Adolescent IQ Research Articles

Relation of Childhood Malnutrition to Adult Mental Disorders

Relation of Childhood Malnutrition to Adult Mental Disorders

Associations between intelligence in adolescence and indicators of health and health behaviors in midlife in a cohort of Swedish women

The objective of this study was to investigate associations between intelligence and indicators of health status and health behaviors at age 43 in a cohort of Swedish women (n=682). Intelligence was measured by standard IQ tests given at ages 10, 13, and 15. At the age of 43, 479 of the women were sampled for a medical examination in which 369 participated (77% participation rate). We performed correlations of IQ and the continuous health variables and we estimated logistic regression models with dichotomous health variables as the dependent variables. No significant correlations were found between IQ and any of the continuous health variables. In unadjusted logistic regression models where the cut-off points were set based on standard health risk levels, four out of sixteen indicators of unfavorable health status and health behaviors showed significant negative associations with intelligence, meaning higher risk with decreasing IQ-score. After adjusting for educational level, two remained statistically significant: being obese, OR 1.51 (95% CI 1.08, 2.12) and having a high systolic blood pressure OR 1.45 (95% CI 1.03, 2.03). For all other health variables, this study finds no support for a sizable association between IQ in adolescence and indicators of health and health behavior in midlife among Swedish women.

Adolescent IQ and Survival in the Wisconsin Longitudinal Study

This study attempts to explain the ubiquitous positive correlation between cognitive ability (IQ) and survival. A sample of 10,317 Wisconsin high school graduates of 1957 was followed until 2009, from ages 18 to 68 years. Mortality was analyzed using a Weibull survival model that includes gender, social background, Henmon-Nelson IQ, and rank in high school class. Rank in high school class, a cumulative measure of responsible performance during high school, entirely mediates the relationship between adolescent IQ and survival. Its effect on survival is 3 times greater than that of IQ, and it accounts for about 10% of the female advantage in survival. Cognitive functioning may improve survival by promoting responsible and timely patterns of behavior that are firmly in place by late adolescence. Prior research suggests that conscientiousness, one of the "Big Five" personality characteristics, plays a key role in this relationship.

Childhood and adolescent antecedents of social skills and leadership potential in adulthood: Temperamental approach/withdrawal and extraversion

This is the first study examining the developmental roots of leadership potential in a longitudinal framework from age 2 to 29 years. Data are derived from the Fullerton Longitudinal Study. Using structural equation modeling ( N = 106), the direct and indirect effects of adolescent personality (extraversion) and intelligence (IQ) on adult social skills and leadership potential were investigated. In addition, we examined their joint effect on leadership potential using both a variable and a pattern approach. The relation between adolescent extraversion and adult leadership potential was completely mediated by adult social skills. Adolescent IQ had neither a direct nor an indirect relationship with adult leadership potential, nor did it interact with extraversion in predicting adult leadership potential. Utilizing longitudinal data from early childhood through adulthood, we delineated a specific developmental pathway to adult leadership potential spanning the first three decades of life. A pathway beginning in early childhood with temperamental approach/withdrawal shows stability throughout childhood and leads to extraversion in adolescence, which in turn relates to leadership potential in adulthood via adult social skills.

The Co-Twin Methodology and Returns to Schooling - Testing a Critical Assumption

Twins-based estimates of the return to schooling feature prominently in the labor economics literature. The validity of such estimates hinges critically on the assumption that within-pair variation in schooling is explained by factors which are unrelated to wage earning ability. This paper develops a framework for testing this assumption, and finds, using a unique dataset of monozygotic twins, strong evidence against it. Differences in adolescent IQ test scores predict within-pair variation in educational attainment, and including IQ in the wage equation causes within-pair point estimates for the returns to schooling to decline significantly. Our results thus cast doubt on the validity of estimates derived from the co-twin literature.

Age‐Related Changes in Drinking Patterns From Mid‐ to Older Age: Results From the Wisconsin Longitudinal Study

Drinking has generally been shown to decline with age in older adults. However, results vary depending on the measure of alcohol consumption used and the study population. The goals of this study were to (i) describe changes in drinking in a current cohort of older adults using a variety of measures of drinking and (ii) examine a number of different possible predictors of change. This is a longitudinal study of a community-based sample surveyed at 2 time points, ages 53 and 64 years. We estimated a series of logistic regressions to predict change and stability in drinking categories of nondrinking, moderate drinking, and heavy drinking. Linear regressions were used to predict change in past-month drinking days, past-month average drinks per drinking day, and past-month total drinks. From age 53 to 64, average drinks per drinking day and heavy drinking decreased. Frequency of drinking increased for men and women, and total drinks per month increased for men. The most consistent predictors of drinking changes were gender, health, and education. Other factors predicted drinking change but were not consistent across drinking measures including: adolescent IQ, income, lifetime history of alcohol-related problems, religious service attendance, depression, debt, and changes in employment. Heavy drinking decreases with age, but we may see more frequent moderate drinking with current and upcoming cohorts of older adults. Components of quantity and frequency of drinking change differently. Composite measures of total alcohol consumption may not be adequate for describing relevant changes in drinking over time. A number of factors predicted patterns of change in drinking and warrant further exploration.

