Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study investigated the neural and cognitive correlates of reality distortion in schizophrenia by using event-related potentials (ERPs) recorded in a recognition memory task for face. This task has been chosen because previous studies have shown that it provides distinct indices related to specific cognitive processes and to the functioning of specific brain regions. ERPs have been recorded in controls and schizophrenia patients separated into high scorers (RD+) and low-scorers (RD-) according to their Reality Distortion score (hallucination and delusion SAPS subscales). The results indicate that RD+ presents abnormalities on various cognitive processes. First, RD+ are deficient at interference inhibition and knowledge integration (reduced P2a and N400 effect). The similar impairments found in RD- suggest that they represent basic traits of the illness. Second, RD+ showed inappropriate stimulus categorization and contextual integration (larger N300 and fronto-central effect). Third, RD+ showed a late index (P600 effect) not different from controls, but larger than in RD-. This result is consistent with a qualitative, rather than quantitative, impairment of mnemonic binding processes (inappropriate binding) in RD+. Since each of the ERP abnormalities observed represents associated with distinct brain dysfunction, the results are further discussed in regard of the respective contribution of the parietal, frontal and hippocampal structures to reality distortion symptoms.
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PMID:The cognitive and anatomo-functional basis of reality distortion in schizophrenia: a view from memory event-related potentials. 1260 16

Evidence of immune activation has occasionally, but not consistently, been reported in schizophrenia. Investigations of cytokine abnormalities in serum, and occasionally in CSF, have yielded inconsistent results, which have been difficult to resolve. In such studies, schizophrenia has been assumed to consist of a single process rather than a group of disorders. This study assesses differences in the pro-inflammatory cytokine, interleukin-6 (IL-6) in the cerebrospinal fluid (CSF) in two previously delineated subtypes of schizophrenics ("delayed-responders"(DR) (n=23) and "poor-responders" (PR) (n=8)) during periods of neuroleptic-free psychotic exacerbation, and in a comparison group of normal controls (n=14). The two response subtypes were separated by subsequent treatment response (greater/less than 60% reduction of SAPS scores from baseline during 6 months of systematic treatment). The IL-6 assay, a sandwich enzyme-linked immunosorbent assay, was sensitive and reliable to detect IL-6 levels in the CSF of all subjects. CSF IL-6 was found to be significantly higher in the DR than the PR (P=0.017) and the controls (P=0.013). In addition to supporting the concept of heterogeneity in schizophrenia, this study also provides evidence that a central immune process may be occurring centrally in one subtype of schizophrenia.
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PMID:Elevated interleukin-6 in the cerebrospinal fluid of a previously delineated schizophrenia subtype. 1279 18

Schizophrenic patients suffer from positive (delusions, hallucinations) and negative signs (social withdrawal) as well as emotional disturbance that included quantitative (blunted affect) and qualitative impairments (discordance of emotional level). Ketamine, a phencyclidine derivative, is a non competitive N-methyl-D-aspartate (NMDA) glutamate receptor antagonist. In healthy subjects its administration induces some positive symptoms (perceptual distortions.), negative symptoms (emotional deficit, apathy, social withdrawal) and cognitive changes (memory impairments and perseverations) that resemble some aspects of the symptoms of schizophrenia. A double blind cross over, placebo controlled was performed in 12 normal subjects with 2 sessions separated by one week of wash-out to determine ketamine-induced effects on behavioral and emotional responses. During each session, subjects received either ketamine or placebo (saline) infusion. A subanesthetic dose of ketamine (0,5 mg/kg) was administered by constant perfusion over 60 min. Behavioral and cognitive responses were assessed using positive and negative symptoms scales (BPRS, items from SAPS and SANS), vigilance and mood visual analog scale, subjective feelings using the Addiction Research Center Inventory (ARCI) and the Profile of Mood States (POMS). Using Philippot's method, emotions were elicited by films segments which induce a diversity of predictable emotions (fear, anger, sadness, joy, disgust and neutral state) and emotional responses were assessed by the Differential Emotions Scale (DES Izard). Low dose of ketamine induced significant effects on 7-items BPRS score (positive and negative items) and significant effects on positive and negative symptoms from SANS and SAPS. This was associated with emotional blunting of visually-induced responses that resemble aspects of schizophrenic emotional impairments. Ketamine impaired ARCI subscales (benzedrine subscale, pentobarbital-chlorpromazine subscale and LSD subscale). The recent findings of ketamine's pharmacology and imaging studies allow to draw several hypothesis related to neurotransmitter systems (glutamate, dopamine, serotonin interactions) and cerebral areas (particularly prefrontal cortex, anterior cingulate cortex, hippocampus) underlying some of these ketamine-induced effects.
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PMID:[Effects of a subanaesthetic dose of ketamine on emotional and behavioral state in healthy subjects]. 1290 92

