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Anil K Malhotra

Publications and source records attributed to Anil K Malhotra.

At least 19 recordsLinked to original sources
PubMed2006

Increased stress and smaller anterior hippocampal volume.

Animal studies indicate that stress negatively impacts hippocampal structure; little is known, however, regarding the relationship between stress and hippocampal morphology in healthy humans. Twenty-one healthy adults underwent structural magnetic resonance imaging examinations and completed the Derogatis Stress Profile. Greater psychological stress at the time of the scan correlated significantly and more strongly with anterior than posterior hippocampal volume. These findings suggest that psychological stress may be associated with structural alterations in the anterior hippocampal formation and that this relationship may differ along the rostrocaudal axis of the hippocampus. Our results may also have implications for neuropsychiatric disorders that have implicated stress and hippocampal abnormalities in their pathogenesis.

Adult↗
PubMed2006

DTNBP1 genotype influences cognitive decline in schizophrenia.

OBJECTIVE: Intellectual decline is common in schizophrenia and predicts functional outcome. While many patients undergo intellectual decline that typically predates the onset of symptoms, few studies have investigated the underlying mechanism through which this occurs. The current study assessed the relationship between intellectual decline in schizophrenia and genetic variation in dysbindin-1 (DTNBP1). METHODS: We assessed cognitive decline in 183 Caucasian patients with schizophrenia using a proxy measure of premorbid IQ with which current general cognitive ability (g) was compared. We then tested for a relationship between the risk haplotype identified in previous work (CTCTAC) and intellectual decline. RESULTS: We found that carriers of the CTCTAC haplotype, demonstrated a significantly greater decline in IQ as compared with non-carriers (p=0.05). CONCLUSIONS: These data suggest that DTNBP1 influences the severity of intellectual decline in schizophrenia and may represent one underlying cause for heterogeneity in cognitive course.

Adult↗
PubMed2006

Disrupted in schizophrenia 1 genotype and positive symptoms in schizophrenia.

BACKGROUND: Converging evidence has demonstrated an association between the Disrupted in Schizophrenia 1 (DISC1) gene and schizophrenia (SZ). Within the DISC1 gene, a single nucleotide polymorphism (SNP), Ser704Cys, has been associated with the structure and function of the hippocampus. Because positive symptoms in SZ have also been associated with hippocampal structure and function, we hypothesized that variation in a DISC1 haplotype containing Ser704Cys would be significantly associated with positive symptomatology in SZ. METHODS: We tested for an association between variation in a haplotype block within the DISC1 gene containing Ser704Cys and lifetime history of positive symptoms in 199 Caucasian patients with SZ. RESULTS: We detected significant associations between a DISC1 haplotype containing Ser704Cys and Ser704Cys genotype and lifetime severity of delusions in SZ. CONCLUSIONS: These data suggest that that the effect of DISC1 genetic variation might be associated with positive symptoms in patients with SZ.

Cysteine↗
PubMed2006

The FEZ1 gene shows no association to schizophrenia in Caucasian or African American populations.

Schizophrenia is a complex psychiatric disorder with both genetic and environmental components and is thought to be in part neurodevelopmental in origin. The DISC1 gene has been linked to schizophrenia in two independent Caucasian populations. The DISC1 protein interacts with a variety of proteins including FEZ1, the mammalian homolog of the Caenorhabditis elegans unc-76 protein, which is involved in axonal outgrowth. Variation at the FEZ1 gene has been associated with schizophrenia in a large Japanese cohort. In this study, nine SNP markers at the FEZ1 locus were genotyped in two populations. A North American Caucasian cohort of 212 healthy controls, 178 schizophrenics, 79 bipolar disorder, and 58 with schizoaffective disorder, and an African American cohort of 133 healthy controls, 162 schizophrenics, and 28 with schizoaffective disorder. No association to schizophrenia, bipolar disorder or schizoaffective disorder was found for any of the nine markers typed in these populations at the allelic or the genotypic level. Additionally no association was found in either population between specific haplotypes and any of the psychiatric disorders. Variation at the FEZ1 locus does not play a significant role in the etiology of schizophrenia, bipolar disorder or schizoaffective disorder in North American Caucasian or African American populations.Neuropsychopharmacology (2007) 32, 190-196. doi:10.1038/sj.npp.1301177; published online 16 August 2006.

Adaptor Proteins, Signal Transducing↗
PubMed2006

COMT genotype and manic symptoms in schizophrenia.

Inconsistencies in the relation between COMT variation and schizophrenia may be clarified by careful delineation of a target phenotype. The present study reports a significant association between a COMT haplotype and the severity of manic symptoms in 162 patients with schizophrenia or schizoaffective disorder (SZ). These data suggest that the effect of COMT variation may be associated with comorbid manic symptoms in SZ.