Why Intelligent People Live Longer

AbstractNumerous studies find a positive relationship between cognitive ability, IQ as measured in childhood or youth, and subsequent survival. Explanations range from the idea that low ability is an indicator of adverse systemic events in early life to the idea that high cognitive functioning is required continuously to maintain health and reduce threats to survival. The Wisconsin Longitudinal Study (WLS) has followed a large cohort of Wisconsin high school seniors from ages 18 to 69. As expected, in the WLS survival varies positively with adolescent IQ. However, rank in high school class accounts completely for the relationship between IQ and survival, and it has a much larger effect on survival. These findings suggest that cognitive functioning improves survival by promoting behaviours that boost health status, minimize exposure to known risks and optimize returns to health producing inputs, and that such behaviours are firmly in place by late adolescence.

The association between IQ in adolescence and a range of health outcomes at 40 in the 1979 US National Longitudinal Study of Youth

A link between pre-morbid intelligence and all cause mortality is becoming well established, but the aetiology of the association is not understood. Less is known about links with cause specific mortality and with morbidity. The aim of this study is to examine the association between intelligence measured in adolescence and a broad range of health outcomes ascertained at 40 years of age. We use data on 7476 participants in the US National Longitudinal Survey of Youth 1979 who had their cognitive ability measured at baseline and completed the ‘Health at 40’ interview module between 1998 and 2004. The Health at 40 module includes assessments of general health and depression, nine medically diagnosed conditions, and 33 common health problems. Higher mental test scores were associated with lower depression scores, better general health, significantly lower odds of having five of the nine diagnosed conditions and 15 of the 33 health problems. A health disadvantage of higher cognitive ability was evident for only three of the 33 health problems.

Antepartum and postpartum exposure to maternal depression: different effects on different adolescent outcomes

Postpartum depression (PPD) is considered a major public health problem that conveys risk to mothers and offspring. Yet PPD typically occurs in the context of a lifelong episodic illness, and its putative effects might derive from the child's exposure to other episodes, in pregnancy or later childhood. The aim of the study is to test two hypotheses: (1) that the effects of PPD on adolescent outcomes are partly explained by antepartum depression (APD) and (2) that the effects of APD and PPD are both explained by later exposure to the mother's depression. A random sample of 178 antenatal patients was drawn from two general medical practices in South London; 171 gave birth to live infants, and 150 (88%) were assessed at 3 months post partum, with 121 of their offspring (81%) assessed for emotional disorders (ED), disruptive behaviour disorders (DBD) and IQ, at 11 and 16 years of age. When APD and subsequent episodes of depression were taken into account, PPD had a significant effect on adolescent IQ, especially for boys, but did not predict psychopathology. ED and DBD in adolescence were predicted by the extent of exposure to maternal depression after 3 months post partum; a significant effect of APD on ED in girls was accounted for by later exposure to the mother's illness. Mothers' symptoms of anxiety, smoking and alcohol use in pregnancy did not predict adolescent outcomes, once maternal depression was taken into account. Some effects attributed to mothers' mental health problems in pregnancy or post partum may be mediated by cumulative exposure to maternal illness, probably reflecting genetic influence and gene-environment correlation. However, PPD has a direct effect on cognition. Clinicians should endeavour to identify women with depression in pregnancy (31% of this sample) and help them to manage their lifelong illness.

The Role of Adolescent IQ and Gender in the Use of Cognitive Support for Remembering in Aging

ABSTRACT The purpose of this study was to examine the role of adolescent IQ (AIQ) and gender in older adults' ability to use cognitive support to enhance memory. Subjects were 269 mid-1940s graduates of the same high school. Adolescent IQ scores were gathered from archives, and subjects' memory for words was tested with tasks that provided increasing cognitive support. Overall, subjects benefited from support; women recalled more words than men; and persons with a high AIQ remembered more words than persons with a lower AIQ. However, while all subjects showed gains from cognitive support, men with a lower AIQ performed worse than men with a high AIQ. Women's performance was not dependent on their AIQ. Analysis of qualitative memory indicators suggested that women and persons with a high AIQ had better encoding and retrieval operations. Men with a lower AIQ appear to be particularly vulnerable to memory deficits in aging. This may be due to low “cognitive reserve” or generally poorer episodic memory function.

