Gender differences in premorbid cognitive performance in a national cohort of schizophrenic patients

Sex differences across developmental domains among children with a familial risk of severe mental disorders

BACKGROUND

Sex differences in brain structure and neurodevelopment occur in non-clinical populations. We investigated whether sex had a similar effect on developmental domains amongst boys and girls with a familial risk of schizophrenia (FHR-SZ), bipolar disorder (FHR-BP), and controls.

METHODS

Through Danish registries, we identified 522 7-year-old children (242 girls) with FHR-SZ, FHR-BP, and controls. We assessed their performance within the domains of neurocognition, motor function, language, social cognition, social behavior, psychopathology, and home environment.

RESULTS

FHR-SZ boys compared with FHR-SZ girls had a higher proportion of disruptive behavior and attention-deficit hyperactivity disorder (ADHD) and exhibited lower performance in manual dexterity, balance, and emotion recognition. No sex differences were found between boys and girls within FHR-BP group. Compared with controls, both FHR-SZ boys and FHR-SZ girls showed impaired processing speed and working memory, had lower levels of global functioning, and were more likely to live in an inadequate home environment. Compared with control boys, FHR-SZ boys showed impaired manual dexterity, social behavior, and social responsiveness, and had a higher proportion of ADHD and disruptive behavior disorder diagnoses. Stress and adjustment disorders were more common in FHR-BP boys compared with control boys. We found no differences between FHR-BP girls and control girls.

CONCLUSIONS

Impairment within neurodevelopmental domains associated within FHR-SZ boys v. FHR-SZ girls was most evident among boys, whereas no sex differences were found within the FHR-BP group (FHR-BP boys v. FHR-BP girls). FHR-SZ boys exhibited the highest proportion of early developmental impairments.

The role of substance use and adult sexual assault severity in the course of schizophrenia: An epidemiological catchment study of sexual assault victims

BACKGROUND

Childhood trauma increases the risk of schizophrenia, yet the role of adult sexual assault in the course of schizophrenia is unknown. This study aims to examine the associations between substance use and sexual assault severity characteristics with the course of schizophrenia among adult sexual assault victims using an epidemiologic study design.

METHODS

Sexual assault data on all individuals received from 2000 to 2010 (N = 2147) at the Center for Care of Sexual Assault Victims at Wolfson Medical Center, the largest medical center for sexual assault victims in the country, were merged with the Israel National Psychiatric Case Registry, that consisted of lifetime psychiatric hospitalizations of schizophrenia (birth to 6 years post-assault). The associations between substance use and adult sexual assault severity characteristics with hospitalizations were quantified using recurrent events Cox modeling.

RESULTS

Schizophrenia with sexual assault survivors occurred in 117 persons. Cox modeling showed that recurrent psychiatric hospitalizations were associated with younger age, sexual assault at older age, previous diagnosis of psychosis, and drug use shortly before or during the assault. Other assault characteristics (number of assailants, means of subdual, penetration type, perpetrator violence, physical injury of the victim) and immediacy of seeking help had a null association with the course of psychiatric hospitalization. These results replicated in two sensitivity analyses.

CONCLUSIONS

Substance use among victims of sexual assault was associated with an exacerbated course of schizophrenia, pointing to a possibly modifiable risk factor that should be targeted in prevention, assessment, treatment formulation and implementation.

Influence of Venus and Mars in the cognitive sky of schizophrenia. Results from the first-step national FACE-SZ cohort

OBJECTIVES

Sex differences can yield important clues regarding illness pathophysiology and its treatment. Schizophrenia (SZ) has a lower incidence rate, and a better prognosis, in women versus men. The present study investigated the cognitive profiles of both sexes in a large multi-centre sample of community-dwelling SZ patients.

METHOD

544 community-dwelling stable SZ subjects (141 women and 403 men; mean age 34.5±12.1 and 31.6±8.7years, respectively) were tested with a comprehensive battery of neuropsychological tests.

RESULTS

Although community-dwelling SZ men had more risk factors for impaired cognition (including first-generation antipsychotics administration and comorbid addictive disorders), women had lower scores on a wide range of cognitive functions, including current and premorbid intellectual functioning, working memory, semantic memory, non-verbal abstract thinking and aspects of visual exploration. However, women scored higher in tests of processing speed and verbal learning, as well as having a lower verbal learning bias. No sex difference were evident for visuospatial learning abilities, cued verbal recall, sustained attention and tests of executive functions, including cognitive flexibility, verbal abstract thinking, verbal fluency and planning abilities.

CONCLUSION

Sex differences are evident in the cognitive profiles of SZ patients. The impact on daily functioning and prognosis, as well as longitudinal trajectory, should be further investigated in the FACE-SZ follow-up study. Sex differences in cognition have implications for precision-medicine determined therapeutic strategies.

LIMITS

Given the restricted age range of the sample, future research will have to determine cognitive profiles across gender in late onset SZ.

Transgenerational effects of genocide exposure on the risk and course of schizophrenia: A population-based study

BACKGROUND

Hypotheses about the sequel of parental genocide exposures on the offspring's risk and course of schizophrenia remain untested.

AIMS

To test hypotheses related to the transgenerational transmission of parental genocide exposure on the risk and course of schizophrenia.

