Neurodevelopmental and neuroprogressive processes in schizophrenia. Antithetical or complementary, over a lifetime trajectory of disease?

Translational evidence for the Inflammatory Response System (IRS)/Compensatory Immune Response System (CIRS) and neuroprogression theory of major depression

Major depressive disorder (MDD) is a common, severe and disabling neuropsychiatric disorder with a heterogenous etiology. Among the most widely recognized etiological models, immunopathogenesis is a predominant one. Numerous studies have demonstrated aberrant levels of inflammatory markers in the peripheral blood, cerebrospinal fluid (CSF) and brain of patients with MDD. Multiple studies including meta-analyses have reported increased peripheral levels of acute phase proteins, and pro-inflammatory cytokines, particularly IL-1β, TNF-α, and IL-6 in MDD. Postmortem brain studies similarly demonstrated upregulated expressions of these pro-inflammatory cytokines. This along with evidence of monocytic, lymphocytic and microglial activation, suggest an activated inflammatory response system (IRS) in MDD. A few studies show increased levels of anti-inflammatory cytokines or defective inflammatory pathways and a deficit in T cell maturation and responses in MDD patients. This suggests the presence of a Compensatory Immune Response System (CIRS), which can counterbalance the effects of IRS in major depression. More recently, simultaneously increased levels of both the pro-and anti-inflammatory cytokines are reported in the brain of MDD patients; this indicates activity of both the IRS and CIRS in MDD. The IRS and CIRS are the evolutionarily conserved and integral elements of an overarching system. The relevance of a dysregulated IRS-CIRS system in the neurobiological construct of MDD is just beginning to be understood. Speculation is rife that the disrupted IRS-CIRS elements might determine the onset, episodes, neuroprogressive processes, treatment response as well as recovery of patients with MDD. Notably, the signatures of an activated IRS-CIRS might emerge as potential biomarkers of MDD. Herein, an attempt has been made to highlight the biology and pathobiological relevance of IRS-CIRS activation in MDD and provide an insight into the role of these components in pharmacological therapy.

Dysregulation of the NF-κB pathway as a potential inducer of bipolar disorder

A century of investigations enhanced our understanding of bipolar disorder although it remains a complex multifactorial disorder with a mostly unknown pathophysiology and etiology. The role of the immune system in this disorder is one of the most controversial topics in genetic psychiatry. Though inflammation has been consistently reported in bipolar patients, it remains unclear how the immunologic process influences the disorder. One of the core components of the immune system is the NF-κB pathway, which plays an essential role in the development of innate and adaptive immunity. Remarkably, the NF-κB pathway received only little attention in bipolar studies, as opposed to studies of related psychiatric disorders where immune dysregulation has been proposed to explain the neurodegeneration in patient conditions. If immune dysregulation can also explains the neurodegeneration in bipolar disorder, it will underscore the role of the immune system in the chronicity and pathophysiology of the disorder and may promote personalized therapeutic strategies. This is the first review to summarize the current knowledge of the pathophysiological functions of NF-κB in bipolar disorder.

Translating the N-methyl-D-aspartate receptor antagonist model of schizophrenia to treatments for cognitive impairment in schizophrenia

The N-methyl-D-aspartate receptor (NMDAR) antagonists, phencyclidine (PCP), dizocilpine (MK-801), or ketamine, given subchronically (sc) to rodents and primates, produce prolonged deficits in cognitive function, including novel object recognition (NOR), an analog of human declarative memory, one of the cognitive domains impaired in schizophrenia. Atypical antipsychotic drugs (AAPDs) have been reported to improve declarative memory in some patients with schizophrenia, as well as to ameliorate and prevent the NOR deficit in rodents following scNMDAR antagonist treatment. While the efficacy of AAPDs to improve cognitive impairment in schizophrenia (CIS) is limited, at best, and controversial, single doses of all currently available AAPDs so far tested transiently restore NOR in rodents following scNMDAR antagonist treatment. Typical antipsychotic drugs (APDs), e.g. haloperidol and perphenazine, are ineffective in this rodent model, and may be less effective as treatments of some domains of CIS. Serotonergic mechanisms, including, but not limited to serotonin (5-HT)2A and 5-HT7 antagonism, 5-HT(1A), and GABA(A) agonism, contribute to the efficacy of the AAPDs in the scNMDAR antagonist rodent models, which are relevant to the loss of GABA interneuron/hyperglutamate hypothesis of the etiology of CIS. The ability of sub-effective doses of the atypical APDs to ameliorate NOR in the scNMDAR-treated rodents can be restored by the addition of a sub-effective dose of the 5-HT(1A) partial agonist, tandospirone, or the 5-HT7 antagonist, SB269970. The mGluR2/3 agonist, LY379268, which itself is unable to restore NOR in the scNMDAR-treated rodents, can also restore NOR when given with lurasidone, an AAPD. Enhancing cortical and hippocampal dopamine and acetylcholine efflux, or both, may contribute to the restoration of NOR by the atypical APDs. Importantly, co-administration of lurasidone, tandospirone, or SB269970, with PCP, to rodents, at doses 5-10 fold greater than those acutely effective to restore NOR following scNMDAR treatment, prevents the effect of scPCP to produce an enduring deficit in NOR. This difference in dosage may be relevant to utilizing AAPDs to prevent the onset of CIS in individuals at high risk for developing schizophrenia. The scNMDAR paradigm may be useful for identifying possible means to treat and prevent CIS.

