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Externalizing psychopathology is a strong risk factor for substance use, whereas the role of internalizing manifestations of distress, and anxiety in particular, in predicting substance use remains unclear. Studies have suggested that anxiety may be either a protective or risk factor for substance use. The present study aimed to clarify evidence for anxiety-specific associations with substance use, examining sex and developmental period (adolescence vs. adulthood) as potential moderators that may help explain conflicting results in the literature. In a longitudinal twin sample, cross-sectional associations of anxiety with substance use differed in adolescents and adults and in girls/women and boys/men. Controlling for externalizing psychopathology and depression, anxiety was associated with reduced substance use in adolescent girls and increased substance use in adult women. In contrast, anxiety-specific associations with substance use were not significant in boys and men. Possible explanations for these contrasting results across development and sex are discussed.

Background: Public acceptance of cannabis continues to increase across the US, yet there has been little research on how cannabis legalization affects young children. The present study compared knowledge of cannabis and other substances among children living in states with different cannabis laws and examined whether the association between such substance knowledge and externalizing behavior varies by state cannabis regulations. Methods: Participants were from the Adolescent Brain Cognitive DevelopmentSM Study (ABCD Study®) at the baseline assessment (N = 11,875, ages 9-11, collected from 2016 to 2018). Chi-square difference tests were used to compare nested models testing group differences in knowledge of substances and the association between externalizing disorder/behavior and substance knowledge as a function of state legality of cannabis use (recreational, medical, low THC/CBD, none). Results: Children living in states with more permissive cannabis laws had a greater knowledge of cannabis and reported more alcohol experimentation. In contrast, knowledge regarding alcohol, tobacco, and other illicit drugs was not greater in children from states with more permissive cannabis laws. Externalizing disorder/behavior was not significantly associated with cannabis knowledge in any group and not significantly different across groups. The association between externalizing disorder/behavior and illicit drug knowledge was significant only in states with the recreational and medical use laws but did not differ significantly across groups. Conclusion: Children living in environments with more permissive cannabis regulations have greater knowledge of cannabis, but not other substances, and report more experimentation with alcohol.

OBJECTIVE Prior research has found a positive association between the quality or adjustment of an individual's intimate relationship, such as marriage, and their physical health. However, it is possible that this association may be due, at least in part, to confounding variables (i.e., variables that are causally associated both with relationship adjustment and health and could account for their covariation), including genetically influenced confounds. This study was conducted using a genetically informative sample of twins to examine the association between intimate relationship adjustment and self-rated health, accounting for unmeasured genetic and environmental confounds. METHOD A Swedish sample of 539 monozygotic and dizygotic twins (321 male twin pairs and 218 female twin pairs) and their spouse or long-term partner completed self-report measures of relationship adjustment and health. RESULTS Relationship adjustment was positively associated with self-rated health in male and female twins. For male twins, nonshared environmental influences largely accounted for the association between relationship adjustment and health; for female twins, this association was generally explained by shared and nonshared environmental influences. For male twins, results obtained from partners' reports of relationship adjustment were largely consistent with those obtained from twins' reports. CONCLUSIONS Results suggest that the association between relationship adjustment and self-rated health remains after accounting for shared genetic influences, and that nonshared environmental influences, such as partners' characteristics, account for the association between relationship adjustment and self-rated health in men. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The present study examined putative environmental predictors of adolescent substance use, using a prospective adoption design to distinguish between environmental mediation (i.e., parenting influencing adolescent substance use), passive gene–environment correlation (i.e., parental genetic predisposition influencing the association between parenting characteristics and adolescent substance use), and evocative gene–environment correlation (i.e., children’s genetic predisposition influencing parenting). Longitudinal data from the Colorado Adoption Project (395 adoptees, 491 nonadoptees, 485 adoptive parents, and 490 biological parents) were examined. Children (48% girls) were assessed at ages 1 to 17 years. Over 90% of the sample were non-Hispanic White. Associations between parenting and adolescent substance use were compared between adoptive and nonadoptive families. Positive, negative, and inconsistent parenting measures in early childhood through adolescence were not consistently associated with adolescent substance use, with only 6% of correlations being statistically significant (r = −0.152 to .207). However, parent–child relationship quality assessed from childhood to adolescence and orientation to parents assessed during adolescence were significantly, negatively associated with adolescent substance use, with 71% of correlations being statistically significant (r = −0.88 to −0.11). There was little evidence of sex differences in the associations. Environmental mediation, rather than passive or evocative gene–environment correlation, explained most associations.