METHODS

Data were extracted from the National Population Register on all offspring (N=51.233; born: 1948-1989) whose parents were born (1922 to 1945) in Nazi- dominated European nations. Both parents either immigrated before (indirect exposure: n=1627, 3.2%) or after (direct exposure: n=49.606, 96.8%) the Nazi era. Offspring subgroups were identified from the initial timing of parental exposure (e.g., likely in utero, combined in utero and postnatal, or postnatal). Schizophrenia disorders were ascertained (1950-2014) from the National Psychiatric Case Registry. Cox models were computed to compare the offspring groups with respect to the risk and the adverse course of schizophrenia, adjusting for confounders.

RESULTS

The offspring rates on the risk and course of schizophrenia did not differ by parental affiliation to the direct and indirect exposure groups. Cox models showed that offspring subgroups with maternal Holocaust exposures in utero only (HR=1.74, 1.13, 2.66) and combined in utero and postnatal (HR=1.48, 1.05, 2.10); as well as paternal Holocaust exposures combined in utero and postnatal (HR=1.48, 1.08, 2.05), and early postnatal (aged 1-2; HR=1.49, 1.10, 2.00) had a significantly (P<0.05) higher psychiatric re-hospitalization rate than the indirect group.

CONCLUSIONS

Transgenerational genocide exposure was unrelated to the risk of schizophrenia in the offspring, but was related to a course of deterioration during selected critical periods of early life.

Exposure to genocide and the risk of schizophrenia: a population-based study

BACKGROUND

No evidence exists on the association between genocide and the incidence of schizophrenia. This study aims to identify critical periods of exposure to genocide on the risk of schizophrenia.

METHOD

This population-based study comprised of all subjects born in European nations where the Holocaust occurred from 1928 to 1945, who immigrated to Israel by 1965 and were indexed in the Population Register (N = 113 932). Subjects were followed for schizophrenia disorder in the National Psychiatric Case Registry from 1950 to 2014. The population was disaggregated to compare groups that immigrated before (indirect exposure: n = 8886, 7.8%) or after (direct exposure: n = 105 046, 92.2%) the Nazi or fascist era of persecutions began. The latter group was further disaggregated to examine likely initial prenatal or postnatal genocide exposures. Cox regression modelling was computed to compare the risk of schizophrenia between the groups, adjusting for confounders.

RESULTS

The likely direct group was at a statistically (p < 0.05) greater risk of schizophrenia (hazard ratio = 1.27, 95% confidence interval 1.06-1.51) than the indirect group. Also, the likely combined in utero and postnatal, and late postnatal (over age 2 years) exposure subgroups were statistically at greater risk of schizophrenia than the indirect group (p < 0.05). The likely in utero only and early postnatal (up to age 2 years) exposure subgroups compared with the indirect exposure group did not significantly differ. These results were replicated across three sensitivity analyses.

CONCLUSIONS

This study showed that genocide exposure elevated the risk of schizophrenia, and identified in utero and postnatal (combined) and late postnatal (age over 2 years) exposures as critical periods of risk.

Sex differences in the course of schizophrenia across diverse regions of the world

This study explores sex differences in the outcomes of patients with schizophrenia (clinical/functional remission and recovery) across diverse regions of the world (Northern Europe, Southern Europe, Central and Eastern Europe, Latin America, East Asia, and North Africa and the Middle East). Data (n=16,380 for this post hoc analysis) were taken from the World-Schizophrenia Health Outcomes Study. In most regions, females had a later age at first service contact for schizophrenia, a lower level of overall/negative symptom severity, lower rates of alcohol/substance abuse and paid employment, and higher percentages of having a spouse/partner and independent living. Overall, females had slightly higher rates of clinical remission (58.0% vs 51.8%), functional remission (22.8% vs 16.0%), and recovery (16.5% vs 16.0%) at 36 months (P<0.001 for all). This pattern was consistently observed in Southern Europe and Northern Europe even after controlling for baseline sex differences, but not in other regions. In Central and Eastern Europe, rates of clinical remission were higher in females at 36 months, but those of functional remission and recovery were similar between males and females. The opposite was observed for Latin America. In East Asia, sex differences were rarely observed for these outcomes. Finally, in North Africa and the Middle East, sex differences in these outcomes were pronounced only in regression analyses. These regional variations shed light on the importance of psychosocial and cultural factors and their effects on sex in the prognosis of schizophrenia.

The effects of pre-natal-, early-life- and indirectly-initiated exposures to maximum adversities on the course of schizophrenia

BACKGROUND

The effects of pre-natal-, early-life- and indirectly-initiated exposures to protracted maximum adversity on the course of schizophrenia are unknown.

AIMS

To compare the aforementioned Holocaust directly exposed subgroups with an indirectly exposed subgroup on the course of schizophrenia.

METHOD

The study population were: Israeli Jews in-uterus or born in Nazi-occupied or dominated European nations by the end of the persecution of the Jews, who were alive in 1950, and who had a last discharge diagnosis of schizophrenia in the Israel National Psychiatric Case Registry by 2013 (N=4933). The population was disaggregated into subgroups who (1) migrated after WWII and who had (1a) pre-natal (n=584, 11.8%) and (1b) early-life (n=3709, 75.2%) initiated exposures to the maximum adversities of the Holocaust, and (2) indirectly exposed individuals to the Holocaust who migrated before the Nazi-era persecution begun (n=640, 13%). Recurrent event survival analyses were computed to examine the psychiatric re-hospitalization risk of the study subgroups, unadjusted and adjusted for age of onset of the disorder and sex.

