MRI correlates of treatment response in first episode psychosis

Interaction of Cannabis Use Disorder and Striatal Connectivity in Antipsychotic Treatment Response

Antipsychotic (AP) medications are the mainstay for the treatment of schizophrenia spectrum disorders (SSD), but their efficacy is unpredictable and widely variable. Substantial efforts have been made to identify prognostic biomarkers that can be used to guide optimal prescription strategies for individual patients. Striatal regions involved in salience and reward processing are disrupted as a result of both SSD and cannabis use, and research demonstrates that striatal circuitry may be integral to response to AP drugs. In the present study, we used functional magnetic resonance imaging (fMRI) to investigate the relationship between a history of cannabis use disorder (CUD) and a striatal connectivity index (SCI), a previously developed neural biomarker for AP treatment response in SSD. Patients were part of a 12-week randomized, double-blind controlled treatment study of AP drugs. A sample of 48 first-episode SSD patients with no more than 2 weeks of lifetime exposure to AP medications, underwent a resting-state fMRI scan pretreatment. Treatment response was defined a priori as a binary (response/nonresponse) variable, and a SCI was calculated in each patient. We examined whether there was an interaction between lifetime CUD history and the SCI in relation to treatment response. We found that CUD history moderated the relationship between SCI and treatment response, such that it had little predictive value in SSD patients with a CUD history. In sum, our findings highlight that biomarker development can be critically impacted by patient behaviors that influence neurobiology, such as a history of CUD.

Neuroimaging markers of antipsychotic treatment response in schizophrenia: An overview of magnetic resonance imaging studies

Antipsychotic drugs are the primary treatment for psychosis, yet individual response to their administration remains variable. At present, no biological predictors of response exist to guide clinicians as they select treatments for patients, and our understanding of the neurobiology underlying the heterogeneity of outcomes remains limited. Magnetic Resonance Imaging (MRI) has been applied by numerous studies to examine the response to antipsychotic treatment, though a large gap remains between their results and our clinical practice. To advance patient care with precision medicine approaches, prior work must be accounted for and built upon with future studies. This review provides an overview of studies that relate treatment outcome to various MRI-related measures, including structural, spectroscopic, diffusion tensor, and functional imaging. Knowledge derived from these studies will be discussed along with future directions for the field.

Neuroimaging in schizophrenia: what does it tell the clinician?

Neuroimaging has been used in clinical practice for over 30 years, but it is still perceived as rarely offering the psychiatrist much help in direct patient management. As newer imaging modalities are introduced (from computed tomography and positron and single photon emission tomography to magnetic and functional magnetic resonance imaging), the promise of imminent clinical utility is reawakened, only to fade as the innovation is shown to be another, albeit useful, research tool. The aim of this article is to update readers on some recent advances that are starting to align the research and clinical functions of neuroimaging. As imaging becomes more accessible and affordable there is real promise that both clinicians and patients will begin to benefit more directly.

PKBγ/AKT3 loss-of-function causes learning and memory deficits and deregulation of AKT/mTORC2 signaling: Relevance for schizophrenia

Psychiatric genetic studies have identified genome-wide significant loci for schizophrenia. The AKT3/1q44 locus is a principal risk region and gene-network analyses identify AKT3 polymorphisms as a constituent of several neurobiological pathways relevant to psychiatric risk; the neurobiological mechanisms remain unknown. AKT3 shows prenatal enrichment during human neocortical development and recurrent copy number variations involving the 1q43-44 locus are associated with cortical malformations and intellectual disability, implicating an essential role in early brain development. Here, we investigated the role of AKT3 as it relates to aspects of learning and memory and behavioral function, relevant to schizophrenia and cognitive disability, utilizing a novel murine model of Akt3 genetic deficiency. Akt3 heterozygous (Akt3^-/+) or null mice (Akt3^-/-) were assessed in a comprehensive test battery. Brain biochemical studies were conducted to assess the impact of Akt3 deficiency on cortical Akt/mTOR signaling. Akt3^-/+ and Akt3^-/- mice exhibited selective deficits of temporal order discrimination and spatial memory, tasks critically dependent on intact prefrontal-hippocampal circuitry, but showed normal prepulse inhibition, fear conditioned learning, memory for novel objects and social function. Akt3 loss-of-function, reduced brain size and dramatically impaired cortical Akt Ser⁴⁷³ activation in an allele-dose dependent manner. Such changes were observed in the absence of altered Akt1 or Akt2 protein expression. Concomitant reduction of the mTORC2 complex proteins, Rictor and Sin1 identifies a potential mechanism. Our findings provide novel insight into the neurodevelopmental role of Akt3, identify a non-redundant role for Akt3 in the development of prefrontal cortical-mediated cognitive function and show that Akt3 is potentially the dominant regulator of AKT/mTOR signaling in brain.

