Childhood exposure to ionizing radiation to the head and risk of schizophrenia

While the association between exposure to ionizing radiation and cancer is well established, its association with schizophrenia is unclear. The aim of our study was to assess risk of schizophrenia after childhood exposure to ionizing radiation to the head (mean dose: 1.5 Gy). The study population included an exposed group of 10,834 individuals irradiated during childhood for treatment of tinea capitis in the 1950s and two unexposed comparison groups of 5392 siblings and 10,834 subjects derived from the National Population Registry individually matched to the exposed group by age, sex (when possible), country of birth, and year of immigration to Israel. These groups were followed for a median 46 years for diagnosis of schizophrenia updated to December 2002. The Cox proportional hazards model stratified by matched sets was used to compare the risk of schizophrenia between the groups. Based on 1,217,531 person-years of follow-up, 451 cases were identified. No statistically significant association was found between radiation exposure and schizophrenia for the total group (hazard ratio per 1 Gy to the brain: 1.05, 95% confidence interval: 0.93-1.18) or within subgroups of sex, dose categories or latent period. When comparing a subgroup of subjects irradiated under 5 years of age with the matched unexposed group, the estimated hazard ratio reached 1.18 (95% confidence interval: 0.96-1.44; P = 0.1). The results of our analysis do not support an association between exposure to ionizing radiation and risk of schizophrenia. More research on possible effects of early exposure to ionizing radiation on schizophrenia specifically and brain tissue in general is needed.

The relation between biological activity of the rain forest and mineral composition of soils

In most soils of the humid tropics, kaolinitic topsoil horizons overlie more gibbsitic horizons. This arrangement cannot be produced simply by leaching. Quantitative measurement of the turnover of chemical elements in the litterfall in an Amazonian ecosystem indicates that the forest cycles a significant amount of elements, particularly silicon. As a result, fluids that percolate through topsoil horizons already contain dissolved silicon. This effect keeps silicon from being leached down and may account for the stability of kaolinite in the soil upper horizons. The soil mineral composition is thus maintained by biological activity.

Incidence of schizophrenia among second-generation immigrants in the jerusalem perinatal cohort

OBJECTIVE

Increased incidence of schizophrenia is observed among some immigrant groups in Europe, with the offspring of immigrants, ie "second-generation" immigrants particularly vulnerable. Few contemporary studies have evaluated the risk of schizophrenia among second-generation immigrants in other parts of the world.

METHODS

We studied the incidence of schizophrenia in relation to parental immigrant status in a population-based cohort of 88 829 offspring born in Jerusalem in 1964-1976. Parental countries of birth were obtained from birth certificates and grouped together as (1) Israel, (2) Other West Asia, (3) North Africa, and (4) Europe and industrialized countries. Cox proportional hazards methods were used in adjusting for sex, parents' ages, maternal education, social class, and birth order.

RESULTS

Linkage with Israel's Psychiatric Registry identified 637 people admitted to psychiatric care facilities with schizophrenia-related diagnoses, before 1998. Incidence of schizophrenia was not increased among second-generation immigrants in this birth cohort, neither overall nor by specific group.

CONCLUSIONS

The difference in risk of schizophrenia among second-generation immigrants in Europe and in this Israeli birth cohort suggests that the nature of the immigration experience may be relevant to risk, including reasons for migration, the nature of entry, and subsequent position in the host country for immigrants and their offspring. Minority status may be of importance as, in later studies, immigrants to Israel from Ethiopia had increased risk of schizophrenia.

Effect of socioeconomic status and parents' education at birth on risk of schizophrenia in offspring

Although it is known that schizophrenia is associated with social class, controversy exists as to the nature of this association. The authors studied the incidence of schizophrenia in relation to social class at birth in a population-based cohort of 88,829 offspring born in Jerusalem in 1964-1976. They constructed a six-point scale to index social class, based on paternal occupation at the time of birth, with each of 108 occupations being ranked by mean education. Cox proportional hazards methods were used in adjusting for sex, parents' ages, duration of marriage and birth order. Linkage with Israel's Psychiatric Registry identified 637 people admitted to psychiatric care facilities with schizophrenia-related diagnoses, before 1998. There was no gradient of risk for schizophrenia associated with social class at birth; however, offspring of fathers in the lowest social class showed a modest increase in risk (adjusted Relative Risk = 1.4; 95% Confidence interval = 1.1-1.8, P = 0.002). These data suggest that in contrast to many other health outcomes, there is not a continuous gradient for increasing schizophrenia with decreasing social class of origin. Instead, a modest increase in risk for schizophrenia was observed only for those born at the bottom of the social ladder.

