Arpana Agrawal1,3, Michael C. Neale1,2,3, Carol A.
Prescott2,3, and Kenneth S. Kendler1,2,3. The influence of early
onset cannabis use on use and abuse/dependence of other illicit drugs:
discordant twin design versus a model-fitting method.
1Department of Human Genetics, Virginia Commonwealth University,
Richmond, VA, 2Department of Psychiatry, Medical College of
Virginia, Virginia Commonwealth University, Richmond, VA, 3Virginia
Institute of Psychiatric and Behavior Genetics, Virginia Commonwealth University,
Richmond, VA
Address: Virginia Institute
of Psychiatric and Behavior Genetics,
Following-up a recent report (M. T. Lynskey,
A.C. Heath, K.K. Bucholz, W.S. Slutske,
P.A. Madden, E.C. Nelson, D.J. Statham, and N.G. Martin, 2003, JAMA, 289(4), 427-33), we used the
discordant twin design to analyze the influence of early onset of cannabis use
on use and abuse/dependence of other illicit drugs. Twins who used cannabis before
the age of 18 years versus non-user co-twins had odds ratios of 2.0-7.5 for
using other illicit drugs. However, the
discordant twin design does not utilize all the available data and has limited
ability to examine the genetic etiology of the relationship between cannabis and
other illicit drug use. Using 1191 male and 934 female same sex twin pairs from
the Mid-Atlantic Twin Registry (K.S. Kendler and,
C.A. Prescott, 1999, Arch. Gen.
Psychiatry, 56, 39-44), we fit three models to our data (M.C. Neale and, Kenneth S. Kendler, 1995,
Am. J. Hum. Genet., 57, 935-953). The correlated liabilities
model most suitably explained the data with a very high correlation of 0.91
between the genetic factors influencing early use of cannabis and other illicit
drug use. A model that only allowed for specific environmental influences to be
correlated (re=0.87) fit poorly. Also, a genetic model of the
gateway hypothesis was not supported. The relationship between early cannabis and
other illicit drug use does not appear to be due to causation at the phenotypic
level (A. Golub and, B.D. Johnson, 1994, J. Stud. Alcohol, 55(5), 607-14) but due
to correlations between factors that influence the individual liabilities.
Thus, prevention of cannabis use may not be successful in curbing use of other
illicit drugs.
Maricela Alarcón1, Rita M. Cantor2, Jussi
Niemi3, Mari Qvarnstrom4, Markku
Ryynanen5, Taisto Leppasaari4, Aarno Palotie2, and Daniel H. Geschwind1. Genomewide scan in Finnish families with dyslexia/dysphasia.
1Department of Neurology, University of
California, Los Angeles CA, 2Department of Human Genetics, University of
California, Los Angeles CA, 3Department of Linguistics, University
of Joensuu, Joensuu,
Finland, 4Department of Otolaryngology, Kuopio
University Hospital, Kuopio, Finland, 5Department
of Obstetrics and Gynecology, University of Oulu, Oulu, Finland
Address: UCLA
Department of Neurology, 710 Westwood Plaza 1-145,
Dyslexia affects approximately 5 to 10% of the population in
the
Juko Ando1 and Yutaka Ono2. Genetic structure of Cloninger's seven factor model revisited.3
1Faculty of Letters, Keio University, Mita
Tokyo, 2Health Center, Keio University, Yokohama Kanagawa, 3Supported
by a Grant-in Aid for Scientific Research(A)from the Ministry of Education,
Science, Sports and Culture
Address: Faculty of
Letters,
Ando et al. (2001, Journal
of Personality, 70,584-609) investigated the genetic structure of R. Cloninger's seven factor model of personality with 296
pairs of Japanese twins with TCI (Cloninger et al.