Schizophrenia as a disorder of too little dopamine: implications for symptoms and treatment

Antipsychotics represent the first effective therapy for schizophrenia, with their benefits linked to dopamine D2 blockade. Schizophrenia was soon identified as a hyperdopaminergic disorder, and antipsychotics proved to be reasonably effective in controlling positive symptoms. However, over the years, schizophrenia has been reconceptualized more broadly, now defined as a heterogeneous disorder with multiple symptom domains. Negative and cognitive features, not particularly responsive to antipsychotic therapy, have taken on increased importance--current thinking suggests that these domains predate the onset of positive symptoms and are more closely tied to functional outcome. That they are better understood in the context of decreased dopamine activity suggests that schizophrenia may fundamentally represent a hypodopaminergic disorder. This shift in thinking has important theoretical implications from the standpoint of etiology and pathophysiology, but also clinically in terms of treatment and drug development.

Pathways underlying neuroprogression in bipolar disorder: focus on inflammation, oxidative stress and neurotrophic factors

There is now strong evidence of progressive neuropathological processes in bipolar disorder (BD). On this basis, the current understanding of the neurobiology of BD has shifted from an initial focus on monoamines, subsequently including evidence of changes in intracellular second messenger systems and more recently to, incorporating changes in inflammatory cytokines, corticosteroids, neurotrophins, mitochondrial energy generation, oxidative stress and neurogenesis into a more comprehensive model capable of explaining some of the clinical features of BD. These features include progressive shortening of the inter-episode interval with each recurrence, occurring in consort with reduced probability of treatment response as the illness progresses. To this end, emerging data shows that these biomarkers may differ between early and late stages of BD in parallel with stage-related structural and neurocognitive alterations. This understanding facilitates identification of rational therapeutic targets, and the development of novel treatment classes. Additionally, these pathways provide a cogent explanation for the efficacy of seemingly diverse therapies used in BD, that appear to share common effects on oxidative, inflammatory and neurotrophic pathways.

White matter integrity and prediction of social and role functioning in subjects at ultra-high risk for psychosis

BACKGROUND

White matter microstructural disruptions have been observed in patients with schizophrenia. However, whether changes exist prior to disease onset or in high-risk individuals is unclear. Here, we investigated white matter integrity, as assessed by diffusion tensor imaging (DTI), in individuals at ultra-high risk for psychosis (UHR) relative to healthy control subjects (HC) and the relationship between baseline DTI measures and functional outcome over time.

METHODS

Thirty-six UHR participants and 25 HCs completed baseline DTI scans. Subjects also completed clinical follow-up assessments approximately 6 months (26 subjects) and 15 months (13 subjects) later. We used a rigorous registration approach (Tract-Based Spatial Statistics [TBSS]) to examine fractional anisotropy (FA) in six major white matter tracts.

RESULTS

Relative to the HC group, UHR subjects showed lower baseline FA in the superior longitudinal fasciculus, the major frontoparietal white matter connection. Cross-sectional analyses demonstrated that UHR youth failed to show the same age-associated increases in FA in the medial temporal lobe (MTL) and inferior longitudinal fasciculus as HCs. Finally, lower baseline FA in the MTL and inferior longitudinal fasciculus predicted deterioration in social and role functioning in UHR participants at 15-month follow-up.

CONCLUSIONS

This is the first investigation of white matter microstructural alterations in a clinical high-risk sample. Our findings indicate that white matter development may be altered in youth at risk for psychosis, possibly due to disrupted developmental mechanisms, and further, that white matter integrity may be predictive of functional outcome.

