Intellectual functioning and the long-term course of schizophrenia-spectrum illness

BACKGROUND

Recent neurodevelopmental models of schizophrenia, together with substantial evidence of neurocognitive dysfunction among people with schizophrenia, have led to a widespread view that general cognitive deficits are a central aspect of schizophrenic pathology. However, the temporal relationships between intellectual functioning and schizophrenia-spectrum illness remain unclear.

METHOD

Longitudinal data from the Copenhagen High-Risk Project (CHRP) were used to evaluate the importance of intellectual functioning in the prediction of diagnostic and functional outcomes associated with the schizophrenia spectrum. The effect of spectrum illness on intellectual and educational performance was also evaluated. The sample consisted of 311 Danish participants: 99 at low risk, 155 at high risk, and 57 at super-high risk for schizophrenia. Participants were given intellectual [Weschler's Intelligence Scale for Children (WISC)/Weschler's Adult Intelligence Scale (WAIS)] assessments at mean ages of 15 and 24 years, and diagnostic and functional assessments at mean ages 24 and 42 years.

RESULTS

Intellectual functioning was found to have no predictive relationship to later psychosis or spectrum personality, and minimal to no direct relationship to later measures of work/independent living, psychiatric treatment, and overall severity. No decline in intellectual functioning was associated with either psychosis or spectrum personality.

CONCLUSIONS

These largely negative findings are discussed in the light of strong predictive relationships existing between genetic risk, diagnosis and functional outcomes. The pattern of predictive relationships suggests that overall cognitive functioning may play less of a role in schizophrenia-spectrum pathology than is widely believed, at least among populations with an evident family history of schizophrenia.

Early maternal and paternal bonding, childhood physical abuse and adult psychopathic personality

BACKGROUND

A significant gap in the literature on risk factors for psychopathy is the relative lack of research on parental bonding.MethodThis study examines the cross-sectional relationship between maternal and paternal bonding, childhood physical abuse and psychopathic personality at age 28 years in a community sample of 333 males and females. It also assesses prospectively whether children separated from their parents in the first 3 years of life are more likely to have a psychopathic-like personality 25 years later.

RESULTS

Hierarchical regression analyses indicated that: (1) poor parental bonding (lack of maternal care and low paternal overprotection) and childhood physical abuse were both associated with a psychopathic personality; (2) parental bonding was significantly associated with psychopathic personality after taking into account sex, social adversity, ethnicity and abuse; (3) those separated from parents in the first 3 years of life were particularly characterized by low parental bonding and a psychopathic personality in adulthood; and (4) the deviant behavior factor of psychopathy was more related to lack of maternal care whereas the emotional detachment factor was related to both lack of maternal care and paternal overprotection.

CONCLUSIONS

Findings draw attention to the importance of different components of early bonding in relation to adult psychopathy, and may have potential implications for early intervention and prevention of psychopathy.

High social class and suicide in persons at risk for schizophrenia

OBJECTIVE

The relationship between suicide and social class has been equivocal. While some authors have reported that higher social class is related to higher rates of suicide, most other studies report that lower social class is associated with higher rates of suicide. Our study attempted to resolve these inconsistencies by using a High Risk for schizophrenia method.

METHOD

Children of women with severe schizophrenia were assessed in 1962. In 2005, when subjects were a mean age of 58 years, we identified those who had committed suicide.

RESULTS

A higher rate of suicide was associated with risk for schizophrenia in the High-Risk sample. Higher social class origin was associated with suicide in persons at risk for mental illness.

CONCLUSION

Higher social class origin was associated with suicide in subjects at genetic risk for schizophrenia (but not those without risk).

Paternal alcoholism predicts the occurrence but not the remission of alcoholic drinking: a 40-year follow-up

OBJECTIVE

To test the effects of father's alcoholism on the development and remission from alcoholic drinking by age 40.

METHOD

Subjects were selected from a Danish birth cohort that included 223 sons of alcoholic fathers (high risk; HR) and 106 matched controls (low risk; LR). Clinical examinations were performed at age 40 (n = 202) by a psychiatrist using structured interviews and DSM-III-R diagnostic criteria.

RESULTS

HR subjects were significantly more likely than LR subjects to develop alcohol dependence (31% vs. 16%), but not alcohol abuse (17% vs. 15%). More subjects with alcohol abuse were in remission at age 40 than subjects with alcohol dependence. Risk did not predict remission from either alcohol abuse or alcohol dependence.

CONCLUSION

Familial influences may play a stronger role in the development of alcoholism than in the remission or recovery from alcoholism.

Assessing the role of genetics in crime using adoption cohorts

The role of genetics in criminal behaviour can be assessed through family, twin and adoption studies. This paper discusses the major findings of adoption studies that have focused on criminal outcome. Results from adoption studies have consistently revealed a relationship between biological parent criminal behaviour and adoptee criminal outcome. This finding has been noted in the case of property crime, but not in the case of violent crime. Violent crime in adopted-away offspring is not related to violent crime in biological parents. Findings from the Danish Adoption Cohort suggest that violent crime may be genetically related to other types of behavioural deviance. In the Danish Adoption Cohort, there is an increased rate of schizophrenia in the adopted-away offspring of biological fathers who are convicted of violent crimes. This father violence-adoptee schizophrenia relationship cannot be accounted for by the potential confounding factors of rearing social status, age at transfer, knowledge of family history of crime, or biological parents' mental illness.

Height, weight and body mass index in early adulthood and risk of schizophrenia

OBJECTIVE

To illuminate the possible associations between height, weight, and body mass index (BMI) during early adulthood and the development of schizophrenia.

