Information processing in schizophrenia and bipolar disorder: a discriminant analysis

Schizophrenia and bipolar disorder are two distinct categories of mental disorders in the DSM-IV. However, it is often difficult to make a differential diagnosis because of the overlapping symptoms. A potential adjunct in the classification of schizophrenia and bipolar disorder is the application of information processing models, as patients with schizophrenia and possibly those with bipolar disorder have information processing deficits. A study was conducted in which a computerized battery of information processing tasks (called COGLAB) was administered to three participant groups: patients with schizophrenia, patients with bipolar disorder, and normal controls. The tasks included the Mueller-Lyer illusion, reaction time, size estimation, a variant of the Wisconsin Card Sorting Test, backward masking, and Asarnow continuous performance. Discriminant analyses were used to investigate the differences among the three groups. Results indicated that COGLAB correctly classified 75.5% of the cases of schizophrenia and bipolar disorder. The Mueller-Lyer illusion and the number of perseverative errors on the card sort most powerfully discriminated the two groups.     

Display visual angle and attentional scanpaths on the span of apprehension task in schizophrenia.

The effect of display visual angle on span of apprehension (SOA) task performance was investigated in patients with schizophrenia and nonpsychiatric individuals. Narrow and wide visual-angle presentations of 3- and 10-letter arrays were compared. Detection rates were significantly higher with narrow than wide visual angle for nonpsychiatric individuals; the performance of those with schizophrenia was stable across visual-angle conditions. Patients with schizophrenia were best discriminated from nonpsychiatric individuals in the narrow-angle, 10-letter condition. Scanpath analyses, which were based on the pattern of detection rates across different target quadrant locations, suggested that the patients with schizophrenia used a similar number and path of covert scan moves as did the controls. Hypotheses are discussed regarding which of the multiple cognitive processes tapped by the SOA task may be impaired in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event-Related fMRI Study of Context Processing in Dorsolateral Prefrontal Cortex of Patients With Schizophrenia.

Context processing is conceptualized as an executive function involved in voluntary, complex actions such as overcoming automatic responses. The present study tested the hypothesis that context-processing deficits in patients with schizophrenia are associated with a dysfunction of left dorsolateral prefrontal cortex (DLPFC). Using event-related functional magnetic resonance imaging (fMRI), 17 controls and 17 medicated patients performed a version of the AX task in which a learned, automatic response had to be inhibited. In controls, left DLPFC activity increased when preparing to overcome an automatic response, whereas patients with schizophrenia showed no differential activation. In controls, context processing appeared to be associated with the differential representation of cues associated with the need to provide top-down support for overcoming automatic responses. This mechanism appeared to be impaired in patients with schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How are psychotic symptoms perceived? A comparison between patients, relatives and the general public

OBJECTIVE: The aim of this study is to compare patients with schizophrenia with their relatives and the general public in their attitudes towards schizophrenic psychotic symptoms. METHOD: We used a case vignette depicting a person with typical schizophrenic psychotic symptoms and compared the attitudes of 44 inpatients and 47 outpatients with schizophrenia, 48 of their relatives and 43 members of the general public. We also compared the attitudes of patients with schizophrenia to their own symptoms and the symptoms described in the vignette. RESULTS: Subjects from the general public tended not to recognise psychotic symptoms as features of mental illness and tended not to consider drug treatment and hospitalisation as required. Sex, education level as well as previous contact with the mentally ill were found to be significant determinants of attitude. The levels of symptom awareness in patients with schizophrenia and their relatives are higher but still relatively low. In addition, we found that patients with schizophrenia who correctly appraised psychotic symptoms in another person were also aware of their own mental symptoms and need of treatment. CONCLUSIONS: The level of recognition of psychotic symptoms and awareness of a need for treatment are low in the general public, as well as in patients with schizophrenia and their relatives. These findings are discussed in relation to the assessment of insight in patients and a need for psychoeducational programs for each group.     

Nondementia nonpraecox dementia praecox? Late-onset schizophrenia

Schizophrenia has traditionally been viewed as a psychotic disorder with onset in adolescence or early adulthood and a deteriorating course. Over the past decade, the authors have been studying patients meeting DSM-III-R as well as specified research criteria for late-onset schizophrenia (onset after age 45) and several comparison groups with psychiatric, neurologic, neuropsychologic, brain-imaging, psychophysiological, and psychosocial assessments. Results to date suggest a number of similarities and differences between late-onset schizophrenia and comparison groups of other older patients with psychoses (including earlier-onset schizophrenia). Later-onset schizophrenia is probably a neurobiologically distinct subtype of schizophrenia. Differential involvement of cortico-striato-pallido-thalamic circuitry may explain differences in age at onset. The authors propose a new conceptual model for level of functioning at different stages of life in late-onset schizophrenia.     