Is treatment-resistant schizophrenia categorically distinct from treatment-responsive schizophrenia? a systematic review

BACKGROUND

Schizophrenia is a highly heterogeneous disorder, and around a third of patients are treatment-resistant. The only evidence-based treatment for these patients is clozapine, an atypical antipsychotic with relatively weak dopamine antagonism. It is plausible that varying degrees of response to antipsychotics reflect categorically distinct illness subtypes, which would have significant implications for research and clinical practice. If these subtypes could be distinguished at illness onset, this could represent a first step towards personalised medicine in psychiatry. This systematic review investigates whether current evidence supports conceptualising treatment-resistant and treatment-responsive schizophrenoa as categorically distinct subtypes.

METHOD

A systematic literature search was conducted, using PubMed, EMBASE, PsycInfo, CINAHL and OpenGrey databases, to identify all studies which compared treatment-resistant schizophrenia (defined as either a lack of response to two antipsychotic trials or clozapine prescription) to treatment-responsive schizophrenia (defined as known response to non-clozapine antipsychotics).

RESULTS

Nineteen studies of moderate quality met inclusion criteria. The most robust findings indicate that treatment-resistant patients show glutamatergic abnormalities, a lack of dopaminergic abnormalities, and significant decreases in grey matter compared to treatment-responsive patients. Treatment-resistant patients were also reported to have higher familial loading; however, no individual gene-association study reported their findings surviving correction for multiple comparisons.

CONCLUSIONS

Tentative evidence supports conceptualising treatment-resistant schizophrenia as a categorically different illness subtype to treatment-responsive schizophrenia. However, research is limited and confirmation will require replication and rigorously controlled studies with large sample sizes and prospective study designs.

Neuroimaging biomarkers to predict treatment response in schizophrenia: the end of 30 years of solitude?

Studies that have used structural magnetic resonance imaging (MRI) suggest that individuals with psychoses have brain alterations, particularly in frontal and temporal cortices, and in the white matter tracts that connect them. Furthermore, these studies suggest that brain alterations may be particularly prominent, already at illness onset, in those individuals more likely to have poorer outcomes (eg, higher number of hospital admissions, and poorer symptom remission, level of functioning, and response to the first treatment with antipsychotic drugs). The fact that, even when present, these brain alterations are subtle and distributed in nature, has limited, until now, the utility of MRI in the clinical management of these disorders. More recently, MRI approaches, such as machine learning, have suggested that these neuroanatomical biomarkers can be used for direct clinical benefits. For example, using support vector machine, MRI data obtained at illness onset have been used to predict, with significant accuracy, whether a specific individual is likely to experience a remission of symptoms later on in the course of the illness. Taken together, this evidence suggests that validated, strong neuroanatomical markers could be used not only to inform tailored intervention strategies in a single individual, but also to allow patient stratification in clinical trials for new treatments.

Magnetic resonance imaging and the prediction of outcome in first-episode schizophrenia: a review of current evidence and directions for future research

Magnetic Resonance Imaging (MRI) measures are promising outcome markers for schizophrenia, since regional frontal and temporal grey matter volumes reductions, and enlargement of the ventricles, have been associated with outcome in this disorder. However, a number of methodological issues have limited the potential clinical utility of these findings. This article reviewed studies that examined brain structure at illness onset as a predictor of outcome, discusses the limitations of the findings, and highlights the challenges that would need to be addressed if structural data are to inform the management of an individual patient.

