The Detection of Environmental Influences on Academic Achievement Appears to Depend on the Analytic Approach.

One long-standing analytic approach in adoption studies is to examine correlations between features of adoptive homes and outcomes of adopted children (hereafter termed 'measured environment correlations') to illuminate environmental influences on those associations. Although results from such studies have almost uniformly suggested modest environmental influences on adopted children's academic achievement, other work has indicated that adopted children's achievement is routinely higher than that of their reared-apart family members, often substantially so. We sought to understand this discrepancy. We examined academic achievement and literacy-promotive features of the home in 424 yoked adoptive/biological families participating in the Early Growth and Development Study (EGDS; i.e., adopted children, adoptive mothers, birth mothers, and biological siblings of the adopted children remaining in the birth homes) using an exhaustive modeling approach. Results indicated that, as anticipated, adopted children scored up to a full standard deviation higher on standardized achievement tests relative to their birth mothers and reared-apart biological siblings. Moreover, these achievement differences were associated with differences in the literacy-promotive features of the adoptive and birth family homes, despite minimal measured environment correlations within adoptive families. A subsequent simulation study highlighted noise in measured environmental variables as an explanation for the decreased utility of measured environment correlations. We conclude that the field's heavy focus on measured environment correlations within adoptive families may have obscured detection of specific environmental effects on youth outcomes, and that future adoption studies should supplement their measured environment analyses with mean differences between reared-apart relatives.

The pernicious role of stress on intergenerational continuity of psychopathology.

Development and Psychopathology has been a premier resource for understanding stressful childhood experiences and the intergenerational continuity of psychopathology. Building on that tradition, we examined the unique and joint influences of maternal stress on children's effortful control (age 7) and externalizing behavior (age 11) as transmitted via genetics, the prenatal environment, and the postnatal environment. The sample included N = 561 adopted children and their biological and adoptive parents. Path models identified a direct effect of biological mother life stress on children's effortful control (ß = -.08) and an indirect effect of her life stress on child externalizing behavior via effortful control (ß = .52), but no main or indirect effects of biological parent psychopathology, prenatal stress, or adoptive mother adverse childhood experiences (ACES). Adoptive mother ACES amplified the association between biological mother life stress and child effortful control (ß = -.08), externalizing behavior (ß = 1.41), and the indirect effect via effortful control, strengthening associations when adoptive mothers reported average or high ACES during their own childhoods. Results suggest that novel study designs are needed to enhance the understanding of how life stress gets "under the skin" to affect psychopathology in the offspring of adults who have experienced stress.

The Finnish Adoptive Family Study of Schizophrenia: differences in somatic diseases and conditions between adoptees with high or low genetic risk for schizophrenia spectrum disorders.

BACKGROUND AND AIMS: There is some evidence that offspring of patients with schizophrenia have higher somatic morbidity, which is thought to be partially due to genetic links between somatic disorders and schizophrenia. This study explored differences in somatic diseases and conditions of adoptees with high genetic risk (HR) or low genetic risk (LR) for schizophrenia spectrum disorders. MATERIAL AND METHODS: The study is part of the Finnish Adoptive Family Study of Schizophrenia. The adoptive research design used made it possible to examine how the somatic health of adoptees raised in similar adoptive families, is affected by their genetic susceptibility to schizophrenia. The study sample consisted of 373 adoptees, of whom 190 had HR and 183 had LR for schizophrenia spectrum disorders. Data on somatic morbidity were gathered from the hospital records and from the national registers of the Care Register of Health Care and the Social Insurance Institution. RESULTS: The only statistically significant difference found was in genitourinary diseases, the likelihood being twofold higher in HR adoptees compared to LR adoptees (16.8% vs. 8.2%; adj. OR = 2.13, 95% CI 1.06-4.25, p = .033). Adoptees who were female and aged over 40 had a higher prevalence of genitourinary illnesses than non-adoptees. CONCLUSION: The significant prevalence of genitourinary diseases in adoptees at risk for schizophrenia spectrum disorders suggests that some specific somatic diseases and schizophrenia may have a shared hereditary etiology. More research is required for specific somatic diseases in study populations that can differentiate between the effects of genetic and environmental factors.