RESULTS

The pre-natal initiated exposure subgroup had a significantly (p<0.05) greater risk of psychiatric re-hospitalizations for schizophrenia than the other subgroups (unadjusted: HR=3.39, 95% CI 2.95, 3.90; adjusted: HR=2.28, 2.00, 2.60). This result replicated in sensitivity analyses for: Poland-born individuals, the years 1922 and 1935; and followed at least 10 years and to the year 2000.

CONCLUSIONS

Pre-natal initiated exposure to the maximal adversity of the holocaust constitutes a consistent risk factor for a worse course of schizophrenia, a possible byproduct of neurodevelopment disruptions induced by maternal stress and/or famine and/or infections.

Suicide attempts in a national population of twins concordant for psychoses

Psychotic disorders are associated with an increased risk of suicide attempts, the etiology of which remains unknown across diagnoses. Thus it is relevant to understand how genetic and environmental factors contribute to the liability of suicide attempts in psychosis. The current study aims to examine the role of genetic and environmental factors in suicide attempts across psychotic disorders in twins concordant for psychosis. The study population consisted of all twin pairs in the Israeli National Psychiatric Case Registry hospitalized with a last discharge diagnosis of a psychotic disorder. Twin pairs (N=116) were born between 1900 and 1993 and hospitalized from 1964 to 2001. Competing genetic models were examined to decompose the variance in suicide attempts into: the individual-specific environment (unique), shared-family environment, and genetic effects. Across schizophrenia, psychosis and non-affective psychosis comparison of genetic models showed a model combining shared-family and unique environmental effects were superior to competing genetic models. Modeling estimates for attempted suicide were: in non-affective psychosis 60% to the shared-family and 40% to the unique environment; in schizophrenia 60% to the shared-family and 40% to the unique environment; and in psychosis 66% to the shared-family and 34% to the unique environment. Across psychosis, schizophrenia and non-affective psychosis vulnerability toward suicide attempts consists predominantly of substantial individual and familial environmental elements.

Gender differences in coerced patients with schizophrenia

BACKGROUND

Despite the recent increase of research interest in involuntary treatment and the use of coercive measures, gender differences among coerced schizophrenia patients still remain understudied. It is well recognized that there are gender differences both in biological correlates and clinical presentations in schizophrenia, which is one of the most common diagnoses among patients who are treated against their will. The extent to which these differences may result in a difference in the use of coercive measures for men and women during the acute phase of the disease has not been studied.

METHODS

291 male and 231 female coerced patients with schizophrenia were included in this study, which utilized data gathered by the EUNOMIA project (European Evaluation of Coercion in Psychiatry and Harmonization of Best Clinical Practice) and was carried out as a multi-centre prospective cohort study at 13 centers in 12 European countries. Sociodemographic and clinical characteristics, social functioning and aggressive behavior in patients who received any form of coercive measure (seclusion and/or forced medication and/or physical restraint) during their hospital stay were assessed.

RESULTS

When compared to the non-coerced inpatient population, there was no difference in sociodemographic or clinical characteristics across either gender. However coerced female patients did show a worse social functioning than their coerced male counterparts, a finding which contrasts with the non-coerced inpatient population. Moreover, patterns of aggressive behavior were different between men and women, such that women exhibited aggressive behavior more frequently, but men committed severe aggressive acts more frequently. Staff used forced medication in women more frequently and physical restraint and seclusion more frequently with men.

CONCLUSIONS

Results of this study point towards a higher threshold of aggressive behavior the treatment of women with coercive measures. This may be because less serious aggressive actions trigger the application of coercive measures in men. Moreover coerced women showed diminished social functioning, and more importantly more severe symptoms from the "excitement/hostile" cluster in contrast to coerced men. National and international recommendation on coercive treatment practices should include appropriate consideration of the evidence of gender differences in clinical presentation and aggressive behaviors found in inpatient populations.

Sex, symptom, and premorbid social functioning associated with perceptual organization dysfunction in schizophrenia

Impairments in visual perceptual organization abilities are a repeatedly observed cognitive deficit in schizophrenia. These impairments have been found to be most prominent among patients with histories of poor premorbid social functioning, disorganized symptoms, and poor clinical outcomes. Despite the demonstration of significant sex differences for these clinical factors in schizophrenia, the extent of sex differences for visual perceptual organization in schizophrenia is unknown. Therefore, we investigated the extent to which previously known correlates (premorbid social sexual functioning and disorganized symptoms) and a novel factor (participant sex) accounted for performance on two perceptual organization tasks (contour integration and Ebbinghaus illusion) that have previously demonstrated sensitivity to schizophrenia. We also determined the relative degree to which each of these factors predicted task scores over and above the others. Schizophrenia patients (N = 109, 43 females) from different levels of care were ascertained. Female patients demonstrated higher contour integration scores, but lower performance on the context sensitivity index of the Ebbinghaus illusion, compared to males. Contour integration performance was significantly associated with poorer premorbid adolescent social sexual functioning and higher levels of disorganized symptoms, supporting past results that indicate a relationship among poor premorbid social sexual functioning, disorganized symptoms, and visual perceptual abnormalities in schizophrenia. However, analyses of Ebbinghaus illusion performance suggests there is a complex relationship among patient sex, clinical factors and perceptual abilities with relatively intact bottom-up grouping processes in females, but greater problems, compared to males with more top-down mediated context sensitivity. Therefore, sex differences may be an important consideration for future studies of visual perceptual organization in schizophrenia.