Adult↗
PubMed2006

Ziprasidone-induced cognitive enhancement in schizophrenia: specificity or pseudospecificity?

OBJECTIVE: Ziprasidone may improve cognition in schizophrenia; however, this could be related to clinical symptom improvement, reflecting "pseudospecificity". We tested the hypothesis that ziprasidone improves cognition in the absence of clinical improvement. METHODS: We conducted a 12-week, open-label study of ziprasidone in 10 schizophrenia patients who met non-response criteria (<20% reduction in BPRS scores over 12 weeks). We conducted comprehensive cognitive testing and assessed change from baseline to end of study. RESULTS: We detected significant improvement on three measures of episodic memory (p<0.01) in these clinically non-responsive patients. Trend-level improvements were noted on tests involving processing speed and executive function. CONCLUSIONS: These data suggest that ziprasidone has cognitive benefits unrelated to an influence on other disease parameters.

Adolescent↗
PubMed2006

Genetic variation in DTNBP1 influences general cognitive ability.

Human intelligence is a trait that is known to be significantly influenced by genetic factors, and recent linkage data provide positional evidence to suggest that a region on chromosome 6p, previously associated with schizophrenia, may be linked to variation in intelligence. The gene for dysbindin-1 (DTNBP1) is located at 6p and has also been implicated in schizophrenia, a neuropsychiatric disorder characterized by cognitive dysfunction. We report an association between DTNBP1 genotype and general cognitive ability (g) in two independent cohorts, including 213 patients with schizophrenia or schizo-affective disorder and 126 healthy volunteers. These data suggest that DTNBP1 genetic variation influences human intelligence.

Adult↗
PubMed2006

Genetic association and brain morphology studies and the chromosome 8p22 pericentriolar material 1 (PCM1) gene in susceptibility to schizophrenia.

CONTEXT: There is evidence of linkage to a schizophrenia susceptibility locus on chromosome 8p21-22 found by several family linkage studies. OBJECTIVES: To fine map and identify a susceptibility gene for schizophrenia on chromosome 8p22 and to investigate the effect of this genetic susceptibility on an endophenotype of abnormal brain structure using magnetic resonance imaging. DESIGN: Fine mapping and identification of a chromosome 8p22 susceptibility gene was carried out by finding linkage disequilibrium between genetic markers and schizophrenia in multiply affected families, a case-control sample, and a trio sample. Variation in brain morphology associated with pericentriolar material 1 (PCM1) alleles was examined using voxel-based morphometry and statistical parametric mapping with magnetic resonance imaging. Setting and Patients A family sample of 13 large families multiply affected with schizophrenia, 2 schizophrenia case-control samples from the United Kingdom and Scotland, and a sample of schizophrenic trios from the United States containing parents and 1 affected child with schizophrenia. MAIN OUTCOME MEASURES: Tests of transmission disequilibrium between PCM1 locus polymorphisms and schizophrenia using a family sample and tests of allelic association in case-control and trio samples. Voxel-based morphometry using statistical parametric mapping. RESULTS: The family and trio samples both showed significant transmission disequilibrium between marker D85261 in the PCM1 gene locus and schizophrenia. The case-control sample from the United Kingdom also found significant allelic association between PCM1 gene markers and schizophrenia. Voxel-based morphometry of cases who had inherited a PCM1 genetic susceptibility showed a significant relative reduction in the volume of orbitofrontal cortex gray matter in comparison with patients with non-PCM1-associated schizophrenia, who, by contrast, showed gray matter volume reduction in the temporal pole, hippocampus, and inferior temporal cortex. CONCLUSIONS: The PCM1 gene is implicated in susceptibility to schizophrenia and is associated with orbitofrontal gray matter volumetric deficits.

Adult↗
PubMed2006

Recognizing and monitoring adverse events of second-generation antipsychotics in children and adolescents.

Although second-generation antipsychotics (SGAs) are used increasingly in children and adolescents, data on the effectiveness and safety in pediatric populations are still sparse. Much of the safety information is derived from studies conducted in adults. This derivation is problematic because children and adolescents are exposed to SGAs during a phase of unparalleled physical and psychologic development that can affect pharmacokinetic and pharmacodynamic drug actions, efficacy, and side-effect patterns. This article presents an overview of SGA-related side effects in children and adolescents and strategies to monitor health outcomes effectively in youngsters receiving SGAs.

Adolescent↗
PubMed2006

Neurocognition as a stable endophenotype in bipolar disorder and schizophrenia.