1993) and revealed that three temperamental dimensions (novelty seeking: NS,
harm avoidance: HA, reward dependence; RD) are genetiucally
independent. The current study is its
replication with larger sample (513 pairs : 330 pairs
of MZs , 116 pairs of same sex DZ, 67 pairs of
opposite sex twins). Univariate
analysis shows that AE model is the best fir for all the dimensions but
self-directedness(SD) and additive genetic contributions are 21% for NS, 45%
for HA, 39% for RD, 34% for PS (persistence) 46% for CO (cooperativeness) and
48% for ST (self-transcendence ). SD can be explained either AE or CE model. Multivariate
analyis by Cholesky decomposition
indicates again that genetic latent factors for three temperamental dimentions are independent.
Andrey P. Anokhin1, Angela Ralano1, and
1Department of Psychiatry , Washington University School of Medicine, St.Louis, MO, 2Supported by grants DA00421-02 from the NIH and CRTG-00-300-01-PBP from the American Cancer society
Address:
Prepulse inhibition (PPI) is a suppression of the startle reflex that occurs when intense startle startling stimulus is preceded by a weaker “prepulse” stimulus. PPI is viewed as an index of sensorimotor gating, a fundamental process of sensory input regulation. PPI deficits have been implicated in the biological bases of schizophrenia and some other neuropsychiatric conditions including substance use disorders and proposed as a possible biological marker ("endophenotype") for genetic studies. However, little is known about the genetic determination of PPI in humans. Accordingly, the purpose of this study was to estimate heritability of PPI in normal human subjects. PPI of acoustic eyeblink startle reflex was assessed in 170 young adult female twins (49 MZ and 36 DZ pairs). Response magnitude was measured as square root of the area under the curve of a rectified, averaged, and smoothed orbicularis oculi EMG signal in the time window of 20-120 ms after stimulus onset. Twin intrapair correlations were significant in MZ (r=0.52, P<0.01), but not in DZ twins (r=0.14, n.s.). Genetic analysis using structural equation modeling showed significant heritability of PPI, suggesting that about 50% of the PPI variance is determined by genetic factors.
Andrey Anokhin1 and Angela Ralano1.
1Department of Psychiatry, Washington University School of Medicine,
St.Louis, MO, 2Supported by grants
DA00421-02 and 5P50 AA11998-03 from the NIH
Address:
Wisconsin Card Sorting Test (WCST) is one of the most widely used assessments
of executive functioning related to prefrontal cortex. Performance on the WCST has been suggested to
indicate familial vulnerability to psychiatric disorders characterized by
executive deficits, such as schizophrenia. However, little is known about
genetic and environmental determinants of individual differences in WCST
performance in the general population. A previous study based on a very small
twin sample did not find significant genetic influences (A. Campana,
F. Macciardi, O. Gambini,
S. Scarone S., 1996, Neuropsychobiology 34, 14-17). The present study assessed heritability of
standard WCST scores in a sample of 166 young female twins including 58 MZ and
25 DZ pairs. A computer-administered version of WCST was used. Several WSCT
indices including total number and percent of errors, and the number of perseverative responses showed modest, but significant
heritability ranging from 37 to 46 %, whereas other indices such as the number
of categories completed and failure to maintain set did not show evidence for
genetic influences. The results suggest that selected aspects of executive functioning
measured by the WCST are moderately influenced by genetic factors.
Jessica H. Baker1,
Kyle L. Gobrogge2, and Kelly L. Klump. A Twin Study of Similarities in Self and Co-twin Reports of
Personality.
1Department of Psychology, Michigan State University, East Lansing,
MI, 2Supported by NIH Grant MH 65447
Address: 129 Psychology
Research Building East Lansing, MI 48824 Phone:517 432
9861 Email: klump@msu.edu
Objective: Several studies
have examined the agreement between self and informant ratings of personality
(Ready 2002; Ready & Clark 2002; Hill et al., 1995; Harkness
et al., 1995). However, few studies have
examined the relative influence of genetic factors on similarities of self and
informant reports of personality. Thus,
the purpose of the current study was to examine genetic and environmental
influences on these reports in male and female twins. Method:
Subjects included 228 MZ and 58 DZ male and female twins participating
in the Michigan State Twin Study.