Gender difference in age at onset of schizophrenia: a meta-analysis

BACKGROUND

Most studies reporting the gender difference in age at onset of schizophrenia show an earlier onset in males, but vary considerably in their estimates of the difference. This may be due to variations in study design, setting and diagnostic criteria. In particular, several studies conducted in developing countries have found no difference or a reversed effect whereby females have an earlier onset. The aim of the study was to investigate gender differences in age of onset, and the impact of study design and setting on estimates thereof.

METHOD

Study methods were a systematic literature search, meta-analysis and meta-regression.

RESULTS

A total of 46 studies with 29,218 males and 19,402 females fulfilled the inclusion criteria and were entered into a meta-analysis. A random-effects model gave a pooled estimate of the gender difference of 1.07 years (95% confidence interval 0.21-1.93) for age at first admission of schizophrenia, with males having earlier onset. The gender difference in age at onset was not significantly different between developed and developing countries. Studies using diagnostic and statistical manual of mental disorders (DSM) criteria showed a significantly greater gender difference in age at onset than studies using International Classification Of Diseases (ICD) criteria, the latter showing no difference.

CONCLUSIONS

The gender difference in age of onset in schizophrenia is smaller than previously thought, and appears absent in studies using ICD. There is no evidence that the gender difference differs between developed and developing countries.

Schizotypal traits and neurocognitive functioning among nonclinical young adults

Neurocognitive deficits and their relationship with symptoms have been documented in schizophrenia and at-risk samples. Limited research has examined relationships of schizotypal traits with cognitive functioning among nonclinical samples. To expand this literature and elucidate a dimensional model of psychosis-proneness, we examined the relationship of schizotypal traits with estimated intellectual functioning, simple and complex attention/working memory, verbal fluency and visuospatial abilities in a nonclinical sample of 63 young adults. As hypothesized, aspects of neurocognition were more closely associated with negative (than positive or disorganized) schizotypal traits. For the total sample, poorer visuospatial performance was associated with more negative and overall schizotypal traits. The magnitude of the majority of findings was strengthened after controlling for depression and anxiety. No other findings were significant. Results partially support Meehl's (1962, 1990) view that processes underlying schizophrenia are expressed along a continuum. Findings suggest a relationship of schizotypal traits with neurocognition that is differentiated by trait dimensions, beyond the contribution of general psychiatric symptoms. Findings have implications for better understanding etiology and potential risk factors for psychosis. While sex distribution did not enable direct examination of sex effects, evidence in the field argues for continued exploration of differential patterns by sex.

Childhood cognitive function and adult psychopathology: associations with psychotic and non-psychotic symptoms in the general population

BACKGROUND

Lower cognitive ability in childhood is associated with increased risk of future schizophrenia, but its relationship with adult psychotic-like experiences and other psychopathology is less understood.

AIMS

To investigate whether this childhood risk factor is shared with adult subclinical psychiatric phenotypes including psychotic-like experiences and general psychiatric morbidity.

METHOD

A population-based sample of participants born in Great Britain during 1 week in March 1946 was contacted up to 20 times between ages 6 weeks and 53 years. Cognition was assessed at ages 8, 11 and 15 years using a composite of age-appropriate verbal and non-verbal cognitive tests. At age 53 years, psychotic-like experiences were self-reported by 2918 participants using four items from the Psychosis Screening Questionnaire and general psychiatric morbidity was assessed using the scaled version of the General Health Questionnaire (GHQ-28).

RESULTS

Psychotic-like experiences were reported by 22% of participants, and were highly comorbid with other psychopathology. Their presence in adults was significantly associated with poorer childhood cognitive test scores at ages 8 and 15 years, and marginally so at age 11 years. In contrast, high GHQ scores were not associated with poorer childhood cognition after adjustment for the presence of psychotic-like experiences.

CONCLUSIONS

Psychotic and non-psychotic psychopathologic symptoms are highly comorbid in the general population. Lower childhood cognitive ability is a risk factor for psychotic-like experiences in mid-life; these phenomena may be one end of a continuum of phenotypic expression driven by variation in early neurodevelopment.

Real-world premorbid functioning in schizophrenia and affective disorders during the early teenage years: a population-based study of school grades and teacher ratings

BACKGROUND

Population-based studies of cognitive and behavioral premorbid functioning in psychotic disorders generally focus on late adolescence in schizophrenia and most are based on IQ test scores.

AIMS

To examine differences in school grades at the ages of 13-14 between persons hospitalized during adulthood for schizophrenia or affective disorders and their peers.

METHODS

Ten years of school report data were ascertained on 8th grade children (n=21,448) in the city of Jerusalem (1978-1988). During adulthood cases with schizophrenia (n=194, 0.9%) or an affective disorder (n=41, 0.19%) were identified based on psychiatric hospitalizations in the National Psychiatric Hospitalization Case Registry of the State of Israel. School assessments of academic performance, nonacademic topics, and teacher ratings of classroom behavior were compared between peers without illness and cases, and their association with illness was examined.

RESULTS

Children subsequently hospitalized with schizophrenia had significantly lower nonacademic performance (ES=.20, p=.007) and teacher ratings on behavior (ES=.18, p=.02) than controls and numerically lower teacher behavior ratings than people subsequently hospitalized for an affective disorder (ES=.25, p=.19). Cox regression modeling showed that poorer nonacademic and lower behavioral ratings were significantly associated with earlier age of onset of schizophrenia.