Cross-generational transmission of genetic risk for alcohol and drug use disorders: the impact of substance availability on the specificity of genetic risk.

BACKGROUND: Among individuals with alcohol use disorder (AUD) and drug use disorder (DUD), is their genetic liability and its specificity moderated by substance availability? METHODS: Offspring (born 1960-1995) and their biological parents from three family types [not-lived-with (NLW) biological father, mother and adoptive] and their AUD and DUD diagnoses were ascertained from Swedish national registers. Parent-offspring resemblance was calculated by tetrachoric correlation. RESULTS: In Swedes born from 1960 to 1995, prevalence rates of AUD were stable while DUD rates increased substantially. Best-estimate tetrachoric correlations (±95% confidence intervals) between AUD in biological parents and AUD and DUD in their offspring were, respectively, +0.19 (0.18-0.20) and +0.18 (0.17-0.20). Parallel results from DUD in parents to AUD and DUD in children were +0.12 (0.10-0.13) and +0.27 (0.26-0.28). When divided into older and younger cohorts, the specificity of DUD transmission increased substantially over time, while the genetic correlation between AUD and DUD significantly decreased. CONCLUSIONS: Raised when alcohol was the preferred substance of abuse and illicit drugs highly stigmatized, AUD in parents reflected a general liability to substance use disorders, as they transmitted similar genetic risk for AUD and DUD to their children raised when both substances were widely available and relatively acceptable. DUD in parents, by contrast, reflected a more specific liability to DUD and, when transmitted to offspring, produced a considerably stronger risk for DUD than for AUD that increased over time. The magnitude and specificity of the genetic liability to psychoactive substances can be influenced by the availability of that substance.

Dysfunctional family functioning in high socioeconomic status families as a risk factor for the development of psychiatric disorders in adoptees: the Finnish Adoptive Family Study of Schizophrenia.

PURPOSE: Earlier findings indicate that socioeconomic status (SES) of family associates with family functioning. This study examined the impacts of family functioning and genetic risk for schizophrenia on psychiatric morbidity of adoptees in families of high SES (HSES) and low SES (LSES). METHODS: The study population is a subgroup of the Finnish Adoptive Family Study of Schizophrenia. Of the adoptees, 152 had high genetic risk for schizophrenia spectrum disorders (HR) and 151 adoptees had low risk (LR). Of the adoptees, 185 (HR = 94, LR = 91) were raised in high-SES (HSES) families and 118 (HR = 58, LR = 60) in low-SES (LSES) families. The family SES was determined by the occupational status of the main provider of the family. The functioning of adoptive families was assessed based on Global Family Ratings (GFRs) and psychiatric disorders on DSM-III-R criteria. RESULTS: In the HSES families, the psychiatric morbidity of the adoptees was emphasized by HR (OR = 4.28, CI 2.14-8.56) and dysfunctional family processes (OR = 6.44, CI 2.75-15.04). In the LSES families, the adoptees´ psychiatric morbidity was almost significantly increased by HR (OR = 2.10, CI 0.99-4.45), but not by dysfunctional family processes (OR = 1.33, CI 0.53-3.34). CONCLUSIONS: This study showed that in HSES families, dysfunctional family processes and HR for schizophrenia increased the likelihoods for the development of psychiatric disorders in adoptees. The results can be utilized in identifying risk factors in the development of psychiatric disorders and focusing preventative strategies on risk groups with acknowledging the importance of family functioning.

Gene × Environment Interactions in the Development of Preschool Effortful Control, and Its Implications for Childhood Externalizing Behavior.

