Search PubMed⌕ Search

Biomedical subjects

M McGue

Publications and source records attributed to M McGue.

At least 37 records · Page 2Linked to original sources
PubMed2000

Strength and anthropometric measures in identical and fraternal twins: no evidence of masculinization of females with male co-twins.

Sharing of intrauterine environment in twins of opposite sex has been hypothesized to result in masculinization of the female twin. We tested this hypothesis by comparing strength (maximum hand-grip pressure) and various anthropometric measures in a newly established survey panel comprising 4,314 middle-aged twins identified through a Danish population-based twin registry. Sex- and zygosity-specific mean values of handgrip strength, height, weight, body mass index, and waist circumference were highly comparable between fraternal twins of opposite sex and fraternal twins of same sex. Our results provide no support for the hypothesis of masculinization of female twins from opposite sex twin pairs.

Anthropometry↗
PubMed2000

Association between the adrenergic alpha 2A receptor gene (ADRA2A) and measures of irritability, hostility, impulsivity and memory in normal subjects.

The noradrenergic system has been implicated in arousal, vigilance, irritability hostility, and memory. This suggests the hypothesis that genetic variants at noradrenergic receptors may be risk factors of these behaviors. To test this hypothesis, the potential association between measures of these traits and genetic variation at the adrenergic2A receptor gene (ADRA2A), using a common single nucleotide polymorphism (SNP) polymorphism of the promoter region, were examined in two independent sets of subjects: university students (student group), and parents of twins in the Minnesota Twin Study (twin group). In the student group, there was a significant linear association by genotype (11 > 12 > 22) for the total Brown ADD score (BADD), and BADD subscores of memory and irritability, and with the total Buss-Durkee Hostility Inventory (BDHI) score and BDHI subscores of indirect hostility, irritability, negativity, and verbal aggression. A multiple analysis of variance (MANOVA) of all the BADD and BDHI subscores was significant at P < or = 0.009. For the twin group, the same genotype associations were significant for the Multidimensional Personality Questionnaire (MPQ) impulsivity scores but not for the MPQ aggression or harm avoidance scores. The ADRA2A gene accounted for 1.8-8.3% of the variance of these scores.

Adult↗
PubMed2000

A behavioral genetic analysis of the relationship between the socialization scale and self-reported delinquency.

This investigation examined the genetic (A), and shared (C) and nonshared (E) environmental variance contributions to the relationship of self-reported delinquency (as measured by the "Delinquent Behavior Inventory" [DBI; Gibson, 1967]) to the Socialization (So) scale of the California Psychological Inventory using univariate and bivariate structural equation models. The scales were administered to 222 male (145 monozygotic; 77 dizygotic) and 159 female (107 monozygotic; 52 dizygotic) 16- to 18-year-old same-sex twin pairs. Principal components analysis with varimax rotation revealed three interpretable So factors representing family/home environment, self-concept, and behavioral control. Univariate modeling suggested sex differences in etiological influences associated with individual differences in most scales. The bivariate ACE model fit the data, suggesting that the covariance between the So scale and self-reported delinquency owes in part to shared etiological factors.

Adolescent↗
PubMed2000

Sex differences, assortative mating, and cultural transmission effects on adolescent delinquency: a twin family study.

The twin study literature contains inconsistencies regarding both the estimates of genetic, shared, and nonshared environmental influence on delinquency and sex differences in the etiological influences on delinquency. Additionally, little is known about assortative mating and cultural transmission effects on delinquency. The present study was aimed at examining the etiology of delinquency in adolescence and examining assortative mating and transmission effects. To this end, we applied the social homogamy structural equation model to self-reported delinquency data from 486 families with 17-year-old male and female twins. We expected stronger shared environmental influences on delinquency among girls than boys and stronger environmental than genetic effects on adolescent delinquency in general. The results indicated nonsignificant sex differences in the estimates of genetic and environmental influences on delinquency. The best-fitting model suggested that 18 %, 56 %, and 26% of the variance in delinquency among both boys and girls is associated with additive genetic, nonshared environmental, and shared environmental factors, respectively. This finding was consistent with our expectation that environmental factors play an important role in adolescent delinquency. Parental cultural effects accounted for a small part of the transmission of delinquency within families while assortative mating was, in part, accounted for by cultural and social background factors. Future work should focus on identifying important environmental factors related to delinquency.