METHODS

Using a set of a priori criteria, we systematically searched Medline and EMBASE databases for articles evaluating brain structure at the time of the first psychotic episode and assessed response to treatment, symptomatic outcome, or functional outcome at any point in the first 12 months of illness.

RESULTS

The 11 studies identified suggest that alterations in medial temporal and prefrontal cortical areas, and in the networks that connect them with subcortical structures, are promising neuroanatomical markers of poor symptomatic and functional outcomes.

CONCLUSION

Neuroimaging data, possibly in combination with other biomarkers of disease, could help stratifying patients with psychoses to generate patient clusters clinically meaningful, and useful to detect true therapeutic effects in clinical trials. Optimization of Treatment and Management of Schizophrenia in Europe (OPTiMiSE), a large multicenter study funded by the FP7 European Commission, could generate these much-needed findings.

Patients with poor response to antipsychotics have a more severe pattern of frontal atrophy: a voxel-based morphometry study of treatment resistance in schizophrenia

Approximately 30% of schizophrenia patients do not respond adequately to the therapy. Previous MRI studies have suggested that drug treatment resistance is associated with brain morphological abnormalities, although region-of-interest analysis of MR studies from nonresponder and responder patients failed to demonstrate a statistically significant difference between these two schizophrenia subgroups. We have used a voxel-based analysis of segmented MR studies to assess structural cerebral differences in 20 nonresponder and 15 responder patients and 16 age-matched normal volunteers. Differences between the three groups emerged bilaterally mainly at the level of the superior and middle frontal gyri, primarily due to reduced grey matter volumes in nonresponders, as compared to both normal volunteers and responder patients. Post hoc direct comparison between the two schizophrenia subgroups demonstrated significantly reduced grey matter volumes in middle frontal gyrus bilaterally, in the dorsolateral aspects of left superior frontal gyrus extending into postcentral gyrus and in the right medial temporal cortex. Our results extend and integrate previous findings suggesting a more severe atrophy in nonresponder schizophrenia patients, compared to responder patients, mainly at the level of the superior and middle frontal gyri. Longitudinal studies in drug-naïve patients are needed to assess the role of these associations.

Outcome studies in schizophrenia

Objectives:To outline the limitations of traditional studies of outcome in schizophrenia and to review the findings arising from ‘first episode’ psychosis studies.

Method:An extensive literature search was performed and relevant papers were examined and analysed.

Results:Current knowledge regarding outcome predictors in schizophrenia has primarily been derived from a series of ‘consecutive admission’ and ‘long-term follow-back’ studies. However, methodological considerations may limit the generalisability of these studies' findings. The prospective evaluation of first episode cohorts has advanced our knowledge regarding the relative importance of premorbid and intercurrent factors in determining outcome in schizophrenia.

Conclusions:To date, the ‘first episode’ strategy has highlighted some potentially clinically modifiable outcome predictors. These findings may open the way for targeted introduction of measures aimed at preventing poor outcomes in schizophrenia.

Magnetic resonance imaging predictors of treatment response in first-episode schizophrenia

Identifying neurobiological predictors of response to antipsychotics in patients with schizophrenia is a critical goal of translational psychiatry. Few studies, however, have investigated the relationship between indices of brain structure and treatment response in the context of a controlled clinical trial. In this study, we sought to identify magnetic resonance (MR) imaging measures of the brain that predict treatment response in patients experiencing a first-episode of schizophrenia. Structural MR imaging scans were acquired in 39 patients experiencing a first-episode of schizophrenia with minimal or no prior exposure to antipsychotics participating in a double-blind 16-week clinical trial comparing the efficacy of risperidone vs olanzapine. Twenty-five patients were classified as responders by meeting operationally defined treatment response criteria on 2 consecutive study visits. Fourteen patients never responded to antipsychotic medication at any point during the clinical trial. MR imaging scans were also acquired in 45 age- and sex-matched healthy volunteers. Cortical pattern matching methods were used to compare cortical thickness and asymmetry measures among groups. Statistical mapping results, confirmed by permutation testing, indicated that responders had greater cortical thickness in occipital regions and greater frontal cortical asymmetry compared with nonresponders. Moreover, among responders, greater thickness in temporal regions was associated with less time to respond. Our findings are consistent with the hypothesis that plasticity and cortical thickness may be more preserved in responders and that MR imaging may assist in the prediction of antipsychotic drug response in patients experiencing a first-episode of schizophrenia.

