Margaret Keyes

The Mental Health of US Adolescents Adopted in Infancy

OBJECTIVE To determine whether adopted adolescents are at excess risk for clinically relevant behavioral and emotional problems. DESIGN We examined whether adopted and nonadopted adolescents differed on quantitative indicators of mental health and the prevalence of childhood disorders and whether differences exist between internationally and domestically placed adoptees. SETTING Assessments occurred at the University of Minnesota from December 11, 1998, to June 4, 2004. PARTICIPANTS Adolescents adopted in infancy were systematically ascertained from records of 3 large Minnesota adoption agencies; nonadopted adolescents were ascertained from Minnesota birth records. The final sample included these adolescents with their rearing parents. Main Exposure The main exposure was adoptive status: nonadopted (n = 540), international adoptive placement (n = 514), or domestic adoptive placement (n = 178). OUTCOME MEASURES Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) clinical assessments based on child and parent reports of attention-deficit/hyperactivity, oppositional defiant, conduct, major depressive, and separation anxiety disorders; teacher reports of psychological health; and contact with mental health professionals. RESULTS Adoptees scored only moderately higher than nonadoptees on quantitative measures of mental health. Nevertheless, being adopted approximately doubled the odds of having contact with a mental health professional (odds ratio [OR], 2.05; 95% confidence interval [CI], 1.48-2.84) and of having a disruptive behavior disorder (OR, 2.34; 95% CI, 1.72-3.19). Relative to international adoptees, domestic adoptees had higher odds of having an externalizing disorder (OR, 2.60; 95% CI, 1.67-4.04). CONCLUSIONS Moderate mean differences in quantitative indicators of mental health can lead to substantial differences in disorder prevalence. Although most adopted adolescents are psychologically healthy, they may be at elevated risk for some externalizing disorders, especially among those domestically placed.

Tests of a direct effect of childhood abuse on adult borderline personality disorder traits: a longitudinal discordant twin design.

We used a longitudinal twin design to examine the causal association between sexual, emotional, and physical abuse in childhood (before age 18) and borderline personality disorder (BPD) traits at age 24 using a discordant twin design and biometric modeling. Additionally, we examined the mediating and moderating effects of symptoms of childhood externalizing and internalizing disorders on the link between childhood abuse and BPD traits. Although childhood abuse, BPD traits, and internalizing and externalizing symptoms were all correlated, the discordant twin analyses and biometric modeling showed little to no evidence that was consistent with a causal effect of childhood abuse on BPD traits. Instead, our results indicate that the association between childhood abuse and BPD traits stems from common genetic influences that, in some cases, also overlap with internalizing and externalizing disorders. These findings are inconsistent with the widely held assumption that childhood abuse causes BPD, and they suggest that BPD traits in adulthood are better accounted for by heritable vulnerabilities to internalizing and externalizing disorders.

Evidence for the construct validity and heritability of the Wilson–Patterson conservatism scale: a reared-apart twins study of social attitudes

Abstract A 28 item version of the Wilson–Patterson Attitude Inventory was administered to 345 participants (twins, spouses, friends, and others) in the Minnesota Study of Twins Reared Apart. An overall conservatism measure demonstrated impressive construct validity. It had strong convergent validity, demonstrated by correlations of 0.72 and 0.58 with the Altemeyer Right Wing Authoritarianism scale and the Multidimensional Personality Questionnaire (MPQ) Traditionalism Scale, respectively. It also had strong discriminant validity, being largely uncorrelated with the other 10 MPQ Scales and WAIS Full Scale IQ. Heritabilities were calculated from fitting models to the variance–covariance matricies based on 54 pairs of monozygotic (MZ) and 46 pairs of dizygotic (DZ) twins reared apart. Conservatism demonstrated significant and sizeable genetic influence ( h 2 =0.56), replicating the results reported in the Virginia 30,000 study of ordinary twins and family members and those of a large Australian twin study.