Personality was measured with the Neuroticism, Extraversion, and
Openness to Experience Personality Inventory Revised (NEO-PI-R) (Costa &
McCrae, 1985). Twins completed two
versions of this instrument, the first asking them to rate themselves, and the
second asking them to rate their co-twin. Biometric model fitting analyses were
used to examine genetic and environmental influences on similarities between
self and informant reports. Results: Model-fitting analyses indicated significant
additive genetic and non-shared environmental influences on most of the
NEO-PI-R subscales. Discussion: Findings suggest greater similarity between
self and co-twin reports of personality in MZ relative to DZ twin pairs that
can be accounted for by genetic and nonshared
environmental factors.
Bojan Basrak.
Copulas in QTL mapping.
Eurandom,
Address: Eurandom (TUE),
Detecting linkage of a marker to a quantitative trait locus (QTL)
in human genetics essentially means detecting a connection between genetic
similarity and similarity of phenotypes. The first similarity is typically
measured using the identity by descent (IBD) status and the second one by the
notion of linear correlation. This also holds for the two most popular methods--the
Haseman-Elston regression method and the variance
components likelihood-ratio test. It is well known that the correlation
coefficient is the most natural measure of stochastic dependence (similarity)
in the world of multivariate normal distributions, but it can be less suitable
when the normality assumption is not met. In practical linkage analysis this
means that the methods that are derived on the basis of normality have to be
used with a great care when this assumption is violated. Not surprisingly, this
problem has attracted a lot of attention recently, see
for instance J. Blangero, J.T. Williams, and L. Almasy, 2000, Genet. Epidemiol.
19, S8-S14 or P.C. Sham, J.H. Zhao, S.S. Cherny,
and J.K. Hewitt, 2000, Genet. Epidemiol. 19, S22-S28. The most general way of expressing
statistical dependence between variables is via copulas. We show how this well
established statistical tool can be applied in QTL linkage analysis with a
little extra effort and potentially many benefits. One particular copula,
namely the bivariate normal copula is discussed in
more detail. In particular, we demonstrate how a statistical analysis based on
the normal copula model deals with problems of non-normality that appear in
many practical studies. Finally we demonstrate applicability and usefulness of
this approach by simulation studies.
Daniel M. Blonigen1,
Brian M. Hicks1, Robert F. Krueger1, Christopher J.
Patrick1, William G. Iacono1, and Matt McGue1. Psychopathic Personality
Traits & Externalizing Psychopathology: Etiologic Connections.
1Department of Psychology,
Address: Department of
Psychology 75 East River Rd. University of Minnesota,
Psychopathic Personality (psychopathy)
is defined as a constellation of interpersonal, affective, and behavioral
features. Our recent factor analytic work with the Psychopathic Personality
Inventory (PPI), a self-report psychopathy measure for
non-incarcerated populations, has shown that it is represented by two
orthogonal factors. The first factor (PPI-I) is related to social dominance and
stress immunity, core features of the affective/interpersonal dimension of psychopathy. The second factor (PPI-II) is marked by
negative emotionality and low constraint, and is strongly related to a
dimension of externalizing psychopathology, defined as the covariance among
child and adult antisocial behavior symptoms, alcohol and drug dependence, and disinhibitory personality traits (R. F. Krueger, B. M.
Hicks, C. J. Patrick, S. R. Carlson, W.G. Iacono, and
M. McGue, 2002, Journal
of Abnormal Psychology 111, 411 - 424).
Although the two factors exhibit distinct relations with personality and
behavioral measures, it is not clear if they are etiologically distinct as well.
In this study we conducted a biometric analysis of the relationship between psychopathy and externalizing in a sample of male and
female twins from the Minnesota Twin Family Study. The Multidimensional
Personality Questionnaire was used to index the two PPI factors, and an
externalizing factor was derived from a principal components analysis of
symptom counts of child and adult antisocial behavior, and alcohol, drug, and
nicotine dependence. We performed a Cholesky
decomposition of the PPI factor scores and externalizing to index the amount of
shared variance among the observed phenotypes that is determined by genetic or
environmental contributions. Ultimately,
the results will address the question of whether or not the two phenotypically distinct dimensions of psychopathy
are preferentially linked to the externalizing dimension at an etiologic level.
