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Biomedical subjects

S A Mednick

Publications and source records attributed to S A Mednick.

At least 73 records · Page 4Linked to original sources
PubMed1988

Adult schizophrenia following prenatal exposure to an influenza epidemic.

In the context of a Finnish birth cohort, we tested the hypothesis that viral infection during the latter two thirds of fetal development would increase the risk of adult schizophrenic outcome. Psychiatric hospital diagnoses were recorded for all individuals in greater Helsinki who were fetuses during the 1957 type A2 influenza epidemic. Those exposed to the viral epidemic during their second trimester of fetal development were at elevated risk of being admitted to a psychiatric hospital with a diagnosis of schizophrenia. This was true for both males and females and independently in several psychiatric hospitals. The second-trimester effect was seen in the elevated proportion of schizophrenics among those admitted to a psychiatric hospital and also in higher rates of schizophrenia per 1000 live births in the city of Helsinki. The study has several limitations: (1) We have no direct evidence that the subjects actually suffered a viral infection. (2) The psychiatric data were obtained only for subjects up to the age of 26 years, 56 days. (3) The findings are based on hospital diagnoses. (4) The determination of stage of gestation at time of exposure to the epidemic is based on date of birth. The viral infection might have occurred outside the official epidemic window; the infant may have had a preterm or postterm delivery. These sources of error, however, should not serve to enhance the findings. The observed viral effect is interpreted as being one of many potential perturbations of gestation. We suggest that it is less the type than the timing of the disturbance during fetal neural development that is critical in determining risk for schizophrenia.

Adult↗
PubMed1988

Motor impairment and antisocial behavior in adolescent males at high risk for schizophrenia.

A familial link between schizophrenia and antisocial behavior has been established (e.g., Silverton, 1985). This study examined this relationship in a Danish cohort. The subjects were 36 high-risk males (offspring of a schizophrenic parent) and 36 low-risk males (offspring of parents without psychopathology). This high-risk subjects exhibited more antisocial behavior than the low-risk subjects. We tested the hypothesis of a correlation between neurointegrative deficits, as defined by motor impairment, and antisocial behavior, rated at ages 10-13, in subjects at genetic risk for schizophrenia. Path analyses were conducted from motor impairment at 1 year and motor impairment at 10-13 years to antisocial behavior separately for high-risk and low-risk subjects. Adolescent motor impairment was a significant predictor of antisocial behavior for high-risk subjects. Motor impairment at 1 year was also associated with antisocial behavior for these subjects, although the association was partly due to the indirect effects of motor impairment at 1 year on motor impairment at 10-13 years, which, in turn, was associated with changes in antisocial behavior. As predicted, none of the path coefficients nor the effect coefficient was significant for low-risk subjects.

Adolescent↗
PubMed1988

Pattern reversal visual evoked potentials after alcohol administration among men at risk for alcoholism.

The P100 component of the pattern reversal visual evoked potential was used to compare men at high risk for alcoholism and control subjects before and after a low (0.5 g/kg) dose of ethanol. The high risk and control subjects did not differ in age, self-reported ethanol consumption, or estimates of ethanol metabolism rates, but changes in the occipital P100 latency differentiated them following ethanol administration. The P100 latency changes that distinguished high risk from control subjects were lateralized and provide preliminary evidence that perceptual visual stimulus processing is differentially affected in the two groups following ethanol administration.

Adult↗
PubMed1988

EEG identification of subgroups of men at risk for alcoholism?

Biological sons of male alcoholics constitute one group at high risk (HR) for the development of alcoholism, and were the subjects of this study. A low dose of alcohol (0.5 g/kg) was administered to HR and control subjects. On the basis of changes in the electroencephalographic (EEG) mean alpha frequency that occurred following alcohol administration, two HR subgroups were identified. Measures obtained after alcohol administration, comprising self-ratings and an observer's assessment, distinguished the HR subgroups and control subjects; measures of visuomotor performance did not. The findings are discussed in relation to two current etiological theories bearing on the development of alcoholism: a biopsychological perspective and an initial tolerance for alcohol effects.

Adolescent↗
PubMed1988

Pattern reversal visual evoked potential among men at risk for alcoholism.

The biological sons of male alcoholics, deemed to be at high risk (HR) for the development of alcoholism, were compared to control males, aged 18 to 21, using measures of the visual evoked potential elicited by checkerboard pattern reversal. Overall, the HR and control groups were not distinguished on the basis of visual evoked potential measures acquired from the occipital scalp region; however, when comparisons were restricted to right-handed subjects, the HR subjects showed more symmetry in a positive component with approximate latency of 242 ms compared with control subjects. The results are discussed in relation to hemispheric differences and alcoholism.