Acute maternal stress in pregnancy and schizophrenia in offspring: a cohort prospective study

Schizophrenia has been linked with intrauterine exposure to maternal stress due to bereavement, famine and major disasters. Recent evidence suggests that human vulnerability may be greatest in the first trimester of gestation and rodent experiments suggest sex specificity. We aimed to describe the consequence of an acute maternal stress, through a follow-up of offspring whose mothers were pregnant during the Arab-Israeli war of 1967. A priori, we focused on gestational month and offspring's sex.

METHOD

In a pilot study linking birth records to Israel's Psychiatric Registry, we analyzed data from a cohort of 88,829 born in Jerusalem in 1964-76. Proportional hazards models were used to estimate the relative risk (RR) of schizophrenia, according to month of birth, gender and other variables, while controlling for father's age and other potential confounders. Other causes of hospitalized psychiatric morbidity (grouped together) were analyzed for comparison.

RESULTS

There was a raised incidence of schizophrenia for those who were in the second month of fetal life in June 1967 (RR = 2.3, 1.1-4.7), seen more in females (4.3, 1.7-10.7) than in males (1.2, 0.4-3.8). Results were not explained by secular or seasonal variations, altered birth weight or gestational age. For other conditions, RRs were increased in offspring who had been in the third month of fetal life in June 1967 (2.5, 1.2-5.2), also seen more in females (3.6, 1.3-9.7) than males (1.8, 0.6-5.2).

CONCLUSION

These findings add to a growing literature, in experimental animals and humans, attributing long term consequences for offspring of maternal gestational stress. They suggest both a sex-specificity and a relatively short gestational time-window for gestational effects on vulnerability to schizophrenia.

Impaired reading comprehension and mathematical abilities in male adolescents with average or above general intellectual abilities are associated with comorbid and future psychopathology

Research indicates that persons with learning disorders often suffer from psychopathology. We assessed current and future psychopathology in male adolescents with discrete impairments in reading comprehension (IRC) or arithmetic abilities (IAA) but with average or above-average general intellectual abilities. Subjects were a population-based cohort of 174,994 male adolescents screened by the Israeli Draft Board with average or above-average intellectual abilities but with low scores (8.6th and 10th lowest percentile respectively) on reading or arithmetic tests. They were compared with adolescents who scored in the 10th percentile and above on these tests (comparison group). Relative to the comparison group, male adolescents with IRC, IAA, or IRC and IAA (0.69%), had poorer scores on most behavioral assessments and higher prevalence of current psychopathology: 4.2% (comparison group), 8.0% (IRC), 7.0% (IAA), and 9.8% (IRC and IAA). Adolescents with IRC were also at increased risk for later hospitalization for schizophrenia (hazard ratios = 1.8, 95% confidence interval: 1.3-2.6). Male adolescents with average and above-average general intellectual abilities but with IRC or IAA are more likely to have current and future psychopathology. Impairments in intellectual functioning and abnormal behaviors leading to mental illnesses may share common neurobiological substrates. The results support screening male adolescents with learning disorders for psychopathology.

Social and cognitive functioning, urbanicity and risk for schizophrenia

BACKGROUND

Previous work suggests that the association between urbanicity and schizophrenia may be greatest in those with pre-existing vulnerability.

AIMS

To test for synergism in risk of schizophrenia between population density and a combined exposure of poor premorbid social and cognitive functioning.

METHOD

For 371 603 adolescent males examined by the Israeli Draft Board on social and cognitive functioning, data on population density of place of residence and later hospitalisation for schizophrenia were obtained from population-based registries.