Deficits in gray matter volume are present in schizophrenia but not bipolar disorder

Studies using magnetic resonance (MR) imaging have provided strong evidence that patients with schizophrenia as a group have structural brain abnormalities, including enlarged ventricles and sulci as well as smaller cortical gray matter volumes. This study was undertaken to investigate whether the brain abnormalities found in schizophrenia could be distinguished from those seen in bipolar disorder. The MR scans of 23 patients with schizophrenia were compared to those of 17 healthy community volunteers and 14 patients with bipolar disorder. Images were processed using computer-based image processing techniques to generate quantitative measures of cerebrospinal fluid (CSF), gray matter and white matter volumes. Compared to the community volunteers, the schizophrenia group had larger total CSF volumes while the bipolar group had larger ventricles. Smaller cortical gray matter volumes were found in the schizophrenia group, but not in the bipolar group. The schizophrenia group had regional deficits in gray matter volumes in comparison with both the community volunteers and the bipolar group. These findings suggest that the brain tissue abnormalities found in schizophrenia and bipolar disorder may be distinguishable using MR imaging.     

Context-processing deficits in schizophrenia: Diagnostic specificity, 4-week course, and relationships to clinical symptoms.

Previous research on schizophrenia suggests that context-processing disturbances are one of the core cognitive deficits present in schizophrenia. However, it is not clear whether such deficits are specific to schizophrenia as compared with other psychotic disorders. To address this question, the authors administered a version of the AX Continuous Performance Test designed to assess context processing in a sample of healthy controls, patients with schizophrenia, and patients with other psychotic disorders. Participants were tested at index (when medication naive and experiencing their first contact with psychiatric services) and 4 weeks later, following medication treatment. At index, patients with schizophrenia and the psychotic comparison group demonstrated similar impairments in context processing. However, context-processing deficits improved in the psychotic comparison group at 4 weeks but did not improve in patients with schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Facial expressions of emotions and schizophrenia: a review

It is generally agreed that schizophrenia patients show a markedly reduced ability to perceive and express facial emotions. Previous studies have shown, however, that such deficits are emotion-specific in schizophrenia and not generalized. Three kinds of studies were examined: decoding studies dealing with schizophrenia patients' ability to perceive universally recognized facial expressions of emotions, encoding studies dealing with schizophrenia patients' ability to express certain facial emotions, and studies of subjective reactions of patients' sensitivity toward universally recognized facial expressions of emotions. A review of these studies shows that schizophrenia patients, despite a general impairment of perception or expression of facial emotions, are highly sensitive to certain negative emotions of fear and anger. These observations are discussed in the light of hemispheric theory, which accounts for a generalized performance deficit, and social-cognitive theory, which accounts for an emotion-specific deficit in schizophrenia.     

Dual-task performance operating characteristics, resource limitations, and automatic processing in schizophrenia.

Performance on a multiple-frame search task (MFST) was investigated in 18 schizophrenia patients and 19 nonpsychiatric controls. Three of 4 indices indicated automation of visual detection responses in both groups on the MFST. In dual-task conditions (MFST during reaction time tasks), the schizophrenia patients showed greater dual-task RT slowing than controls, suggesting reduced resource availability in schizophrenia patients. Performance operating characteristic representations also indicated greater resource limitations in schizophrenia patients but showed similar allocation policy in both groups. The results suggest that schizophrenia patients have reduced availability of processing resources, which is not likely to be due to faulty resource allocation. However, these data do not confidently resolve whether schizophrenia patients reach a normal level of automation. Implications for frontal-subcortical models of schizophrenia are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Catecholamine storage in schizophrenia

After administration of isadrine excretion of noradrenaline was increased in schizophrenic patients with symptoms of depression or anxiety. This phenomenon was not observed in healthy persons and in patients with circular depression. Data on liberation of noradrenaline by other amines in schizophrenia and displacement of noradrenaline in schizophrenia by isadrine, which does not accumulate in normal storage sites, suggest that storage of noradrenaline is impaired in schizophrenia.     

Clinician attributions associated with the diagnosis of schizophrenia in African American and non-African American patients.

