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J Parnas

Publications and source records attributed to J Parnas.

At least 19 recordsLinked to original sources
PubMed2003

Anomalies of subjective experience in schizophrenia and psychotic bipolar illness.

OBJECTIVE: Contemporary psychopathology, as a result of behaviourally dominated epistemological stance, downplays anomalies of the patient's subjectivity. This neglect has probably deleterious consequences for research in the causes and the boundaries of the schizophrenia spectrum conditions. The purpose of this study is to explore frequency of qualitative, not-yet-psychotic, anomalies of subjective experience in patients with residual schizophrenia and psychotic bipolar illness in remission. METHOD: The patients were examined with the Danish version of the Bonn Scale for the Assessment of Basic Symptoms (BSABS). Anomalies of experience were condensed into rational scales with good internal consistencies. RESULTS: Diagnosis of schizophrenia was associated with elevated scores on the scales measuring perplexity (loss of immediate meaning), disorders of perception, disorders of self-awareness, and marginally so, disorders of cognition. CONCLUSION: These findings, in conjunction with those from other, methodologically similar studies, suggest that certain anomalies of subjective experience aggregate significantly in schizophrenia. These experiential anomalies appear to be relevant for early differential diagnosis and therefore potentially useful in the preonset detection of the schizophrenia spectrum illness.

Adult↗
PubMed2003

Schizophrenia, neurodevelopment and corpus callosum.

The Zeitgeist favors an interpretation of schizophrenia as a condition of abnormal connectivity of cortical neurons, particularly in the prefrontal and temporal cortex. The available evidence points to reduced connectivity, a possible consequence of excessive synaptic pruning in development. A decreased thalamic input to the cerebral cortex appears likely, and developmental studies predict that this decrease should entail a secondary loss of both long- and short-range cortico-cortical connections, including connections between the hemispheres. Indeed, morphological, electrophysiological and neuropsychological studies over the last two decades suggest that the callosal connections are altered in schizophrenics. However, the alterations are subtle and sometimes inconsistent across studies, and need to be investigated further with new methodologies.

Agenesis of Corpus Callosum↗
PubMed2001

Visual binding abilities in the initial and advanced stages of schizophrenia.

OBJECTIVE: The study tests the hypothesis that intramodal visual binding is disturbed in schizophrenia and should be detectable in all illness stages as a stable trait marker. METHOD: Three groups of patients (rehospitalized chronic schizophrenic, first admitted schizophrenic and schizotypal patients believed to be suffering from a pre-schizophrenic prodrome) and a group of normal control subjects were tested on three tasks targeting visual 'binding' abilities (Muller-Lyer's illusion and two figure detection tasks) in addition to control parameters such as reaction time, visual selective attention, Raven's test and two conventional cortical tasks of spatial working memory (SWM) and a global local test. RESULTS: Chronic patients had a decreased performance on the binding tests. Unexpectedly, the prodromal group exhibited an enhanced Gestalt extraction on these tests compared both to schizophrenic patients and to healthy subjects. Furthermore, chronic schizophrenia was associated with a poor performance on cortical tests of SWM, global local and on Raven. This association appears to be mediated by or linked to the chronicity of the illness. CONCLUSION: The study confirms a variety of neurocognitive deficits in schizophrenia which, however, in this sample seem to be linked to chronicity of illness. However, certain aspects of visual processing concerned with Gestalt extraction deserve attention as potential vulnerability- or prodrome- indicators. The initial hypothesis of the study is rejected.

Adult↗
PubMed2000

Haplotypes and linkage disequilibrium at the phenylalanine hydroxylase locus, PAH, in a global representation of populations.

Because defects in the phenylalanine hydroxylase gene (PAH) cause phenylketonuria (PKU), PAH was studied for normal polymorphisms and linkage disequilibrium soon after the gene was cloned. Studies in the 1980s concentrated on European populations in which PKU was common and showed that haplotype-frequency variation exists between some regions of the world. In European populations, linkage disequilibrium generally was found not to exist between RFLPs at opposite ends of the gene but was found to exist among the RFLPs clustered at each end. We have now undertaken the first global survey of normal variation and disequilibrium across the PAH gene. Four well-mapped single-nucleotide polymorphisms (SNPs) spanning approximately 75 kb, two near each end of the gene, were selected to allow linkage disequilibrium across most of the gene to be examined. These SNPs were studied as PCR-RFLP markers in samples of, on average, 50 individuals for each of 29 populations, including, for the first time, multiple populations from Africa and from the Americas. All four sites are polymorphic in all 29 populations. Although all but 5 of the 16 possible haplotypes reach frequencies >5% somewhere in the world, no haplotype was seen in all populations. Overall linkage disequilibrium is highly significant in all populations, but disequilibrium between the opposite ends is significant only in Native American populations and in one African population. This study demonstrates that the physical extent of linkage disequilibrium can differ substantially among populations from different regions of the world, because of both ancient genetic drift in the ancestor common to a large regional group of modern populations and recent genetic drift affecting individual populations.