METHOD

This prospective study is based on an all-male sample of 3210 individuals from the Copenhagen Perinatal Cohort, comprising individuals born between 1959 and 1961. In 1999, cases of schizophrenia were identified in the Danish Psychiatric Central Register, and the cases were compared with the cohort pool of controls with respect to height, weight, and BMI from draft records. The effect of low BMI was adjusted for parental social status when the cohort members were 1 year old, birth weight, birth length, and maternal pre-pregnancy BMI.

RESULTS

Forty-five cases of schizophrenia had a lower young adult mean body weight and BMI than controls. A significant inverse relationship between BMI and risk of later schizophrenia was found. For each unit increase in BMI, the adjusted odds ratio was 0.81 (95% CI, 0.70-0.93) and the risk of schizophrenia decreased by 19%. Excluding individuals who had been admitted to an in-patient facility before or within 5 years after appearing before the draft board, yielded virtually the same results. No significant differences between cases and controls were observed with respect to adult height.

CONCLUSION

Independent of several possible confounders, an inverse relationship between young adult BMI and risk of later development of schizophrenia was demonstrated in this all-male sample.

Breastfeeding and risk of schizophrenia in the Copenhagen Perinatal Cohort

OBJECTIVE

The aim was to study whether early weaning from breastfeeding may be associated with increased risk of schizophrenia.

METHOD

The current sample comprises 6841 individuals from the Copenhagen Perinatal Cohort of whom 1671 (24%) had been breastfed for 2 weeks or less (early weaning) and 5170 (76%) had been breastfed longer. Maternal schizophrenia, parental social status, single mother status and gender were included as covariates in a multiple regression analysis of the effect of early weaning on the risk of hospitalization with schizophrenia.

RESULTS

The sample comprised 93 cases of schizophrenia (1.4%). Maternal schizophrenia was the strongest risk factor and a significant association between single mother status and elevated offspring risk of schizophrenia was also observed. Early weaning was significantly related to later schizophrenia in both unadjusted and adjusted analyses (adjusted odds ratio 1.73 with 95% CI: 1.13-2.67).

CONCLUSION

No or <2 weeks of breastfeeding was associated with elevated risk of schizophrenia. The hypothesis of some protective effect of breastfeeding against the risk of later schizophrenia is supported by our data.

Prediction of mortality at age 40 in Danish males at high and low risk for alcoholism

OBJECTIVE

This prospective high-risk study examined the influence of father's alcoholism and other archival-generated measures on premature death.

METHOD

Sons of alcoholic fathers (n = 223) and sons of non-alcoholic fathers (n = 106) have been studied from birth to age 40. Archival predictors of premature death included father's alcoholism, childhood developmental data, and diagnostic information obtained from the Psychiatric Register and alcoholism clinics.

RESULTS

By age 40, 21 of the 329 subjects had died (6.4%), a rate that is more than two times greater than expected. Sons of alcoholic fathers were not more likely to die by age 40. Premature death was associated with physical immaturity at 1-year of age and psychiatric/alcoholism treatment. No significant interactions were found between risk and archival measures.

CONCLUSION

Genetic vulnerability did not independently predict death at age 40. Death was associated with developmental immaturities and treatment for a psychiatric and/or substance abuse problem.

Male criminals with organic brain syndrome: two distinct types based on age at first arrest

OBJECTIVE

This study examined whether criminals with organic brain syndrome could be divided into two distinct types. The authors proposed that early starters (onset of criminal activity by age 18) would display a persistent, long-lasting pattern of deviance that was largely independent of their brain disorder, whereas late starters (onset at age 19 or after) would exhibit deviant behaviors that began late in life and were more directly related to their brain disorder.

METHOD

Subjects were 1,130 male criminal offenders drawn from a birth cohort of all individuals born between January 1, 1944, and December 31, 1947, in Denmark. The main study group included all men with both a history of criminal arrest and a hospitalization for organic brain syndrome (N=565). In addition, for a subset of analyses, the authors examined a randomly selected, same-size comparison group of men with a history of criminal arrest who were not hospitalized for organic brain syndrome. Data were available on all arrests and all psychiatric hospitalizations for individuals in this cohort through the age of 44.

RESULTS

Among those with organic brain syndrome, early starters were significantly more likely than late starters to 1) be arrested before the onset of organic brain syndrome, 2) show a higher rate of offending before but not after the onset of organic brain syndrome, 3) be both recidivists and violent recidivists, and 4) have a diagnosis of antisocial personality disorder.

CONCLUSIONS

Male criminals with organic brain syndrome can be meaningfully divided into two distinct types on the basis of age at first arrest. Early starters show a more global, persistent, and stable pattern of offending than late starters. These results have implications for treatment and risk assessment.

Early educational and health enrichment at age 3-5 years is associated with increased autonomic and central nervous system arousal and orienting at age 11 years: evidence from the Mauritius Child Health Project

Little is known about the effects of environmental enrichment on psychophysiological measures of arousal and orienting in humans. This study tests the hypothesis that early educational and health enrichment is associated with long-term increases in psychophysiological orienting and arousal. One hundred children were experimentally assigned to a two-year enriched nursery school intervention at ages 3-5 years and matched at age 3 years on psychophysiological measures, gender, and ethnicity to 100 comparisons who received the normal educational experience. Children were retested 6-8 years later at age 11 years on skin conductance (SC) and electroencephalogram (EEG) measures of arousal and attention during pre- and postexperimental rest periods and during the continuous performance task. Nursery enrichment was associated with increased SC amplitudes, faster SC rise times, faster SC recovery times, and less slow-wave EEG during both rest and CPT conditions. This is believed to be the first study to show that early environmental enrichment is associated with long-term increases in psychophysiological orienting and arousal in humans. Results draw attention to the important influence of the early environment in shaping later psychophysiological functioning.