CONCLUSIONS

Premorbid behavior and nonacademic deficits are evident in early adolescence among persons subsequently hospitalized with schizophrenia and different from those hospitalized with affective disorders. This suggests that these ratings may have diagnostic specificity between schizophrenia and affective disorders.

Schizophrenia is associated with dysregulation of a Cdk5 activator that regulates synaptic protein expression and cognition

Cyclin-dependent kinase 5 is activated by small subunits, of which p35 is the most abundant. The functions of cyclin-dependent kinase 5 signalling in cognition and cognitive disorders remains unclear. Here, we show that in schizophrenia, a disorder associated with impaired cognition, p35 expression is reduced in relevant brain regions. Additionally, the expression of septin 7 and OPA1, proteins downstream of truncated p35, is decreased in schizophrenia. Mimicking a reduction of p35 in heterozygous knockout mice is associated with cognitive endophenotypes. Furthermore, a reduction of p35 in mice results in protein changes similar to schizophrenia post-mortem brain. Hence, heterozygous p35 knockout mice model both cognitive endophenotypes and molecular changes reminiscent of schizophrenia. These changes correlate with reduced acetylation of the histone deacetylase 1 target site H3K18 in mice. This site has previously been shown to be affected by truncated p35. By restoring H3K18 acetylation with the clinically used specific histone deacetylase 1 inhibitor MS-275 both cognitive and molecular endophenotypes of schizophrenia can be rescued in p35 heterozygous knockout mice. In summary, we suggest that reduced p35 expression in schizophrenia has an impact on synaptic protein expression and cognition and that these deficits can be rescued, at least in part, by the inhibition of histone deacetylase 1.

The cross-sectional GRAS sample: a comprehensive phenotypical data collection of schizophrenic patients

BACKGROUND

Schizophrenia is the collective term for an exclusively clinically diagnosed, heterogeneous group of mental disorders with still obscure biological roots. Based on the assumption that valuable information about relevant genetic and environmental disease mechanisms can be obtained by association studies on patient cohorts of ≥ 1000 patients, if performed on detailed clinical datasets and quantifiable biological readouts, we generated a new schizophrenia data base, the GRAS (Göttingen Research Association for Schizophrenia) data collection. GRAS is the necessary ground to study genetic causes of the schizophrenic phenotype in a 'phenotype-based genetic association study' (PGAS). This approach is different from and complementary to the genome-wide association studies (GWAS) on schizophrenia.

METHODS

For this purpose, 1085 patients were recruited between 2005 and 2010 by an invariable team of traveling investigators in a cross-sectional field study that comprised 23 German psychiatric hospitals. Additionally, chart records and discharge letters of all patients were collected.

RESULTS

The corresponding dataset extracted and presented in form of an overview here, comprises biographic information, disease history, medication including side effects, and results of comprehensive cross-sectional psychopathological, neuropsychological, and neurological examinations. With >3000 data points per schizophrenic subject, this data base of living patients, who are also accessible for follow-up studies, provides a wide-ranging and standardized phenotype characterization of as yet unprecedented detail.

CONCLUSIONS

The GRAS data base will serve as prerequisite for PGAS, a novel approach to better understanding 'the schizophrenias' through exploring the contribution of genetic variation to the schizophrenic phenotypes.

Sustained attention and planning deficits but intact attentional set-shifting in neuroleptic-naïve first-episode schizophrenia patients

INTRODUCTION

The nature of deficits in tests of sustained attention, planning and attentional set-shifting has not been investigated in neuroleptic-naïve first-episode (FE) schizophrenia patients. Based on previous literature of chronic and medicated FE schizophrenia patients, we predicted that the neuroleptic-naïve patients would show deficits in these cognitive processes.

METHODS

Twenty-nine neuroleptic-naïve FE schizophrenia patients and 33 healthy controls - matched by age, gender, and nicotine consumption - performed 3 tests from the Cambridge Automated Neuropsychological Test Battery (CANTAB) thought to measure these cognitive processes: the Rapid Visual Information Processing task (RVIP, sustained attention), the Stockings of Cambridge task (SOC, planning), and the Intradimensional/Extradimensional set-shifting task (IDED, attention shifting).

RESULTS

The patients were significantly impaired in the sensitivity index (A') of the RVIP, and in the number of problems solved with minimum moves on the SOC. Nevertheless, the groups did not differ regarding the number of participants who failed at the crucial extradimensional shift stage of the IDED.

CONCLUSION

Sustained attention and planning abilities are already impaired in neuroleptic-naïve FE schizophrenia patients, whereas set-shifting abilities as measured with the IDED task seem to be intact at illness onset. Since chronic schizophrenia patients have been shown to have impaired IDED performance, we tentatively propose that IDED performance deteriorates over time with illness chronicity and/or medication.

Gender influences the detection of spatial working memory deficits in bipolar disorder

OBJECTIVE

Despite evidence that gender may influence neurocognitive functioning, few studies have examined its effects in bipolar disorder (BD) a priori. The aim of this study was to examine how gender influences executive-type functions, which are potentially useful as endophenotypes for BD.

METHODS

The performance of 26 euthymic patients (12 males, 14 females) with DSM-IV BD (20 BD type I and six BD type II) was compared to that of 26 controls (12 males, 14 females) on tests of executive function. Controls were matched to patients on an individual basis for sex, age and premorbid IQ. Tests assessed spatial working memory (SWM), planning, attentional set-shifting and verbal fluency.