Stefan M. Brudzynski. Quantitative
parameters of the ultrasonic communication in rats.1
Department of Psychology and Centre for Neuroscience,
Address: Department of
Psychology,
There is ample evidence that ultrasonic calls emitted by rats are
used for intraspecies communication, which plays an
adaptive role in improving chances of individual and group
survival. Ultrasonic calls are emitted
in biologically significant situations and they have acoustic features, which
are not only specifically recognized by the recipients but also contain a
quantitative dimension reflecting the magnitude of the emitter's response. The
goal of the presentation is to review the features of the ultrasonic calls in
search of the acoustic parameters, which could reflect the quantitative aspect
of the rat vocal communication in addition to the commonly recorded rate of
calling. Isolation calls of rat pups have a variable sound frequency and call
duration, and have changing sonographic structure
over time. It has been concluded that the "message" is encoded in one
or more of the alternative sweeps of frequency, which facilitate attending and
retrieval of the pup by the dam. Isolation calls are replaced with age by two
other ultrasonic call patterns. The, so called 22-kHz calls, or alarm calls,
are emitted predominantly in agonistic and other aversive situations. They are
characterized by a relatively constant sound frequency,
and remarkable variability in the duration of single calls. This variability
and the results of pharmacological studies suggest that the quantitative aspect
in the vocal expression of these calls seems to be encoded in the length of
individual calls. Finally, the 50-kHz calls have
been reported in positive, non-agonistic behavioural
situations. They are characterized by a very short and
relatively constant single call duration, and by a variable sound frequency.
Results of the pharmacological studies and the variability of sound frequency
suggest that the peak sound frequency is likely to reflect the quantitative
aspect in the vocal expression in this type of calls.
Susan A. Brunelli. Selective
breeding for an infantile phenotype (rat pup ultrasonic vocalizations): A
window on developmental processes.1,2
Department of Developmental Psychobiology, New York State
Psychiatric Institute & Columbia University, New York NY, 1Supported
by NIMH Grant MH40430, 2Supported by NIMH Grant MH54027
Address:
A series of studies posed two questions: (1) How generations of
selective breeding of rats for high (High USV line) or low (Low USV line)
levels of USV responses at 10 days of age may affect the time course of USV
response development over the postnatal period; and (2) How the development of
other behavioral and psychological traits may have been altered over the same
period in association with changes in the selected trait. Longitudinal and cross-sectional studies of
rat pups from litters of High, Low and Random lines were conducted in which two
cohorts of litters were tested: one at
3, 10 and 18 days postnatal age, and the second at 7, 14 and 21 days. In addition to the USV response to two minute
isolation tests, other isolation-induced behaviors, physical markers of
maturation and measures of thermoregulation were studied. The results support
the idea that the developmental trajectories of High and Low lines have been
altered differently, i.e., the two lines are not mirror images, and
developmental paths are independent of each other.
Tanya Button1,
Anita Thapar2, and Peter McGuffin1. Maternal smoking during
pregnancy and antisocial outcomes in young people.3
1Social, Genetic and Developmental Psychiatry Research Centre, Institute
of Psychiatry, King's College London, 2Department of Psychological
Medicine, University of Wales College of Medicine, 3Supported by MRC
PhD Scholarship
Address: PO 80, Social,
Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry,
King's College London, De Crespigny Park, London, SE5
8AF Phone: +44 (0) 20 7848 0629 Fax: +44 (0) 20 7848 0575 Email: t.button@iop.kcl.ac.uk
Maternal smoking during pregnancy is associated with conduct
problems in young people. One possible explanation for this association is the
effects of the cigarettes on the brain of the developing fetus, and there is evidence
that nicotine exposure affects brain development. An alternative explanation is
that smoking during pregnancy is an index of maternal antisocial behavior, and
offspring conduct problems may result from genetic transmission for the propensity
to antisocial behavior. This study
examines the relationship between maternal prenatal smoking and antisocial
behavior using data from 1896 twins pairs from the
Greater Manchester and Lancashire Twin Registry. Twins behavior and mothers prenatal
smoking habits were analysed using structural
equation modelling.