Introduction Both rumination, a pattern of repetitive, self-focused thought in response to distress, and deficits in executive functions (EFs), a set of cognitive abilities that facilitate higher-order thinking, have transdiagnostic associations with psychopathology. Although empirical studies suggest associations between EFs and rumination, this literature has not examined subtypes of rumination and different components of EFs. It also has not examined whether rumination and EFs explain overlapping variance in psychopathology, which is relevant to theoretical models suggesting that rumination might mediate the EF–psychopathology association. Methods We used structural equation modeling to examine the association between latent factors for two types of rumination (anger and depressive) and three components of EF (a Common EF factor, and factors specific to updating working memory and shifting mental sets) and whether they independently relate to internalizing and externalizing psychopathology in a population sample of 764 young adults (mean age 23 years) from the Colorado Longitudinal Twin Study. Results Depressive and Anger Rumination showed small correlations with a Common EF factor (rs = –.09 to –.11). Anger Rumination and Common EF ability were associated with independent variance in externalizing psychopathology, whereas Depressive Rumination, but not Common EF, was associated with internalizing psychopathology. Limitations Examination of cross-sectional relations in a population sample led to low symptom endorsement for psychopathology and necessitated examination of lifetime, rather than past-year, psychopathology. Conclusions Inconsistent with mediation hypotheses, Common EF abilities and rumination are correlated yet largely independent constructs that both predict psychopathology.

Exposure to stressful life events increases risk for both internalizing and externalizing psychopathology, but less is known about moderators of the association between stressful life events and psychopathology. The present study examined the influence of stressful life events, psychopathy, and their interaction on internalizing and externalizing psychopathology in 3,877 individuals from the community. We hypothesized that (1) exposure to stressful life events would be a transdiagnostic risk factor for psychopathology, (2) primary and secondary psychopathy would be differentially associated with internalizing psychopathology, and (3) primary psychopathy would moderate the association between stressful life events and internalizing psychopathology. Confirming existing findings, our results were consistent with the first and second hypotheses. In contrast to our third hypothesis, primary psychopathy was not associated with stressful life events in childhood, inconsistently associated with stressful life events in adolescence, and did not moderate the association between stressful life events and internalizing psychopathology. Furthermore, stressful life events across development were associated with secondary psychopathy and internalizing and externalizing psychopathology. We also found similar associations between stressful life events, psychopathy, and psychopathology in females and males. Future studies investigating the impact of stressful life events on psychopathology should include psychopathic traits and stress-reactivity.

Although prior theory suggests that rumination contributes to cognitive impairments associated with depression, recent work suggests that rumination is associated with higher levels of intelligence. The present study examined the relations between two ruminative subtypes (brooding and reflective pondering) and multiple measures and types of intelligence (verbal and performance) after controlling for rumination's overlapping variance with depression. Participants were 751 individuals from the Colorado Longitudinal Twin Study who completed the Ruminative Response Scale; the Center for Epidemiological Studies-Depression Scale and a fully structured clinical interview as measures of depression; and verbal and performance intelligence tasks at age 16 and the Raven's Advanced Progressive Matrices at age 23. Reflective pondering was positively associated with all measures of intelligence, whereas brooding was not associated with intelligence. Our findings indicate that any negative associations between rumination and intelligence are attributable to shared variance with depression, and that examination of rumination as a multifaceted construct may provide new insights into the relations between rumination and cognition.

Although stress is frequently considered an environmental factor, dependent stressful life events (SLEs) -- stressors that result from one’s actions or behaviors -- may in fact be evoked by a genetic liability. It has been suggested that dependent SLEs may be partially caused by poor executive function (EFs), higher-level cognitive abilities that enable individuals to implement goal-directed behavior. We investigated the possibility of genetic and environmental overlap between SLEs and EFs in a longitudinal twin study. We found high genetic stability in the number of dependent SLEs from age 23 to age 29, suggesting that the number of dependent stressors show persistence across time due to their genetic etiology. In addition, there was a nominally significant negative genetic correlation between a Common EF latent factor and dependent SLEs at age 23. The genetic stability of dependent SLEs and association with Common EF provides insight into how some behaviors may lead to persistent stress.