Connexin 50 gene on human chromosome 1q21 is associated with schizophrenia in matched case control and family-based studies

BACKGROUND

The gap junction subunit connexin permits direct intercellular exchange of ions and molecules including glutamate, and plays an important role in the central nervous system. The connexin 40 (Cx40) and connexin 50 (Cx50) genes are located on chromosome 1q21.1, a region strongly linked with schizophrenia. These lines of evidence suggest that Cx40 and Cx50 may play a role in schizophrenia.

METHODS

Using an allele-specific PCR assay, four polymorphisms each were genotyped for Cx40 and Cx50 in 190 Caucasian patients with schizophrenia and 190 controls matched for sex, age and ethnicity. Following up, Cx50 rs989192 and rs4950495 were investigated in 99 Canadian and 163 Portuguese trios and nuclear families with schizophrenia probands. Hardy-Weinberg equilibrium and linkage disequilibrium (LD) block identification was carried out with HaploView, and association analysis for alleles and haplotypes with a permutation test of 10 000 simulations was carried out using the UNPHASED software program.

RESULTS

Distributions of genotype frequencies of all markers were in Hardy-Weinberg equilibrium in Caucasian patients, controls and families. One rs989192-rs4950495 LD block was found in patients but not in controls. We found a significant association between the Cx50 rs989192-rs4950495 haplotype and schizophreniay (chi(2) = 29.55, p<0.01). The A-C haplotype had a higher frequency in patients (chi(2) = 7.153, p<0.01). Family studies also showed that the A-C haplotype was transmitted more often to patients with schizophrenia (chi(2) = 8.43, p<0.01). No association of Cx40 with schizophrenia was found for allele, genotype or haplotype analyses.

CONCLUSIONS

Our matched case-control and family study indicate that Cx50, but not Cx40, may play a role in the genetic susceptibility to schizophrenia.

Maternal infection and white matter toxicity

Studies examining maternal infection as a risk factor for neurological disorders in the offspring have suggested that altered maternal immune status during pregnancy can be considered as an adverse event in prenatal development. Infection occurring in the mother during the gestational period has been implicated in multiple neurological effects. The current manuscript will consider the issue of immune/inflammatory conditions during prenatal development where adverse outcomes have been linked to maternal systemic infection. The discussions will focus primary on white matter and oligodendrocytes as they have been identified as target processes. This white matter damage occurs in very early preterm infants and in various other human diseases currently being examined for a linkage to maternal or early developmental immune status. The intent is to draw attention to the impact of altered immune status during pregnancy on the offspring for the consideration of such contributing factors to the general assessment of developmental neurotoxicology.

Immune activation during pregnancy in mice leads to dopaminergic hyperfunction and cognitive impairment in the offspring: a neurodevelopmental animal model of schizophrenia

BACKGROUND

Maternal viral infection is associated with increased risk for schizophrenia. It is hypothesized that the maternal immune response to viruses may influence fetal brain development and lead to schizophrenia.

METHODS

To mimic a viral infection, the synthetic double strand RNA polyriboinosinic-polyribocytidilic acid (poly I:C) was administered into pregnant mice. Behavioral evaluations (thigmotaxis, methamphetamine [MAP]-induced hyperactivity, novel-object recognition test [NORT]), sensorimotor gating (prepulse inhibition [PPI]), and biochemical evaluation of the dopaminergic function of the offspring of phosphate-buffered saline (PBS)-treated dams (PBS-mice) and that of poly I:C-treated dams (poly I:C-mice) were examined.

RESULTS

In juveniles, no difference was found between the poly I:C-mice and PBS-mice. However, in adults, the poly I:C-mice exhibited attenuated thigmotaxis, greater response in MAP-induced (2 mg/kg) hyperlocomotion, deficits in PPI, and cognitive impairment in NORT compared with the PBS-mice. Cognitive impairment in the adult poly I:C-mice could be improved by subchronic administration of clozapine (5.0 mg/kg) but not haloperidol (.1 mg/kg). Increased dopamine (DA) turnover and decreased receptor binding of D2-like receptors, but not D1-like receptors, in the striatum were found in adult poly I:C-mice.

CONCLUSIONS

Prenatal poly I:C administration causes maturation-dependent increased subcortical DA function and cognitive impairment in the offspring, indicating a neurodevelopmental animal model of schizophrenia.