Cognitive Functioning in Healthy Aging: The Role of Reserve and Lifestyle Factors Early in Life

According to the reserve perspective on cognitive aging, individuals are born with or can develop resources that help them resist normal and disease-related cognitive changes that occur in aging. The reserve perspective is becoming more sophisticated, but gaps in knowledge persist. In the present research, we considered three understudied questions about reserve: Is reserve primarily static (unchangeable) throughout the life course or dynamic (changeable, in terms of increases or decreases)? Can reserve be increased at any point in life, or are there optimal time periods--such as early life, midlife, or late life--to increase it? Does participation in different types of leisure and occupational activities in early life and midlife have different effects depending on specific domains of late-life cognitive functioning? Here we link early cognitive and activity data--gathered from archival sources--with cognitive data from older adults to examine these issues. 349 participants, all mid-1940s graduates of the same high school, underwent telephone cognitive screening. All participants provided access to adolescent IQ scores; we determined activity levels from yearbooks. We used path analysis to evaluate the complex relationships between early life, midlife, and late-life variables. Adolescent IQ had strong direct effects on global cognitive functioning, episodic memory, verbal fluency, and processing speed. Participants' high school mental activities had direct effects on verbal fluency, but physical and social activities did not predict any cognitive measure. Education had direct effects on global cognitive functioning, episodic memory, and, most strongly, processing speed, but other midlife factors (notably, occupational demands) were not significant predictors of late-life cognition. There were weak indirect effects of adolescent IQ on global cognitive functioning, episodic memory, and processing speed, working through high school mental activities and education. Verbal fluency, in contrast, was affected by adolescent IQ through links with high school mental activities, but not education. Our study suggests that reserve is dynamic, but it is most amenable to change in early life. We conclude that an active, engaged lifestyle, emphasizing mental activity and educational pursuits in early life, can have a positive impact on cognitive functioning in late life.

Predicting School Dropout and Adolescent Sexual Behavior in Offspring of Depressed and Nondepressed Mothers

To examine predictors of school dropout and adolescent sexual behavior in offspring of depressed and nondepressed mothers. Possible moderators of the relation between maternal depression and these outcomes also were explored. Participants were 240 mothers and adolescents assessed annually from 6th through 12th grade. Interviews and questionnaires measured the chronicity and severity of the mother's depressive episodes, the mother's educational attainment, socioeconomic status, the presence of a father, the adolescent's IQ, externalizing behaviors, and substance use disorders. Substance use disorders before ninth grade significantly predicted higher rates of both school dropout and adolescent sexual behavior. Lower levels of mother's educational attainment and higher rates of adolescent's externalizing behaviors in grades 6 through 8 predicted higher school dropout. Higher IQ was associated with a lower likelihood of dropping out among offspring of never or moderately depressed mothers, but not for offspring of chronic/severely depressed mothers. Among offspring of never or moderately depressed mothers, the presence of a male head of household was associated with lower rates of adolescent sexual behavior, but not among offspring of chronically/severely depressed mothers. These findings have implications for the development of programs aimed at preventing behavior problems in high-risk adolescents.

Achievement and Ascription in Educational Attainment: Genetic and Environmental Influences on Adolescent Schooling

The classic (“status attainment”) model of educational and occupational attainment suffers from three related shortcomings when used as a tool for comparative or policy-oriented research on social mobility: (1) ambiguity of model parameters as measures of opportunity for achievement vs. ascription; (2) vulnerability to incomplete specification of family background; and (3) confounding of environmental and genetic influences. These issues can be addressed in part by using a (“behavior genetic”) model that distinguishes variance components associated with genetic endowment, shared (or common) family environment, and unshared (or specific) environment. Size of the genetic component (heritability) measures opportunity for achievement; size of the shared environment component (environmentality) measures social ascription. A multivariate behavior genetic model of adolescent verbal IQ, grade point average and college plans is estimated using data for six types of adolescent sibling pairs living in the same household: MZ twins, DZ twins, full siblings, half siblings, cousins and non-related siblings. Results show large genetic components, relatively small shared environmental components, and large unshared environmental components for all three outcomes. Parameters of the behavior genetic model can be used to compare mobility regimes across social contexts and the model therefore provides an important tool for comparative social mobility research.

Comment on IQ, Sustained Attention, and Visual Processing Speed in Children and Adolescents with Schizophrenia Spectrum Disorders

This paper is intended to lend support to the 2005 findings of McCarthy, Kraseski, Schvartz, Mercado, Daisy, Tobing, and Ryan in relation to the WISC-III performance of children and adolescents with Schizophrenia Spectrum Disorders. Relevant evidence from the literature and recent studies conducted by our group at the Institute of Psychiatry, UK, are discussed.