Africa↗
PubMed1999

MMPI variables predictive of schizophrenia in the Copenhagen High-Risk Project: a 25-year follow-up.

Moldin et al. (1) have identified a cluster of Minnesota Multiphasic Personality Inventory (MMPI) scales that discriminate adolescents at risk for schizophrenia from those not at risk. The present study examines how well Moldin's scales predict schizophrenic decompensation in a sample of 207 Danish adolescents at high genetic risk for schizophrenia. Subjects were assessed using a modified, 304-item MMPI in 1962 (mean age= 15.1 years) and diagnosed in 10-year and 25-year follow-ups. Premorbidly, schizophrenic subjects (n=31) scored higher than subjects with no mental illness on the frequency (F) and psychoticism (PSY) scales. When paranoid and non-paranoid preschizophrenics were separated, three scales (F, Pz (paranoid schizophrenia) and PSY) significantly discriminated paranoid preschizophrenics. Discriminant function analyses confirmed these results. It is concluded that the MMPI may be useful for identifying schizophrenia premorbidly.

Adolescent↗
PubMed1999

From predisposition to psychosis: progression of symptoms in schizophrenia.

Schizophrenia is increasingly viewed as a neurodevelopmental process caused by an interaction between genetic factors and environmental stressors. Prospective studies and retrospective research using objective data indicate that behavioural deviations can be dated to early infancy and cut across multiple behavioural domains. In adolescence, preschizophrenics exhibit subtle changes in cognition and affect as well as a variety of anomalous subjective experiences (so-called 'basic symptoms'), suggesting 'trait' status of these features. Prodromal symptoms occur in a substantial proportion of preschizophrenics, followed by a short prepsychotic phase with the crystallization of a psychotic syndrome. Clinical, phenomenological and conceptual aspects of these early preschizophrenic phases are reviewed, and their neurobiological implications are briefly addressed. It is concluded that there is an urgent need for detailed and multidisciplinary prospective studies, but that the evidence accumulated to date is sufficient to justify research-based secondary prevention programmes.

Age Factors↗
PubMed1998

Epilepsy and non-organic non-affective psychosis. National epidemiologic study.

BACKGROUND: This study tests the hypothesis that epilepsy increases the risk of developing schizophrenia and other non-affective functional psychoses using a nationwide sample of people with epilepsy. METHOD: A record linkage study between a sample from the National Patient Register, consisting of 67,116 people with epilepsy, and the Danish Psychiatric Register identified all people with non-affective psychoses with onset after the first epilepsy diagnosis. The relation between risk of psychiatric disorder in people with epilepsy and the general Danish population was estimated. RESULTS: The incidences of the spectrum of non-organic non-affective psychosis, non-affective psychosis and schizophrenia were significantly increased both for men and women, even after exclusion of people diagnosed as suffering from a learning disability or substance misuse. CONCLUSION: This study supports the notion of an association between epilepsy and the risk of subsequent non-affective psychosis.

Denmark↗
PubMed1998

School teacher ratings predictive of psychiatric outcome 25 years later.

BACKGROUND: The current study examines teacher ratings as a tool for identifying students at risk of developing psychosis. Follow-up and follow-back studies have shown that teachers are capable of identifying individuals who later develop serious mental illness. METHOD: We examine the long-term outcomes for individuals at genetic risk who were identified as showing markedly deviant behaviour and those identified who did not show markedly deviant behaviour. RESULTS: Teachers were able to correctly anticipate 35% of students who developed schizophrenia. Furthermore, those identified as showing markedly deviant behaviour had poorer clinical and psychiatric outcomes 10 and 25 years later than those identified as not behaving with marked deviance. Their ratings also differentiated, within the group of people with schizophrenia, which individuals would show evidence of poorer functioning 25 years later. These results were replicated in a group of students not at genetic risk of schizophrenia. Within this low-risk group, teachers were able to predict which students would develop psychotic disorders. CONCLUSIONS: Teacher ratings were particularly useful in predicting clinical and psychiatric outcomes 10 and 25 years later. The applicability of these findings in early intervention and treatment research is discussed.