Linkage and association studies have paid increasing attention to neurocognition as a putative endophenotype. However, there exists little documentation of its trait stability in schizophrenia or bipolar disorder. Our aim was to determine the longitudinal stability of neurocognitive performance in bipolar versus schizophrenia probands. We administered a neurocognitive battery at two time points, approximately 5 years apart, in 16 schizophrenia and 16 bipolar disorder age-matched subjects. There were no significant changes over time on variables including education, estimated IQ, depression, psychosis, global functioning, or medication status. Schizophrenia subjects showed significant deterioration in one measure of executive functioning but no significant changes in seven of eight other domains. Bipolar patients showed stability over time in attentional measures but greater variability in other domains. These preliminary findings suggest that neurocognitive domains appear longitudinally stable across broad domains in schizophrenia. In contrast, stable functioning may be more limited to attentional domains in bipolar disorder.

Adult↗
PubMed2006

DRD2 promoter region variation as a predictor of sustained response to antipsychotic medication in first-episode schizophrenia patients.

OBJECTIVE: All antipsychotics act on the dopamine D(2) receptor. The present study extends prior pharmacogenetic investigations of the D(2) receptor gene (DRD2) by examining, in first-episode schizophrenia patients, promoter region variation as a predictor of response time to two first-line atypical antipsychotics. METHOD: Patients experiencing their first episode of schizophrenia (N=61) were genotyped for two DRD2 promoter region polymorphisms (A-241G and -141C Ins/Del) and were randomly assigned to receive 16 weeks of treatment with either risperidone or olanzapine. Time until sustained response (two consecutive ratings without significant positive symptoms) for rare allele carriers versus wild types was examined by using Kaplan-Meier curves. RESULTS: Relative to wild type homozygotes, G carriers (A-241G) exhibited a significantly faster time until response, whereas -141C Del carriers took a significantly longer time to respond. Diplotype analysis revealed similar results. CONCLUSIONS: These findings suggest that variation in the D(2) receptor gene can, in part, explain variation in the timing of clinical response to antipsychotics in patients with first-episode schizophrenia.

Adolescent↗
PubMed2006

Dysbindin genotype and negative symptoms in schizophrenia.

OBJECTIVE: Converging evidence has demonstrated an association between variants in the dysbindin gene (DTNBP1) and schizophrenia. Recently, a DTNBP1 risk haplotype, associated with both schizophrenia and neurocognitive dysfunction, has been identified. Because neurocognitive dysfunction is commonly accompanied by negative symptoms (avolition, alogia, and affective flattening) in schizophrenia, the authors hypothesized that the presence of the risk haplotype would be significantly associated with negative symptoms. METHOD: The authors tested for an association between a DTNBP1 risk haplotype and a lifetime history of negative symptoms in 181 Caucasian patients with schizophrenia. RESULTS: A significant association was found between the presence of the risk haplotype and negative symptoms. CONCLUSIONS: These data suggest that the effect of DTNBP1 genetic variation may be associated with negative symptoms in patients with schizophrenia.

Adult↗
PubMed2005

COMT genetic variation confers risk for psychotic and affective disorders: a case control study.

BACKGROUND: Variation in the COMT gene has been implicated in a number of psychiatric disorders, including psychotic, affective and anxiety disorders. The majority of these studies have focused on the functional Val108/158Met polymorphism and yielded conflicting results, with limited studies examining the relationship between other polymorphisms, or haplotypes, and psychiatric illness. We hypothesized that COMT variation may confer a general risk for psychiatric disorders and have genotyped four COMT variants (Val158Met, rs737865, rs165599, and a SNP in the P2 promoter [-278A/G; rs2097603]) in 394 Caucasian cases and 467 controls. Cases included patients with schizophrenia (n = 196), schizoaffective disorder (n = 62), bipolar disorder (n = 82), major depression (n = 30), and patients diagnosed with either psychotic disorder NOS or depressive disorder NOS (n = 24). RESULTS: SNP rs2097603, the Val/Met variant and SNP rs165599 were significantly associated (p = 0.004; p = 0.05; p = 0.035) with a broad "all affected" diagnosis. Haplotype analysis revealed a potentially protective G-A-A-A haplotype haplotype (-278A/G; rs737865; Val108/158Met; rs165599), which was significantly underrepresented in this group (p = 0.0033) and contained the opposite alleles of the risk haplotype previously described by Shifman et al. Analysis of diagnostic subgroups within the "all affecteds group" showed an association of COMT in patients with psychotic disorders as well as in cases with affective illness although the associated variants differed. The protective haplotype remained significantly underrepresented in most of these subgroups. CONCLUSION: Our results support the view that COMT variation provides a weak general predisposition to neuropsychiatric disease including psychotic and affective disorders.

Journal Article↗
PubMed2005

DISC1 and neurocognitive function in schizophrenia.

