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Biomedical subjects

A E Pulver

Publications and source records attributed to A E Pulver.

16 recordsLinked to original sources
PubMed1992

Schizophrenia: gender and familial risk.

The morbid risks for schizophrenia and any nonaffective psychosis in the first degree relatives of male and female schizophrenic probands were compared utilizing Cox proportional hazards models. The schizophrenic probands (275 male; 106 female) were drawn from a larger sample of hospitalized patients obtained by systematically screening all psychiatric admissions to 15 facilities over a six-year period. Proband diagnoses (DSM-III) were based on a direct assessment of the patient and a review of medical records. The family history method was used to obtain information about the first degree relatives of the probands. Cox proportional hazards models were adjusted for duration of illness of the proband and gender of the relatives. First degree relatives of female probands had significantly higher morbid risks for schizophrenia and nonaffective psychosis than relatives of male probands. The differential risk for schizophrenia in the relatives of male and female probands demonstrated in this study, as well as others, suggests that males and females may be at different risk for subtypes of the disorder.

Adult↗
PubMed1992

Risk factors in schizophrenia. Season of birth, gender, and familial risk.

The risk for schizophrenia among first-degree relatives of schizophrenic probands obtained from an epidemiological sample using family history methods was examined to determine whether month of birth of the proband was associated with familial risk. The results of this study of the first-degree relatives of 106 female schizophrenics and 275 male schizophrenics suggested that the relatives of probands born in the months February to May had the highest risk, although the association between month of birth and familial risk among the male probands was present only for those relatives who had onset of schizophrenia before the age of 30.

Adult↗
PubMed1992

Season of birth of siblings of schizophrenic patients.

The hypothesis that mothers of winter-spring-born schizophrenics have an unusual pattern of conception which results in an excess of winter-spring births was tested by studying the distribution of birth-dates of 401 siblings of 120 winter-spring-born schizophrenics and 157 siblings of 59 winter-spring-born controls. All analyses were gender-specific. The results suggest there is no association between the probability of a winter-spring date of birth and being a sibling of a winter-spring-born schizophrenic or control.

Adult↗
PubMed1991

Estimating effects of proband characteristics on familial risk: II. The association between age at onset and familial risk in the Maryland schizophrenia sample.

In this report we apply methods outlined in the companion paper [Liang, Genet Epidemiol 8:329-338, 1991] to study the association between proband age at onset and familial risk among first-degree relatives of 374 schizophrenic probands. The analyses take into consideration the potential problems of censoring and correlation of age at onset within families. All analyses were done by gender of the proband; age at onset was dichotomized. The results of the analyses of the male probands suggest that there is an increased risk of schizophrenia among the relatives of male probands who have an onset prior to age 17 when compared to relatives of male probands who have an onset later than 16. We did not find an association between age at onset and familial risk among the female probands, but this may be due to the smaller number of female probands and the lower power associated with the analyses.

Adolescent↗
PubMed1991

Psychiatric morbidity in the relatives of patients with DSM-III schizophreniform disorder: comparisons with the relatives of schizophrenic and bipolar disorder patients.

Risks for psychiatric disorders (RDC) among first degree relatives of DSM-III schizophreniform, bipolar, and schizophrenic probands obtained from an epidemiologic sample using family history methods were examined. The relatives of the schizophreniform probands differed from the relatives of the schizophrenic and bipolar probands. The relatives of schizophreniform probands had significantly higher rates of affective illnesses (with the exception of bipolar illness) than the relatives of schizophrenic probands, and they had a significantly higher rate of psychotic affective disorders than the relatives of the bipolar probands.

Adolescent↗
PubMed1990

Age-incidence artifacts do not account for the season-of-birth effect in schizophrenia.

Contrary to the position taken by Lewis (1989), several articles have demonstrated an association between season of birth and the risk of schizophrenia after controlling for the age-incidence effect. The method used by Pulver et al. (1983) was misinterpreted by Lewis. Clarification of this method is provided along with additional references related to the season-of-birth issue.

Adult↗
PubMed1990

Schizophrenia: age at onset, gender and familial risk.