Optimized voxel brain morphometry: association between brain volumes and the response to atypical antipsychotics

To date, few studies have addressed the relationship between brain structure alterations and responses to atypical antipsychotics in schizophrenia. To this end, in this study, magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) were used to assess the relationship between the brain volumes of gray (GM) and white (WM) matters and the clinical response to risperidone or olanzapine in 30 schizophrenia patients. In comparison with healthy controls, the patients in this study showed a bilateral decrease in the anteromedial cerebellar hemispheres, the rectal gyrus and the insula, together with bilateral increases in GM in the basal ganglia. Both patient groups had a significantly smaller volume of WM in a region encompassing the internal and external capsules as compared to the controls. We found an inverse association between striatal size and the degree of clinical improvement, and a direct association between the degree of insular volume deficit and its improvement. The non-responder patient group showed a significant decrease in their left rectal gyrus as compared with the responder group. This study reveals a pattern of structural alterations in schizophrenia associated with the response to risperidone or olanzapine.

Review: The biological basis of antipsychotic response in schizophrenia

Schizophrenia is a severe mental illness affecting approximately 1% of the population worldwide. Antipsychotic drugs are effective in symptom control in up to two-thirds of patients, but in at least one-third of patients the response is poor. The reason for this is not clear, but one possibility is that good and poor responders have different neurochemical pathologies, and may therefore benefit from different treatment approaches. In this selective review we summarise research findings investigating the biological differences between patients with schizophrenia who show a good or a poor response to treatment with antipsychotic drugs.

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.

Cortisol levels in relation to hippocampal sub-regions in subjects with first episode schizophrenia

The etiology of hippocampal volumetric reductions in schizophrenia is largely unknown. In addition to genetic factors, environmental factors might also play a role. High levels of glucocorticoids are known to affect hippocampal volume in disorders such as Cushing's syndrome, but the relationship between cortisol and hippocampal volumes has not been studied in schizophrenia. We obtained diurnal salivary cortisol levels and MRI images to explore the link between cortisol levels and regional hippocampal volumes in healthy controls (N=29) and subjects with first episode schizophrenia (N=16) at the time of first admission. T1-weighted coronal MR images (slice thickness=1.5 mm) were acquired through the whole head using a 3D Fast SPGR IR Prep sequence on a 1.5 T GE imaging system. Using ANOVA, cumulative daily cortisol exposure calculated as area under the curve for each subject revealed significantly higher cortisol levels in the patient group [F(1,43)=4.4 p=0.04]. However, there were no statistically significant associations between the cortisol measures and regional hippocampal volumes in the subjects, except a trend level link between anterior hippocampal volume and cortisol in the positive direction, in parallel to previous findings in healthy adolescents. Our findings do not suggest a robust association between cortisol levels and hippocampal volumes in a first episode schizophrenia sample. Larger scale studies are needed to conclude a link between the two measures, yet it is possible that the negative association that was previously shown in other disorders may not apply to schizophrenia.

Brain volume in first-episode schizophrenia: systematic review and meta-analysis of magnetic resonance imaging studies

BACKGROUND

Studies of people with schizophrenia assessed using magnetic resonance imaging (MRI) usually include patients with first-episode and chronic disease, yet brain abnormalities may be limited to those with chronic schizophrenia.

AIMS

To determine whether patients with a first episode of schizophrenia have characteristic brain abnormalities.

METHOD

Systematic review and meta-analysis of 66 papers comparing brain volume in patients with a first psychotic episode with volume in healthy controls.