The present study examined empathy deficits in toddlerhood (age 14 to 36 months) as predictors of antisocial personality disorder (ASPD) symptoms and psychopathy measured by the Levenson Self-Report Psychopathy scale (Levenson, Kiehl, & Fitzpatrick, 1995) in adulthood (age 23 years) in 956 individuals from the Colorado Longitudinal Twin Study. Consistent with the hypothesis that antisocial behavior is associated with “active” rather than “passive” empathy deficits, early disregard for others, not lack of concern for others, predicted later ASPD symptoms. Early disregard for others was also significantly associated with factor 1 of the Levenson Self-Report Psychopathy Scale, which includes items assessing interpersonal and affective deficits, but not with factor 2, which includes items assessing impulsivity and poor behavioral control. The association between early disregard for others and psychopathy factor 2 was near zero after controlling for the shared variance between psychopathy factors 1 and 2. These results suggest that there is a propensity toward adulthood ASPD symptoms and psychopathy factor 1 that can be assessed early in development, which may help identify individuals most at risk for stable antisocial outcomes.

The e4 allele of APOE is a well-established genetic risk factor for cognitive aging and dementia, but its influence on early life cognition is unknown. Consequently, we assessed associations of APOE genotypes with cognitive performance during 7, 12, and 16 year-assessments in our ongoing Colorado Adoption/Twin Study of Lifespan behavioral development (CATSLife). In general, APOE e4 was associated with lower Verbal, Performance, and Full Scale IQ scores during childhood and adolescence (e.g., Full Scale IQ was lower by 1.91 points per e4 allele, d = −0.13), with larger effects in females (e.g., average Full Scale IQ scores were 3.41 points lower in females per each e4 allele vs. 0.33 points lower in males). Thus, these results suggest that deleterious effects of the APOE e4 allele are manifested before adulthood, especially in females, and support both early origin theories and differential life-course vulnerabilities for later cognitive impairment.

BACKGROUND AND AIMS: Adolescents with conduct and substance use problems are at increased risk for premature mortality, but the extent to which these risk factors reflect family- or individual-level differences and account for shared or unique variance is unknown. This study examined common and independent contributions to mortality hazard in adolescents ascertained for conduct disorder (CD) and substance use disorder (SUD), their siblings and community controls, hypothesizing that individual differences in CD and SUD severity would explain unique variation in mortality risk beyond that due to clinical/control status and demographic factors. DESIGN: Mortality analysis in a prospective study (Genetics of Antisocial Drug Dependence Study) that began in 1993. Multi-site sample recruited in San Diego, California and Denver, Colorado, USA. PARTICIPANTS: A total of 1463 clinical probands were recruited through the juvenile correctional system, court-mandated substance abuse treatment programs and correctional schools, along with 1399 of their siblings, and 904 controls. MEASUREMENTS: Mortality and cause-of-death were assessed via National Death Index search (released October, 2017). FINDINGS: There were 104 deaths documented among 3766 (1168 female) adolescents and young adults (average age 16.79 years at assessment, 32.69 years at death/censoring). Mortality hazard for clinical probands and their siblings was 4.99 times greater than that of controls (95% confidence interval = 2.40-10.40; P

Lower self-control is a significant correlate or predictor of a wide range of adult outcomes, and this association may be due to more general tendencies toward childhood externalizing problems. The present study examined the association between toddlerhood self-control expressed within a “don’t” compliance task (at 14 to 36 months) and later externalizing problems (parent-reported externalizing problems from age 4 to 12 years, teacher-reported externalizing problems from age 7 to 12 years, and self-reported conduct disorder symptoms at age 17 years) in a longitudinal, genetically informative study. The slope of self-control, but not its intercept, predicted later teacher-reported, but not parent- or self-reported, externalizing problems. That is, increase in self-control during toddlerhood was associated with lower levels of later teacher-reported externalizing problems. The slope of self-control was no longer a significant predictor of teacher-reported externalizing problems after controlling for observed disregard for others, a robust predictor of externalizing problems. Thus, the hypothesis that self-control is the primary predictor of externalizing problems was not supported. Results from genetic analyses suggested that the covariance between the slope of self-control and teacher-reported externalizing problems is due to both genetic and shared environmental influences.