Human p53 tumor suppressor gene (TP53) and schizophrenia: case-control and family studies

The human p53 tumor suppressor gene (TP53) is considered as a candidate susceptibility gene for schizophrenia because of its functions in neurodevelopment. To test for an association between TP53 and schizophrenia, both the case-control study and the transmission disequilibrium test (TDT) were performed on genotype data from eight polymorphisms in TP53. Our samples included 286 Toronto schizophrenia cases and 264 controls, and 163 Portuguese nuclear families. In the Toronto case-control study significant differences of allele frequencies of the CAA Ins/Del (p=0.027) and the 16bp Ins/Del (p=0.022) were detected. In TDT analysis we found significant differences for transmission of the CAA Ins/Del (p=0.017) in Portuguese schizophrenia families. Haplotype analysis also showed a significant association between TP53 and schizophrenia. These results provide further evidence that TP53 may play a role in the pathogenesis of schizophrenia.

A “deficient environment” in prenatal life may compromise systems important for cognitive function by affecting BDNF in the hippocampus

The intrauterine environment has the capacity to mold the prenatal nervous system. Particularly, recent findings show that an adverse prenatal environment produces structural defects of the hippocampus, a critical area sub-serving learning and memory functions. These structural changes are accompanied by a disruption in the normal expression pattern of brain-derived neurotrophic factor (BDNF) and its cognate tyrosine kinase B (TrkB) receptor. The important role that the BDNF system plays in neural modeling and learning and memory processes suggests that fetal exposure to unfavorable intrauterine conditions may compromise proper cognitive function in adult life. These findings have implications for disorders that involve a dysfunction in the BDNF system and are accompanied by cognitive deficits.

Tumor suppressor gene TP53 is genetically associated with schizophrenia in the Chinese population

Schizophrenia is a debilitating mental disorder. The TP53 tumor suppressor gene, encoding a phosphoprotein, is a key element in maintaining genomic stability and cell apoptosis. Recently, reduced risk of cancer in patients of schizophrenia has been reported. Some evidence also suggests the possible implication of TP53 in neurodevelopment. In order to examine the role of the TP53 gene in the pathogenesis of schizophrenic disorders, we investigated the genetic association between a functional polymorphism rs1042522 and schizophrenia by sequencing the fragment covering 72Pro> Arg in 701 cases and 695 controls in this work. In addition, we studied two other SNPs rs2078486 and rs8064946 by allele-specific PCR in the same samples. Though rs1042522 and rs8064946 did not show positive association with schizophrenia, we did observe statistically significant differences on SNP rs2078486 (P-value = 0.029; OR = 1.21; 95% CI 1.02-1.42) and on haplotype CAC (P-value = 0.0068; OR = 1.36; 95% CI 1.09-1.70). These results demonstrated that TP53 might play a role in susceptibility to schizophrenia.

Positive association of the human frizzled 3 (FZD3) gene haplotype with schizophrenia in Chinese Han population

Frizzled 3 (FZD3) gene is located on chromosome 8p21, a region that has been implicated in schizophrenia in genetic linkage studies. The FZD3 is a transmembrane receptor required for Wnt signal transduction cascades that have been thought to be involved in producing the cytoarchitectural defects observed in schizophrenia. Previous work has showed a strong association between FZD3 locus and schizophrenia in family-based study. To confirm this issue further, we investigated a genetic association between four single nucleotide polymorphisms (SNPs) located in the FZD3 gene and schizophrenia by case-control study using polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) in the Chinese Han population. Our studies showed the SNPs rs2323019 and rs880481 have significant differences in both genotype and allele frequencies between control subjects and schizophrenic patients (rs2323019: Allele A > G, chi2 = 6.7277, df = 1, P = 0.0095; Genotype, chi2 = 10.6583, df = 2, P = 0.0049; rs880481: Allele A > G, chi2 = 10.3945, df = 1, P = 0.0013; Genotype, chi2 = 16.8049, df = 2, P = 0.0002). In addition, we constructed three-locus haplotypes to test their association with schizophrenia. The globe chi-squared test for haplotype analysis showed a significant association (chi2 = 66.38, df = 7, P < 0.000001). These results suggested that the FZD3 gene might be involved in the predisposition to schizophrenia.

Longitudinal assessment of psychopathological domains over late-stage schizophrenia in relation to duration of initially untreated psychosis: 3-year prospective study in a long-term inpatient population

There remains uncertainty regarding any progressive nature of psychopathology and cognitive dysfunction in late-stage schizophrenia, and whether duration of initially untreated psychosis (DUP) might be associated with such 'progression'. This study examines longitudinally, over 3 years, the psychopathology and neuropsychology in 82 inpatients with DSM-IV schizophrenia, many of whom were admitted in the pre-neuroleptic era. Increase in executive dysfunction exceeded that in general cognitive impairment. Positive but not negative symptom severity decreased modestly; the primary predictor of negative symptom severity was DUP. On index assessment, psychopathology evidenced a three-factor structure; at follow-up, psychomotor poverty evidenced greater prominence and cohesion, and was on both occasions predicted primarily by DUP, while reality distortion was altered and disorganisation disassembled into alternative elements. It would appear that as years of chronic, refractory illness accrue, psychomotor poverty becomes more sharply delineated and dominant within the overall structure of psychopathology, and its prominence is predicted enduringly by DUP.