Two models were fitted. In the first it was assumed that maternal
smoking had a direct environmental effect (the environmental mediation model), whilst
in the second it was assumed that the correlation between conduct disorder and
maternal smoking was mediated via the mothers' genotype (the genetic mediation
model). The results confirmed that
adolescents whose mother smoked during pregnancy scored significantly higher
for antisocial behavior than those whose mothers were non-smokers. This
increased with the number of cigarettes smoked daily. The genetic mediation
model was a slightly better fit than the environmental model calling into
question the frequent assumption that the effects of maternal smoking on later
antisocial behavior in offspring result from direct toxic effects on the
developing fetus.
Michèle Carlier1,2, Charles Cohen-Salmon1,3, Chabane Chérif1, Fatima Marouf
Verray1, Paricia Arechi1, Fabienne Godin1, Franz Sluyter1,4, Brice
Marcet5, Bernard Verrier5, and Pierre L. Roubertoux1,6. Development of congenic
strains for mitochondrial DNA in mice. Implication of mtDNA in pre-weaning development and motor behavior.
1CNRS Génétique
Address: Centre de recherche en Psychologie de la
Cognition, du Langage et de l’Émotion (PsyCLÉ EA 3273), Université de Provence, 29 avenue Robert Schuman,
13624 Aix en
Mammalian mitochondrial (mt) genome that
encodes 13 subunits and specifies 22 tRNAs
and 2 rRNAs is exclusively maternally transmitted.
The implication of the 13 proteins in respiratory chain and ATP synthase has been demonstrated. Their possible impact on
cognitive or other behavioral processes has been previously suspected. As the
number of mtDNA molecules is large per one somatic cell (more than 1,000) the
gene targeting strategy cannot be used to address the implication of mtDNA
genes in cognition. For this reason, we developed congenic
strains for mtDNA. We selected NZB/BlN and CBA/H mice
that carry mtDNA from different origins. We present here the development of this
quartet of congenic strains, controls for mtDNA cross-transfer
and for the isogenicity of the nuclear background. mtDNA modulates
motor development as soon as the pre-weaning period in interaction with nuclear
DNA. This effect persist in adults and an interaction between mtDNA, nuclear
DNA and age is observed for a wide set of motor measurements.
Penny L. Biersach Clark, Carol A. Van Hulle,
Erri Hewitt, and H. Hill
Goldsmith1. Exploring the genetic architecture of social
and non-social fear in infancy.2
1Department of Psychology,
Address: Department of
Psychology,
Many researchers have examined the development of fear in infancy.
The majority of this research has focused on social fear, which has been shown
to be moderately heritable. Additionally, genetic influences account for the
largest portion of the covariation in parent-report
and observed measures of social fear (Goldsmith et al., 1999, Developmental Psychology 35(4),
972-985). Fewer studies have examined the development of non-social fear in
infancy. Recent research suggests social and non-social fear are differentially
related to vulnerabilities for disruption in emotion regulation (Locke&
Goldsmith, 2002, poster presented at ICIS,
R. P. Corley1,
S. E. Young1, M. C. Stallings1, J. K. Hewitt1, A.
Smolen1, and D. Huizinga2. Sibling resemblance for adolescent problem
behavior: National Youth Survey and CADD.3
1Institute for Behavioral Genetics, University of Colorado, Boulder,
CO, 2Institute of Behavioral Science, University of Colorado, Boulder,
CO, 3Supported by grants DA-05131 and DA-11015, HD-10333, MH-43899,
and AA-11949
Address: Institute for
Behavioral Genetics, Campus
The National Youth Survey (D. S. Elliott, D. Huizinga,
and S. Menard, 1989, Multiple Problem
Youth: Delinquency, Drugs and Mental Health Problems.
