Battery (HRNB) and the Wechsler Memory Scale-Revised (WMS-R). Images were analyzed using a semi-quantitative reading and a quantified region of interest analysis. We found that schizophrenic patients showed hypoperfusion in the frontal and temporal lobes and hyperperfusion in the basal ganglia. Schizophrenic patients with both negative and positive symptoms showed asymmetric perfusion in the temporal lobe. Schizophrenic patients with prominent negative symptoms also showed asymmetric perfusion in the prefrontal lobes. Negative symptoms showed a significantly negative correlation with regional cerebral blood flow (rCBF) in the left frontal lobe. Improved memory quotient (MQ) was significantly correlated with increased rCBF in the left temporal lobe. These findings from Chinese patients confirm a similar regional neuroanatomic dysfunction as in Western patients with the disease.

Increased pituitary volume in antipsychotic-free and antipsychotic-treated patients of the AEsop first-onset psychosis study

Subjects at their first psychotic episode show an enlarged volume of the pituitary gland, but whether this is due to hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, or to stimulation of the prolactin-secreting cells by antipsychotic treatment, is unclear. We measured pituitary volume, using 1.5-mm, coronal, 1.5 T, high-resolution MRI images, in 78 patients at the first psychotic episode and 78 age- and gender-matched healthy controls. In all, 18 patients were antipsychotic-free (12 of these were antipsychotic-naïve), 26 were receiving atypical antipsychotics, and 33 were receiving typical antipsychotics. As hypothesized, patients had a larger pituitary volume than controls (+22%, p< 0.001). When divided by antipsychotic treatment, and compared to controls, the pituitary volume was 15% larger in antipsychotic-free patients (p=0.028), 17% larger in patients receiving atypicals (p=0.01), and 30% larger in patients receiving typicals (p<0.001). Patients receiving typicals not only had the largest pituitary volume compared to controls but also showed a trend for a larger pituitary volume compared to the other patients grouped together (+11%, p=0.08). When divided by diagnosis, and compared to controls, the pituitary volume was 24% larger in patients with schizophrenia/schizophreniform disorder (n=40, p<0.001), 19% larger in depressed patients (n=13, p=0.022), 16% larger in bipolar patients (n=16, p=0.037), and 12% larger in those with other psychoses (n=9, p=0.2). In conclusion, the first-episode of a psychotic disorder is associated with a larger pituitary independently of the presence of antipsychotic treatment, and this could be due to activation of the HPA axis. Typical antipsychotics exert an additional enlarging effect on pituitary volume, likely to be related to activation of prolactin-secreting cells. This activation of the hormonal stress response could participate to the important metabolic abnormalities observed in patients with psychosis.

Chronic haloperidol promotes corticostriatal long-term potentiation by targeting dopamine D2L receptors

Reduced glutamate-mediated synaptic transmission has been implicated in the pathophysiology of schizophrenia. Because antipsychotic agents might exert their beneficial effects against schizophrenic symptoms by strengthening excitatory transmission in critical dopaminoceptive brain areas, in the present study we have studied the effects of acute and chronic haloperidol treatment on striatal synaptic plasticity. Repetitive stimulation of corticostriatal terminals in slices induced either long-term depression or long-term potentiation (LTP) of excitatory transmission in control rats, whereas it invariably induced NMDA receptor-dependent LTP in animals treated chronically with haloperidol. Haloperidol effects were mimicked and occluded in mice lacking both D2L and D2S isoforms of dopamine D2 receptors (D2R-/-), in mice lacking D2L receptors and expressing normal levels of D2S receptors (D2R-/-;D2L-/-), and in mice lacking D2L receptors and overexpressing D2S receptors (D2L-/-). These data indicate that the blockade of D2L receptors was responsible for the LTP-favoring action of haloperidol in the striatum. In contrast, overexpression of D2S receptors uncovered a facilitatory role of this receptor isoform in LTP formation because LTP recorded from D2L-/- mice, but not those recorded from wild-type, D2R-/-, and D2R-/-;D2L-/- mice, was insensitive to the pharmacological blockade of D1 receptors. The identification of the cellular, molecular, and receptor mechanisms involved in the action of haloperidol in the brain is essential to understand how antipsychotic agents exert their beneficial and side effects.