Associations of obesity and cardiovascular health with neighborhood walkability have been observed in the literature; however, limited research has evaluated self-selection that may underlie associations. We measured accessibility to parks and trails using geospatial measurements as well as self-reported activity-friendliness of neighborhoods (ease of walking, biking, and recreating) in 1140 participants (ages 28-49 years) in the ongoing Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging (CATSLife). Physical health indicators included BMI, resting heart rate, and mean arterial blood pressure. The relative similarity of siblings’ accessibility was evaluated to consider self-selection; all models were adjusted for sociodemographics including education. BMI was associated with accessibility to parks, with each increasing log(mile) distance associated with 1.2 BMI unit increase (se=.49, p0.40). Measures of park accessibility tended to be more similar among identical twins (median ICC = 0.30) than fraternal twins or siblings (median ICC = 0.15) or siblings in adoptive families (median ICC = 0.12), excluding siblings who live together. Measures of trail accessibility were consistent across sibling types (median ICCs = 0.25-0.27). Sibling similarity for park accessibility modestly increased with genetic relatedness suggesting potential heritable contributions, whereas comparable similarity was apparent for trail accessibility. Altogether, small associations were observed for park and trail access with physical health, with indications of environmental selection.

This study examined whether executive functions (EFs) might be common features of internalizing and externalizing behavior problems across development. We examined relations between three EF latent variables (a common EF factor and factors specific to updating working memory and shifting sets), constructed from nine laboratory tasks administered at age 17, to latent growth intercept (capturing stability) and slope (capturing change) factors of teacher- and parent-reported internalizing and externalizing behaviors in 885 individual twins aged 7 to 16 years. We then estimated the proportion of intercept–intercept and slope–slope correlations predicted by EF as well as the association between EFs and a common psychopathology factor (P factor) estimated from all 9 years of internalizing and externalizing measures. Common EF was negatively associated with the intercepts of teacher-rated internalizing and externalizing behavior in males, and explained 32% of their covariance; in the P factor model, common EF was associated with the P factor in males. Shifting-specific was positively associated with the externalizing slope across sex. EFs did not explain covariation between parent-rated behaviors. These results suggest that EFs are associated with stable problem behavior variation, explain small proportions of covariance, and are a risk factor that that may depend on gender.

Recent work on procrastination has begun to unravel the genetic and environmental correlates of this problematic behavior. However, little is known about how strongly procrastination is associated with internalizing and externalizing psychopathology, and the extent to which shared genetic/environmental factors or relevant personality constructs (e.g., fear of failure, impulsivity, and neuroticism) can inform the structure of these associations. The current study examined data from 764 young adult twins who completed questionnaires assessing procrastination and personality and structured interviews regarding psychopathology symptoms. Results indicated that procrastination was positively correlated with both internalizing and externalizing latent variables and that these correlations were driven by shared genetic influences. Moreover, the association between procrastination and internalizing was accounted for by fear of failure and neuroticism, whereas the association between procrastination and externalizing was primarily explained by impulsivity. The role of procrastination in psychopathology is discussed using a framework that highlights common and broadband-specific variance.