RESULTS

There was an interaction between population density (five levels) and poor premorbid social and cognitive functioning (interaction chi(2)=4.6, P=0.032). The adjusted increase in cumulative incidence associated with one unit change in population density was 0.10% in the vulnerable group (95% CI 0.019-0.18, P=0.015), nine times larger than that in the non-vulnerable group (0.011%, 95% CI 0.0017-0.020, P=0.021).

CONCLUSIONS

Risk of schizophrenia may increase when people with a genetic liability to the disorder, expressed as poor social and cognitive functioning, need to cope with city life.

Premorbid behavioral and intellectual functioning in schizophrenia patients with poor response to treatment with antipsychotic drugs

INTRODUCTION

Approximately one third of schizophrenia patients show partial or no response to pharmacotherapy. Despite intensive investigations, the phenomenological and biological characteristics of such patients are far from elucidated. This study examined the premorbid behavioral and intellectual functioning of schizophrenia patients who showed poor response to antipsychotic treatment.

METHOD

One hundred twenty-nine schizophrenia patients who showed poor response to treatment were ascertained from a national register and matched by gender, age and education to 129 patients who showed adequate response. The groups were compared on premorbid measures of behavioral and intellectual functions.

RESULTS

As a group, treatment-resistant male patients had significantly lower (worse) social functioning [p=0.002], and individual autonomy [p<0.0001] scores before the onset of the illness compared to treatment non-resistant patients. Male and female treatment-resistant patients did not differ from non-resistant patients in premorbid intellectual functioning [p>0.1].

CONCLUSIONS

Low premorbid social functioning and individual autonomy, but not intellectual functioning, could serve as predictors of poor treatment response in schizophrenia.

Tetrachloroethylene exposure and risk of schizophrenia: offspring of dry cleaners in a population birth cohort, preliminary findings

Tetrachloroethylene is a solvent used in dry cleaning with reported neurotoxic effects. Using proportional hazard methods, we examined the relationship between parental occupation as a dry cleaner and risk for schizophrenia in a prospective population-based cohort of 88,829 offspring born in Jerusalem from 1964 through 1976, followed from birth to age 21-33 years. Of 144 offspring whose parents were dry cleaners, 4 developed schizophrenia. We observed an increased incidence of schizophrenia in offspring of parents who were dry cleaners (RR=3.4, 95% CI, 1.3-9.2, p=0.01). Tetrachloroethylene exposure warrants further investigation as a risk factor for schizophrenia.

Maternal household crowding during pregnancy and the offspring's risk of schizophrenia

BACKGROUND

Animal models of schizophrenia suggest a link between maternal crowding during pregnancy and increased risk of the offspring to develop physiological, developmental, and behavioral abnormalities that are comparable to those observed in schizophrenia. We tested the hypothesis that a similar link is present in humans.

METHOD

We investigated whether prenatal exposure to household crowding was associated with the risk of schizophrenia in a sub-cohort of the Jerusalem Perinatal Study (JPS) consisting 11,015 individuals born between 1964 and 1976. During these years mothers participated in face to face interviews in early pregnancy. The prenatal and birth data, including the number of rooms and individuals living in the mothers' household, was cross-linked with the Israel Psychiatric Registry by ministry personnel.

RESULTS

104 schizophrenia cases were identified in the cohort. Offspring who, while in utero, their mother resided in a household with five or more individuals had RR of 1.47 (95% CI: 0.99-2.16, p=0.05) to develop schizophrenia, compared to those whose mother resided with four or fewer individuals. However, when adjusted for paternal age, the RR was reduced to 1.18 (95% CI: 0.76-1.84, p=0.46). The number of rooms in the household and the household crowding during pregnancy did not significantly impact the offspring's risk to develop schizophrenia.

CONCLUSION

The link between maternal household crowding during pregnancy and the offspring's risk of schizophrenia was explained primarily by the impact of paternal age. The authors discuss the results in view of findings from animal and human studies.