Adolescent↗
PubMed1997

Structural brain abnormalities in schizophrenia: a family study.

Structural brain abnormalities such as ventricular enlargement are robust correlates of schizophrenia, but the degree of difference compared with unrelated normal controls is only moderate (< 1 standard deviation), and only 40% of patients have values on these measures that fall outside of the normal distribution. Family studies can help to clarify the meaning of this overlap by controlling for some of the non-schizophrenia-related genetic variation in neuroanatomical traits. Computerized tomographic scans of the brain were used to measure ventricular and sulcal cerebrospinal fluid (CSF) to brain ratios (VBR and SBR) for each hemisphere in 16 pairs of discordant siblings from the Copenhagen Schizophrenia High-Risk Project. Schizophrenics' values for VBR and SBR exceeded those of their nonschizophrenic siblings in 75% of the pairs; on average, patients' values on these measures were 1 and 5 standard deviations larger, respectively, than those of their nonschizophrenic siblings. Sulcal and left hemisphere effects were significantly more pronounced than ventricular and right hemisphere effects. After controlling for between-family variation, structural brain abnormalities appear to be more prevalent and more pronounced in schizophrenia than has previously been assumed, with relatively greater deviation observed for cortical and left hemisphere measures of CSF space enlargement.

Adult↗
PubMed1997

Childhood behavior precursors of schizotypal personality disorder.

No study has yet reported specifically on the early behavior of individuals later diagnosed with schizotypal personality disorder (SPD). This study examines prospectively collected teacher reports on school behavior as a means of assessing childhood precursors of SPD. Thirty-six DSM-III-R diagnosed schizotypal subjects were compared with four other groups: 31 schizophrenia patients, 37 diagnosed as nonpsychotic mentally ill, 68 who were not mentally ill but had mothers with schizophrenia, and 60 who were not mentally ill and had normal parents. These individuals were compared on a teachers' school report questionnaire obtained when the subjects averaged 15.1 years old. Those who later developed SPD were found to be more passive and unengaged and more hypersensitive to criticisms compared with the nonschizophrenia groups. Similar results were found when males and females were examined separately, except that males who developed SPD were found to be less disruptive and hyperexcitable compared with males with schizophrenia; females with SPD did not differ from females with schizophrenia. A receiver operating characteristic analysis found these factors to predict 73.5 percent of future SPDs; the ability of these factors to predict future SPDs is comparable for males and females. These findings suggest that preschizotypal traits may be identified in late childhood or adolescence.

Adolescent↗
PubMed1997

Effects of child-rearing by schizophrenic mothers: a 25-year follow-up.

We conducted a 25-year follow-up study of 50 children of schizophrenic mothers, consisting of 25 children reared by their mothers and 25 children reared apart. The children's adult psychiatric status was evaluated in a 3-h structured interview employing a battery of syndrome check-lists and scales. A slightly higher incidence of psychopathology (including schizophrenia-spectrum disorders) was found among the reared-apart subjects. This may possibly be attributed to their greater genetic predisposition, as suggested by their mothers' more severe illnesses. Lifetime diagnoses do not provide evidence that psychopathology in offspring at genetic risk is increased by rearing by a schizophrenic mother.

Adolescent↗
PubMed1995

The latent structure of schizotypy: I. Premorbid indicators of a taxon of individuals at risk for schizophrenia-spectrum disorders.

A taxometric analysis (R. R. Golden & P. E. Meehl, 1979) was conducted to test the hypotheses that liability for schizophrenia-spectrum disorders is dichotomously distributed and that this liability can be detected premorbidly with behavioral indicators analogous to many of the criteria for schizotypal personality disorder. Behaviors were assessed in 207 offspring of schizophrenic mothers and 104 matched offspring of normal parents in 1962, when participants' mean age was 15 years. Diagnoses on the basis of the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) were made in 1986-1989, when participants were nearly through the risk period for developing schizophrenia. The aggregation of indicators was consistent with a bimodal latent liability distribution. Membership in the schizotypal class was a sensitive and specific predictor of the emergence of schizophrenia-spectrum disorders in adulthood.

Adolescent↗
PubMed1994

Developmental brain abnormalities in the offspring of schizophrenic mothers. II. Structural brain characteristics of schizophrenia and schizotypal personality disorder.