Neuroticism, a dispositional trait of heightened negative emotionality, is a vulnerability factor for psychopathology. Given neuroticism's strong association with rumination, a repetitive thought pattern that intensifies and prolongs emotions, some question whether these constructs capture the same or unique information about vulnerability for psychopathology. The present study examined whether neuroticism is genetically and environmentally distinct from two clinically relevant ruminative subtypes-anger and depressive rumination-and whether genetic and environmental influences specific to rumination versus shared with neuroticism overlap with internalizing and externalizing psychopathology. These analyses were conducted on 439 same-sex twin pairs in the Colorado Longitudinal Twin study. Rumination and neuroticism latent variables were created from multiple rumination questionnaires administered at age 23 and shortened Eysenck Personality Questionnaires administered at ages 17 and 21, respectively. Lifetime psychopathology symptoms, assessed by two structured clinical interviews, were used to create ordinal composite variables. Multivariate Cholesky decompositions indicated that neuroticism, anger rumination, and depressive rumination have common genetic and nonshared environmental influences but are differentiated by nonshared environmental influences specific to each ruminative subtype. Genetic influences common to rumination and neuroticism explained considerable variance in internalizing psychopathology, suggesting possible genetic mediation or common genetic causes. Genetic and environmental influences on externalizing psychopathology did not substantially overlap with those on neuroticism and rumination. These findings suggest that rumination and neuroticism share most genetic influences yet are influenced by distinct environmental influences. Furthermore, our results indicate that a comprehensive understanding of transdiagnostic risk factors must include an examination of both genetic and environmental influences. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Youth with loss of control eating (LOC) have poorer social relationships than youth without LOC. However, perceived family functioning among youth reporting LOC is relatively unexplored. We examined perceived family functioning among 990 twins (age = 17.47 ± 0.71 years, 53% female) from the Colorado Center for Antisocial Drug Dependence with (n = 158) and without (n = 832) LOC. LOC was assessed with one binary item. Associations between family functioning and LOC were examined using general linear models that accounted for dependence in twin data. Girls with greater family conflict had higher odds of endorsing LOC (p = .02), but not after accounting for depressive symptoms (p = .26). Further analysis indicated that depressive symptoms mediated the association between LOC and family conflict (p = .04). This finding is consistent with an interpersonal model, which proposes that interpersonal difficulties lead to negative emotional states, which promotes LOC as a method of coping with negative affect. Family cohesion and expressiveness were not associated with LOC in girls, and none of the family functioning variables were associated with LOC in boys (ps > .05). Future studies are needed to clarify these relations and to determine any relevant treatment indications.

Meta-analytic findings suggest that antisocial behavior, broadly defined, may relate to a Common Executive Function (EF) factor that captures covariance across response inhibition, working memory updating, and mental set shifting tasks. However, it is unclear whether this common factor, which is isomorphic with individual differences in response inhibition, accounts for all of the EF variance in antisocial behavior and psychopathy, or if they also relate to updating- and shifting-specific abilities. Moreover, findings that antisocial behavior and lower cognitive ability are particularly associated with the psychopathy dimension reflecting impulsivity and irresponsibility, compared to the dimension reflecting affective–interpersonal functioning, raise the possibility that EF relates to the variance shared between the impulsive–irresponsible psychopathy dimension and antisocial personality disorder. We examined these questions in a young adult twin sample (N = 765) with measures of multiple EF latent variables, Levenson Self-Report Psychopathy (LSRP) Primary (affective–interpersonal) and Secondary (impulsive–irresponsible) scales, and antisocial personality disorder symptoms (ASPDsx). Phenotypically, higher ASPDsx and LSRP Secondary psychopathy, but not LSRP Primary psychopathy, were associated with lower Common EF. Moreover, both psychopathy dimensions were negatively correlated with Updating-Specific ability, which was unrelated to ASPDsx. Results from twin models indicated that the association between LSRP Secondary psychopathy and ASPDsx was due to both genetic and nonshared environmental influences; however, Common EF's association with ASPDsx was primarily genetic, whereas its association with LSRP Secondary psychopathy had a significant environmental component. Thus, the interrelations among these constructs may reflect heterogeneous etiological pathways.

To our knowledge, this is the first study to examine the Diagnostic and Statistical Manual of Mental Disorders (DSM)-5-defined conduct disorder (CD) with limited prosocial emotions (LPE) among adolescents in substance use disorder (SUD) treatment, despite the high rates of CD in this population. We tested previously published methods of LPE categorization in a sample of male conduct-disordered patients in SUD treatment (N = 196). CD with LPE patients did not demonstrate a distinct pattern in terms of demographics or comorbidity regardless of the categorization method utilized. In conclusion, LPE, as operationalized here, does not identify a distinct subgroup of patients based on psychiatric comorbidity, SUD diagnoses, or demographics.

The genetic and environmental contributions to the variation and longitudinal stability in childhood aggressive behavior were assessed in two large twin cohorts, the Netherlands Twin Register (NTR), and the Twins Early Development Study (TEDS; United Kingdom). In NTR, maternal ratings on aggression from the Child Behavior Checklist (CBCL) were available for 10,765 twin pairs at age 7, for 8,557 twin pairs at age 9/10, and for 7,176 twin pairs at age 12. In TEDS, parental ratings of conduct disorder from the Strength and Difficulty Questionnaire (SDQ) were available for 6,897 twin pairs at age 7, for 3,028 twin pairs at age 9 and for 5,716 twin pairs at age 12. In both studies, stability and heritability of aggressive behavioral problems was high. Heritability was on average somewhat, but significantly, lower in TEDS (around 60%) than in NTR (between 50% and 80%) and sex differences were slightly larger in the NTR sample. In both studies, the influence of shared environment was similar: in boys shared environment explained around 20% of the variation in aggression across all ages while in girls its influence was absent around age 7 and only came into play at later ages. Longitudinal genetic correlations were the main reason for stability of aggressive behavior. Individual differences in CBCL-Aggressive Behavior and SDQ-Conduct disorder throughout childhood are driven by a comparable but significantly different genetic architecture. © 2016 Wiley Periodicals, Inc.