The impact of human rights advocacy, mental health legislation and psychiatric reform on the epidemiology of involuntary psychiatric hospitalizations

Several years ago, the Ministry of Health published a report on the epidemiology of involuntary psychiatric hospitalizations. Many developments (advances in human rights advocacy, mental health legislation and the nascent Psychiatric Reform) have occurred in the mental health field in Israel since 1990 when the earlier report was released. Those favorable developments in mental health care were thought to have the capacity to modify the admission rates. We explored several parameters to check the hospitalization patterns (eg, by demographic factors, diagnosis) and found no substantial modifications. The case for an analytic study was clearly established.

XAS study of iron and arsenic speciation during Fe(II) oxidation in the presence of As(III)

The speciation of As and Fe was studied during the oxidation of Fe(II)-As(III) solutions by combining XAS analysis at both the Fe and As K-edges. Fe(II) and As(III) were first hydrolyzed to pH 7 under anoxic conditions; the precipitate was then allowed to oxidize in ambient air for 33 h under vigorous stirring. EXAFS analysis at the As K-edge shows clear evidence of formation of inner-sphere complexes between As(III) and Fe(II), i.e., before any oxidation. Inner-sphere complexes were also observed when Fe became sufficiently oxidized, in the form of edge-sharing and double-corner linkages between AsIIIO3 pyramids and FeIIIO6 octahedra. XAS analyses at the Fe K-edge reveal that the presence of As(III) in the solution limits the polymerization of Fe(II) and the formation of green rust and inhibits the formation of goethite and lepidocrocite. Indeed, As(III) accelerates the Fe(II) oxidation kinetics and leads to the formation of nanosized Fe-As subunits of amorphous aggregates. These observations, rather than a presumed weaker affinity of As(III) for iron oxyhydroxides, might explain why As(III) is more difficult to remove than As(V) by aerating reducing groundwater.

Cancer in schizophrenia: is the risk higher or lower?

Studies exploring the relationship between schizophrenia and cancer have shown conflicting results. Our study explores this association in three Jewish-Israeli population groups defined by their continent/place of birth (Israel, Europe-America, and Africa-Asia). The identification of the patients was made through the linkage of the nationwide psychiatric and cancer registries. The incidence of cancer in patients diagnosed with schizophrenia was compared with the incidence in the general population. The results showed that the cancer standardized incidence ratios (SIRs) for all sites were significantly lower among men and women with schizophrenia, 0.86 [95% confidence interval (CI) 0.80-0.93] and 0.91 (95% CI 0.85-0.97), respectively. This reduced overall risk was clearest for those born in Europe-America, both men (SIR 0.85, 95% CI 0.74-0.97) and women (SIR 0.86, 95% CI 0.77-0.94). Among women diagnosed with schizophrenia, the SIR was statistically higher for cancer in the breast among those born in Asia-Africa (1.37, 95% CI 1.12-1.63) and in the corpus uteri among the Israel-born (2.75, 95% CI 1.69-3.81) than among their counterparts in the general population. Lung cancer was significantly higher in men born in Asia-Africa diagnosed with schizophrenia than in the respective comparison population group (1.58, 95% CI 1.13-2.2). Our findings, and those of the literature, justify conducting a multinational study that includes identification of cancer-related risk factors among patients with schizophrenia and their families, and information on the use of psychotropic medications. This effort may clarify an epidemiological puzzle that remains outstanding.

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.

Cognitive performance of male adolescents is lower than controls across psychiatric disorders: a population-based study

OBJECTIVE

Psychiatric patients, as well as humans or experimental animals with brain lesions, often concurrently manifest behavioral deviations and subtle cognitive impairments. This study tested the hypothesis that as a group, adolescents suffering from psychiatric disorders score worse on cognitive tests compared with controls.

METHOD

As part of the assessment for eligibility to serve in the military, the entire, unselected population of 16-17-year old male Israelis undergo cognitive testing and screening for psychopathology by the Draft Board. We retrieved the cognitive test scores of 19 075 adolescents who were assigned any psychiatric diagnosis, and compared them with the scores of 243 507 adolescents without psychiatric diagnoses.