The authors examined the schizophrenia diagnosis in 292 psychiatric inpatients in a largely African American community. Clinicians completed a free-response questionnaire that described their diagnostic decisions. Psychotic symptoms such as hallucinations, which were attributed to African American and non-African American patients at different rates, did not necessarily correspond to differences in diagnostic rates. Rather, symptoms not differentially attributed between groups often corresponded with higher rates of schizophrenia for African American patients. Attributions of negative symptoms showed the largest differences between African American and non-African American patients in rates of schizophrenia diagnosis; thought disorder equalized rates of the diagnosis between the 2 groups of patients. Logistic regression analyses suggested that different aggregate decision models were applied to patients of differing race. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative D2 dopamine receptor PET and structural MRI changes in late-onset schizophrenia

Late-onset schizophrenia (LOS) is likely a syndrome of diverse etiology. In a series of related studies, we compared LOS patients with normal controls, elderly patients with early-onset schizophrenia (EOS), and Alzheimer's disease patients, using magnetic resonance imaging (MRI) and neuroreceptor positron emission tomography measures, which had previously been reported to be abnormal in EOS. EOS and LOS patients showed similar MRI changes. LOS drug-naive patients had elevated Bmax (receptor density) values for dopamine D2 receptors compared with age and gender norms, a phenomenon previously reported by our group in young schizophrenia patients.     

Glutamatergic neurotransmission involves structural and clinical deficits of schizophrenia

BACKGROUND: Phencyclidine and ketamine induce a syndrome closely resembling schizophrenia due to their blockade of N-methyl-D-aspartate (NMDA) receptor. These findings suggested that some aspects of schizophrenia are associated with decreased NMDA--glutamatergic function. We hypothesized that structural and symptomatic deficits in schizophrenia are related to glutamatergic neurotransmission. METHODS: We studied the relationships among cerebrospinal fluid (CSF) glutamatergic markers, clinical presentation of schizophrenia, and CT parameters of brain structure in drug-free schizophrenics. RESULTS: We found no significant differences between patients with schizophrenia and controls in CSF glutamatergic markers. When patients with schizophrenia were considered as a group, significant negative correlations between glutamatergic markers and brain structural measures as well as clinical measures were observed. Cluster analysis reveals a group of lower indices of glutamatergic neurotransmission, and more prominent thought disorder as well as ventricular enlargement, and a group with increased glutamate level. CONCLUSIONS: The findings support the hypothesis that altered glutamatergic neurotransmission plays a role in the brain structure and the clinical symptoms of schizophrenia.     

Learning and forgetting in schizophrenia.

Recent studies of patients with schizophrenia have consistently demonstrated marked deficits on measures of initial learning. However, contradictory results have been reported concerning retention and forgetting. The present study examined the level of initial and delayed recall of stories and visual figures in a group of 76 patients with schizophrenia and 51 normal controls. Schizophrenia patients demonstrated marked impairments in initial and delayed recall as well as significantly worse percentage retention scores. However, schizophrenia patients and healthy controls individually matched on level of initial recall had nearly identical delayed recall performance. The results suggest a primary deficit in the initial acquisition of information rather than an accelerated rate of forgetting in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition of posed and genuine facial expressions of emotion in paranoid and nonparanoid schizophrenia.

Most previous research reporting emotion-recognition deficits in schizophrenia has used posed facial expressions of emotion and chronic-schizophrenia patients. In contrast, the present research examined the ability of patients with acute paranoid and nonparanoid (disorganized) schizophrenia to recognize genuine as well as posed facial expressions of emotion. Evidence of an emotion-recognition deficit in schizophrenia was replicated, but only when posed facial expressions were used. For genuine expressions of emotion, the paranoid-schizophrenia group was more accurate than controls, nonparanoid-schizophrenia patients, and depressed patients. Future research clearly needs to consider the posed versus genuine nature of the emotional stimuli used and the type of schizophrenia patients examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Demographics, family history, premorbid functioning, developmental characteristics, and course of patients with deteriorated affective disorder