RESULTS

A total of 52 cross-sectional studies included 1424 patients with a first psychotic episode; 16 longitudinal studies included 465 such patients. Meta-analysis suggests that whole brain and hippocampal volume are reduced (both P<0.0001) and that ventricular volume is increased (P<0.0001) in these patients relative to healthy controls.

CONCLUSIONS

Average volumetric changes are close to the limit of detection by MRI methods. It remains to be determined whether schizophrenia is a neurodegenerative process that begins at about the time of symptom onset, or whether it is better characterised as a neurodevelopmental process that produces abnormal brain volumes at an early age.

Population-based and family-based association study of 5'UTR polymorphism of the reelin gene and schizophrenia

Reelin is a glycoprotein involved in the migration and positioning of proliferating neurons and synaptic connectivity during neurodevelopment. It may also modulate neuronal plasticity throughout life. Therefore, the reelin gene is a candidate gene for schizophrenia. We examined the association of the CGG repeat polymorphism in the 5'-untranslated region of the reelin gene with schizophrenia in 266 unrelated French Caucasian patients, 156 of their parents, and 103 controls. We found no difference in the allele distribution between patients and controls although there was a significant higher prevalence of the genotype 8-8 in controls (CLUMP T3: chi(2) = 6.3, P = 0.035). There was no significant transmission disequilibrium in intrafamilial analysis. To refine our phenotypic characterization and in accordance with converging evidence suggesting that treatment resistance is associated with indices of abnormal neurodevelopment, we studied the association between reelin gene polymorphism and response to antipsychotics. Patients who responded to antipsychotics had a higher frequency of both the (CGG)(10) allele and (CGG)(10)-containing genotypes (P = 0.02; P = 0.006, respectively), with an odd ratio for genotypes of 4.2 (CI = [1.4;12.4]). Our results weakly support an association of reelin gene variants with schizophrenia as a whole, yet suggest that reelin could be associated with treatment-resistant schizophrenia.

Direct association between orbitofrontal atrophy and the response of psychotic symptoms to olanzapine in schizophrenia

The study of cerebral variables associated with response to neuroleptics holds interest from both theoretical and clinical points of view. To date, no studies have aimed to identify predictors of response to olanzapine based on cerebral measurements. Here, we used magnetic resonance to assess the relationship between volumes of the prefrontal (dorsolateral and orbitofrontal) and temporal (temporal lobe and hippocampus) cortical regions and ventricles and, on the other hand, the response to olanzapine in 16 schizophrenic patients. Data from 42 healthy controls were used to calculate volume residuals in the patients, defined as deviations from the expected values, given individual age and intracranial volume. Residuals thus represent the effect of illness on regional measurements. The association between clinical change and those residuals was calculated separately for the positive, negative and total scores from the Positive and Negative Syndrome Scale (PANSS). There was a significant direct association between the degree of orbitofrontal atrophy and the improvement of positive symptoms with olanzapine. No predictors were found for change in the negative dimension. A trend was found for patients with larger ventricles to show a greater global decrease in total PANSS scores. Neither age nor duration of illness explained a significant proportion of the symptom improvement. This result, together with others from the literature, supports the idea that atypical antipsychotics may offer some benefit to patients with significant regional atrophy, and this may have implications for the choice of antipsychotic in clinical practice.

Anatomical and functional cerebral variables associated with basal symptoms but not risperidone response in minimally treated schizophrenia

In schizophrenia, structural and functional cerebral variables show an unclear association with clinical features and their value as predictors of response to a typical antipsychotic agents has yet to be determined. The goal of this study was to investigate the relationships between clinical variables (baseline syndromes and response to risperidone) and anatomo-functional brain variables. We studied 19 minimally treated patients with schizophrenia of recent onset using magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (FDG-PET) under resting conditions. The following brain variables were studied: volume of the cerebrospinal fluid (CSF) and gray matter (GM) of the dorsolateral prefrontal cortex (DLPFC) and temporal lobe; hippocampal metabolic activity and volume; and metabolic activity of the DLPFC, temporal lobe, putamen and caudate. Anatomical volume measurements were corrected for age and intracranial size using regression parameters determined from a matched sample of control subjects. Using stepwise multiple regression, we assessed the relation between these brain measures and basal scores of symptom dimensions (positive, disorganization, negative and total), as well as their change in response to risperidone. We found that positive and disorganization symptoms improved with risperidone treatment and that hippocampal metabolism, DLPFC CSF volume, and temporal CSF volume predicted baseline symptoms. However, none of the brain measures predicted response to treatment. We conclude that there is evidence of a significant association between basal symptoms and DLPFC atrophy and limbic hyperactivity at rest in recent-onset schizophrenic patients.