RESULTS

Overall, patients showed deficits in SWM strategy (p < 0.001) and made more SWM errors relative to controls (p < 0.001). These deficits were more apparent in male-only comparisons (both p < 0.001) than in female-only comparisons (both p < 0.05). When examined in isolation, male controls were significantly better at performing the SWM task than female controls (both p < 0.05). This pattern was not observed in the patient cohort: male patients had poorer strategy scores than female patients (p < 0.05), but made a similar number of SWM errors.

CONCLUSIONS

These findings provide evidence that gender can influence the detection of SWM deficits in the euthymic phase of BD, as the sex-related disequilibrium in SWM identified in healthy controls was disrupted in BD.

Neurocognition and conversion to psychosis in adolescents at high-risk

This study examined neurocognitive predictors of conversion to Axis I psychosis among adolescents at high-risk for psychosis (AHRP). There were no significant differences in neurocognitive performance between adolescents at high-risk for psychosis who converted (AHRP+) and adolescents at high-risk for psychosis who did not convert (AHRP-). Within-sex comparisons revealed a relation between risk status and performance among females, with AHRP+ performing below AHRP-, but this effect did not hold for males. Between-sex comparisons revealed AHRP- males performed worse than AHRP- females on several measures. Across groups, males performed better than their female counterparts on select measures. Results are discussed in terms of implications for use of neurocognitive profiles as bio-risk markers of psychosis, while considering sex differences.

Premorbid adjustment in schizophrenia--an important aspect of phenotype definition

Schizophrenia is a heterogeneous disorder, and early signs of disorder such as poor premorbid adjustment (PMA) are often present before the onset of diagnosable illness. Differences in PMA between patients may be suggestive of differing aetiological pathways. Poor PMA in schizophrenia has repeatedly been reported to be associated with male sex, earlier age at onset, illness severity, negative symptoms, and poor outcome. Studies of schizophrenia patients systematically assessed for PMA have used small patient samples and have rarely used controls.

OBJECTIVE

To investigate possible correlations of PMA, as measured with the Cannon-Spoor Premorbid Adjustment Scale (PAS), with such meaningful clinical characteristics as sex, age at onset, negative symptoms etc. using one of the largest samples of schizophrenia inpatients as well as controls characterised for PMA to date.

METHOD

PMA, diagnosis and lifetime symptoms were assessed in 316 inpatients with schizophrenia and 137 population based controls using the PAS and the Structured Clinical Interview for DSM.

RESULTS

Controls demonstrated better PAS scores than inpatients with schizophrenia. Earlier age at onset and negative symptoms were found to be associated with poorer PAS scores. There was no difference in PAS ratings between males and females in patients with schizophrenia. Among the control probands, females showed significantly better PAS scores than males.

CONCLUSION

PAS scores are worse in individuals who eventually develop schizophrenia, and the distribution of these scores among schizophrenia inpatients is correlated with specific clinical features. Earlier findings, which had reported an association with age at onset and negative symptoms in small patient samples, were substantiated. The widely reported association of poor PMA with male sex, if genuinely present, does not appear to be disease specific. Our findings suggest that PMA is in itself a valuable phenotype characteristic and that it may represent a specific biological phenotype which may be of value in sub-sample selection.

A new dimension of sensory dysfunction: stereopsis deficits in schizophrenia

BACKGROUND

Schizophrenia is a neurocognitive disorder with a wide range of cognitive and sensory impairments. Early visual processing has been shown to be especially impaired. This article investigates the integrity of binocular depth perception (stereopsis) in schizophrenia.

METHODS

Seventeen schizophrenia patients and 19 healthy control subjects were compared on the Graded Circles Stereo Test. Results of stereoacuity were compared between patients and control subjects using t test.

RESULTS

Schizophrenia patients demonstrated significantly (p = .006) reduced stereoacuity (mean = 142 arcseconds) versus control subjects (mean = 55 arcseconds). At the normative level for adults, patients performed below chance.

CONCLUSIONS

These findings demonstrate an impairment of binocular depth perception and further confirm deficits of early visual processing in schizophrenia. Findings are discussed in context of magnocellular/dorsal stream processing with implications for visual processing and cognitive deficits.

Impaired working speed and executive functions as frontal lobe dysfunctions in young first-degree relatives of schizophrenic patients

The aim of the investigation was to detect neuropsychological markers, such as sustained and selective attention and executive functions, which contribute to the vulnerability to schizophrenia especially in young persons. Performance was assessed in 32 siblings and children of schizophrenic patients and 32 matched controls using Wisconsin Card Sorting Test, Colour-Word-Interference-Test, Trail Making Test, and d2-Concentration-Test. The first-degree relatives showed certain impairments on all four tests, in particular, slower times on all time-limited tests. These results suggest the need for more time when completing neuropsychological tasks involving selected and focused attention, as well as cognitive flexibility, as a possible indicator of genetic vulnerability to schizophrenia.

Premorbid intra-individual variability in intellectual performance and risk for schizophrenia: a population-based study

BACKGROUND

Some, but not most, schizophrenia patients have below-average intelligence years before they manifest psychosis. However, it is not clear if those whose intelligence falls within-normal-range nevertheless have cognitive abnormalities. We examined the association between intra-individual variability in intellectual performance and risk for schizophrenia in individuals with normal IQ.

METHODS

555,326 adolescents, mandatory assessed by the Israeli Draft Board were followed up over 8 to 17 years for psychiatric hospitalization by means of the Israeli National Psychiatric Hospitalization Case Registry. Data were available on 4 intelligence sub-tests, and on behavioral and psychosocial variables. Variability was computed from the variance of the four intelligence tests' standardized scores.