Adolescent↗
PubMed2000

Age differences in genetic and environmental influences on eating attitudes and behaviors in preadolescent and adolescent female twins.

A sample of 680 11- and 602 17-year-old female twins was used to examine (a) age differences in genetic and environmental influences on disordered eating attitudes and behaviors and (b) associations between body mass index (BMI) and eating attitudes and behaviors. Univariate, biometrical model-fitting analyses indicated that 11-year-old twins exhibited less genetic and greater shared environmental influence on eating attitudes and behaviors than 17-year-old twins. Bivariate model-fitting analyses indicated that the relationship between BMI and eating attitudes was mediated primarily by common shared environmental influences in 11-year-old twins and common genetic influences in 17-year-old twins. Nonetheless, the majority of genetic influences on eating attitudes and behaviors in older twins were due to genetic effects that are independent of those operating in BMI.

Adolescent↗
PubMed1999

Behavioral disinhibition and the development of substance-use disorders: findings from the Minnesota Twin Family Study.

One variant of substance-use disorder is characterized by behavioral disinhibition. In this report, we martial evidence for a model for the development of this variant. We hypothesize that genetic liability for this variant is reflected in a spectrum of risk indicators linked to the inability or unwillingness to inhibit behavioral impulses. Included in this spectrum are personality traits suggesting low constraint, and externalizing psychopathology, including conduct, oppositional defiant, and attention-deficit disorder in children and antisocial personality disorder and behavior in adults. We further hypothesize that these individual differences in behavioral disinhibition are manifestations of underlying central nervous system processes associated with various psychophysiological anomalies, some of which may index genetic risk for substance abuse. Support for the model is derived from the analysis of findings from the Minnesota Twin Family Study, an epidemiological investigation of approximately 2,700 adolescent twins and their parents.

Adolescent↗
PubMed1999

Searching for interactive effects in the etiology of early-onset substance use.

This study sought to expand the modest literature investigating gene x environment interactions in the prediction of substance use. Our sample consisted of 591 male twins from the Minnesota Twin Family Study. Their relative genetic risk was estimated from their parents' substance-related diagnoses and their environmental risk from their affiliations at age 11 with social groups likely to either encourage or discourage substance use. At age 14, the boys' own substance use was assessed. We hypothesized both main effects and an interaction between our genetic- and environmental-risk variables in the prediction of substance use by this young age. We further theorized that the boys' inherited risk might take the form of temperament, specifically externalizing tendencies. Using regression analyses and biometrical modeling, we corroborated earlier research by finding evidence for a significant interactive effect in the etiology of substance use. Our results suggest that low levels of environmental risk may buffer against the potentially unfavorable effects of high familial risk; however, when environmental risk is high, the degree of familial risk is consequential. We were not able to support our second hypothesis; rather, temperament predicted substance use only through shared environmental factors.

Adolescent↗
PubMed1999

Personality and substance use disorders: II. Alcoholism versus drug use disorders.

The relationship between personality and substance use disorders was investigated in a community-based sample of 638 individuals who were alcoholic and/or had a drug use disorder, and 1,530 individuals who did not have a substance use disorder. Personality was assessed by the Multidimensional Personality Questionnaire; substance use diagnoses were based on standard criteria as assessed by interview. Data were analyzed using a 3-factor (Gender x Alcoholism x Drug Use Disorder) multivariate analysis of variance. The significant alcoholism main effect was associated primarily with negative emotionality, whereas the significant drug use disorder main effect was associated primarily with constraint. No significant interactions with gender were observed. These findings suggest that the elevated levels of behavioral disinhibition observed with alcoholic individuals may be attributable to a subset of alcoholic individuals who also abuse drugs other than alcohol.

Adult↗
PubMed1999

Effects of ADHD, conduct disorder, and gender on substance use and abuse in adolescence.