Neuropsychological impairments in neuroleptic-responder vs. -nonresponder schizophrenic patients and healthy volunteers

To determine whether two groups of schizophrenic patients representing the two extremes of the neuroleptic response-spectrum (consistent responders vs. consistent nonresponders) differ with respect to their neuropsychological profile. Neuroleptic-responder (R; n=36) and -nonresponder (NR; n=39) schizophrenic patients were recruited according to a priori defined criteria of responsiveness to typical neuroleptics. Seven neuropsychological domains were assessed and compared between groups: attention-vigilance, abstraction-flexibility, spatial organization, visual-motor processing, visual memory, verbal abilities, and verbal memory and learning. All measures were standardized using the scores of 36 healthy volunteers. NR schizophrenic patients performed worse in all neuropsychological domains compared to normal controls and R schizophrenic patients. However, only performances on visual memory, verbal abilities, and verbal memory and learning were significantly poorer in NR compared to R patients. Only the latter domain significantly differentiated NR patients from the other two groups. R patients performed at an intermediate level in all domains. This report of differences in neuropsychological profile between neuroleptic-responder and -nonresponder schizophrenic patients adds to the growing evidence supporting the value of distinguishing schizophrenic patients on the basis of their therapeutic response to neuroleptics.

A review of MRI findings in schizophrenia

After more than 100 years of research, the neuropathology of schizophrenia remains unknown and this is despite the fact that both Kraepelin (1919/1971: Kraepelin, E., 1919/1971. Dementia praecox. Churchill Livingston Inc., New York) and Bleuler (1911/1950: Bleuler, E., 1911/1950. Dementia praecox or the group of schizophrenias. International Universities Press, New York), who first described 'dementia praecox' and the 'schizophrenias', were convinced that schizophrenia would ultimately be linked to an organic brain disorder. Alzheimer (1897: Alzheimer, A., 1897. Beitrage zur pathologischen anatomie der hirnrinde und zur anatomischen grundlage einiger psychosen. Monatsschrift fur Psychiarie und Neurologie. 2, 82-120) was the first to investigate the neuropathology of schizophrenia, though he went on to study more tractable brain diseases. The results of subsequent neuropathological studies were disappointing because of conflicting findings. Research interest thus waned and did not flourish again until 1976, following the pivotal computer assisted tomography (CT) finding of lateral ventricular enlargement in schizophrenia by Johnstone and colleagues. Since that time significant progress has been made in brain imaging, particularly with the advent of magnetic resonance imaging (MRI), beginning with the first MRI study of schizophrenia by Smith and coworkers in 1984 (Smith, R.C., Calderon, M., Ravichandran, G.K., et al. (1984). Nuclear magnetic resonance in schizophrenia: A preliminary study. Psychiatry Res. 12, 137-147). MR in vivo imaging of the brain now confirms brain abnormalities in schizophrenia. The 193 peer reviewed MRI studies reported in the current review span the period from 1988 to August, 2000. This 12 year period has witnessed a burgeoning of MRI studies and has led to more definitive findings of brain abnormalities in schizophrenia than any other time period in the history of schizophrenia research. Such progress in defining the neuropathology of schizophrenia is largely due to advances in in vivo MRI techniques. These advances have now led to the identification of a number of brain abnormalities in schizophrenia. Some of these abnormalities confirm earlier post-mortem findings, and most are small and subtle, rather than large, thus necessitating more advanced and accurate measurement tools. These findings include ventricular enlargement (80% of studies reviewed) and third ventricle enlargement (73% of studies reviewed). There is also preferential involvement of medial temporal lobe structures (74% of studies reviewed), which include the amygdala, hippocampus, and parahippocampal gyrus, and neocortical temporal lobe regions (superior temporal gyrus) (100% of studies reviewed). When gray and white matter of superior temporal gyrus was combined, 67% of studies reported abnormalities. There was also moderate evidence for frontal lobe abnormalities (59% of studies reviewed), particularly prefrontal gray matter and orbitofrontal regions. Similarly, there was moderate evidence for parietal lobe abnormalities (60% of studies reviewed), particularly of the inferior parietal lobule which includes both supramarginal and angular gyri. Additionally, there was strong to moderate evidence for subcortical abnormalities (i.e. cavum septi pellucidi-92% of studies reviewed, basal ganglia-68% of studies reviewed, corpus callosum-63% of studies reviewed, and thalamus-42% of studies reviewed), but more equivocal evidence for cerebellar abnormalities (31% of studies reviewed). The timing of such abnormalities has not yet been determined, although many are evident when a patient first becomes symptomatic. There is, however, also evidence that a subset of brain abnormalities may change over the course of the illness. The most parsimonious explanation is that some brain abnormalities are neurodevelopmental in origin but unfold later in development, thus setting the stage for the development of the symptoms of schizophrenia. Or there may be additional factors, such as stress or neurotoxicity, that occur during adolescence or early adulthood and are necessary for the development of schizophrenia, and may be associated with neurodegenerative changes. Importantly, as several different brain regions are involved in the neuropathology of schizophrenia, new models need to be developed and tested that explain neural circuitry abnormalities effecting brain regions not necessarily structurally proximal to each other but nonetheless functionally interrelated. (ABSTRACT TRUNCATED)