Schizophrenia, schizoaffective and bipolar disorder within an epidemiologically complete, homogeneous population in rural Ireland: small area variation in rate

While a controversy has endured as to whether schizophrenia evidences the geographical variations in rate that characterise essentially all medical conditions, even less is known of such fundamental aspects of the epidemiology of schizoaffective and bipolar disorder. Within an ethnically and socioeconomically homogeneous region of rural Ireland, population 29,542, several methodological refinements were adopted to seek an epidemiologically complete population of 'all' cases of these disorders, with each potential case interviewed and diagnosed. Prevalence and morbid risk were calculated over the region as a whole and for each of the 39 constituent District Electoral Divisions [DEDs], by place at birth and by place at onset. Using multiple sources of information, 115 cases of schizophrenia, 33 of schizoaffective disorder and 77 of bipolar disorder were identified. Unremarkable overall prevalence and morbid risk values obscured marked variation between District Electoral Divisions for schizophrenia. No such variation was observed for bipolar disorder. These data indicate, using improved methodology, that what is often interpreted as an invariant overall rate of schizophrenia across countries and cultures may not apply to spatial microstructure; macroscopic rates can obscure small area variations when ethnic and socioeconomic diversity are minimised and effects of urbanicity are absent. Under these conditions, small area variations in bipolar disorder may be limited.

The human frizzled-3 (FZD3) gene on chromosome 8p21, a receptor gene for Wnt ligands, is associated with the susceptibility to schizophrenia

Neurodevelopmental abnormalities have been reported in studies on the pathogenesis of schizophrenia. The Wnt-signaling pathway has been implicated in a variety of processes in neurodevelopment, and the frizzled proteins have been identified as receptors for Wnt ligands. Of the frizzled proteins, frizzled-3 (FZD3) is required for formation of the neural crest and for development of major fiber tracts in the CNS. The human FZD3 gene is located on chromosome 8p21, a positive linkage locus for schizophrenia. We analyzed polymorphisms of the FZD3 gene in patients with schizophrenia and control subjects in the Japanese population. We found a significant association between schizophrenia and the FZD3 gene in single nucleotide polymorphisms and haplotype analyses. Our data suggest that dysregulation of the Wnt-signaling pathway may be involved in the susceptibility to schizophrenia.

Immunohistochemical study of brain-derived neurotrophic factor and its receptor, TrkB, in the hippocampal formation of schizophrenic brains

Recently, the pathogenesis of schizophrenia has been investigated from the perspective of neurodevelopmental dysfunction theory. On the other hand, it has been indicated that neurotrophic factors, such as nerve growth factors, brain-derived neurotrophic factor (BDNF), and neurotrophin-3, are significantly involved in the development and functional differences of central nervous system (CNS). Some reports proposed that the dysfunction of these factors could explain the pathogenesis of schizophrenia possibly. In this study, the authors investigated immunohistochemically the distribution and/or morphology of BDNF and TrkB, its peculiar receptor, in the hippocampal formation of schizophrenic brain. As a result, BDNF-positive pyramidal cells in the CA2 and neurons in the CA3 and the field of the CA4 were intensely stained compared to those of normal control. Staining of TrkB-positive neurons showed a signet-ring like shape in the hippocampus of normal control brains. Such figures were not observed on staining of those neurons from schizophrenic brains. In the control cases, TrkB-immunopositive varicose fibers were frequently seen. Those observed differences between schizophrenic and normal cases may indicate the existence of dysfunction of BDNF and TrkB in schizophrenic brain, and this dysfunction may be one of the factors involved in the pathogenesis of schizophrenia.

Developmental abnormalities of the hippocampus in first-episode schizophrenia

BACKGROUND

The human hippocampus becomes visible during the first trimester and folds to form the hippocampal fissure (HF) in the second trimester. The walls of this fissure fuse by 30 weeks, although small residual cavities can occur if development is disrupted. The primary purpose of this study was to determine if hippocampal fissures are evident in schizophrenia. A second goal was to assess the association between HF size and premorbid and clinical features of the illness.