RESULTS

There was a significant monotonic association between increased intra-individual variability in intellectual performance and risk of schizophrenia in individuals with within-normal-range IQ. Individuals with the highest variability were 3.8 times more likely to have schizophrenia [95%CI: 2.32-6.08; p < 0.0001] compared with individuals with the lowest variability. This association held after controlling for the effects of potential confounders.

CONCLUSIONS

Despite within-normal-range premorbid IQ, apparently healthy adolescents who will later on manifest schizophrenia, nevertheless have cognitive abnormalities such as increased variability across intellectual tasks, possibly related to frontal lobe abnormalities.

Impairments in generation of early-stage transient visual evoked potentials to magno- and parvocellular-selective stimuli in schizophrenia

OBJECTIVE

Patients with schizophrenia demonstrate significant impairments of early visual processing, potentially implicating dysfunction of the magnocellular visual pathway. The present study evaluates transient visual evoked potential (tVEP) responses to stimuli biased toward the magnocellular (M) or parvocellular (P) systems in patients with schizophrenia vs. normal volunteers first to evaluate relative contributions of M and P systems to specific tVEP components in schizophrenia and, second, to evaluate integrity of early M and P processing in schizophrenia.

METHODS

Seventy-four patients with schizophrenia and schizoaffective disorder were compared with 59 control subjects using separate stimuli to assess the tVEP response to M, P and mixed M/P conditions. Stimuli were biased toward M vs. P processing by manipulation of chromatic and achromatic contrast. C1, P1, N1 and P2 components were compared between patients and controls. All subjects showed 20/32 vision or better.

RESULTS

Waveforms were obtained to low contrast (M), chromatic contrast (P) and high contrast (mixed M/P) stimuli in both patients and controls. C1 was present to P and mixed M/P stimuli. Patients showed a significant reduction in amplitude and an increase in latency of the C1 component. P1 was elicited primarily by M and mixed M/P stimuli, whereas N1 was elicited primarily by P and mixed M/P stimuli. Patients showed reductions in both P1 and N1 amplitudes across conditions. However, only reductions in P1 amplitude survived covariation for between group differences in visual acuity. Further, P1 amplitude reductions in the M condition correlated with a proxy measure of global outcome.

CONCLUSIONS

M- and P-selective stimuli elicit differential components of the tVEP. Patients with schizophrenia show significant reductions in response even to simple visual stimuli. Deficits, particularly within the M system, may correlate significantly with global outcome and level of community functioning.

SIGNIFICANCE

Whereas deficits in high-order cognitive processing have been extensively documented in schizophrenia, integrity of early-stage sensory processing has been studied to a lesser degree. The present findings suggest that deficits in early-stage visual processing are significantly related to overall clinical outcome in schizophrenia. Further, between-group differences in visual acuity may influence VEP results, even for subjects with 'normal' vision (20/32 or better).

Differential patterns of premorbid academic and social deterioration in patients with schizophrenia

Schizophrenia is a neurodevelopmental disorder that is characterized by a number of behavioral abnormalities that are present prior to onset. These premorbid abnormalities may serve as unique markers for the disorder. The current study examines academic and social functioning prior to schizophrenia onset in a group of 58 males diagnosed with schizophrenia. The pattern of deterioration for social and academic functioning was examined across three age periods including childhood, early adolescence, and late adolescence, using the retrospective Premorbid Adjustment Scale (PAS). Results indicated that while increasing deterioration was present for both social and academic adjustment across age periods, there was a significant difference in deterioration between academic and social functioning (p<.05) during late adolescence, with greater deterioration in academic functioning. Results of the current study suggest that premorbid academic functioning is particularly susceptible to deterioration during late adolescence, with accelerating deterioration as schizophrenia onset becomes imminent. When considered together with results from other studies, the present findings suggest that deterioration in premorbid academic functioning from early to late adolescence may be a unique premorbid marker for schizophrenia.

Altered myelination of the hippocampal formation in subjects with schizophrenia and bipolar disorder

Myelination of the frontal and temporal lobes occurs at a similar time period as symptom onset in schizophrenia. To assess this potential relationship, we compared myelination and oligodendrocyte numbers in the hippocampal formation of controls and matched subjects with schizophrenia and bipolar disorder. The levels and distribution of the myelin marker myelin basic protein (MBP) and the oligodendrocyte marker adenomatous polyposis coli (APC) were measured using immunocytochemistry. MBP immunoreactivity (IR) was increased in several hippocampal subregions of control females versus control males. Female subjects with schizophrenia and bipolar disorder exhibited decreased myelination in the hippocampal formation while male subjects with bipolar disorder showed increased MBP levels in the superior medullary lamina. In contrast, the number of APC immunoreactive cells did not differ in any disorder or region. Our results demonstrate an interaction between gender, mental illness, and myelination, and may be related to cognitive deficits seen in schizophrenia and bipolar disorder.

Sensitivity of ICD-10 diagnosis of psychotic disorders in the Israeli National Hospitalization Registry compared with RDC diagnoses based on SADS-L

OBJECTIVE

The Israeli National Psychiatric Hospitalization Registry is a nationwide list of all psychiatric hospitalizations in the country and has been widely used as a source of data for psychiatric research. This study assessed the sensitivity of the diagnosis of psychotic disorders ( International Statistical Classification of Diseases, 10th Revision [ ICD-10 ] F20.0-F29.9) and schizophrenia ( ICD-10 F20.0-F20.9) in the Registry.