Three-factor model of schizotypal personality: invariance across culture, gender, religious affiliation, family adversity, and psychopathology

Whilst the syndrome approach to schizotypy has recently demonstrated differential correlates of a three-factor model of schizotypal personality, variations in the nature of these factors question a basic assumption of this approach. This study tested competing models of the factor structure of schizotypal personality using the Schizotypal Personality Questionnaire (SPQ) in a sample of 1,201 Mauritians. Factor invariance across gender, ethnicity, family adversity, and religion and across a psychopathologically select group was also assessed. Results suggest that a three-factor model, Cognitive-Perceptual Deficits, Interpersonal Deficits, and Disorganization, underlies individual differences across widely varying groups. Other competing three-factor schizotypal personality models did not fit the data better. It is argued that the three-factor Disorganized model is a well-replicated model of DSM schizotypal personality in community samples but possibly not in some clinical samples.

Major mental disorders and criminal violence in a Danish birth cohort

BACKGROUND

This epidemiological investigation was designed to examine the relationships between each of the major mental disorders and criminal violence. Specifically, we assessed whether a significant relationship exists between violence and hospitalization for a major mental disorder, and whether this relationship differs for schizophrenia, affective psychoses, and organic brain syndromes.

METHODS

Subjects were drawn from a birth cohort of all individuals born between January 1, 1944, and December 31, 1947, in Denmark (N = 358 180). Because of the existence of accurate and complete national registers, data were available on all arrests for violence and all hospitalizations for mental illness that occurred for individuals in this cohort through the age of 44 years.

RESULTS

There was a significant positive relationship between the major mental disorders that led to hospitalization and criminal violence (odds ratios 2.0-8.8 for men and 3.9-23.2 for women). Persons hospitalized for a major mental disorder were responsible for a disproportionate percentage of violence committed by the members of the birth cohort. Men with organic psychoses and both men and women with schizophrenia were significantly more likely to be arrested for criminal violence than were persons who had never been hospitalized, even when controlling for demographic factors, substance abuse, and personality disorders.

CONCLUSIONS

Individuals hospitalized for schizophrenia and men hospitalized with organic psychosis have higher rates of arrests for violence than those never hospitalized. This relationship cannot be fully explained by demographic factors or comorbid substance abuse.

Prenatal teratogens and the development of adult mental illness

Our findings in the Helsinki Influenza Study and the Danish Forty Year Study lead us to conclude that a 2nd-trimester maternal influenza infection may increase risk for adult schizophrenia or adult major affective disorder. More recently we have also reported an increase of unipolar depression among offspring who were exposed prenatally to a severe earthquake (7.8 on the Richter scale) in Tangshan, China. Among the earthquake-exposed males (but not the females), we observed a significantly greater depression response for those individuals exposed during the 2nd trimester of gestation. These findings suggest that maternal influenza infection and severe maternal stress may operate (in different ways) as teratogens, disrupting the development of the fetal brain and increasing risk for developing schizophrenia or depression in adulthood.

Skin-conductance orienting deficits and increased alcoholism in schizotypal criminals

This study tested the interaction hypothesis that a subgroup of criminals with schizotypal personality would show skin-conductance orienting deficits and increased alcoholism. In a prospective, longitudinal study of alcoholism in 134 males, schizotypy was assessed during adolescence, skin-conductance orienting was assessed at ages 18-20 years, and criminal offending and alcohol abuse were assessed at ages 30-33 years. A significant interaction between schizotypy and criminality indicated that schizotypal criminals were characterized by autonomic orienting deficits. Furthermore, the rate of alcoholism in schizotypal criminals (54.8%) was significantly higher than in criminals (23.8%), schizotypal noncriminals (13.9%), and comparisons (21.7%). It is argued that schizotypal criminals are a relatively distinct group and that prefrontal dysfunction may underlie both orienting deficits and alcoholism in this group.

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

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

Skin-conductance orienting deficits and increased alcoholism in schizotypal criminals

This study tested the interaction hypothesis that a subgroup of criminals with schizotypal personality would show skin-conductance orienting deficits and increased alcoholism. In a prospective, longitudinal study of alcoholism in 134 males, schizotypy was assessed during adolescence, skin-conductance orienting was assessed at ages 18-20 years, and criminal offending and alcohol abuse were assessed at ages 30-33 years. A significant interaction between schizotypy and criminality indicated that schizotypal criminals were characterized by autonomic orienting deficits. Furthermore, the rate of alcoholism in schizotypal criminals (54.8%) was significantly higher than in criminals (23.8%), schizotypal noncriminals (13.9%), and comparisons (21.7%). It is argued that schizotypal criminals are a relatively distinct group and that prefrontal dysfunction may underlie both orienting deficits and alcoholism in this group.

Maternal smoking during pregnancy and adult male criminal outcomes

BACKGROUND

Perinatal risk factors are related to persistent and violent criminal outcomes. Prenatal maternal smoking may represent an additional perinatal risk factor for adult criminal outcomes. Our study examines maternal smoking during pregnancy as a predictor of offspring crime in the context of a prospective, longitudinal design.

METHODS

Subjects were a birth cohort of 4169 males born between September 1959 and December 1961 in Copenhagen, Denmark. During the third trimester of pregnancy, mothers self-reported the number of cigarettes smoked daily. When the male offspring were 34 years of age, their arrest histories were checked in the Danish National Criminal Register. Additional data were collected concerning maternal rejection, socioeconomic status, maternal age, pregnancy and delivery complications, use of drugs during pregnancy, paternal criminal history, and parental psychiatric hospitalization.

RESULTS

Results indicate a dose-response relationship between amount of maternal prenatal smoking and arrests for nonviolent and violent crimes. Maternal prenatal smoking was particularly related to persistent criminal behavior rather than to arrests confined to adolescence. These relationships remained significant after potential demographic, parental, and perinatal risk confounds were controlled for.