Region specific distribution of levomepromazine in the human brain

OBJECTIVE

The aim of this study was to examine concentrations of levomepromazine and its metabolite desmethyl-levomepromazine in different regions of human brain and in relationship to drug-free time.

METHODS

Drug concentrations were measured in up to 43 regions of 5 postmortem human brains of patients previously treated with levomepromazine. To enable statistical comparison across brain regions several smaller brain areas were put together to form larger brain areas (cortex cerebri, limbic system, cerebellum, basal ganglia, thalamus). Mean values of drug concentrations in these larger brain areas were used in a repeated measurement ANOVA to analyze for region specific distribution. The elimination half-life in brain tissue was estimated with a NONMEM population kinetic analysis using the mean value of all brain regions of an individual case.

RESULTS

Levomepromazine and desmethyl-levomepromazine appear to accumulate in human brain tissue relative to blood. Mean concentrations differed largely between individual brains, in part due to differences in dose of drug, duration of treatment and drug-free time before death. There was an apparent region-specific difference in levomepromazine concentrations with highest values in the basal ganglia (mean 316 ng/g) and lowest values in the cortex cerebri (mean 209 ng/g). The elimination half-life from brain tissue is longer than from blood and was calculated to be about one week. Similar results were obtained with desmethyl-levomepromazine.

CONCLUSIONS

Levomepromazine shows a region-specific distribution in the human brain with highest values in the basal ganglia. This might be the consequence of low expression of the metabolic enzyme Cyp2D6 in the basal ganglia. If this finding is true also for other neuroleptic drugs it might increase our understanding of preferential toxicity of neuroleptic drugs against basal ganglia structures and higher volumes of basal ganglia of neuroleptic-treated patients. Furthermore, patients exposed to levomepromazine cannot be considered to be free of residual effects of the drug for a number of weeks after withdrawal.

Volumetric MRI measurement of caudate nuclei in antipsychotic-naive patients suffering from a first episode of psychosis

Magnetic resonance imaging (MRI) studies measuring basal ganglia volumes in first episode patients suggest that treatment with typical neuroleptics leads to alteration in these brain structures. However, caudate nuclei volumes (CNV) of untreated first-episode patients may even be smaller than in healthy controls. We investigated whether CNV of newly diagnosed neuroleptic-naive psychotic patients differ as compared to an age- and sex-matched healthy control group to detect possible treatment effects early in the course of this illness. Magnetic resonance images were acquired in 37 un-medicated psychotic patients and 37 healthy controls. Ten of the patients were re-examined after 12 weeks of treatment with the second generation antipsychotic quetiapine. Regions of interest (ROI) delineating the caudate nuclei bilaterally were drawn manually using Brain Image software. The neuroleptic-naive patients showed a mean CNV of 8.40 cc (SD=1.01) and the controls of 8.55 cc (SD=1.16). There was no significant difference between groups (F=.600; P=.441). In contrast to previous studies in patients treated with typical neuroleptics, this cross-sectional MRI study did not find significant differences in CNV of neuroleptic-naive first-episode patients compared to healthy controls.

Sustained activation of the hippocampus in response to fearful faces in schizophrenia

BACKGROUND

In healthy individuals, the activity of the medial temporal lobe habituates rapidly with the repeated presentation of a stimulus. Using functional magnetic resonance imaging (fMRI), we tested the hypothesis that habituation of the medial temporal lobe is reduced in schizophrenia.

METHODS

During fMRI scanning, fearful and happy faces were presented repeatedly to healthy control subjects (n =16) and patients with schizophrenia (n =18). Habituation of medial temporal lobe structures was measured by comparing the hemodynamic response occurring during the early and late portions of the presentation of each face.

RESULTS

Control subjects demonstrated significant medial temporal lobe habituation to fearful but not to happy faces. In contrast, patients with schizophrenia did not demonstrate medial temporal lobe habituation in response to fearful or happy faces. In a direct, between-group comparison, right hippocampal habituation to fearful faces was significantly greater in control subjects than in the schizophrenia patients. Also, there were no significant differences between the patients and control subjects in the early medial temporal lobe response to fearful faces, suggesting that attenuated hippocampal habituation in schizophrenia is not associated with a reduction in initial activation.

CONCLUSIONS

These findings suggest that there is abnormal modulation of hippocampal responses to fearful faces in schizophrenia.