Danielle M. Dick1,
Richard J. Viken1, Jaakko Kaprio2,
Lea Pulkkinen3, & Richard J. Rose1. Parents: The
Anti-Drug? Clarifying the role of
parental influence on adolescent smoking and drinking using data from
FinnTwin12.4
1Department of Psychology, Indiana University, Bloomington IN, 2Department
of Public Health, University of Helsinki, FINLAND, 3Department of
Psychology, University of Jyvaskyla, FINLAND, 4FinnTwin12
is supported by NIH (AA 12502), and by the Academy of Finland.
Address: Department of
Medical and Molecular Genetics, Indiana University School of Medicine,
In 1998, the White House Office of National Drug Control Policy
launched the National Youth Anti-Drug Media Campaign, an initiative that has
emphasized the role parents can play in preventing their adolescents from using
drugs. We sought to better clarify the
influence of parents on their adolescents' substance use using data from a
longitudinal twin-family study on the development of smoking and drinking
patterns across adolescence. The sample
for this study, FinnTwin12, consists of five consecutive birth cohorts of
Finnish twins, born 1983-1987. Twins
were assessed with questionnaires at ages 11-12 and reported on several aspects
of their relationship with their parents, such as the amount of time spent
engaged in activities with their parents, and the degree to which their parents
monitor their behavior. The twins were
reassessed at age 14, at which time they reported on their use of cigarettes
and alcohol. Nearly all measures of
parental relations at age 12 predicted smoking and drinking behavior at age
14: children who spent more time with
their parents, reported more parental monitoring and a better home atmosphere
were less likely to be smoking or drinking at age 14. However, twins' reports of parenting were
under a modest degree of genetic influence, as were their substance use
patterns at age 14. Therefore, to
clarify the role of genetic and environmental influences on the relationship
between parenting and substance use, we fit bivariate
models to reported parental supervision and smoking/alcohol use. For all measures of parenting and substance
use, shared genetic influence could be dropped from the model. This suggests that the association between
perceived parenting and substance use is not confounded by a shared genetic
liability. Genetically informative twin
designs provide a useful method for differentiating these developmental
influences.
Brian D_Onofrio1,
Eric Turkheimer1, Robert Emery1, Jane Mendle1, Stacy Lynch1,
Wendy Slutske2, Andrew
Heath3, Nick Martin4. Association Between Parental Divorce and Offspring Life Transitions: Selection or Causation?
1Department of Psychology, University of Virginia, Charlottesville,
VA, 2Department of Psychological Science, University of Missouri,
Columbia, MO, 3Department of Psychiatry, Washington University, St.
Louis, MO, 4Genetic Epidemiology Section, Queensland Institute of
Medical Research,
Address: Psychology
Department, University of Virginia, 102 Gilmer Hall, PO Box 400400,
Charlottesville, VA 22904-4400, Phone: 804-982-4750, Email: briand@virginia.edu
Previous research has shown that children of divorced parents are
more likely to initiate harmful behaviors at younger ages and engage in
untraditional family transitions than children from intact households. However, the causes underlying these
associations are unclear. Genetically
informed designs, including the Children of Twins design, help delineate the
possible genetic and environmental processes that account for the association
between parental characteristics and child outcomes. In order to disentangle
the relation between parental divorce and life transitions in the offspring, a
longitudinal study of twins and their adult children was utilized. The sample
included 2,554 offspring from 889 twin pairs from the Australian Twin Registry.
Results indicated that children from divorced families started to use alcohol,
drink heavily, smoke cigarettes, try marijuana, and engage in sexual
intercourse at earlier ages than children from intact families. They were also
more likely to have a child before they were 18, live with a cohabiting
partner, and experience marital separation themselves. Genetically informed analyses revealed that
environmental processes within nuclear families that are associated with
parental divorce accounted for the relations. Shared genetic factors and
environmental factors which influence twin families could did not mediate the
intergenerational associations.