OBJECTIVE: This exploratory study examined the characteristics of a group of unusual and previously undescribed patients with major affective disorder who not only had been continuously symptomatic for prolonged periods of time but were also so functionally impaired that they required years of continuous care in psychiatric facilities or by family members. METHOD: Twenty-seven inpatients with major mood disorders and 29 inpatients with schizophrenia were recruited from a large state hospital; 27 outpatients with major mood disorders were recruited from an affiliated outpatient facility. The research battery included the Structured Clinical Interview for DSM-III-R--Patient Version, the Premorbid Adjustment Scale, and a semistructured interview designed to assess demographic, family history, developmental, and course information. RESULTS: Inpatients with deteriorated affective disorder differed from outpatients with nondeteriorated affective disorder along several important dimensions, including family history of mental illness, birth-related problems, physical disorders in infancy, premorbid functioning, presence of mixed episodes and rapid cycling, and medication non-compliance between hospitalizations. Inpatients with deteriorated affective disorder differed from inpatients with schizophrenia on the Premorbid Adjustment Scale. Patients with bipolar affective disorder differed from those with unipolar disorder on many of the variables associated with deterioration of functioning. CONCLUSIONS: Birth-related problems, physical disorders in infancy, and poor premorbid adjustment in childhood and adolescence appear to play an important role in deterioration of functioning among patients with unipolar depression. Disruption in treatment because of medication noncompliance and the appearance of mixed episodes and rapid cycling are associated with functional decline in bipolar affective disorder. Several characteristics previously considered specific to deterioration of functioning in schizophrenia, such as a high rate of birth complications and poor premorbid adjustment, appear to be associated with functional deterioration among patients with major depression as well.     

The life of Maurice Virenque (1888-1946). From "Gueules Cassées" to cervicofacial facelift

Neuroimaging and neuropsychological studies have consistently implicated dorsolateral prefrontal cortex as abnormal in schizophrenia. However, other areas of frontal cortex have received far less attention. In particular, few studies have examined orbital frontal regions with other than olfactory tests. In the present study we wished to assess the functional capability of orbital frontal cortex using a test developed by Bechara et al. (1994) that assesses a subject's capacity to acquire a preference through reward and punishment, using a gambling task that involved gains and losses of play money. Thirty normal subjects and 12 patients with schizophrenia (three undifferentiated, eight paranoid, one schizoaffective) comprised the sample in the present study. We found that patients with schizophrenia exhibited a pattern of findings similar to that of normals and dissimilar to that of patients with known orbital frontal damage. In our study, both normal subjects and schizophrenic patients chose most frequently from decks of cards in which there were frequent rewards and infrequent penalties, as might be expected on the basis of operant conditioning literature. We also found that performance on this task was not correlated with tests of working memory or long-term memory, suggesting that the development of a preference may occur implicitly. Our findings also argue against a general deficit in schizophrenia, as performance on the gambling task appeared relatively uncompromised.     

Clinical outcome of mild fetal ventriculomegaly

The presence of antibodies against neural antigens was investigated in the serum of patients with schizophrenia, major depression and normal controls. Different immunological abnormalities, humoral and cellular, were reported in schizophrenia and major depression. The pathogenesis of schizophrenia is multifactorial. An autoimmune mechanism was suggested as a possible factor. We tested the serum of 26 patients with schizophrenia, eight patients with major depression and 22 normal controls. The serum samples were tested for antibody binding to protein extracts of IMR-32 neuroblastma cell line using Western blot analysis. Immunoglobulins of eight patients with schizophrenia (30.71%) reacted with a protein of 80-85 kDa. Serum samples from subjects of other groups did not react with this protein. Sera of all patients with major depression but one, and all normal controls reacted with HSP 60 kDa to different extent. This is an apparent discrepancy with the findings of Kilidireas et al. [Kilidireas, K., Latov, N., Strauss, D.H., Gorig, A.D., Hashim, G.A., Gorman, J.M., Sadig, S.A., 1992. Antibodies to the human 60 kDa heat shock protein in patients with schizophrenia. Lancet 340, 569-572.] who demonstrated the presence of antibodies against HSP 60 kDa in 44% of patients with schizophrenia tested and 8% of normal subjects. HSP 60 kDa is an antigen of many pathogens and antibodies against it might be a result of an infection and cannot be a good indicator for an autoimmune process. The presence of antibodies against a protein of 80-85 kDa should be investigated as a possible specific indicator.     

The T cell populations mediating rejection of MHC class I disparate skin grafts in mice

Numerous studies have demonstrated a lateralized impairment of attention in schizophrenia. In this study, attention in schizophrenia is investigated with a task that involves centering a rod while blindfolded. Symptoms were rated on the Brief Psychiatric Rating Scale (BPRS) for each of the 20 schizophrenic subjects. The more symptomatic patients demonstrated a right-sided hemineglect compared to the less symptomatic patients (p = 0.013). Furthermore, the difference between more and less symptomatic patients was even more distinct when they were categorized by the BPRS schizophrenia subscale alone (p = 0.0025). These findings support the hypothesis that the pathophysiology of schizophrenia involves a lateralized defect in the control of attention, and that this defect is associated with the severity of symptoms. This raises the possibility that effects of neuroleptic medication may be asymmetric, which could account for some of the inconsistencies in studies of hemispheric dysfunction in schizophrenia.