RESULTS

Mean test scores of cases were significantly poorer then controls for all diagnostic groups, except for eating disorders. Effect sizes ranged from 0.3 to 1.6.

CONCLUSION

As group, adolescent males with psychiatric disorders manifest at least subtle impairments in cognitive functioning.

Body mass index and future schizophrenia in Israeli male adolescents

BACKGROUND

Compared with the general population, individuals suffering from schizophrenia are more likely to be overweight, a finding attributed to the effect of antipsychotic medications, poor nutrition, and sedentary lifestyle. As evidence accumulates indicating that some aspects of the illness manifest before the onset of psychosis and establishment of the diagnosis, it has been suggested that increased weight, like other metabolic dysfunctions, might precede active illness.

METHOD

Data on height and weight of 203,257 male adolescents assessed by the Israeli Draft Board, and followed for 2-6 years for later hospitalization for schizophrenia using the Israeli National Psychiatric Hospitalization Case Registry, were analyzed.

RESULTS

From the entire cohort, 309 (0.15%) were later hospitalized for schizophrenia (ICD-10). After removing adolescents with evidence of illness before or within 1 year of the Draft Board assessment, 204 future schizophrenia patients were available for analysis. Compared with the rest of the cohort, future schizophrenia patients had lower body mass indexes (21.24 +/- 3.3 kg/m2 vs. 21.77 +/- 3.5 kg/m2; F = 4.682, df = 1, p = .03) and weighed slightly but significantly less (64.2 +/- 11.6 kg vs. 66.3 +/- 12.0 kg; F = 6.615, df = 1, p = .01). The mean height of the future patients did not differ significantly from the mean height of the remaining cohort (173.63 +/- 6.7 cm vs. 174.40 +/- 6.9 cm; F = 2.520, df = 1, p = .112). When reanalyzing the data, controlling for physical activity and socioeconomic status, the differences between the groups remained significant.

CONCLUSION

Before the onset of illness, future schizophrenia patients are not heavier compared with their peers. This implies that the increased weight of patients with schizophrenia is related to illness effects, including the effects of antipsychotic medication.

Higher rates of cigarette smoking in male adolescents before the onset of schizophrenia: a historical-prospective cohort study

OBJECTIVE

The prevalence of cigarette smoking among schizophrenia patients is significantly higher than in the general population; this may reflect self-medication of symptoms and/or adverse effects of neuroleptics. The authors examined the prevalence of cigarette smoking in apparently healthy adolescents later hospitalized for schizophrenia.

METHOD

Each year, a random sample of male Israeli military recruits, who have been screened and found not to be suffering from major psychopathology, complete a smoking questionnaire. Through the Israeli National Psychiatric Hospitalization Case Registry, 14,248 of these adolescents were followed to determine later psychiatric hospitalization.

RESULTS

Of the 14,248 adolescents assessed, 4,052 (28.4%) reported smoking at least one cigarette a day. Over a 4-16-year follow-up, the prevalence of schizophrenia in the entire cohort was 0.3% (N=44). Smokers were at greater risk for later schizophrenia; the adjusted relative risk was 1.94, and the 95% confidence interval (CI) was 1.05-3.58. The number of cigarettes smoked was significantly associated with the risk for schizophrenia. Compared to nonsmokers, adolescents who smoked 1-9 cigarettes/day were 1.38 times (95% CI=0.48-4.00) as likely to be hospitalized later for schizophrenia, and adolescents who smoked 10 cigarettes/day or more were 2.28 times (95% CI=1.19-4.34) as likely; the latter difference was statistically significant.

CONCLUSIONS

Taken together with the existing data on abnormalities in nicotinic transmission in patients and their relatives, this higher prevalence of smoking in future schizophrenia patients, before the onset of their illness, might indicate that impaired nicotinic neurotransmission is involved in the pathophysiology of schizophrenia.

Self-reported drug abuse in male adolescents with behavioral disturbances, and follow-up for future schizophrenia

BACKGROUND

The prevalence of illicit drug abuse in persons with schizophrenia is greater then in the general population and has been attributed to self-medication of the symptoms of the illness; however, limited data indicate that drug abuse is already prevalent before the manifestation of psychosis, consistent with the possibility that drug abuse might be associated with increased risk for schizophrenia.