Cathy Fernandes1,
Jose Paya-Cano1, Frans Sluyter1,
Ursula D'Souza1, Robert Plomin1, and Leonard C. Schalkwyk1. The power of gene
expression profiling and mouse models to unravel behaviour.
1Social, Genetic and Developmental Psychiatry Research Centre,
Address: Social, Genetic
and Developmental Psychiatry Research Centre, PO 82, Institute of Psychiatry,
King's College London, De Crespigny Park, London SE5
8AF, U.K. Tel: +44(0)207 848 0279 Fax: +44(0)207 848 0801 Email spjgcaf@iop.kcl.ac.uk
Understanding the genetic component of complex traits such as
behaviour has long been a formidable task as it has been difficult to study
multiple genes and their products in a single system. Gene expression profiling using microarrays is an exciting new technology that can take a
snapshot of the simultaneous gene expression across thousands of genes. The mouse is an excellent model for such
functional genomics research as there is considerable genetic overlap with
humans, behavioural phenotypes have been well
characterized and a great deal of genomic information is available. Moreover,
both genes and environment can be manipulated or controlled in mice, which
makes it possible to study the relationship between genes and environment at
the level of gene expression. I will
present data on a study comparing hippocampal gene
expression profiles across eight different inbred mouse strains (A/J, C3H/HeJ,
FVB/NJ, DBA/2J, C57BL/6J, Balb/cByJ, 129S1/SvImJ and
SJL/J) using the Affymetrix GeneChip
system. I will focus on the ways in
which the microarray data can be analysed
to identify novel candidate genes and potential gene interactions, using
examples of gene expression profiles that replicate previous findings and those
that nominate novel candidate genes in this study. The potential of using a range of inbred
strains of mice for quantitative analysis of genetic and environmental
influences on gene expression profiles will be considered.
Tom A Fowler1,
Jane Scourfield1, Anita Thapar1, and Anne Farmer2. Does Disabling Fatigue in
Children & Adolescents Share Common Genes with Depression?
1Department of Psychological Medicine,
Address: Department of
Psychological Medicine, University of
Medicine,
INTRODUCTION: Due to the
overlap of symptomology between chronic disabling
fatigue and depression it has been suggested that Chronic Fatigue Syndrome (K.
Fukuda, S.E. Straus, I. Hickie, et al. 1994, Annals of Internal Medicine, 121, 953-9)
is simply a form of depression. A twin method has been employed to examine
whether chronic fatigue and depression in adolescence overlap in terms of
genetic aetiology. METHOD: A screening questionnaire for lifetime ever
disabling fatigue was completed by the parents of 1457 twins, aged 8-17 years, identified
from the
Amber L. Gahagan1 and Irwin D.
Waldman1. Pubertal Maturation
differences in Genetic and Environmental Influences on Conduct Disorder.