CONCLUSIONS

Maternal prenatal smoking predicts persistent criminal outcome in male offspring. This relationship has not been accounted for by related parental characteristics or perinatal problems. Potential physiologic or central nervous system mediators between maternal smoking during pregnancy and offspring criminal outcomes need further study.

Mental illness and criminal violence

This article examines the relationship between criminal violence and mental illness. Our data suggest that mentally ill persons tend to have an increased risk for committing violent offenses, and that the violent offending by these individuals tends to be recidivistic. Our findings suggest that parents who have both committed violent offenses and experienced a psychiatric hospitalization increase the risk of violent offending among their offspring. We propose the hypothesis that mentally ill parents transmit a biological characteristic which may genetically predispose their child towards criminal violence. Prenatal disturbances during critical periods of fetal development may provide clues regarding the etiology of criminal violence.

School teacher ratings predictive of psychiatric outcome 25 years later

BACKGROUND

The current study examines teacher ratings as a tool for identifying students at risk of developing psychosis. Follow-up and follow-back studies have shown that teachers are capable of identifying individuals who later develop serious mental illness.

METHOD

We examine the long-term outcomes for individuals at genetic risk who were identified as showing markedly deviant behaviour and those identified who did not show markedly deviant behaviour.

RESULTS

Teachers were able to correctly anticipate 35% of students who developed schizophrenia. Furthermore, those identified as showing markedly deviant behaviour had poorer clinical and psychiatric outcomes 10 and 25 years later than those identified as not behaving with marked deviance. Their ratings also differentiated, within the group of people with schizophrenia, which individuals would show evidence of poorer functioning 25 years later. These results were replicated in a group of students not at genetic risk of schizophrenia. Within this low-risk group, teachers were able to predict which students would develop psychotic disorders.

CONCLUSIONS

Teacher ratings were particularly useful in predicting clinical and psychiatric outcomes 10 and 25 years later. The applicability of these findings in early intervention and treatment research is discussed.

Fearlessness, stimulation-seeking, and large body size at age 3 years as early predispositions to childhood aggression at age 11 years

BACKGROUND

Previous cross-sectional research in Western societies has linked adolescent stimulation-seeking, fearlessness, and body size to antisocial behavior. However, it is unclear how early in life these factors exert their influence, and nothing is known about their specificity to aggressive behavior per se. This study tests the hypotheses that stimulation-seeking, fearlessness, and increased body size at age 3 years predict aggression at age 11 years.

METHODS

Behavioral measures of stimulation-seeking and fearlessness, together with height and weight, were measured at age 3 years and related to ratings of aggression at age 11 years in 1130 male and female Indian and Creole children from the island of Mauritius.

RESULTS

Aggressive children at age 11 years were characterized by increased measures of stimulation-seeking, fearlessness, height, and weight at age 3 years. Stimulation-seeking and height were independently related to aggression, whereas the fearlessness-aggression relationship was mediated by height. Large body size at age 3 years but not 11 years was related to increased aggression at age 11 years, indicating a critical period in development for the influence of body size on aggression.

CONCLUSIONS

Results (1) implicate large body size, stimulation-seeking, and fearlessness in the development of childhood aggression; (2) suggest that there may be a critical period in development in which biological processes influence later aggression; and (3) highlight the importance of early processes in the etiology of aggression.

Structural brain abnormalities in schizophrenia: a family study

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

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

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

Low resting heart rate at age 3 years predisposes to aggression at age 11 years: evidence from the Mauritius Child Health Project

OBJECTIVE

Previous studies indicate that low resting heart rate is probably the best-replicated biological correlate of childhood antisocial and aggressive behavior. Nevertheless, there have been few longitudinal tests of this relationship, little control over potential confounds and mediators, and no test of its cross-cultural generalizability. This study tests the hypothesis that low resting heart rate at age 3 years predicts aggression at age 11 years.

METHOD

Resting heart rate at age 3 years was assessed in 1,795 male and female children from Mauritius. Aggressive and nonaggressive forms of antisocial behavior were assessed at age 11 years using the Child Behavior Checklist.

RESULTS

Aggressive children had lower heart rates than nonaggressive children (p < .001). Conversely, those with low heart rates were more aggressive than those with high heart rates (p < .003). There were no interactions with gender or ethnicity. Evidence was found for specificity of low heart rate to aggressive forms of antisocial behavior. Group differences in heart rate were not attributable to 11 biological, psychological, and psychiatric mediators and confounds.

CONCLUSIONS

It is concluded that low resting heart rate, a partly heritable trait reflecting fearlessness and stimulation-seeking, is an important, diagnostically specific, well-replicated, early biological marker for later aggressive behavior.

Interaction between birth complications and early maternal rejection in predisposing individuals to adult violence: specificity to serious, early-onset violence

OBJECTIVE

The authors previously reported that birth complications interact with early maternal rejection in predisposing individuals to violence at age 18 years. This study extended the follow-up period for violent offending from 18 years to 34 years, thus increasing the sample of violent offenders threefold and allowing more detailed analyses on onset and type of violence, the form of maternal rejection, and the effect of maternal mental illness.

METHOD

Complications in the births of 4,269 males in Denmark, maternal rejection of these individuals before the age of 1 year, and their histories of criminal offenses at age 34 years were assessed.

RESULTS

The biosocial interaction previously observed held for violent but not nonviolent crime, was specific to more serious forms of violence and not threats of violence, held for early-onset but not late-onset violence, and was not accounted for by psychiatric illness in the mothers. Being reared in a public care institution in the first year of life and the mother's attempt to abort the fetus were the key aspects of maternal rejection that interacted with birth complications in predisposing a subject to violence.

CONCLUSIONS

These findings 1) indicate that the mechanisms underlying early-onset, serious violence differ from those for less serious, late-onset violence, 2) implicate very early factors in the development of violence, 3) highlight the potential importance of integrating psychosocial with biological factors in understanding and preventing violence, and 4) suggest that interventions to reduce birth complications and maternal rejection may help reduce violence.