Adolescent↗
PubMed1988

Congenital determinants of violence.

Specialization--the predisposition to violent behavior persisting over an extended period of time--is considered in relation to congenital factors, to determine whether such factors are contributory to this predisposition. Congenital factors include inherited characteristics and perinatal experiences. Evidence for inherited characteristics in criminal behavior is approached through family studies, the study of twins, and adoption studies. Of those three, adoption studies provide the most fertile ground for study. Predisposition toward criminal behavior is noted to be limited to property crime. The second congenital factor is the perinatal experience. Minor physical anomalies appear to be strongly related to hyperactivity and later criminal involvement, but only if the offender was reared in an unstable, nonintact family. Indices of perinatal problems relate to later violent crime, rather than to property crime, and may have as their basis some form of trauma occurring very early in life.

Adolescent↗
PubMed1987

The Copenhagen High-Risk Project, 1962-86.

Since 1962 we have followed a sample of 207 children at high risk for schizophrenia as well as 104 control children. For these individuals, the following factors and their interaction are related to an increased risk for schizophrenic breakdown: (1) greater schizophrenia family backgrounds, (2) perinatal trauma, and (3) unstable parenting and public institutional child care. The perinatal difficulties are positively related to adult periventricular atrophy. Results of a subsequent study tentatively suggest that part of the neurological deviance in schizophrenia may be produced by disruption occurring in the second trimester of fetal development.

Adolescent↗
PubMed1987

Seasonality, birth complications and schizophrenia in a high risk sample.

It has been suggested that viral infections, more prevalent in the winter months, might increase pregnancy and birth complications, which might in turn be responsible for the excess of winter-born patients with schizophrenia. In this study it was found that the rate of schizophrenia among high risk winter-urban births who had suffered a perinatal complication was significantly greater than that for those who had not, thus supporting the hypothesis.

Female↗
PubMed1987

The Copenhagen high-risk project. The diagnosis of maternal schizophrenia and its relation to offspring diagnosis.

The Copenhagen longitudinal high-risk study of offspring of 129 schizophrenic mothers commenced in 1962. At that time, the mothers were diagnosed according to contemporary Danish criteria. We have re-examined all of the hospital records of these mothers: 108 (84%) fulfil present-day DSM-III criteria for schizophrenia and 95 (74%) were diagnosed as paranoid schizophrenic according to ICD-8 criteria. In a follow-up at mean age 24, the offspring of the paranoid schizophrenic mothers were themselves found to be less frequently schizophrenic (5%) than were the offspring of non-paranoid schizophrenic mothers (29%).

Adult↗
PubMed1985

Neurological dysfunctioning in offspring of schizophrenics in Israel and Denmark. A replication analysis.

Neurological functioning was compared in children at risk for schizophrenia from samples recruited in Israel and Denmark. In both samples neurological signs were assessed in school-age children with one schizophrenic parent and a matched group of children with no mentally ill parents. Multidimensional Scalogram Analysis of data identified, in both samples, a radex structure of neurological functioning, radiating from motor to sensory-perceptual signs. In both samples, the gradient of neurological functioning differed between the offspring of schizophrenics and controls. For both the offspring of schizophrenics and controls, the largest number of children showed no or few signs of neurological dysfunctioning. A subgroup of the offspring of schizophrenics, but not the controls, showed multiple signs of neurological dysfunctioning that varied in pattern among individuals.

Adolescent↗
PubMed1985

The EEG in persons at risk for alcoholism.

Alcoholics tend to have a relatively small amount of alpha and a large amount of beta activity in their EEG. This pattern may be a consequence or an antecedent of alcoholism. Attempts to demonstrate this EEG pattern in subjects who were at high risk (HR) for alcoholism (because they had alcoholic fathers) have yielded equivocal results. However, electrophysiological changes elicited by a single dose of alcohol differentiated HR subjects from controls. The HR subjects exhibited greater increases of slow-alpha energy and greater decreases of fast-alpha energy after alcohol administration than controls. In another study, the HR subjects showed a greater decrease of a late positive component of the auditory-evoked potential after alcohol than controls. Thus the HR subjects show greater electrophysiological responses to alcohol than controls. These effects are not related to differences in alcohol metabolism, and they may reflect a biologic marker for CNS sensitivity to alcohol. Alternative interpretations of these findings are discussed and suggestions for further research are offered.

Alcoholism↗