1Department
of Psychology,
Address: Department of Psychology,
Theories of the
development of antisocial behavior have posited greater genetic influences and
lesser environmental influences on early- as compared with late-onset
antisocial behavior. In this study, we
examine the effects of pubertal maturation (PM) on the genetic and
environmental influences on Conduct Disorder (CD) in children and adolescents. The participants were twin pairs from the
Georgia Twin Registry, a registry of all multiple births recorded in the state
birth records of
Jody M. Ganiban1. Mothering and Adolescent Externalizing Behavior:
A Behavioral Genetic Exploration.2
1Department of Psychology, The George Washington University, Washington,
DC, 2The Swedish Twin Mothers Project was supported by a grant from
the NIMH (R01 MH54610, PI: Dr. David Reiss)
Address: Department of
Psychology, The
20052. Telephone: (202) 994-7571 Fax: (202) 994-1602 Email: ganiban@gwu.edu
Previous research indicates that distal family-level factors such
as marital dissatisfaction and parents’ mental health are related to
adolescents’ behavior problems, and that these associations are mediated by
parenting style. Although these findings are well-established, the mechanisms
that account for them are less clear. This paper will examine the degree to
which associations between distal family factors and maternal negativity are
explained by genetic and environmental factors. Additionally, exploratory
analyses will examine whether associations between family factors and
adolescents’ externalizing behaviors are best explained by passive genetic
transmission or by evocative gene-environment processes. Data from the Swedish Twin Mothers Project
will be presented (Reiss, D., Cederblad, M.,
Pedersen, N., et al, 2001, Family Process,
8, 40, 261-272). This study included female twins, their partners, and
their children. The sample consisted of 150 MZ and 176 DZ female twin pairs
(mean age = 44 + 4.5 years), and 552 children (322 male cousins, and 330 female
cousins; average age = 15 + 2.2 years). Self-report measures were used to
assess the women’s depressive symptoms, marital dissatisfaction, and parenting
style. Mothers also rated their adolescents’ externalizing behaviors. Factor
analyses were used to create composite scores for marital dissatisfaction and
maternal negativity towards her child. Preliminary
analyses indicate that maternal depressive symptoms and marital dissatisfaction
contribute to maternal negativity through different channels: while genetic factors primarily explained
associations between depressive symptoms and maternal negativity, associations
between marital dissatisfaction and maternal negativity were explained by nonshared environment factors. Exploratory analyses will capitalize upon the
inclusion of adolescent cousins who vary in genetic relatedness in this study,
and estimate the degree to which associations between maternal
negativity and adolescents’ externalizing behaviors are explained by the
passive transmission of genes from mother to child, or by the adolescents’
unique genetic makeup.
Heather L. Gelhorn1,
Michael C. Stallings1, Susan E. Young1, Robin P. Corley1,
John K. Hewitt1, Thomas J. Crowley2. A Detailed Investigation of DSM-IV Conduct
Disorder Symptoms: Heritability of Individual Items and a Comparison of
Selected and Unselected
Samples.3
1Institute for Behavioral Genetics, University of Colorado, Boulder,
CO, 2Dept. of Psychiatry, U. of Colorado Health Sciences Center, Denver,
CO, 3Supported by NIDA grants DA-05131, DA-11015, DA-12845
Address: Institute for
Behavioral Genetics, Campus Box 447 University of Colorado,
Research on antisocial traits from twin and adoption studies has consistently
implicated genetic factors in the etiology of conduct disorder (CD). However
few studies have looked at individual symptoms to determine the extent to which
these behavioral problems may be genetically or environmentally influenced. Additionally, researchers frequently employ case-control
designs where CD symptoms are compared between selected samples and unselected
controls. Such strategies assume that the selected cases simply represent the
extremes of an underlying distribution that is shared with the controls. There has been very little research to
directly support this assumption. The
current study uses both patient and community-based adolescents participating
in the Center for Antisocial Drug Dependence at the
Kyle L. Gobrogge1
and Kelly L. Klump1. Homosexual Mating Preferences from an
Evolutionary Perspective.2
1Department of Psychology,
Address:
Objective: Several studies
have examined mating behavior from an evolutionary perspective in both
heterosexual and homosexual male populations (Silverthorne & Quinsey, 2000; Bailey et al., 1994; Jankowiak
et al., 1992; Freund et al., 1973).
These investigations have shown that both heterosexual and homosexual
men prefer younger partners compared to heterosexual women. However, most studies relied on
laboratory-based assessments that required subjects to hypothesize about their
preferences and did not specify what types of relationships were desired for
each preference. The purpose of the present
study was to examine these issues naturalistically by comparing partner
preferences of homosexual and heterosexual men who placed internet personal
advertisements. Method: Subjects included 338 homosexual and 265
heterosexual men placing internet personal ads on lavalife.com in each of the
50 states in the
to replicate the current findings.
Detre A. Godinez1, Michael C. Stallings1, Susan
E. Young1, Robin P. Corley1, John K. Hewitt1. Investigating Genetic and Environmental
Influences on Age at Onset of Alcohol Use and the Latency from First Use to
Regular Use in the
1Institute for Behavioral Genetics,