This study examined the role of gene × environment interaction (G × E) in the development of effortful control (EC) and externalizing symptoms (EXT). Participants included 361 adopted children, and their Adoptive Parents (APs) and Birth Mothers (BMs), drawn from the Early Growth and Development Study. The primary adoptive caregivers' (AP1) laxness and overreactivity were assessed when children were 27-months-old, and used as indices of environmental influences on EC. Heritable influences on child EC were assessed by the BMs' personality characteristics (emotion dysregulation, agreeableness). Secondary adoptive caregivers (AP2) reported on children's EC at 54 months, and EXT at 7 years. Interactions between BM characteristics and AP1 laxness were related to EC and indirectly predicted EXT via EC. Parental laxness and EC were positively associated if children had high heritable risk for poor EC (BM high emotion dysregulation or low agreeableness), but negatively associated if children had low heritable risk for poor EC (BM low emotion dysregulation or high agreeableness). BM agreeableness also moderated associations between AP1 overreactivity and effortful control, and yielded a similar pattern of results. Our findings suggest that G × E is an important first step in the development of EXT via its effect on EC. Consistent with "goodness of fit" models, heritable tendencies can affect which parenting practices best support EC development.

Separating Measured Genetic and Environmental Effects: Evidence Linking Parental Genotype and Adopted Child Outcomes.

There has been widespread adoption of genome wide summary scores (polygenic scores) as tools for studying the importance of genetics and associated life course mechanisms across a range of demographic and socioeconomic outcomes. However, an often unacknowledged issue with these studies is that parental genetics impact both child environments and child genetics, leaving the effects of polygenic scores difficult to interpret. This paper uses multi-generational data containing polygenic scores for parents (n = 7193) and educational outcomes for adopted (n = 855) and biological (n = 20,939) children, many raised in the same families, which allows us to separate the influence of parental polygenic scores on children outcomes between environmental (adopted children) and environmental and genetic (biological children) effects. Our results complement recent work on "genetic nurture" by showing associations of parental polygenic scores with adopted children's schooling, providing additional evidence that polygenic scores combine genetic and environmental influences and that research designs are needed to separate these estimated impacts.

Minnesota Center for Twin and Family Research.

The Minnesota Center for Twin and Family Research (MCTFR) comprises multiple longitudinal, community-representative investigations of twin and adoptive families that focus on psychological adjustment, personality, cognitive ability and brain function, with a special emphasis on substance use and related psychopathology. The MCTFR includes the Minnesota Twin Registry (MTR), a cohort of twins who have completed assessments in middle and older adulthood; the Minnesota Twin Family Study (MTFS) of twins assessed from childhood and adolescence into middle adulthood; the Enrichment Study (ES) of twins oversampled for high risk for substance-use disorders assessed from childhood into young adulthood; the Adolescent Brain (AdBrain) study, a neuroimaging study of adolescent twins; and the Siblings Interaction and Behavior Study (SIBS), a study of adoptive and nonadoptive families assessed from adolescence into young adulthood. Here we provide a brief overview of key features of these established studies and describe new MCTFR investigations that follow up and expand upon existing studies or recruit and assess new samples, including the MTR Study of Relationships, Personality, and Health (MTR-RPH); the Colorado-Minnesota (COMN) Marijuana Study; the Adolescent Brain Cognitive Development (ABCD) study; the Colorado Online Twins (CoTwins) study and the Children of Twins (CoT) study.

Genetics, the Rearing Environment, and the Intergenerational Transmission of Divorce: A Swedish National Adoption Study.

We used classical and extended adoption designs in Swedish registries to disentangle genetic and rearing-environment influences on the intergenerational transmission of divorce. In classical adoption analyses, adoptees ( n = 19,715) resembled their biological parents, rather than their adoptive parents, in their history of divorce. In extended adoption analyses, offspring ( n = 82,698) resembled their not-lived-with fathers and their lived-with mothers. There was stronger resemblance to lived-with mothers, providing indirect evidence of rearing-environment influences on the intergenerational transmission of divorce. The heritability of divorce assessed across generations was 0.13. We attempted to replicate our findings using within-generation data from adoptive and biological siblings ( ns = 8,523-53,097). Adoptees resembled their biological, not adoptive, siblings in their history of divorce. Thus, there was consistent evidence that genetic factors contributed to the intergenerational transmission of divorce but weaker evidence for a rearing-environment effect of divorce. Within-generation data from siblings supported these conclusions.