METHODS

Magnetic resonance imaging scans were obtained on 33 patients with first-episode schizophrenia and 19 healthy volunteers. Hippocampal fissures were measured using semi-automated procedures, and hippocampi were manually traced. Birth history and premorbid functioning were assessed using maternal report.

RESULTS

Patients had a significantly larger mean HF volume and a nonsignificantly smaller hippocampal volume. Hippocampal fissure size was significantly associated with poor educational achievement and with anxiety-depression symptoms during the onset of illness. Smaller hippocampal size was associated with poor premorbid adjustment.

CONCLUSIONS

Larger HF size and an association between low educational achievement and enlarged HFs suggest abnormal neurodevelopment in schizophrenia. The association between HF size and anxiety-depression symptoms suggests that hippocampal abnormalities underlying HF dilatation may be a predisposing factor for increased stress sensitivity.

The human dihydropyrimidinase-related protein 2 gene on chromosome 8p21 is associated with paranoid-type schizophrenia

BACKGROUND

The dihydropyrimidinase-related protein (DRP) family, also called the collapsin response mediator protein, is implicated in the developmental process of the nervous system. Dysfunction of DRPs may result in neurodevelopmental abnormalities, which may be a factor in the pathogenesis of schizophrenia. The expression of one member of DRP-2 in humans has been reported to be decreased in the brains of people with schizophrenia. In addition, the DRP-2 gene (Dihydropyrimidinase-like 2; DPYSL2) is located on chromosome 8p21, a region that has been implicated in schizophrenia in genetic linkage studies.

METHODS

We investigated a genetic association between five polymorphisms of the DRP-2 gene and schizophrenia in the Japanese population.

RESULTS

The *2236T>C polymorphism in the 3' untranslated region (3'UTR) exhibited significant differences with respect to the distribution of the genotype and allele in patients compared with control subjects. The frequency of the *2236C allele was significantly higher in control subjects than patients with schizophrenia (p =.0097) and paranoid-type schizophrenia (p =.0083).

CONCLUSIONS

Our results suggest that the *2236C allele in the 3'UTR of the DRP-2 gene, or an unknown mutation in linkage disequilibrium with this allele, may reduce the susceptibility to schizophrenia, especially the paranoid subtype.

Association study between the fibronectin gene and schizophrenia

Fibronectin is one of the cell adhesion proteins. Adhesion molecules play an important role in neural and synaptic genesis, and their dysfunction may result in neurodevelopmental abnormalities, which have been assumed to be a factor in the pathogenesis of schizophrenia. To examine the possible involvement of fibronectin in the etiology of schizophrenia, we analyzed six polymorphisms, located in introns 2, 21, 24, and 26, and exons 20 and 28, in the human fibronectin gene (FN1) of schizophrenic patients in the Japanese population (n = 104) and age-and gender-matched controls (n = 104). No significant positive association was observed between either of the polymorphisms and schizophrenia, nor was an association found between either of the polymorphisms and any subtypes of schizophrenia. These data did not provide evidence for a contribution of the FN1 gene to susceptibility to schizophrenia.

3D laser surface scanning and geometric morphometric analysis of craniofacial shape as an index of cerebro-craniofacial morphogenesis: initial application to sexual dimorphism

BACKGROUND

Over early fetal life, when disturbances in schizophrenia have been posited and craniofacial dysmorphogenesis reported, cerebral morphogenesis proceeds in embryological intimacy with craniofacial morphogenesis. Digitization technologies now allow 3D recording of craniofacial surface landmarks and modeling of craniofacial shape differences using geometric morphometrics.

METHODS

Using normal sexual dimorphism as an exemplar, facial surfaces of 131 Medical School employees [82 females, 49 males] were recorded in 3D using a portable, hand-held laser scanner; 3D coordinate data were then analyzed using geometric morphometrics.

RESULTS

Males and females differed markedly on an omnibus test of craniofacial shape. Logistic regression analysis of 16 principal components of shape variability, explaining 84.9% of the overall sample variance, generated 8 principal components as significant and independent discriminators. On visualization, the female face is wider and flatter; the eyes are more lateral, anterior and are further apart, and nasal bridge is posterior; the nose is smaller; the lips are fuller and the chin more forward. These findings are complementary to sexual dimorphism in cerebral structures.

CONCLUSIONS

This technique reliably discriminates geometric features of craniofacial morphology that are associated with aspects of cerebral morphology, and may inform on putative neurodevelopmental disorders characterised by dysmorphogenesis.