Heart rate and skin conductance in behaviorally inhibited Mauritian children

This study tested predictions that inhibited versus uninhibited children exhibit higher heart rate (HR) and skin conductance (SC) arousal. Mauritian children (N = 1,795) were tested at age 3 and classified as inhibited, middle, or uninhibited on the basis of social behavior. HR level and several SC measures were obtained immediately before or during a tone task. Inhibited children displayed significantly higher HR and SC levels and longer SC latency relative to uninhibited children. Results remained regardless of ethnicity, gender, height, weight, respiratory complaints, or crying behavior. Findings suggest that HR and SC levels may be early indicators of inhibited or uninhibited behavior at age 3 and support the notion of heightened sympathetic reactivity due to limbic arousal in inhibited children.

Psychophysiological protective factors for male subjects at high risk for criminal behavior

OBJECTIVE

This study examines the role of elevated autonomic nervous system reactivity in protecting individuals at high risk for criminal behavior from antisocial outcomes. The authors hypothesized that subjects with criminal fathers who did not become criminals themselves were biologically protected from such an outcome because of, in part, heightened responsiveness of the autonomic nervous system.

METHOD

Ninety-four male subjects were placed into one of four study groups: criminal with criminal father (N = 26), noncriminal with criminal father (N = 24), criminal with noncriminal father (N = 20), and noncriminal with noncriminal father (N = 24). Skin conductance and heart rate data were gathered in an orienting paradigm.

RESULTS

Skin conductance and heart rate orienting reactivity were found to be significantly higher in the group of noncriminal subjects with criminal fathers than in the other three groups.

CONCLUSIONS

For subjects at high risk for criminal behavior, heightened autonomic nervous system responsiveness appears to be associated with lower likelihood of criminal outcome.

Heart rate and skin conductance in behaviorally inhibited Mauritian children

This study tested predictions that inhibited versus uninhibited children exhibit higher heart rate (HR) and skin conductance (SC) arousal. Mauritian children (N = 1,795) were tested at age 3 and classified as inhibited, middle, or uninhibited on the basis of social behavior. HR level and several SC measures were obtained immediately before or during a tone task. Inhibited children displayed significantly higher HR and SC levels and longer SC latency relative to uninhibited children. Results remained regardless of ethnicity, gender, height, weight, respiratory complaints, or crying behavior. Findings suggest that HR and SC levels may be early indicators of inhibited or uninhibited behavior at age 3 and support the notion of heightened sympathetic reactivity due to limbic arousal in inhibited children.

Adult major affective disorder after prenatal exposure to an influenza epidemic

BACKGROUND

We have previously reported an increase in schizophrenia diagnoses in a population exposed during the second trimester to the 1957 influenza epidemic. These basic findings together with a fair number of replications have been interpreted as supporting a neurodevelopmental contribution to the origins of schizophrenia. Recent neuroimaging findings suggest that affective illness may also have a neurodevelopmental origin. We examined the hypothesis that exposure to an influenza epidemic during the second trimester would increase the risk for adult major affective disorder.

METHODS

The subjects had been exposed as fetuses to the type A2/Singapore influenza epidemic in greater Helsinki, Finland. Control subjects were born in the 6 years before the epidemic.

RESULTS

We found a significant (P < .001) increase in the proportion of hospital diagnoses for major affective disorder for individuals exposed to the influenza epidemic during their second trimester of fetal development compared with control subjects (13% vs 2%). This second-trimester effect seems somewhat stronger in men (16% vs 2%) (P < .001), although the rates of major affective disorder in women (8% vs 3%) (P > .05) were similar. The second-trimester effect remained when we estimated population-based rates (2.1 vs 0.6 per 1000) (P < .05) of major affective disorder. Additional analyses revealed that the increase of major affective disorder among subjects in the index group who were exposed during the second trimester was due to a significant (P < .002) elevation of unipolar forms, although a similar though not significant (P > .05) elevation was observed for the bipolar forms of major affective disorder.

CONCLUSIONS

These data are consistent with the hypothesis concerning the possible neurodevelopmental contribution to the origins of some forms of major affective disorder, especially unipolar depressive disorder. These encouraging findings, if replicated, may suggest that some mental disorders may stem, in part, from a disturbance in the development of the fetal brain during the second trimester.

Childhood behavior precursors of schizotypal personality disorder

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

Mental disorder and crime. Evidence from a Danish birth cohort

BACKGROUND

Evidence has accumulated since the mid 1960s from a number of different countries indicating an association between mental disorder and crime and particularly between the major mental disorders and violence. Registries in Denmark were used to identify a birth cohort and to document all psychiatric admissions and all criminal proceedings of the 324401 members of this cohort up to the age of 43 years.

METHODS

Persons who had been admitted to a psychiatric ward were assigned to a diagnostic category according to a hierarchy of principal discharge diagnoses. They were compared with persons never admitted to a psychiatric ward as to the prevalence, type, and frequency of criminal convictions.

RESULTS

Women and men who had been hospitalized in psychiatric wards were more likely to have been convicted of a criminal offense than persons with no history of psychiatric hospitalization. The offenders who were hospitalized committed all types and, on average, as many offenses as did the never-hospitalized group of the same sex.

CONCLUSIONS

These findings confirm those from 2 other post-World War II Scandinavian birth cohorts that have found an association between psychiatric hospitalization and criminal convictions. They also concur with findings that patients discharged from psychiatric wards are more likely than other persons living in the same community to commit crimes and with results from North America showing elevated rates of major mental disorders among incarcerated offenders. Generalization of these findings is limited to nations with similar criminal justice, mental health, and social welfare systems.