Deficits in adolescent social functioning, dysfunctional family processes and genetic risk for schizophrenia spectrum disorders as risk factors for later psychiatric morbidity of adoptees.

Social functioning deficits during adolescence are associated with later psychiatric morbidity, particularly in offspring at high genetic risk for schizophrenia spectrum disorders. However, a shortcoming of earlier study findings is the lack of control of the impact of the family rearing environment. The study was aimed to examine the association of adoptees' social functioning during adolescence, adoptive family functioning, and adoptees' high (HR) or low (LR) genetic risk for schizophrenia spectrum disorders with adoptees' later psychiatric morbidity. The present subsample from the nationwide Finnish Adoptive Family Study of Schizophrenia included 57 HR and 60 LR adoptees. Adolescent social functioning was assessed using UCLA Social Attainment Survey (UCLA SAS). Adoptive family functioning was based on Global Family Ratings (GFRs) and psychiatric disorders on DSM-III-R criteria. The results indicated that, after controlling for adoptive family functioning and genetic risk for schizophrenia spectrum disorders, deficits in peer relationships during adolescence were associated with an increased likelihood of psychiatric morbidity of adoptees. Our findings highlight social functioning deficits during adolescence, specifically in peer relationships, as plausible independent risk factors for later psychiatric disorders. These results can be utilized in identifying possible at-risk groups and targets for prevention and in developing preventive strategies.

Using adopted individuals to partition indirect maternal genetic effects into prenatal and postnatal effects on offspring phenotypes.

Maternal genetic effects can be defined as the effect of a mother's genotype on the phenotype of her offspring, independent of the offspring's genotype. Maternal genetic effects can act via the intrauterine environment during pregnancy and/or via the postnatal environment. In this manuscript, we present a simple extension to the basic adoption design that uses structural equation modelling (SEM) to partition maternal genetic effects into prenatal and postnatal effects. We examine the power, utility and type I error rate of our model using simulations and asymptotic power calculations. We apply our model to polygenic scores of educational attainment and birth weight associated variants, in up to 5,178 adopted singletons, 943 trios, 2687 mother-offspring pairs, 712 father-offspring pairs and 347,980 singletons from the UK Biobank. Our results show the expected pattern of maternal genetic effects on offspring birth weight, but unexpectedly large prenatal maternal genetic effects on offspring educational attainment. Sensitivity and simulation analyses suggest this result may be at least partially due to adopted individuals in the UK Biobank being raised by their biological relatives. We show that accurate modelling of these sorts of cryptic relationships is sufficient to bring type I error rate under control and produce asymptotically unbiased estimates of prenatal and postnatal maternal genetic effects. We conclude that there would be considerable value in following up adopted individuals in the UK Biobank to determine whether they were raised by their biological relatives, and if so, to precisely ascertain the nature of these relationships. These adopted individuals could then be incorporated into informative statistical genetics models like the one described in our manuscript to further elucidate the genetic architecture of complex traits and diseases.

Adoption of potato varieties and their role for climate change adaptation in India.

Adoption of improved varieties is an important strategy to adapt to the negative implication associated with climate change and variability. However, incomplete data on varietal release and adoption is often the reality in many countries hindering informed decision-making on breeding and varietal dissemination strategies to effectively adapt to climate change. In taking the example of potatoes in India, we analyze the extent to which the potato sector is resilient to climate change. We do so by comparing state-level climate change projections with adoption of high resistant and tolerant potato varieties to major abiotic and biotic stresses. Release and adoption data was collected in 2016 in six expert elicitation workshops conducted with 130 experts from the potato value chain in Bihar, Gujarat, Karnataka, Punjab, Uttar Pradesh, and West Bengal. We found that from the total of 81 releases, 45 improved varieties are adopted in India and that in each state high resistant and tolerant varieties are cultivated providing some degree of varietal resilience. Early maturity has been the most important and heat tolerance is the least important trait. Comparing climate projections with adoption rates of high resistant and tolerant varieties, we found that Gujarat is relatively most resilient. In other states we found some mismatches between climate projections and adopted specific varietal traits. Our results allow policy-makers and breeders to better prioritize investments into breeding for specific traits and dissemination strategies.