In a family history study of 366 schizophrenic probands and their 1851 first-degree relatives, we found a relationship between age at onset of psychosis in the male probands and the risk for schizophrenia in their relatives. The relatives of male schizophrenic probands whose onset of psychosis occurred when they were younger than 17 years of age had an increased risk of schizophrenia when compared with the relatives of male probands with an age at onset greater than 17. We did not find an association between age at onset of psychosis in the female probands and familial risk. Cox proportional hazards models permitted us to examine the relationship between age at onset of psychosis in the probands and familial risk while controlling for possible confounding effects.

Adolescent↗
PubMed1989

Availability of schizophrenic patients and their families for genetic linkage studies: findings from the Maryland epidemiology sample.

It has been suggested that collections of affected sib pairs, or their nuclear families, may be an efficient method for screening for genetic linkages in schizophrenia. We present the data collected in five years from 15 hospitals in the state of Maryland in an effort to determine if such a collection scheme will be feasible. Probands in our sample were eligible for inclusion in the sample if they were white, were age 16 years or older, and carried a research diagnosis of schizophrenia. Family data are reported for 258 probands. Using the most stringent category of affected (RDC schizophrenia) revealed ten families with two or more affected sibs. The broadest category of affected (any psychotic disorder or psychiatric hospitalization) identified only 36 families with two or more affected sibs. We conclude that, if schizophrenia is a heterogeneous disorder with decreased penetrance, an effort to collect multiplex nuclear families is unlikely to provide enough data to identify genetic linkage. Alternatively, an effort to seek out and collect larger multiplex, multigenerational families rather than a collection of affected sib pairs may be more efficacious.

Adolescent↗
PubMed1989

An epidemiologic investigation of alcohol-dependent schizophrenics.

Most clinicians agree that alcoholism is frequent in schizophrenic patients. However, little is known about the clinical or familial characteristics of this group. We compared alcoholic schizophrenics and nonalcoholic schizophrenics with respect to sociodemographic and clinical characteristics and the rate of various psychiatric illnesses among their first-degree relatives. The only difference in the sociodemographic characteristics was a higher proportion of males among the alcoholic schizophrenics. Clinically, the alcoholic schizophrenics were more likely to report experiencing hallucinations, depressive episodes, manic episodes (females only) and multiple substance abuse (males only). In addition, the male alcoholic schizophrenics were younger at first hospitalization than the male nonalcoholic schizophrenics. This effect was reversed for females. The relatives of alcoholic schizophrenics were 2.6 times more likely to be alcoholic than the relatives of the nonalcoholic schizophrenics. The morbidity for other psychiatric disorders was similar in the two groups.

Adult↗
PubMed1988

The power of analysis: statistical perspectives. Part 1.

Failure to consider statistical power when achieving apparently "negative" results prevents accurate interpretation of the results. A nonsignificant result can be obtained when one includes an insufficient number of subjects to permit observation of a true effect (low power to detect an effect), or when one has an adequate number of subjects, but a meaningful effect does not exist (high power, no effect); one can also have a situation of lower power and no real effect. Without considering power, one is unable to distinguish a "negative" experiment from an inadequate one. This article examines 154 published nonsignificant t-test results. When power is calculated with an effect size equal to a standardized difference of unity, over 50% of the tests have inadequate power.

Clinical Trials as Topic↗
PubMed1988

The power of analysis: statistical perspectives. Part 2.

A discussion of the importance of statistical power in research is presented accompanied by nomograms for determining sample size and statistical power for the Student's paired and unpaired t tests with a Type I error of 5%. A brief review of statistical inference is presented. Some findings from Part I are reviewed.

Clinical Trials as Topic↗
PubMed1986

Season of birth: schizophrenia and bipolar disorder.

Studies investigating the association between the risk of schizophrenia and season of birth are reviewed and the association clearly established. This association cannot be explained on the basis of age-incidence or age-prevalence artifacts. Other studies suggest there may be an association between bipolar disorder and season of birth. The leading theory in explaining the season of birth phenomenon is that a seasonal factor (such as viral infection, malnutrition, vitamin deficiency, prenatal or obstetrical complications, or ambient temperature) can damage an infant's brain and thereby predispose the child to later development of psychosis. Evidence suggests that the seasonal effect is associated with a subgroup of schizophrenics who have early onset of psychosis, less genetic loading than other schizophrenics, and better prognosis. Case-control studies are needed comparing winterborn to nonwinter-born schizophrenics.

Adolescent↗