The timing of neurodevelopmental abnormality in schizophrenia: an integrative review of the neuroimaging literature

In this paper we will review recent neuroimaging research in schizophrenia, with an aim to critically evaluate several recent proposals concerning the nature and the timing of the neuroanatomic abnormalities underlying the disorder. Specifically, enlargement of cerebrospinal fluid spaces, deficits in cortical gray matter, and reduced volume of mesiotemporal structures have all been reported in patients in the first episode of schizophrenia, their first-degree relatives, and individuals with schizotypal personality disorder, supporting the possibility that these abnormalities reflect a genetically mediated neurodevelopmental disorder. These findings from the empirical literature will be synthesized from the perspective of dual cytoarchitectonic trends theory of neurodevelopment, as well as in relation to current conceptions of the schizophrenia prodrome. We believe that the evidence shows that sufficient groundwork has been laid to begin longitudinal neuroimaging studies of adolescents at clinical risk for schizophrenia, in order to more definitively determine the pathophysiology of the disorder. Such information could have significant implications in terms of understanding the prediction, treatment, and ultimately the prevention of schizophrenia.

Prodromal schizophrenia and atypical antipsychotic treatment

Early recognition and intervention in psychosis is the focus of more intensive research. In this paper, we critically review the ideas that have emerged in this field. We also propose a model or hypothesis for testing in the prodromal phase of schizophrenia. Attention to practical and ethical issues, particularly with the use of atypical antipsychotics in one arm of the protocol, is addressed. Studies by Yung and Falloon describe prodromal intervention with psychosocial strategies and time-limited low potency neuroleptics, respectively, that suggest benefits of such a model. Although we have respect for the DSM system, this paper is written more from a Bleulerian than Kraepelinian perspective in that we emphasize affective, cognitive, and negative symptoms in addition to positive symptoms. The paper recognizes the strong conceptual disagreements implicit in this area stemming not only from Kraepelin and Bleuler but work from the 1930s by Cameron. The clinical research advocated is timely in that the atypicals are more congruent to the Bleulerian conception with a neurodevelopmental hypothesis of schizophrenia. We also have exciting new imaging and genetic technologies to refine our concepts of schizophrenia and its prodromal and premorbid phases.