Interaction of genetic vulnerability to schizophrenia and family functioning in adopted-away offspring of mothers with schizophrenia.

OBJECTIVE: The aim of this study was to examine the association of family functioning to psychiatric disorders of adoptees with and without genetic vulnerability to schizophrenia. METHODS: The data is based on the Finnish Adoptive Family Study of Schizophrenia. The study sample consisted of 346 adoptive families, of which 175 adoptees had high (HR) and 171 low (LR) genetic risk for schizophrenia. DSM-III-R was used for diagnostic criteria. Family functioning was assessed using the Global Family Ratings. Childhood adversities covered early parental divorce and death occurring before 18 years of age of the adoptees. RESULTS: Approximately two thirds of the adoptees had lived in families with mildly dysfunctional processes (30%) or dysfunctional processes (28.4%). An increased likelihood for psychiatric disorders of the adoptees was related to dysfunctional family processes both in HR (OR = 4.8, 95% CI 2-11.4) and LR (OR = 2.6, 95% CI 1.1-6.3) adoptees, but not to early parental death or divorce. CONCLUSIONS: The risk for psychiatric disorders was increased for adoptees in families with dysfunctional processes, especially for those adoptees with genetic vulnerability to schizophrenia. These results emphasize the importance of policies and practices that aim to strengthen and support family functioning.

It Runs in the Family: A Study of Political Candidacy Among Swedish Adoptees.

What motivates citizens to run for office? Recent work has shown that early life parental socialization is strongly associated with a desire to run for office. However, parents not only shape their children's political environment, they also pass along their genes to those same children. A growing area of research has shown that individual differences in a wide range of political behaviors and attitudes are linked to genetic differences. As a result, genetic factors may confound the observed political similarities among parents and their children. This study analyzes Swedish register data containing information on all nominated and elected candidates in the ten parliamentary, county council, and municipal elections from 1982 to 2014 for a large sample of adoptees and their adoptive and biological parents. By studying the similarity in political ambition within both adoptive and biological families, our research design allows us to disentangle so-called "pre-birth" factors, such as genes and pre-natal environment, and "post-birth" factors like parental socialization. We find that the likelihood of standing as a political candidate is twice as high if one's parent has been a candidate. We also find that the effects of pre-birth and post-birth factors are approximately equal in size. In addition, we test a number of potential pre- and post-birth transmission mechanisms. First, disconfirming our expectations, the pre-birth effects do not seem to be mediated by cognitive ability or leadership skills. Second, consistent with a role modeling mechanism, we find evidence of a strong transmission in candidacy status between rearing mothers and their daughters.

Genetic Influences on Alcoholism Risk: A Review of Adoption and Twin Studies.

Researchers have used two different strategies to determine the relative contributions of genes and shared environment to the development of alcoholism among family members: the adoption study and the twin study. Adoption studies compare the risk to biological relatives with the risk to adoptive relatives of alcoholics. Twin studies compare identical and fraternal pairs of twins reared in the same environment. Evidence indicates an important genetic influence on alcoholism risk; this influence appears as strong in women as in men. These results have been remarkably consistent despite major differences between research methods.

Adoption Studies.

Researchers use adoption studies to determine the contributions of genetic and environmental factors to the development of alcohol problems. These studies generally compare the outcomes of adoptees who have biological parents with alcohol problems and who grow up in various adoptive environments with the outcomes of adoptees without such family backgrounds but raised in similar environments. Using certain statistical approaches, adoption studies also allow for the evaluation of specific gene-environment interactions in determining an outcome such as alcoholism. To obtain data that allow meaningful and generalizable conclusions, however, scientists must select a representative group of study subjects, obtain valid information about these subjects from a wide variety of sources, and consider biases inherent in adoption practices.