METHOD

Registry discharge diagnoses of psychotic disorders ( ICD-10 F20.0-F29.9) and schizophrenia ( ICD-10 F20.0-F20.9) were compared with research diagnoses derived from best-estimate procedures based on Research Diagnostic Criteria (RDC) using structured clinical research interviews, hospital records, and family information.

RESULTS

Out of 169 patients meeting RDC for psychotic disorder, 150 also had a diagnosis of psychotic disorders in the Registry, yielding a sensitivity of 0.89. Re-running this analysis for the narrow definition of schizophrenia identified 94 patients who were diagnosed with schizophrenia using RDC; 82 of those patients also had a diagnosis of schizophrenia in the Registry, yielding a sensitivity of 0.87.

CONCLUSION

In 87% to 89% of cases with psychotic disorders or with schizophrenia, Registry diagnoses agreed with RDC diagnoses, a rate of agreement comparable with those of other, similar registries. Because a large number of analyses derived from this and similar national registries will be published in the coming years, this constitutes relevant information.

Family-based and case-control study of catechol-O-methyltransferase in schizophrenia among Palestinian Arabs

COMT is a ubiquitous enzyme crucial to catechol metabolism. The molecular basis of COMT thermolability, that leads to three to fourfold differences in enzyme activity, is due to a substitution of valine with methionine in the Val158/108Met polymorphism. Of special interest is the role of this gene in major psychoses especially since a microdeletion (22q11) containing the COMT gene (velo-cardio-facial syndrome) also carries with it several types of behavioral disorders, including an increased prevalence of schizophrenia. Almost 20 genetic studies have examined the role of COMT in schizophrenia with ambiguous results. Towards clarifying the role of this polymorphism in conferring risk for psychosis, we examined a large group of culturally and ethnically akin Palestinian Arab schizophrenic triads (N = 276) using both a case-control and family-based study. In 194 informative triads with at least one heterozygote parent, no preferential transmission of either COMT allele was observed in this sample (TDT statistic chi-square = 0.14 NS; 131 COMT valine alleles were transmitted and 125 alleles not transmitted). However, using a case-control design a significant increase (Likelihood ratio = 3.935, P = 0.047) in the valine allele was observed in the group of schizophrenic patients (N = 276) compared to an ethnically matched control group (N = 77). The association was stronger in female patients (P = 0.012) similar to other studies showing that some COMT behavioral effects are gender sensitive. In summary, by case-control design but not by a family-based study, there is a weak effect in female patients of the high activity COMT allele in conferring risk for schizophrenia.

Gender differences in schizophrenia

Sex differences in schizophrenia can be caused by the disease process itself, by genetic and hormonal differences, by differences in the maturation and morphology of the brain and in age- and gender-specific behavioural patterns. These hypotheses will be tested on the major results reported in the literature as well as on different levels (epidemiology, risk factors, animal experiments, a controlled clinical study) on data from the ABC Schizophrenia Study. Symptomatology, lifetime risk and symptom-related course of illness-the latter without consideration of age-show no gender differences. However, until menopause illness onset is delayed and severity of illness is reduced by oestrogen on the level of gene expression and transmitter functioning. Oestrogen has an antagonistic effect on the-familial or exogenous-predisposition to illness. As a result, the age distribution of onset and the severity of first-episode illness in young men and post-menopausal women differ from the normal. First intervention trials with oestrogen substitution of neuroleptic therapy have demonstrated antipsychotic effects. The poorer social course of schizophrenia in men than in premenopausal women is accounted for by men's lower level of social development at illness onset and the subsequent impediment of their further development. Men's socially adverse illness behaviour, too, is a contributing factor. Scarcity of the knowledge of differences in the development, morphology and functioning of the male and female brain does not yet allow any definitive conclusions about gender differences in schizophrenia.

Early maternal deprivation alters hippocampal levels of neuropeptide Y and calcitonin-gene related peptide in adult rats

Stressful events early in life are reported to be more prevalent among patients with an adult life psychiatric disorder. Early maternal deprivation is considered an animal model of early life stress. Maternally deprived adult rats display long-term alterations in the neuroendocrine system, brain and behavior that are in many ways analogous to depressive and schizophrenic symptomatology. Neuropeptide Y (NPY) and calcitonin-gene related peptide (CGRP) have been implicated in both disorders and also been suggested to play a role in the neuroadaptational response to stress. Consequently, male Wistar rat-pups were subjected to early maternal deprivation or control handling, on postnatal day (pnd) 9. On pnd 21, pups were weaned and split into two groups that were reared either on a saw-dust floor or on a grid-floor, considered to be a mild stressor. On pnd 67, all animals were subjected to the prepulse inhibition test. One week later, the animals were sacrificed, the brains removed and dissected on ice. Levels of NPY-like immunoreactivity (LI) and CGRP-LI were quantified by radioimmunoassay in brain regional extracts. Maternal deprivation led to a significant reduction in basal startle amplitude and disruption of prepulse inhibition. These findings were paralleled by significantly reduced levels of NPY and CGRP in the hippocampus and occipital cortex. It is hypothesised that these changes may be of relevance to aspects of schizophrenic and affective symptomatology. The present study further shows that brain NPY and, in particular, CGRP are sensitive to long-term mild stress and further implicate the involvement of these peptides in the neuroendocrine stress response.