We aimed to investigate the reliability and the clinical sensitivity of the World Health Organization Quality of Life (WHOQOL-100) scale for patients diagnosed with schizophrenia because of its multilingual, multidimensional, and cross-cultural properties. Fifty-four stabilized outpatients with schizophrenia and 49 age-, sex-, and occupation-matched healthy control subjects were recruited. The scale showed high internal consistency (Cronbach alpha = 0.94). While there was no correlation between total scores of psychopathology measures (Brief Psychiatric Rating Scale [BPRS], Scale for the assessment of Negative Symptoms [SANS], Scale for the Assessment of Positive Symptoms [SAPS], and Clinical Global Impression [CGI]), significant negative correlations were obtained especially between subscales of the BPRS, SANS, SAPS, and QOL domains. Stepwise multiple regression analysis also revealed that the BPRS anxiety/depression and SANS anhedonia subcales were the predictor variables in five of six QOL domains in the schizophrenia group. The better quality-of-life scores of the mild group on physical and psychological domains indicate that the WHOQOL-100 could be used as an outcome measure in clinical studies. Thus, the WHOQOL-100 scale is a reliable, subjective quality-of-life scale for patients diagnosed with schizophrenia. The clinical sensitivity should also be assessed in large follow-up studies.
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PMID:The sensitivity of quality-of-life scale WHOQOL-100 to psychopathological measures in schizophrenia. 1467 38

There is growing evidence for a relationship between the duration of untreated psychosis (DUP) and the prognosis in schizophrenia. The objective of this study is to evaluate whether DUP and premorbid level of social functioning are related to treatment response in acute treatment of first-episode schizophrenia. Seventy-nine first-episode schizophrenia patients were assessed with BPRS, SAPS, and SANS on admission and discharge during their first hospitalisation. Percentage of the difference between admission and discharge in total scores of all scales were taken as measures of absolute symptom reduction. The median DUP was 6 months (mean=8.6). DUP was correlated with reduction in BPRS and SAPS scores but not SANS scores. Patients with a short DUP (n=41) also showed a higher reduction in BPRS, and SAPS scores than those with a long DUP. Premorbid Adjustment Scale (PAS) scores were inversely correlated with age at onset and positively correlated with BPRS scores at admission. We did not find any relationship between PAS scores and response to treatment. Our findings suggest that DUP may be an important predictor of response in acute treatment of first-episode schizophrenia and thus, attempts for early diagnosis may also have a positive effect on acute treatment response.
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PMID:Duration of untreated psychosis may predict acute treatment response in first-episode schizophrenia. 1475 30

Previous reports have described accelerated loss of cerebral white matter in schizophrenia. Others have reported changes of ventricle volumes in schizophrenic patients, with greatest increases following remission of psychotic symptoms. In this study changes in cerebral white matter volumes and psychotic symptoms were measured in 16 recently decompensated schizophrenic patients from neuroleptic-free baseline to 4 weeks later during treatment with antipsychotics. Serial white matter assessments were also performed in eight controls at similar intervals. Thirteen of 16 patients showed reduction of psychotic symptoms (reduction of SAPS scores by 24.4+/-12.6) during treatment. Three patients failed to respond (increase of SAPS scores by 15.7+/-13.8). Serial volumetric studies of cerebral white matter during the 4-week period showed a decrease of white matter volume in the responders by 8.2+/-8.2 cm(3) (P=0.003). Patients who failed to respond showed a non-significant increase in white matter during the same period by 11.4+/-11.7 cm(3). Absolute and percentage changes change in white matter volumes during the 4-week period were positively correlated with changes in SAPS scores (both P<0.01). Cerebral white matter, composed of myelin-containing oligodendrocytes, is highly sensitive to excitotoxicity. Swelling of myelin and of white matter, associated interference with the speed of neurotransmission through myelinated axons, and dyssynchrony of information processing by subcortical and cortical networks may be associated with psychosis exacerbation. Partial remission of symptoms may mark temporary reduction of an active, toxic process that interferes with information processing.
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PMID:State-related changes in cerebral white matter may underlie psychosis exacerbation. 1497 69