High rates of violence, crime, academic problems, and behavioral problems in males with both early neuromotor deficits and unstable family environments

BACKGROUND

It is commonly assumed that individuals with both biological and psychosocial deficits are more likely to become criminal, but there is surprisingly little empirical support for this assumption. We test the hypothesis that a group with biosocial risk factors are more likely to develop behavioral and academic problems in adolescence and violent criminal offending in adult-hood compared with groups with only biological or only social risk factors.

METHODS

Hypotheses were tested on a sample of 397 male subjects, using obstetric and early neuromotor measures collected in the first year of life; family, social, demographic, and behavioral measures at age 17 to 19 years; and criminal data at 20 to 22 years of age.

RESULTS

Cluster analysis of the risk factors indicated a group with obstetric risk factors only, a group with poverty risk factors only, and a biosocial group with both early neuromotor deficits and unstable family environments. The biosocial group had more than double the adult violence, theft, and total crime rates of the other 2 groups and had significantly more behavioral and academic problems in adolescence.

CONCLUSIONS

When early neuromotor deficits and negative family factors cluster together, individuals are particularly likely to become criminal and violent compared with those with only poverty or only obstetric risk factors. Because this biosocial group accounted for 70.2% of all crimes committed in the entire sample, early interventions that tackle these deficits might significantly reduce violence.

The electroencephalogram after alcohol administration in high-risk men and the development of alcohol use disorders 10 years later

BACKGROUND

In 1979 through 1980, electroencephalographic (EEG) responses to an alcohol challenge in 19 year-old sons of alcoholics as well as in sons of nonalcoholic control subjects were examined. The familial risk status of the subjects and greater EEG sensitivity to alcohol were hypothesized to predict the development of alcoholism 10 years later.

METHODS

In 1990 through 1992, diagnostic interviews were completed to ascertain alcohol and other substance use disorders in these subjects and to update their family history.

RESULTS

Updated family history of alcoholism predicted the development of substance dependence. Density of alcoholic relatives (the number of alcoholic relatives divided by the number of known relatives) was positively related to the severity of alcohol use disorders in the probands. Contrary to expectation, a greater EEG response at age 19 years was not related to the later development of alcohol dependence. Instead, the opposite was observed: a smaller EEG alpha frequency response to alcohol at age 19 years was related to the development of alcohol dependence and high quantity and frequency of alcohol consumption 10 years later.

CONCLUSIONS

Lower EEG response to a small dose of alcohol may be associated with the later development of alcohol dependence. This result is based on a small number of subjects and should be interpreted with caution. Although this result is opposite to our 1980 hypothesis, it is consistent with much of the recent literature.

Risk factors of psychosis: identifying vulnerable populations premorbidly

This article reviews premorbid indicators of psychosis that may be relevant to primary intervention. These risk markers are divided into two categories: (1) precursors related to early etiological factors (family psychiatric history, perinatal and obstetric complications, neurobehavior deficits, early parental separation, institutionalization, and poor family function) and (2) precursors signaling latent mental illness (personality measurements indicating proneness to psychosis, and teacher ratings indicating emotional lability, social anxiety, social withdrawal, passivity, poor peer relations, and disruptive and aggressive behavior). Because teacher ratings have been shown to be powerful predictors of adult mental breakdown, part of this article focuses on a specific study that assesses such ratings as predictors of psychosis in a high-risk population. Risk indicators may also provide clues about protective factors relevant for primary prevention.

Rhesus incompatibility as a risk factor for schizophrenia in male adults

BACKGROUND

Rhesus (Rh) incompatibility is a cause of hemolytic disease of the fetus and newborn. Hemolytic disease results from the transplacentally transmitted maternal antibodies against Rh factor D and can cause permanent neurological damage in the affected newborn. This study examines the hypothesis that Rh incompatibility may be a risk factor for schizophrenia.

METHODS

A sample of 1867 male subjects was divided into two groups, 535 Rh incompatible and 1332 Rh compatible, and compared on rate of schizophrenia.

RESULTS

The rate of schizophrenia was significantly higher in the Rh-incompatible group (2.1%) compared with the Rh-compatible group (0.8%) (P < .03). In addition, since the risk for Rh hemolytic disease increases with second and later Rh incompatible pregnancies, it is noteworthy that the second- and later-born incompatible offspring exhibited a significantly higher rate of schizophrenia than second- and later-born compatible offspring (P < .05). Also, as predicted, the rate of schizophrenia among firstborn incompatible subjects was not significantly different from that of firstborn compatible subjects (1.1% vs 0.7%).

CONCLUSION

Rh incompatibility may be a risk factor for schizophrenia.

The stability of inhibited/uninhibited temperament from ages 3 to 11 years in Mauritian children

Stability of inhibited/uninhibited temperament was assessed using 1,795 Mauritian children tested at ages 3, 8, and 11 years. Children were divided into uninhibited, middle, and inhibited groups at each age based on social behavior. Results indicated that, relative to uninhibited children (1) those inhibited at age 3 obtained larger inhibition scores at age 8 (p < .0001), (2) those inhibited at age 8 obtained larger inhibition scores at age 11 (p < .002), and (3) those remaining inhibited from ages 3 to 8 obtained larger inhibition scores at age 11 (p < .002). Relative to children who changed classification from ages 3 to 8, those remaining inhibited obtained larger inhibition scores (p < .05) and those remaining uninhibited obtained smaller inhibition scores (p < .015) at age 11. Inhibition scores tended to be higher in females by age 11. Results remained regardless of ethnicity. The results provide some support that inhibited/uninhibited temperament remains stable from ages 3 to 8 and may continue to age 11. The results suggest cross-cultural generalizability of these findings with implications regarding the development of anxiety disorders in the Mauritian population.