METHODS

The Israeli Draft Board screens the entire, unselected population of 16- to 17-year-old male adolescents for behavioral or personality disturbances. In a cohort of 270,000 male adolescents screened, 50,413 adolescents were suspected of having behavioral or personality disturbances and were questioned about drug use and abuse. These adolescents were followed for hospitalization for schizophrenia using a national, population-based psychiatric hospitalization registry; 268 of 50,413 (.5%) were hospitalized for schizophrenia over the following 5-11 years.

RESULTS

The prevalence of self-reported drug abuse in adolescents later hospitalized for schizophrenia was 12.4%, compared with 5.9% prevalence of drug abuse in adolescents not later hospitalized; adjusted RR = 2.016, 95% confidence interval: 1.309-3.104.

CONCLUSIONS

In this cohort of male adolescents with behavior disturbances, these results further support the hypothesis that drug abuse may be associated with increased risk for future schizophrenia.

No relationship between risk of schizophrenia and prenatal exposure to stress during the Six-Day War or Yom Kippur War in Israel

AIM

Maternal stress during pregnancy is a possible risk factor for schizophrenia in the offspring. Using data from the Israel Psychiatric Registry we examined the impact of wars in Israel.

METHOD

Retrospective birth cohort study.

RESULTS

Relative risks for cohorts exposed to Six-Day War and Yom Kippur War were 0.98 (95% CI: 0.85-1.13) and 1.00 (0.86-1.16).

CONCLUSION

The evidence for maternal stress as a risk factor for schizophrenia remains insufficient.

Generalized cognitive impairment in male adolescents with schizotypal personality disorder

Schizotypal Personality Disorder (SPD) shares common genetic and biological substrates with schizophrenia, and patients with SPD have been reported to suffer both from specific cognitive impairments, and from a generalized cognitive dysfunction, similar to those found in schizophrenia. The aim of this cross-sectional, population-based study was to assess general cognitive functioning in adolescents with SPD. The Israeli Draft Board systematically assesses cognitive functioning and administers psychiatric screening in all 16-17-year-old males in the population. Of 341,511 males assessed, the cognitive test scores of adolescents with SPD (N = 326) were retrieved, and compared to the scores of adolescents diagnosed as suffering from schizophrenia (N = 901), and adolescents with no neurological or psychiatric diagnosis (controls, N = 293,820). Male adolescents with SPD or with schizophrenia scored lower on all measures compared to healthy individuals (effect sizes ranging from 0.6-0.88, all P < 0.001). The SPD patients scored significantly higher than the schizophrenia patients on the sub-tests of similarities and Ravens Progressive Matrices, tests that reflect abstract reasoning. On the sub-tests of arithmetic and instruction comprehension, tests that rely on concentration, SPD and schizophrenia patients' scores did not differ significantly from each other. These results might be interpreted to imply that a generalized cognitive impairment, in the presence of schizotypal personality traits and in the absence of psychosis, might be conceptualized as being the core of the schizotaxia syndrome. The greater impairment in abstract reasoning in the schizophrenia patients might be correlated with the psychotic symptoms that differentiate schizophrenia from SPD.

Association between nonpsychotic psychiatric diagnoses in adolescent males and subsequent onset of schizophrenia

BACKGROUND

Nonpsychotic psychiatric symptoms may occasionally herald the later development of schizophrenia. This study followed a population-based cohort of adolescents with nonpsychotic, non-major affective psychiatric disorders to ascertain future hospitalization for schizophrenia.

METHODS

Results of the medical and mental health assessments on 124 24416- to 17-year-old males screened by the Israeli draft board were cross-linked with the National Psychiatric Hospitalization case registry, which contains data on all psychiatric hospitalizations in the country, during a 4- to 8-year-long follow-up through age 25 years. In the cohort, 9365 adolescents were assigned a nonpsychotic, non-major affective diagnosis by the draft board.