The present study was undertaken to test Frith's [The Cognitive Neuropsychology of Schizophrenia, 1992. Erlbaum (UK) Taylor and Francis, East Sussex] model which states that certain symptoms of schizophrenia arise from diminished capacity to regulate willed (goal-directed) and stimulus-driven action systems. A total of 107 patients were administered the Rey Auditory Verbal Learning Test (RAVLT), a task that on interference trials requires individuals to recall target material while suppressing non-target distracting stimuli from memory. Symptom ratings were obtained using the SANS/SAPS [Andreasen, N.C., 1984. Scale for the Assessment of Negative Symptoms/Scale for the Assessment of Positive Symptoms [Manual] University of Iowa Press, Iowa City]. It was predicted that (1) negative symptoms would result in diminished recall, reflecting compromised activation of the willed action system, and (2) disorganized symptoms would be associated with heightened interference susceptibility resulting from diminished ability to suppress the stimulus-driven action system. Results revealed that diminished recall was related to negative, but not disorganized or positive symptoms. Symptom ratings were also evaluated in a subset of patients with intrusion error data (n=38). In this subset, it was found that patients who committed intrusion errors on the interference trials evidenced more disorganized, but not negative or positive symptoms, than individuals failing to commit such errors. These findings provide some support for Frith's hypothesis that impaired regulation of action systems may underlie some of the specific symptoms and cognitive impairments of this illness.
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PMID:Symptoms and interference from memory in schizophrenia: evaluation of Frith's model of willed action. 1514 69

Both elevated cardiovascular mortality and low cardio-vagal (parasympathetic) heart rate variability (HRV)--a risk factor for postmyocardial infarction--are reported in schizophrenia (SZ). Since a number of medications have strong effects of cardiac conductivity, we thought it important to examine if typical neuroleptic medications might also affect HRV. We examined cardiac vagal activity during both neuroleptic treatment and a drug-free condition in seven SZ patients who were participating in a pilot double-blind, crossover study of placebo and haloperidol treatment. Twenty-four-hour Holter electrocardiograms were analyzed for high frequency HRV, quantitated as the percent of successive normal interbeat intervals greater than 50 milliseconds (PNN50), which is a good index of parasympathetic cardiac modulation. The patients showed unchanged PNN50 (8.4+/-9.5 versus 8.3+/-10.5; t=.22, df=6, P=.5) between the haloperidol treatment and drug-free conditions. Despite the elapsed time, change in medication, and altered clinical state, the PNN50s were highly correlated (Spearman r=.98, P=.000). SAPS positive symptom scores declined with treatment from 12.8+/-6.5 to 8.5+/-3.5; paired t=3.26: df=6; P=.01. PNN50s were significantly associated with positive (r=-.86, df=6, P=.012) and negative symptom scores (r=-.87, df=6, P=.01). We found low cardiovagal modulation in medication-free SZ patients that was associated with core SZ symptoms and was unchanged by haloperidol and benztropine treatment. The reduced HRV in SZ patients at baseline may render them at greater cardiovascular risk than healthy subjects when treated with medications having strong cardiovascular effects.
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PMID:Low heart rate variability is not caused by typical neuroleptics in schizophrenia patients. 1525 49

This study compares globus pallidus (GP) volume between neuroleptic naive patients with schizophrenia and healthy controls using structural MRI. The volume of the external segment of the GP (GPe) was positively correlated with the severity of global symptoms, as measured by the Scale for the Assessment of Negative Symptoms and Scale for the Assessment of Positive Symptoms (SANS/SAPS, Andreasen and Olsen, 1982). The volume for the GP, GPe, and internal segment (GPi) did not differ between groups.
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PMID:Globus pallidus volume is related to symptom severity in neuroleptic naive patients with schizophrenia. 1565 65

One possible reason of the inconsistent results of linkage analyses of schizophrenia, a complex disorder, was mainly due to the small sample size of studies. This Taiwan Schizophrenia Linkage Study (TSLS) was designed to collect a large family sample with at least two affected siblings of a single ethnicity. The 17.6 millions of Taiwanese Chinese, age over 15, was the sample population, and 78 psychiatric hospitals or health centers participated in this TSLS program. Before data collection started, every study subject signed the informed consent. The ascertainment protocol for data collection included blood sample, structured Diagnostic Interview for Genetic Studies (DIGS), Structured Interview for Schizotypy (SIS), scales for assessment of positive and negative symptoms (SAPS, SANS), and continuous performance test (CPT), Wisconsin card sort test (WCST) of neuropsychological functions. We have contacted 831 families for this study and 607 families, comprised 2,490 subjects, were successfully recruited. The recruitment rate was 38.4% from the estimated total of 1,582 families with at least two affected siblings. These collected family samples were fairly evenly distributed all over Taiwan. Those 2,490 study subjects (1,283 male, 1,117 female) comprised 1,568 siblings (mean age 35.7 years old) and 922 parents (mean age 63.6 years old). Of these 1,568 siblings, 1,258 (80.2%) were affected (male 795, female 463), and the mean age of onset was 22.6 years old. Among 922 parents, 65 were affected (male 14, female 51) and the age of onset was 33.1 years old. This TSLS demonstrated a successful establishment of an efficient research infrastructure to collect a large nation-wise sample of schizophrenic family for genetic linkage study.
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PMID:Taiwan schizophrenia linkage study: the field study. 1568 25


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