The enrichment study of the Minnesota twin family study: Increasing the yield of twin families at high risk for externalizing psychopathology

The Enrichment Study (ES) was designed to extend the Minnesota Twin Family Study (MTFS) by oversampling 11-year-old twins at especially high risk for substance use disorders by virtue of having a childhood disruptive disorder. The sample was ascertained from Minnesota birth records. To identify high-risk twins, we conducted telephone screening interviews for parent-reported symptoms of attention-deficit/hyperactivity disorder (ADHD) and conduct disorder (CD) as well as indications of academic disengagement. Twins who exceeded a predetermined threshold were invited to participate. To facilitate comparison with the previously ascertained MTFS participants, a random sample of 11-year-old twins was also recruited. As part of the ES study, 499 twin pairs, and their parents, visited the University of Minnesota, where each participant completed a clinical interview, psychophysiological evaluation, and thorough assessment of environmental risk. We were highly successful in recruiting at-risk twins; 52% of the screened male twins and 41% of the screened females met criteria for a diagnosis of ADHD, CD, or oppositional defiant disorder (ODD). At the pair level, 63% of the screened pairs had at least one member with a childhood disruptive disorder. This article provides an overview of the study design and includes a review of recent findings using this sample of twins.

Parental Smoking and Adolescent Problem Behavior: An Adoption Study of General and Specific Effects

OBJECTIVE It is essential to understand the effect of parental smoking on offspring tobacco use. In biologically related families, parents who smoke may transmit a nonspecific genetic risk for offspring disinhibited behavior, including tobacco use. Studying adoptive families allows one to control for genetic confounding when examining the environmental effect of exposure to parental smoking. The purpose of this study was to examine the genetic and environmental contributions to the risk represented by exposure to parental smoking and to assess the specificity of that risk. METHODS Adolescents adopted in infancy were systematically ascertained from records of three private Minnesota adoption agencies; nonadopted adolescents were ascertained from Minnesota birth records. Adolescents and their rearing parents participated in all assessments in person. The main outcome measures were self-reports of behavioral deviance, substance use, and personality, as well as DSM-IV clinical assessments of childhood disruptive disorders. RESULTS The data from adoptive families suggest that exposure to parental smoking represents an environmental risk for substance use in adolescent offspring. In biologically related families, the effect of exposure to parental smoking is larger and more diverse, including substance use, disruptive behavior disorders, delinquency, deviant peer affiliations, aggressive attitudes, and preference for risk taking. CONCLUSIONS This study provides evidence for an environmentally mediated pathway by which parental smoking increases risk specifically for substance use in adolescent offspring. The data are also consistent with a genetically mediated pathway by which nonadoptive parents who smoke may also transmit a nonspecific genetic risk to their offspring for disinhibited behavior.

Tests of a direct effect of childhood abuse on adult borderline personality disorder traits

We used a longitudinal twin design to examine the causal association between sexual, emotional, and physical abuse in childhood (before age 18) and borderline personality disorder (BPD) traits at age 24 using a discordant twin design and biometric modeling. Additionally, we examined the mediating and moderating effects of symptoms of childhood externalizing and internalizing disorders on the link between childhood abuse and BPD traits. Although childhood abuse, BPD traits, and internalizing and externalizing symptoms were all correlated, the discordant twin analyses and biometric modeling showed little to no evidence that was consistent with a causal effect of childhood abuse on BPD traits. Instead, our results indicate that the association between childhood abuse and BPD traits stems from common genetic influences that, in some cases, also overlap with internalizing and externalizing disorders. These findings are inconsistent with the widely held assumption that childhood abuse causes BPD, and they suggest that BPD traits in adulthood are better accounted for by heritable vulnerabilities to internalizing and externalizing disorders.

The Impact of Attention-Deficit/Hyperactivity Disorder on Preadolescent Adjustment May Be Greater for Girls than for Boys.

Whether gender differences exist in the impairment associated with attention-deficit/hyperactivity disorder (ADHD) is still largely unknown, because most samples have few affected girls or include only one sex. The current study evaluated whether ADHD affects adjustment differently for girls than boys in a population-based cohort of 11-year-olds (520 girls, 478 boys). Those with a DSM-IV diagnosis of ADHD (predominantly inattentive, hyperactive-impulsive, or combined) were compared to those without ADHD on teacher, parent, and child reports of academics, peer relationships, self-concept, clinical symptoms, and treatment. Although boys and girls with ADHD experienced difficulties in all areas, girls with ADHD, especially the inattentive subtype, were more negatively affected in academics and peer relationships. Inattentive girls were less popular and more likely to be bullied than girls without ADHD, whereas inattentive boys were not. The social isolation experienced by many girls with ADHD deserves greater attention.