OBJECTIVE: The relationships of attention deficit hyperactivity disorder (ADHD), conduct disorder, and gender to substance abuse were studied in a large population-based sample of adolescent twins. METHOD: Structured interviews were administered to 626 pairs of 17-year-old twins (674 girls and 578 boys) and their mothers to generate lifetime psychiatric diagnoses, and computerized measures of current substance use were obtained. Hierarchical logit analyses were performed to assess the independent effects of ADHD, conduct disorder, and gender on current substance use, frequency of substance use, and DSM-III-R diagnoses of substance use disorders. RESULTS: Conduct disorder was found to increase the risk of substance use and abuse in adolescents regardless of gender. In contrast, independent of its association with conduct disorder, an ADHD diagnosis did not significantly increase the risk of substance use problems. CONCLUSIONS: This study found no significant gender differences in the effects of ADHD and conduct disorder on substance use and abuse, although there was some suggestion that girls with ADHD might be at slightly higher risk than boys for substance abuse. In addition, increased risk of substance abuse among adolescents with conduct disorder may be primarily confined to those with persistent conduct disorder.

Adolescent↗
PubMed1999

A Danish population-based twin study on general health in the elderly.

OBJECTIVES: To study the relative influence of genetic and environmental factors on self-rated health and hospitalization patterns in the elderly. METHODS: A survey among all 3,099 Danish twins ages 75 years and older identified in the Danish Twin Registry. An interview was conducted with 77% of the twins. The number of hospitalizations in the previous 18 years was obtained through register linkage, thereby obtaining health information on 96% of the study population, including all nonresponders. RESULTS: Structural equation modeling suggested that approximately a quarter of the variation in the liability to self-reported health and the number of hospitalizations could be attributed to genetic factors. The remaining variation was most likely due to nonfamilial environment. Analyses of the hospitalization patterns of proxy responders and nonresponders suggest that the estimates of the genetic influence on health outcomes in the study are conservative. DISCUSSION: The present study indicates that variation in general health among the elderly is partly explained by genetic factors.

Aged↗
PubMed1999

Intrinsic and extrinsic religiousness: genetic and environmental influences and personality correlates.

This report presents findings for the Intrinsic (IR) and Extrinsic (ER) religiousness scales from the Minnesota Study of Twins Reared Apart. The scales were shown to be internally consistent, sufficiently distinct from the scales of the California Psychological Inventory and the Multidimensional Personality Questionnaire and unrelated to a number of measures of response style to justify treating them as distinct traits. The I scales also showed considerable evidence of construct validity in its correlations with religious fundamentalism and authoritarianism as assessed by the MMPI and Altemeyer's Right-Wing Authoritarianism scale. Data on IR and ER from 35 pairs of monozygotic twins reared apart (MZA) and 37 pairs of dizygotic twins reared apart (DZA) were fitted to a biometric model and demonstrated significant heritability (0.43 and 0.39), with a model containing genetic plus environmental factors fitting significantly better than a model containing only an environmental component. Twin similarity could not be explained by placement on a self-reported measure of family Moral Religious Emphasis as measured by the Family Environment Scale.

Adult↗
PubMed1999

Individual differences in electrodermal responsivity to predictable aversive stimuli and substance dependence.

To determine if the inability to take advantage of the predictability of an aversive stimulus to diminish its psychological impact reflects a deficit in inhibitory control related to the development of substance dependence, we recorded skin conductance responses (SCRs), heart rate (HR), and anticipatory electrodermal nonspecific fluctuations (NSFs) from 175 16-18-year-old boys when a white noise blast was either unpredictable or temporally predictable. Compared with boys who had moderately reduced or augmented SCRs to predictable blasts (moderate and poor modulators, respectively), boys whose SCRs were greatly reduced (good modulators) had fewer symptoms of alcohol and nicotine dependence and more anticipatory NSFs. HR appeared to index an active coping response for good and moderate modulators. The autonomic response pattern evident for good modulators may index an inhibitory control mechanism protecting them from developing substance dependence.

Acoustic Stimulation↗
PubMed1999

A twin study of state and trait anxiety in childhood and adolescence.

Little research has addressed the relative influence of genetic and environmental factors on subclinical levels of anxiety in children. Of the two twin studies to date, one concluded that measures of adolescents' self-reported trait anxiety were best explained by shared environmental factors (Thapar & McGuffin, 1995), while the second determined that approximately half the variance was attributable to genetic effects (Topolski et al., 1997). The present study, using a sample of 547 twin pairs, reached conclusions similar to those of Topolski et al. Heritability was estimated at 45%. Measures of state anxiety conformed more closely to Thapar and McGuffin's findings, with environmental factors accounting for the variance.