Type I and Type II Alcoholism: An Update.

A commonly cited alcoholism typology, the type I-type II typology, was developed from the findings of a study of Swedish adoptees and their biological and adoptive parents. Type I alcoholism affects both men and women, requires the presence of a genetic as well as an environmental predisposition, commences later in life after years of heavy drinking, and can take on either a mild or severe form. Type II alcoholism, in contrast, affects mainly sons of male alcoholics, is influenced only weakly by environmental factors, often begins during adolescence or early adulthood, is characterized by moderate severity, and usually is associated with criminal behavior. Additional studies have demonstrated that type I and type II alcoholics also differ in characteristic personality traits (e.g., harm avoidance and novelty seeking) as well as in certain neurophysiological markers. A replication study with a second group of Swedish adoptees has confirmed many of the findings of the original adoption study.

Genetic and familial environmental effects on suicide attempts: a study of Danish adoptees and their biological and adoptive siblings.

OBJECTIVES: Genetic factors have been found to influence the risk of suicide. It is less clear if this also applies to attempted suicide. We have investigated genetic and familial environmental factors by studying the occurrence of suicide attempts in biological and adoptive siblings of adoptees who attempted suicide compared to siblings of adoptees with no suicide attempts. METHOD: We used a random sample of 1933 adoptees from the Danish Adoption Register, a register of non-familial adoptions of Danish children, i.e. the adoptive parents are biologically unrelated to the adoptee. Analyses were conducted on incidence rates of attempted suicide in biological and adoptive siblings given occurrence of attempted suicide in the adoptees while also taking into account psychiatric disorders. Information about suicidal attempt and history of psychiatric disorder was based on hospital admissions. RESULTS: The rate of attempted suicide in full siblings of adoptees who attempted suicide before age 60 years was higher than in full siblings of adoptees who had not attempted suicide (incidence rate ratios (IRR)=3.45; 95% confidence interval [CI]=0.94-12.7). After adjustment for history of psychiatric admission of siblings the increased rate was statistically significant (IRR=3.88; 95% CI-1.42-10.6). LIMITATIONS: Information on attempted suicide and psychiatric history was limited to that which involved hospitalisation. CONCLUSIONS: Genetic factors influence risk of suicide attempts.

Stability in MMPI among adoptees with high and low genetic risk for schizophrenia and with low Communication Deviance of their adoptive parents.

Stability has been considered an important aspect of vulnerability to schizophrenia. The temporal stability of the scales in the Minnesota Multiphasic Personality Inventory (MMPI) was examined, using adoptees from the Finnish Adoptive Family Study of Schizophrenia. Adoptees who were high-risk (HR) offspring of biological mothers having a schizophrenia spectrum disorder (n=28) and low-risk (LR) controls (n=46) were evaluated using 15 MMPI scales at the initial assessment (HR, mean age 24 years; LR, mean age 23 years) and at the follow-up assessment after a mean interval of 11 years. Stability of the MMPI scales was also assessed in the groups of adoptees, assigned according to the adoptive parents'(n=44) communication style using Communication Deviance (CD) scale as an environmental factor. Initial Lie, Frequency, Correction, Psychopathic Deviate, Schizophrenia, Manifest Hostility, Hypomania, Phobias, Psychoticism, Religious Fundamentalism, Social Maladjustment, Paranoid Schizophrenia, Golden-Meehl Indicators, Schizophrenia Proneness and 8-6 scale scores significantly predicted the MMPI scores at the follow-up assessment indicating stability in the characteristics of thinking, affective expression, social relatedness and volition. Low CD in the family had an effect on the stabilization of personality traits such as social withdrawal and restricted affectivity assessed by Correction and Hostility.