RESULTS

After excluding 167 adolescents who were hospitalized before or up to 1 year after the draft board assessment, 1.03% of the adolescents assigned a nonpsychotic, non-major affective psychiatric diagnosis, compared with only 0.23% of the adolescents without any psychiatric diagnosis, were later hospitalized for schizophrenia. Of the patients with schizophrenia, 26.8%, compared with only 7.4% in the general population, had been assigned a nonpsychotic, non-major affective psychiatric diagnosis in adolescence (overall odds ratio [OR], 4.5; 95% confidence interval [CI], 3.6-5.6), ranging from OR, 21.5 (95% CI, 12.6-36.6) for schizophrenia spectrum personality disorders to OR, 3.6 (95% CI, 2.1-6.2) for neurosis.

CONCLUSION

These results reflect the relatively common finding of impaired functioning in patients later hospitalized for schizophrenia and the relatively low power of these disorders in predicting schizophrenia.

Advancing paternal age and the risk of schizophrenia

BACKGROUND

A major source of new mutations in humans is the male germ line, with mutation rates monotonically increasing as father's age at conception advances, possibly because of accumulating replication errors in spermatogonial cell lines.

METHOD

We investigated whether the risk of schizophrenia was associated with advancing paternal age in a population-based birth cohort of 87 907 individuals born in Jerusalem from 1964 to 1976 by linking their records to the Israel Psychiatric Registry.

RESULTS

Of 1337 offspring admitted to psychiatric units before 1998, 658 were diagnosed as having schizophrenia and related nonaffective psychoses. After controlling for maternal age and other confounding factors (sex, ethnicity, education [to reflect socioeconomic status], and duration of marriage) in proportional hazards regression, we found that paternal age was a strong and significant predictor of the schizophrenia diagnoses, but not of other psychiatric disorders. Compared with offspring of fathers younger than 25 years, the relative risk of schizophrenia increased monotonically in each 5-year age group, reaching 2.02 (95% confidence interval, 1.17-3.51) and 2.96 (95% confidence interval, 1.60-5.47) in offspring of men aged 45 to 49 and 50 years or more, respectively. Categories of mother's age showed no significant effects, after adjusting for paternal age.

CONCLUSIONS

These findings support the hypothesis that schizophrenia may be associated, in part, with de novo mutations arising in paternal germ cells. If confirmed, they would entail a need for novel approaches to the identification of genes involved in schizophrenia.

Rehospitalization rates of chronically ill schizophrenic patients discharged on a regimen of risperidone, olanzapine, or conventional antipsychotics

OBJECTIVE

The purpose of this study was to compare the rehospitalization rates of patients discharged from the hospital while being treated with risperidone, olanzapine, or conventional antipsychotics.

METHOD

By using Israel's National Psychiatric Hospitalization Case Registry, rehospitalization status was monitored for all patients with schizophrenia who were discharged from any inpatient psychiatric facility in Israel while taking risperidone (N=268) or olanzapine (N=313) between Jan. 1, 1998, and Dec. 31, 1998, and a group of patients discharged during that time who were treated with conventional antipsychotics (N=458). Time to readmission over the course of 2 years was measured by the product-limit (Kaplan-Meier) formula.

RESULTS

The readmission rate for patients discharged while taking conventional antipsychotics was higher than the rates for patients treated with either risperidone or olanzapine. At 24 months, 67% of the risperidone-treated patients and 69% of the olanzapine-treated patients remained in the community, as compared to 52% of the patients treated with conventional antipsychotics.

CONCLUSIONS

This study suggests that the rehospitalization rates of patients taking the novel antipsychotics risperidone and olanzapine are not different from each other and are considerably lower than the rate for patients treated with conventional antipsychotics. The results confirm findings of previous studies suggesting that the levels of overall effectiveness of risperidone and olanzapine are not very different and offers evidence that these drugs are more effective in preventing rehospitalization than conventional antipsychotic drugs.