Association study of the p53-gene Pro72Arg polymorphism in schizophrenia

The p53 tumor-suppressor gene, encoding a phosphoprotein, is a key element in maintaining genomic stability and cell apoptosis. It is also implicated in nervous-system development. In order to examine the role of the p53 gene for the pathogenesis of schizophrenic disorders, patients (n=155) and control subjects (n=168) were genotyped for the p53-Pro72Arg polymorphism. The results demonstrated no association with schizophrenia and/or age of onset for this polymorphism.

The origin and course of schizophrenia: implications for clinical practice

The authors first review current evidence concerning abnormalities of brain structure and function in schizophrenia and interpret them within a "network" pathophysiological model of the disorder. This information is then placed within a contemporary neurodevelopmental framework that "roots" the illness in adverse events during early pregnancy, which result in a developmentally compromised nervous system. They then consider the controversy as to whether the subsequent expression of psychosis reflects an active morbid process and, in a more general sense, whether the disorder is characterized by subsequent progression and clinical deterioration. The authors argue that the developmental and progressive models should not be considered in an either-or manner, since this perspective is not logical and favors nihilistic approaches to intervention and treatment, but rather should be integrated within a lifetime trajectory model. Finally, implications for current psychiatric practice are considered.

Relationship of the factor structure of psychopathology in schizophrenia to the timing of initial intervention with antipsychotics

Timing of intervention with antipsychotic medication may influence long-term outcome in schizophrenia in a manner that is poorly understood. This study evaluated psychopathology, its factor structure, and cognitive dysfunction in older patients with chronic schizophrenia in relation to the intervals from onset of psychosis to initiation of treatment with antipsychotics, and from initiation of antipsychotic treatment to current assessments. The subjects were 129 patients with schizophrenia, many of whom became ill in the preneuroleptic era. Their current psychopathology was assessed using the Positive and Negative Syndrome Scale, and its factor structure examined using principal component analysis. Current general and executive cognitive function was evaluated using the Mini-Mental State Examination and the Executive Interview, respectively. Using multiple regression modelling, increasing duration of initially unmedicated psychosis, but not the much longer duration of subsequently treated illness, was the primary predictor of psychomotor poverty (negative symptoms) but not of reality distortion or disorganisation over the three domains of psychopathology resolved; duration of initially unmedicated psychosis marginally predicted the severity of general, but not of executive, cognitive dysfunction. Delayed intervention with antipsychotics appears associated with poorer long-term course in terms of increased severity of psychopathology in the psychomotor poverty domain.

Long-term adaptive life functioning in relation to initiation of treatment with antipsychotics over the lifetime trajectory of schizophrenia

BACKGROUND

There is evidence that the stage of illness at which antipsychotic treatment is initiated in schizophrenia may have consequences for its subsequent course. How this might relate to impaired adaptive life functioning in the long-term is poorly understood.

METHODS

Thirty-eight inpatients, many of whom had been admitted in the preneuroleptic era, were assessed using the Social-Adaptive Functioning Evaluation (SAFE); constituent clinical and medication phases of the lifetime trajectory of their illnesses were then analyzed to identify predictors of SAFE score using multiple regression modeling.

RESULTS

The primary, independent predictor of SAFE score was duration of initially unmedicated psychosis, which accounted for 22% of variance (p<.001) therein. Conversely, duration of subsequently treated illness, although decades longer, failed to predict SAFE score.

CONCLUSIONS

These findings are consistent with some form of "progressive" process, particularly over the first several years following the emergence of psychosis, which is associated with accrual of deficits in adaptive life functioning.

The role of endogenous sensitization in the pathophysiology of schizophrenia: implications from recent brain imaging studies

Long-term sensitization is a process whereby exposure to a given stimulus such as a drug or a stressor results in an enhanced response at subsequent exposures. Sensitization of mesolimbic dopamine systems has been postulated by several authors to underlie the development of dopaminergic abnormalities associated with schizophrenia. In this review, core features of stimulant-induced sensitization of dopamine systems in rodents are briefly reviewed, as well as the behavioral and clinical evidence suggesting the relevance of this process to drug-induced psychosis and schizophrenia. Results of recent brain imaging studies relevant to the question of sensitization in schizophrenia are then discussed. These studies indicate that schizophrenia is associated with increased amphetamine-induced dopamine release. This exaggerated response was detected in patients experiencing an episode of clinical deterioration but not in clinically stable patients. Since increased stimulant-induced dopamine release is a hallmark of sensitization, these results support the view that schizophrenia is associated with a process of endogenous sensitization. Based on the preclinical evidence that dopamine projection to the prefrontal cortex acts as a buffer that oppose the development of sensitization in subcortical dopamine projections, we propose that, in schizophrenia, neurodevelopmental abnormalities of prefrontal dopaminergic systems might result in a state of enhanced vulnerability to sensitization during late adolescence and early adulthood. It is also proposed that D(2) receptor blockade, if sustained, might allow for an extinction of this sensitization process, with possible re-emergence upon treatment discontinuation. A better understanding of the neurocircuitry associated with endogenous sensitization and its consequence in schizophrenia might be important for the development of better treatment and relapse prevention strategies.