We recently reported an association between DISC1 and schizophrenia, schizoaffective disorder, and bipolar disorder. Convergent evidence suggests that DISC1 has a direct effect on central nervous system functioning. However, there is a paucity of data investigating the effects of DISC1 on neurocognition. Thus, we analyzed the relationship between five single-nucleotide polymorphisms that influenced risk for schizophrenia in our previous study and neurocognition in 250 patients with schizophrenia. DISC1 genotype was related to neurocognitive performance on measures of rapid visual search and verbal working memory, when controlling for age and premorbid intellectual capacity, and explained 3%-4% of the variance. These data suggest that DISC1 is associated with neurocognitive functioning in schizophrenia.

Adult↗
PubMed2005

White matter abnormalities in obsessive-compulsive disorder: a diffusion tensor imaging study.

CONTEXT: Several neurobiological models of obsessive-compulsive disorder (OCD) posit a primary role for dysfunction of the anterior cingulate gyrus. Both functional and structural neuroimaging studies have implicated anterior cingulate gray matter abnormalities in the pathophysiology of OCD, but there has been little investigation of the anterior cingulate white matter in this disorder. OBJECTIVE: To test the hypothesis that patients with OCD have abnormal white matter microstructure in the anterior cingulate gyrus compared with healthy volunteers as inferred from diffusion tensor imaging. Additional analyses examined group differences in white matter integrity across the entire brain. DESIGN, SETTING, AND PARTICIPANTS: Fifteen patients with a DSM-IV diagnosis of OCD and 15 healthy volunteers matched for age, sex, and handedness underwent diffusion tensor imaging and structural magnetic resonance imaging examinations. Fractional anisotropy (FA), a robust intravoxel measure of water self-diffusion, was compared between groups on a voxel-by-voxel basis in the anterior cingulate white matter after standardization in Talairach space. MAIN OUTCOME MEASURES: Clinical ratings of symptom severity (ie, Yale-Brown Obsessive-Compulsive Scale) and FA. RESULTS: Compared with healthy volunteers, patients demonstrated significantly lower FA bilaterally in 3 areas of the anterior cingulate gyrus white matter. Additional analyses conducted across the rest of the brain white matter revealed lower FA bilaterally in the parietal region (supramarginal gyri), right posterior cingulate gyrus, and left occipital lobe (lingual gyrus). No areas of significantly higher FA were observed in patients compared with healthy volunteers. Lower FA in the parietal region correlated significantly with higher Yale-Brown Obsessive-Compulsive Scale scores. CONCLUSIONS: These preliminary findings provide evidence of an abnormality that involves the anterior cingulate white matter in the pathogenesis of OCD and are consistent with neurobiological models that posit a defect in connectivity in the anterior cingulate basal ganglia-thalamocortical circuit. White matter abnormalities in other brain regions may also be implicated in the neurobiology of OCD.

Adult↗
PubMed2005

White matter abnormalities in first-episode schizophrenia or schizoaffective disorder: a diffusion tensor imaging study.

OBJECTIVE: The goal of this study was to investigate brain white matter abnormalities by using diffusion tensor imaging in patients with schizophrenia or schizoaffective disorder close to illness onset. METHOD: Ten patients experiencing a first episode of schizophrenia or schizoaffective disorder and 13 healthy volunteers received diffusion tensor imaging and structural magnetic resonance imaging examinations. Voxel-wise analysis was used to compare fractional anisotropy maps in the white matter of the two groups following intersubject registration to Talairach space. RESULTS: Compared with healthy volunteers, patients demonstrated lower fractional anisotropy in the left internal capsule and left-hemisphere white matter of the middle frontal gyrus and posterior superior temporal gyrus. There were no areas of significantly higher fractional anisotropy in patients compared with healthy volunteers. CONCLUSIONS: These findings suggest that white matter pathology is present early in the course of schizophrenia and may be less pronounced than has been found in previous diffusion tensor imaging studies of patients with chronic illness. Further, these data are consistent with hypotheses regarding frontotemporal dysfunction and the failure of left-hemisphere lateralization in the pathophysiology of schizophrenia.

Adult↗
PubMed2005

Genetics and psychopharmacology: prospects for individualized treatment.

This article provides a clear and succinct description of the components of inheritance, such as trait transmission, genetic variability, and gene interaction. Genetic sequences constitute the prime focus of pharmacogenetic studies. Variations in drug-metabolizing enzyme systems tend to be monogenic, whereas the pharmacologic effects of medications appear to be polygenic, i.e., complex phenotypes shaped by the interaction of genes and environment. Translated into clinical terms, a history of a good response to a drug in a close relative of a patient is presumed to predict a good response to the same medication by the patient. This seems to hold for antidepressants, antipsychotics, and lithium, but the evidential studies generally have meaningful limitations. Bit by bit, information about the relationship between particular genetic formations and the effectiveness of these medications as well as their side effects, is appearing. The authors cite a number of examples, one such being an association between impaired antidepressant activity and the short allele of SLC6A4. This research promises to strengthen the accuracy, effectiveness, safety, and cost of our psychopharmacological practices.

Affect↗