7: The relationship between seizure variables, demographics, IQ and social competence in adolescents with epilepsy

7: The relationship between seizure variables, demographics, IQ and social competence in adolescents with epilepsy

Paternal age and intelligence: implications for age-related genomic changes in male germ cells

A robust association between advancing paternal age and schizophrenia risk is reported, and genetic changes in the germ cells of older men are presumed to underlie the effect. If that is so, then the pathway may include effects on cognition, as those with premorbid schizophrenia are reported to have lower intelligence. There are also substantial genetic influences on intelligence, so de novo genetic events in male germ cells, which accompany advancing paternal age, may plausibly influence offspring intelligence. An association of paternal age with IQ in healthy adolescents may illuminate the mechanisms that link it to schizophrenia. We examined the association of paternal age and IQ scores using the Israeli Army Board data on 44 175 individuals from a richly described birth cohort, along with maternal age and other potential modifiers. A significant inverted U-shaped relationship was observed between paternal age and IQ scores, which was independent from a similar association of IQ scores with maternal age. These relationships were not significantly attenuated by controlling for multiple possible confounding factors, including the other parent's age, parental education, social class, sex and birth order, birth weight and birth complications. Overall, parental age accounted for approximately 2% of the total variance in IQ scores, with later paternal age lowering non-verbal IQ scores more than verbal IQ scores. We found independent effects of maternal and paternal age on offspring IQ scores. The paternal age effect may be explained by de novo mutations or abnormal methylation of paternally imprinted genes, whereas maternal age may affect fetal neurodevelopment through age-related alterations in the in-utero environment. The influence of late paternal age to modify non-verbal IQ may be related to the pathways that increase the risk for schizophrenia in the offspring of older fathers.

Sustained Attention, Visual Processing Speed, and IQ in Children and Adolescents with Schizophrenia Spectrum Disorder and Psychosis Not otherwise Specified

To investigate the cognitive functioning of children and adolescents with Schizophrenia Spectrum disorders and Psychosis Not Otherwise Specified, 22 child and adolescent psychiatric inpatients and day-hospital patients at a state psychiatric hospital with Schizophrenia Spectrum disorders, 30 with Psychosis Not Otherwise Specified, and 130 with other psychiatric disorders, ages 8 to 17 years, were administered the Wechsler Intelligence Scale for Children-III for psychological assessment at admission. The Performance IQs of the ADHD and the Conduct Disorder and Oppositional Defiant Disorder groups were significantly higher than those of the Schizophrenia Spectrum and the Psychosis Not Otherwise Specified groups, and the Full Scale IQs of the Conduct Disorder and Oppositional Defiant Disorder group were significantly higher than those of the Schizophrenia Spectrum group and the Psychosis Not Otherwise Specified group. The Coding scores of the ADHD group were significantly higher than those of the Schizophrenia Spectrum, the Psychosis Not Otherwise Specified, and the Bipolar Disorder groups. There was a significant negative correlation between age and Digit Span for the Schizophrenia Spectrum disorders group.

139 Estimate Scores of Iq in Adolescents with Low Birthweight. The Choice of Shortforms Make A Difference

139 Estimate Scores of Iq in Adolescents with Low Birthweight. The Choice of Shortforms Make A Difference

Brain structural correlates of IQ in healthy and schizophrenic adolescents

Brain structural correlates of IQ in healthy and schizophrenic adolescents

Brain anatomy, gender and IQ in children and adolescents with fragile X syndrome.

This study utilized MRI data to describe neuroanatomical morphology in children and adolescents with fragile X syndrome, the most common inherited cause of developmental disability. The syndrome provides a model for understanding how specific genetic factors can influence both neuroanatomy and cognitive capacity. Thirty-seven children and adolescents with fragile X syndrome received an MRI scan and cognitive testing. Scanning procedures and analytical strategies were identical to those reported in an earlier study of 85 typically developing children, permitting a comparison with a previously published template of normal brain development. Regression analyses indicated that there was a normative age-related decrease in grey matter and an increase in white matter. However, caudate and ventricular CSF volumes were significantly enlarged, and caudate volumes decreased with age. Rates of reduction of cortical grey matter were different for males and females. IQ scores were not significantly correlated with volumes of cortical and subcortical grey matter, and these relationships were statistically different from the correlational patterns observed in typically developing children. Children with fragile X syndrome exhibited several typical neurodevelopmental patterns. Aberrations in volumes of subcortical nuclei, gender differences in rates of cortical grey matter reduction and an absence of correlation between grey matter and cognitive performance provided indices of the deleterious effects of the fragile X mutation on the brain's structural organization.