Risk of Suicide Attempt in Adopted and Nonadopted Offspring

OBJECTIVE: We asked whether adoption status represented a risk of suicide attempt for adopted and nonadopted offspring living in the United States. We also examined whether factors known to be associated with suicidal behavior would mediate the relationship between adoption status and suicide attempt. METHODS: Participants were drawn from the Sibling Interaction and Behavior Study, which included 692 adopted and 540 nonadopted offspring and was conducted at the University of Minnesota from 1998 to 2008. Adoptees were systematically ascertained from records of 3 large Minnesota adoption agencies; nonadoptees were ascertained from Minnesota birth records. Outcome measures were attempted suicide, reported by parent or offspring, and factors known to be associated with suicidal behavior including psychiatric disorder symptoms, personality traits, family environment, and academic disengagement. RESULTS: The odds of a reported suicide attempt were ∼4 times greater in adoptees compared with nonadoptees (odds ratio: 4.23). After adjustment for factors associated with suicidal behavior, the odds of reporting a suicide attempt were reduced but remained significantly elevated (odds ratio: 3.70). CONCLUSIONS: The odds for reported suicide attempt are elevated in individuals who are adopted relative to those who are not adopted. The relationship between adoption status and suicide attempt is partially mediated by factors known to be associated with suicidal behavior. Continued study of the risk of suicide attempt in adopted offspring may inform the larger investigation of suicidality in all adolescents and young adults.

Gene-environment interplay between parent-child relationship problems and externalizing disorders in adolescence and young adulthood.

BACKGROUND Previous studies have shown that genetic risk for externalizing (EXT) disorders is greater in the context of adverse family environments during adolescence, but it is unclear whether these effects are long lasting. The current study evaluated developmental changes in gene-environment interplay in the concurrent and prospective associations between parent-child relationship problems and EXT at ages 18 and 25 years. METHOD The sample included 1382 twin pairs (48% male) from the Minnesota Twin Family Study, participating in assessments at ages 18 years (mean = 17.8, s.d. = 0.69 years) and 25 years (mean = 25.0, s.d. = 0.90 years). Perceptions of parent-child relationship problems were assessed using questionnaires. Structured interviews were used to assess symptoms of adult antisocial behavior and nicotine, alcohol and illicit drug dependence. RESULTS We detected a gene-environment interaction at age 18 years, such that the genetic influence on EXT was greater in the context of more parent-child relationship problems. This moderation effect was not present at age 25 years, nor did parent-relationship problems at age 18 years moderate genetic influence on EXT at age 25 years. Rather, common genetic influences accounted for this longitudinal association. CONCLUSIONS Gene-environment interaction evident in the relationship between adolescent parent-child relationship problems and EXT is both proximal and developmentally limited. Common genetic influence, rather than a gene-environment interaction, accounts for the long-term association between parent-child relationship problems at age 18 years and EXT at age 25 years. These results are consistent with a relatively pervasive importance of gene-environmental correlation in the transition from late adolescence to young adulthood.

Levels of risk: maternal-, middle childhood-, and neighborhood-level predictors of adolescent disinhibitory behaviors from a longitudinal birth cohort in the United States

OBJECTIVE: Disruptive behavior in adolescence may indicate a broad vulnerability to disinhibition, which begins in childhood and culminates in adult externalizing psychopathology. We utilized prospective birth cohort data to assess childhood predictors of adolescent disinhibition. We also examined the effect of pre-adolescent fluctuation in cognitive ability. METHODS: Data were drawn from the Child Health and Development Study cohort, born 1961-1963; we used the subsample who participated in follow-up through adolescence (n=1752). Six indicators of behavioral disinhibition (BD), reported in adolescence, were analyzed as a count outcome. Predictor variables were drawn from several waves of data collection and included individual-, maternal-, and neighborhood-level measures. Cognitive ability was assessed with the Peabody Picture Vocabulary Test at two time points. Neighborhood characteristics were assessed using census data from 1970. RESULTS: Number of BD indicators was predicted by maternal characteristics at prenatal assessment (maternal age and alcohol consumption) and age-10 assessment (maternal smoking, education, and separation from father). Characteristics of the child that predicted BD included birth order and conduct problems in middle childhood. Neighborhood poverty did not predict BD. Regardless of initial cognitive ability score, movement to a higher quartile by adolescence was associated with lower BD, while movement to a lower quartile was associated with higher BD. CONCLUSION: Risk for adolescent BD exists prenatally and extends through middle childhood. Change in cognitive ability during pre-adolescence emerged as a potentially important factor that merits further investigation. A greater focus on the life course can aid in comprehensively understanding disruptive behavior emergence in adolescence.