Assessing the predictive value of teacher reports in a high risk sample for schizophrenia: a ROC analysis

We examined teachers' reports to determine early patterns of school behavior that identify children who were diagnosed schizophrenic in adulthood. High risk subjects (n = 207) in the Copenhagen High Risk for schizophrenia project were examined on a 25-item questionnaire completed by teachers. A likelihood ratio approach was used to create a classification index relating school report to DSM-IIIR diagnoses made 31 years later. A standard receiver operating characteristic (ROC) analysis was used to evaluate the efficacy of the classification indices for distinguishing preschizophrenics from children who later developed schizotypal disorder, other nonpsychotic disorders, and no mental illness. Different items predicted schizophrenia in males and females. To a significantly greater degree than their controls, preschizophrenic males were lonely and rejected, behaved inappropriately, were disciplinary problems, emotionally high strung, and were more likely to have repeated a grade; preschizophrenic females were nervous and passive. Both preschizophrenic males and females were judged by teachers to be vulnerable to future psychotic problems. These findings are consistent with our preliminary findings, as well as with other research. They highlight the ability of teachers to identify school behaviors that may be used to select future schizophrenics for early intervention.

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

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

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

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

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

BACKGROUND

We examined differences in ventricular and sulcal cerebrospinal fluid-to-brain ratios as a function of lifetime psychiatric diagnosis in the offspring of schizophrenic mothers (high-risk sample) and in the offspring of normal parents (low-risk sample).

METHODS

We used a cohort analytic study of 17 high-risk individuals with schizophrenia, 31 high-risk individuals with schizotypal personality disorder, 33 high-risk individuals with nonschizophrenia-spectrum psychiatric disorders, 45 high-risk individuals with no disorders, 31 low-risk individuals with psychiatric disorders of all types, and 46 low-risk individuals with no disorders, evaluated initially in 1962 when they were a mean age of 15 years, and reexamined from 1986 through 1989 with psychiatric interviews and computed tomographic scans of the brain.

RESULTS

High-risk individuals with schizophrenia and schizotypal personality disorder evidenced an equivalent degree of cortical sulcal enlargement, and both groups evidenced significantly greater sulcal enlargement than did high-risk individuals with nonschizophrenia-spectrum disorders and no disorders and low-risk individuals with psychiatric disorders and no disorders. High-risk individuals with schizophrenia evidenced significantly greater ventricular enlargement than did high-risk and low-risk subjects with other disorders and no disorders, including those with schizotypal personality disorder. These differences were independent of age, gender, history of substance dependence, and history of organic brain syndromes and head injuries.

CONCLUSIONS

Among the offspring of schizophrenic parents, cortical abnormalities are expressed equally across the range of syndromes in the schizophrenia spectrum. Subcortical abnormalities (ie, ventricular enlargement) are more pronounced in the more severe syndrome (ie, schizophrenia).

Birth complications combined with early maternal rejection at age 1 year predispose to violent crime at age 18 years

BACKGROUND

This study tests the bisocial interaction hypothesis that birth complications when combined with early maternal rejection of the infant predispose to adult violent crime.

METHODS

This hypothesis was tested using a cohort of 4269 consecutive live male births on whom measures of birth complications (age 0), early maternal rejection (age 1 year), and violent crime (age 18 years) were collected.

RESULTS

A significant interaction (P < .0001) between birth complications and early maternal rejection indicated that those who suffered both birth complications and early child rejection were most likely to become violent offenders in adulthood. While only 4.5% of the subjects had both risk factors, this small group accounted for 18% of all violent crimes. The effect was specific to violence and was not observed for nonviolent criminal offending.

CONCLUSIONS

To our knowledge, this is the first study to show that birth complications in combination with early child rejection predispose to violent crime. The findings illustrate the critical importance of integrating biological with social measures to fully understand how violence develops and also suggest that prenatal, perinatal, and early postnatal health care interventions could significantly reduce violence.

Learning theory approach to the deterrence of criminal recidivism

Data on punishment and criminal arrests in a total birth cohort of men in Denmark (N = 28,879) was used to test the following hypotheses derived from learning theory: (a) the imposition of sanctions reduces rates of subsequent criminal arrest; (b) the more severe the sanction received for an arrest, the lower the rate of recidivism; (c) different types of sanctions have similar effects on recidivism; (d) the higher the proportion of sanctions received for past arrests, the lower the rates of future arrest; (e) continuous sanctions reduce arrest rates more than intermittent sanctions; and (f) discontinuation of punishment results in recovery of criminal arrests. Results support the above hypotheses, except Hypothesis b; our results suggest that sanctions have similar effects on recidivism regardless of their severity.

Impaired autonomic nervous system-habituation in those at genetic risk for schizophrenia

BACKGROUND

Schizophrenia has been associated with habituation of skin conductance activity. Skin conductance data from the Copenhagen High Risk Project were analyzed. We hypothesized that genetic risk for schizophrenia and development of schizophrenia later in life are related to impaired habituation of autonomic nervous system activity.

METHODS

Data were collected in 1962, when subjects averaged 15 years of age and had not yet qualified for a psychiatric diagnosis. Nonspecific fluctuations in electrodermal activity were monitored during a rest period free of sensory stimulation.

RESULTS

We found that an increasing level of genetic risk for schizophrenia was related to impaired habituation of autonomic nervous system activity over time. Individuals with two schizophrenia-spectrum parent evidenced no habituation, those with one spectrum parent evidence some habituation, and those with normal parents evidenced rapid habituation. Subjects who developed schizophrenia in adulthood evidenced significant deficits in habitation in adolescence.

CONCLUSIONS

These results suggest that impaired habituation of spontaneous autonomic nervous system activity may represent a behavioral marker of the genetic predisposition to schizophrenia.