BACKGROUND: We examined differences in ventricular and sulcal cerebrospinal fluid-to-brain ratios as a function of lifetime psychiatric diagnosis in the offspring of schizophrenic mothers (high-risk sample) and in the offspring of normal parents (low-risk sample). METHODS: We used a cohort analytic study of 17 high-risk individuals with schizophrenia, 31 high-risk individuals with schizotypal personality disorder, 33 high-risk individuals with nonschizophrenia-spectrum psychiatric disorders, 45 high-risk individuals with no disorders, 31 low-risk individuals with psychiatric disorders of all types, and 46 low-risk individuals with no disorders, evaluated initially in 1962 when they were a mean age of 15 years, and reexamined from 1986 through 1989 with psychiatric interviews and computed tomographic scans of the brain. RESULTS: High-risk individuals with schizophrenia and schizotypal personality disorder evidenced an equivalent degree of cortical sulcal enlargement, and both groups evidenced significantly greater sulcal enlargement than did high-risk individuals with nonschizophrenia-spectrum disorders and no disorders and low-risk individuals with psychiatric disorders and no disorders. High-risk individuals with schizophrenia evidenced significantly greater ventricular enlargement than did high-risk and low-risk subjects with other disorders and no disorders, including those with schizotypal personality disorder. These differences were independent of age, gender, history of substance dependence, and history of organic brain syndromes and head injuries. CONCLUSIONS: Among the offspring of schizophrenic parents, cortical abnormalities are expressed equally across the range of syndromes in the schizophrenia spectrum. Subcortical abnormalities (ie, ventricular enlargement) are more pronounced in the more severe syndrome (ie, schizophrenia).

Adult↗
PubMed1994

The influence of parental socioeconomic status on CT studies of schizophrenia.

A sample of 19 DSM-III-R schizophrenics and 94 controls with no mental illness from the Copenhagen high-risk project was used to test the hypothesis that social class of origin is related to adult CT measures of ventricular, sulcal, Sylvian fissure and anterior interhemispheric fissure enlargement, cerebellar pathology, and brain volume. The schizophrenics and controls were divided into high and low SES-of-origin. No significant differences emerged between the high and low SES-of-origin subjects within the schizophrenic and control groups on any of the six CT measures.

Adolescent↗
PubMed1994

The concept of borderline conditions: a critical comment on validity issues.

It is pointed out that many published empirical studies on the issue of borderline conditions suffer from methodological shortcomings due to the prevailing empiricist simplification of research. Attention is drawn to the fact that the current psychiatric research in classification issues is dominated by an exaggerated quest for reliability at the expense of concern with validity issues. Concepts of operational criteria, polythetic-prototypic systems, and epistemic peculiarities of psychiatric, clinical typification are briefly exposed. It is suggested that future scientific progress in the area of personality research must take into account these general methodological considerations: repotentiate clinical-phenomenological observation, include prototypical approaches, extend studied samples with subjects drawn from the general population and import insights from personality trait research in normal psychology. Some of the claims of Gunderson and Torgersen (this volume) are discussed.

Borderline Personality Disorder↗
PubMed1993

Developmental brain abnormalities in the offspring of schizophrenic mothers. I. Contributions of genetic and perinatal factors.

OBJECTIVE: We examined the contributions of genetic risk for schizophrenia and obstetric complications to brain morphological abnormalities in the offspring of schizophrenic and normal patents. METHODS: We used a cohort analytic study of 60, 72, and 25 individuals with neither, one, or two parents, respectively, who were affected with schizophrenia spectrum disorders, evaluated initially in 1962 when they were on average 15 years old, and reexamined from 1986 through 1989 with psychiatric interviews and computed tomographic scans of the brain. RESULTS: After controlling for the effects of age, gender, substance abuse, and history of organic brain syndromes and head injuries, there were significant stepwise, linear increases in cortical and ventricular cerebrospinal fluid-brain ratios with increasing level of genetic risk for schizophrenia. Genetic risk for schizophrenia also interacted with prospectively assessed birth complications in predicting selectively to enlargement of the ventricular system; ie, the effect of birth complications on ventricular enlargement was greater among those with two affected parents compared with those with one affected parent, and greater among those with one affected parent compared with those with normal parents. Perinatal exposure to ether anesthesia was associated with a generalized increase in brain abnormality, which varied in severity according to level of genetic risk for schizophrenia. CONCLUSIONS: The type and degree of brain abnormalities shown by adult offspring of schizophrenic and normal parents are strongly predicted by the independent and interacting influences of genetic risk for schizophrenia and obstetric complications. The findings further substantiate the hypothesis that structural brain abnormalities in schizophrenia are at least in part neurodevelopmental in origin.

Adolescent↗