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

Despite significant research, there are still inconsistent findings regarding gender differences in cognitive performance in individuals already diagnosed with schizophrenia; studies have found that males suffering from schizophrenia are more, less or equally impaired compared with females. Gender differences in cognitive performance in individuals suffering from schizophrenia may be influenced by gender differences in premorbid cognitive performance; the very few and very small N studies published indicated that males have a poorer pre-morbid cognitive performance than females. This study examined the gender differences in premorbid cognition, utilizing cognitive assessments performed on female and male adolescents before induction into military service. The Israeli Draft Board Registry, which contains cognitive assessments equivalent to IQ scores on 16-18 year old Israeli adolescents, was linked with the Israeli National Psychiatric Hospitalization Case Registry, which records all psychiatric hospitalizations in the country. Scores on premorbid cognitive performance in schizophrenia were examined in 90 female-male case pairs matched for school attended as a proxy for socio-economic status. The mean age of first hospitalization was 20. 1+/-1.8 years of age for males and 19.6+/-1.8 years of age for females. A repeated-measures ANCOVA with age of first hospitalization and years of formal education as covariates, and controlling for gender differences in cognitive performance in healthy adolescents, revealed a significant difference in pre-morbid cognitive performance between males and females on all four cognitive measures [F(1,87)=8.07, P=0.006] with females scoring lower (worse) than males. In this national cohort, pre-morbid cognition was poorer in female, compared with male, adolescents who will suffer from schizophrenia in the future, a result consistent with some, but not all, similar studies. These results may be valid only for patients with first hospitalization around age 20. Hence, gender differences in premorbid cognition should be taken into account when assessing gender differences in cognition in schizophrenia.

The goals and limitations of Israel's psychiatric case register

The Israeli Ministry of Health maintains a psychiatric case register that includes basic demographic and clinical information for all psychiatric hospital admissions since 1950. Currently, the case register includes information about some 130,000 people who have been hospitalized. The case register is an important tool in many aspects of mental health care planning, such as delineating problem populations, developing interventions, assessing the ramifications of policies, enacting programs for quality control, and conducting research. In certain situations stipulated by law, some information in the case register is shared with other authorities. Although the full potential of the psychiatric case register has not been exploited so far, creation of additional linkages with other databases and increased application of case register data in field studies could enhance its usefulness.

Critical anatomic dimensions for intrathoracic circulatory assist devices

The design of totally implantable circulatory support devices must account for the anatomical constraints of the body cavity. To aid development of an implantable electrohydraulic ventricular assist device (EVAD), thoracic anatomical measurements and fit trials were performed. Various dimensions of the thoracic cavity were measured in 19 preserved and fresh cadavers. The mean left ventricle apex to chest wall distance was 2.7 +/- 0.2 cm. The mean sagittal radius of curvature at the fifth rib was 11.1 +/- 0.4 cm, and the transverse radius at the fifth rib was 9.4 +/- 0.3 cm. The mean sternal length was 18.9 +/- 1.2 cm. Using these measurements a model measuring 17.5 x 10.5 x 3.8 cm was designed. This model was placed in the chest of 11 patients undergoing open heart surgery. In one patient there was significant lung compression and in another hypotension suggesting great vessel compression. Finally, 1 of 11 patients had a short sternum and a small thorax, and the device did not fit. In conclusion, thoracic measurements may be used in the design of circulatory support devices. The model fit adequately in 73% of patient trials.

Electrohydraulic ventricular assist device development

A 64 ml (effective stroke volume) in vitro electrohydraulic ventricular assist device (VAD) prototype has been built. The energy converter is an axial flow pump driven by a brushless direct current (DC) motor. Systole begins as silicone oil is pumped from the volume displacement chamber (VDC) into the ventricle, displacing the flexing diaphragm separating the oil and the blood. In diastole, the motor reverses, providing active filling by pumping oil from the ventricle into the VDC. The surface mount electronic internal controller provides motor commutator, energy management, telemetry, and physiologic control functions. Energy is supplied externally by either a 12 V DC power supply or a 12 V DC rechargeable battery and is transmitted through the skin by a transcutaneous energy transformer (TET). Energy can also be supplied by a 12 V DC rechargeable internal battery. Bidirectional infrared telemetry is used to transmit information between the internal and external controllers.