Prenatal factors in the pathogenesis of schizophrenia

The excess of winter-spring births among individuals suffering from schizophrenia provides strong evidence for the existence of some prenatally occurring factors in the pathogenesis of schizophrenia. Recent epidemiological findings suggest that maternal viral infections during the second trimester of pregnancy may play a crucial role in the aetiology of adult schizophrenia. A 'two-hit window' hypothesis of the mechanism of action of prenatal factors in the pathogenesis of schizophrenia suggests at least two time-specific prenatal aetiological events. The observed association between prenatal viral infection and increased incidence of adult schizophrenia need not be a direct cytotoxic result of the viral infection, but may be caused indirectly, for example from foetal minor cerebral haemorrhages produced by the anticoagulant effects of aspirin.

The influence of parental socioeconomic status on CT studies of schizophrenia

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

Prenatal influenza infections and adult schizophrenia

We reported previously that residents of Greater Helsinki, Finland, whose mothers were exposed to the 1957 influenza epidemic during their second trimester of gestation had a significantly elevated risk of developing adult schizophrenia. The majority of the replication studies to date have not determined whether the mothers actually contracted an infection or the stage of gestation based on mother's last menstruation. We read prenatal clinic records of the mothers of the Helsinki-born schizophrenia subjects to determine timing of infection, as noted by the prenatal clinic obstetric nurse at a time close to the actual infection. Schizophrenia subjects who were exposed in the second trimester had a significantly higher rate of definite influenza infection (86.7%) in that period compared to those who were exposed during the first and third trimesters (20.0%). These results are interpreted with caution because of the small number of cases.

Lifetime DSM-III-R diagnostic outcomes in the offspring of schizophrenic mothers. Results from the Copenhagen High-Risk Study

OBJECTIVES

To perform a long-term prospective follow-up of children at high risk for schizophrenia to identify risk factors for the development of this disorder.

DESIGN

Prospective follow-up population study of children of schizophrenic mothers and their matched controls from age 15 years to age 42 years, with multiple diagnostic assessments performed by senior clinicians using structured interviews blindly with respect to the group membership of the subject.

PARTICIPANTS

Two hundred seven offspring of schizophrenic mothers and 104 control children without schizophrenic parents matched to the index group on age, sex, paternal socioeconomic status, urban/rural residence, and the amount of time spent during childhood in institutional rearing.

MAIN OUTCOME MEASURE

The prevalence of the DSM-III-R disorders during the subjects lifetime.

RESULTS

A significant aggregation of schizophrenia (16.2%) and other nonaffective, nonorganic psychosis (4.6%), and Cluster A personality disorders (21.3%) occurred among the offspring of schizophrenic mothers compared with the controls (1.9%, 0.9%, and 5%, respectively). No evidence of increased aggregation of (psychotic and nonpsychotic) affective disorders was noted among the offspring of schizophrenics.

CONCLUSION

These results coincide with the results of other family studies in demonstrating a significant and specific familial aggregation of schizophrenia and nonpsychotic schizophrenia spectrum disorders among the biological relatives of schizophrenics.

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

OBJECTIVE

We examined the contributions of genetic risk for schizophrenia and obstetric complications to brain morphological abnormalities in the offspring of schizophrenic and normal patents.

METHODS

We used a cohort analytic study of 60, 72, and 25 individuals with neither, one, or two parents, respectively, who were affected with schizophrenia spectrum disorders, evaluated initially in 1962 when they were on average 15 years old, and reexamined from 1986 through 1989 with psychiatric interviews and computed tomographic scans of the brain.

RESULTS

After controlling for the effects of age, gender, substance abuse, and history of organic brain syndromes and head injuries, there were significant stepwise, linear increases in cortical and ventricular cerebrospinal fluid-brain ratios with increasing level of genetic risk for schizophrenia. Genetic risk for schizophrenia also interacted with prospectively assessed birth complications in predicting selectively to enlargement of the ventricular system; ie, the effect of birth complications on ventricular enlargement was greater among those with two affected parents compared with those with one affected parent, and greater among those with one affected parent compared with those with normal parents. Perinatal exposure to ether anesthesia was associated with a generalized increase in brain abnormality, which varied in severity according to level of genetic risk for schizophrenia.

CONCLUSIONS

The type and degree of brain abnormalities shown by adult offspring of schizophrenic and normal parents are strongly predicted by the independent and interacting influences of genetic risk for schizophrenia and obstetric complications. The findings further substantiate the hypothesis that structural brain abnormalities in schizophrenia are at least in part neurodevelopmental in origin.

Research experiences with Fini Schulsinger

For the past 31 years (1961-1992) Fini Schulsinger and I have been exploring the origins of schizophrenia. We have started a number of longitudinal projects that are still keeping us rather busy; after all, retirement just means more time for research. Through our students and these projects, our collaboration may never end.

The schizophrenia high-risk project in Copenhagen: three decades of progress

We describe the design, theoretical approach and major recent findings of a prospective longitudinal study of the offspring of schizophrenic mothers and controls, initiated in 1962 by Sarnoff Mednick and Fini Schulsinger in Copenhagen, Denmark. Over 90% of the original 207 high-risk and 104 low-risk subjects have been successfully followed up since the initial assessment. At the time of the most recent assessment (1989), the subjects averaged 42 years of age and were nearly completely through the risk period for developing schizophrenia. By relating the lifetime psychiatric diagnoses of the subjects back to information on their premorbid experiences and functioning, we have identified several precursors of schizophrenia. This paper reviews our recent findings concerning whether outcomes of schizophrenia that differ in the relative prominence of negative versus positive symptoms represent discrete longitudinal syndromes. Predominantly negative and predominantly positive symptom schizophrenia were found to follow different patterns of symptom development from adolescence through the adult course of illness and were predicted by different combinations of genetic and environmental influences. Taken together, the findings suggest that the pathological processes underlying these two forms of schizophrenia are 1) partly independent of each other, 2) at least partly active during the premorbid state and 3) to some degree stable in the adult course of illness.