Early cerebro-craniofacial dysmorphogenesis in schizophrenia: a lifetime trajectory model from neurodevelopmental basis to 'neuroprogressive' process

Understanding the temporal origin(s) of schizophrenia, through specifying the earliest identifiable pathology, might indicate when to look for etiological factor(s), what their nature might be, and how course of illness might evolve from these origins. From this premise, earlier formulations are elaborated to offer a rigorously data-driven model that roots schizophrenia in cerebro-craniofacial dysmorphogenesis, particularly along the mid-line but involving other structures, over weeks 9/10 through 14/15 of gestation. However, a brain that has been compromised very early in fetal life is still subject to the normal endogenous programme of developmental, maturational and involutional processes on which a variety of exogenous biological insults and psychosocial stressors can impact adversely over later pregnancy, through infancy and childhood, to maturation and into old age, to sculpt brain structure and function; it should be emphasised that the effects of such endogenous programmes and exogenous insults on such an already developmentally-compromised brain may be different from their effects on a brain whose early fetal origins were unremarkable. From these early origins, a lifetime trajectory model for schizophrenia from developmental basis to 'neuroprogressive' process is constructed. Thereafter, consideration is given to what the model can explain, including cerebral asymmetry and homogeneity, what it cannot explain, what empirical findings would challenge or disprove the model, what cellular and molecular mechanisms might underpin the model, and what are its implications.

No association between an intronic presenilin-1 gene polymorphism and schizophrenia in a Chinese population

We investigated the association between schizophrenic psychosis and an intronic polymorphism of the presenilin-1 (PS1) gene in a Chinese population. Schizophrenic and control groups had similar PS1 genotype distributions and allele frequencies, indicating that this polymorphism may not be involved in the development of schizophrenia.

The neurodevelopmental basis of schizophrenia: clinical clues from cerebro-craniofacial dysmorphogenesis, and the roots of a lifetime trajectory of disease

A "read-back" analysis of schizophrenia, from chronic illness, through the first psychotic episode, to psychosocial and neurointegrative abnormalities of childhood and infancy, leads to the intrauterine period as a primary focus for etiological events. Evidence for a characteristic topography of cerebro-craniofacial dysmorphology in schizophrenia is reviewed, and interpreted to estimate: (i) the timing of dysmorphic event(s); (ii) the nature of early cellular and molecular mechanisms which might determine that topography of dysmorphogenesis; and (iii) the population homogeneity of these processes. It is argued that early cerebro-craniofacial dysmorphogenesis in schizophrenia should be conceptualized as a first stage not in a static but rather in a dynamic, lifetime trajectory of disease.

An integrated view of pathophysiological models of schizophrenia

Pathophysiological processes that underlie the profound neuropsychiatric disturbances in schizophrenia are poorly understood. However, the clinical course of the disease, and a number of clinical and basic science observations, provide direction for formulating pathophysiological models that could be empirically tested. For example, repeated psychostimulant administration to healthy subjects can induce psychotic symptoms, and acute stimulant challenge in schizophrenia patients can precipitate psychosis. Also, NMDA antagonists induce positive, negative, and cognitive schizophrenic-like symptoms in healthy volunteers and precipitate thought disorder and delusions in schizophrenia patients. These human studies provide support for the dopamine and NMDA receptor hypofunction hypotheses of schizophrenia. Well-documented effects of NMDA antagonists on dopamine systems provide a basis to integrate the dopamine and NMDA receptor hypofunction hypotheses. Furthermore, it has become apparent that prominent actions of antipsychotic drugs, especially those with 'atypical' properties, involve antagonism of behavioral, electrophysiological and brain metabolic effects produced by administration of NMDA receptor antagonists. A confluence of clinical and basic science data suggests that an early developmental insult, potentially involving reduced NMDA receptor function, could facilitate sensitization of dopamine systems, leading to the formal onset of schizophrenia in late adolescence and early adulthood. Although clearly speculative, this conceptual model is consistent with existing evidence and suggests lines of future experimental investigation.