Adolescent↗
PubMed1998

Genetic analysis of diagnostic systems of alcoholism in males.

BACKGROUND: Research into genes involved in alcoholism could benefit from use of diagnostic systems most sensitive to detecting genetic influences. In this study, heritable influences were estimated in a single twin sample with commonly used criteria for alcoholism. METHODS: Male twin probands ascertained through alcohol and drug abuse treatment programs and their same-sex cotwins (54 monozygotic and 65 dizygotic pairs) were diagnosed independently by DSM-III (alcohol dependence and alcohol abuse and/or dependence), Feighner (probable and definite alcoholism), and Cloninger (type 1 and type 2 alcoholism) systems. Using univariate structural equation modeling, heritability was estimated for each diagnostic system. RESULTS: The highest heritability estimates were obtained for Feighner probable alcoholism (h2 = .63), Cloninger type 2 alcoholism (h2 = .54), and DSM-III alcohol dependence (h2 = .52). CONCLUSIONS: Certain diagnostic systems appear to have greater sensitivity for detecting genetic influence and may therefore be more appropriate for use in molecular genetic studies attempting to find genes for alcoholism.

Adolescent↗
PubMed1998

The structure of self-concept in female preadolescent twins: a behavioral genetic approach.

Two hundred and forty-three female monozygotic (MZ) and 164 female dizygotic (DZ) twin pairs, aged 11 and 12 years, who participated in the ongoing Minnesota Twin Family Study, completed six specific scales of the Piers-Harris Children's Self-Concept Scale (P-H). Model-fitting analyses yielded three major conclusions. First, approximately 30% of the variance in specific self-concepts in female preadolescents was due to genetic factors, with the remaining variance being accounted for primarily by nonshared environmental factors and measurement error. Second, the underlying common genetic, shared environmental, and nonshared environmental factors influenced specific facets of self-concept directly and independently, rather than through an intervening phenotypic general self-concept. Finally, whereas genetic, shared environmental, and nonshared environmental factors were necessary to explain the commonality among the specific self-concept scales, only genetic and nonshared environmental factors were sufficient to explain the specificity of those scales.

Analysis of Variance↗
PubMed1998

Genetic and environmental influences on human behavioral differences.

Human behavioral genetic research aimed at characterizing the existence and nature of genetic and environmental influences on individual differences in cognitive ability, personality and interests, and psychopathology is reviewed. Twin and adoption studies indicate that most behavioral characteristics are heritable. Nonetheless, efforts to identify the genes influencing behavior have produced a limited number of confirmed linkages or associations. Behavioral genetic research also documents the importance of environmental factors, but contrary to the expectations of many behavioral scientists, the relevant environmental factors appear to be those that are not shared by reared together relatives. The observation of genotype-environment correlational processes and the hypothesized existence of genotype-environment interaction effects serve to distinguish behavioral traits from the medical and physiological phenotypes studied by human geneticists. Behavioral genetic research supports the heritability, not the genetic determination, of behavior.

Behavior↗
PubMed1998

Age differences in the nature and origin of individual differences in memory: a behavior genetic analysis.

Measures of memory performance and cognitive and lifestyle variables were obtained from 147 younger twin pairs (27 to 60 years) and 194 older twin pairs (60 to 94 years) as part of the Minnesota Twin Study of Adult Development and Aging. Correlational and behavior genetic analyses were combined to investigate age differences in 1) the relationship between memory performance and cognitive and lifestyle variables, 2) genetic and environmental influences on memory performance, and 3) genetic and environmental mediation of the relationship between memory and predictor variables. No age differences in heritability were found. Qualitative age differences in memory processes were suggested by age group differences in the correlations between memory and cognitive factors. Even though age differences in phenotypic correlations had been demonstrated, no age differences in the genetic and environmental mediation of the correlations were found. In other words, the magnitude of the correlation between memory and cognitive factors varied across age groups but the nature of the relationship did not.

Adult↗