Background It is unclear whether cannabis use causes cognitive decline; several studies show an association between cannabis use and cognitive decline, but quasi-experimental twin studies have found little support for a causal effect. Here, we evaluate the association of cannabis use with general cognitive ability and executive functions (EFs) while controlling for genetic and shared environmental confounds in a longitudinal twin study. Methods We first examined the phenotypic associations between cannabis initiation, frequency, and use disorder with cognitive abilities, while also controlling for pre-use general cognitive ability and other substance involvement. We tested the concurrent association between the cannabis use variables and cognitive abilities in late adolescence and young adulthood and the longitudinal association between cannabis use variables during adolescence and young adulthood cognitive abilities. Next, we used multilevel models to test whether these relations reflect between- and/or within-twin pair associations. Results Phenotypically, cannabis use was related to poorer cognitive functioning, although most associations were negligible after accounting for other substance use. Nevertheless, there were few significant within-family twin-specific associations, except that age 17 cannabis frequency was associated with worse age 23 Common EF and general cognitive ability. Conclusions We found little support for a potential causal effect of cannabis use on cognition, consistent with previous twin studies. Results suggest that cannabis use may not cause decline in cognitive ability among a normative sample of cannabis users.

Developing self-restraint, or the inhibition of behavior in response to a prohibition, is an important process during toddlerhood. The objective of the present study was to gain a better understanding of individual differences in the development of self-restraint during toddlerhood by examining stable elements and growth of temperament (i.e., attentional control, behavioral inhibition, negative emotionality), general intelligence, and self-restraint. Participants were 412 same-sex twin pairs (approximately 90% European American) from predominately middle-class households in Colorado. Data were collected at 14, 20, 24, and 36 months. Results indicated that higher behavioral inhibition, attentional control, and intelligence were independently associated with better self-restraint, whereas higher negative emotionality was an independent predictor of lower self-restraint. The associations between temperament and self-restraint generally appeared to be stable from 14 to 36 months.

Background Studies have shown a correlation between language abilities and alcohol use; however, results are inconsistent. A recent study using a discordant twin design showed an association between early child language development and later alcohol use behaviors; i.e., the twin with more advanced language abilities was more likely to try alcohol earlier in adolescence (Latvala et al., 2014). The authors suggested that this could result from better socialization of individuals with greater language abilities, which could lead to more opportunities for alcohol experimentation. The findings by Latvala et al. raise interesting questions, but the study has limitations, and replication is needed. Method We aimed to replicate and build upon these results utilizing 488 same sex twin pairs from the Colorado Longitudinal Twin Study, a longitudinal sample with quantitative measures of language abilities starting when the twins were 14 months old. Results We found no significant correlations between a latent measure of child language abilities or measures of general cognitive ability at ages 14, 20, and 24 months and a latent alcohol use variable at ages 17 and 22 years. Conclusion Our results did not replicate the association between early language ability and later alcohol use reported by Latvala et al. Possible reasons for differing results across samples, including varying cultural norms as well as differences in educational attainment, peer influences, and novelty seeking, were discussed.

Background Prior research has found a reliable and robust association between poor dyadic (e.g., marital) adjustment and depression and anxiety. However, it is possible that this association may be due, at least in part, to confounding variables (i.e., variables that are causally associated both with marital adjustment and psychopathology and could account for their covariation). The present study was conducted using a genetically informative sample of twins to examine the association between dyadic adjustment and symptoms of depression and anxiety, accounting for unmeasured genetic and shared environmental confounds. Methods A Swedish sample of monozygotic and dizygotic twins (218 female twin pairs and 321 male twin pairs) and their spouse or long-term partner completed self-report measures of dyadic adjustment, depressive symptoms, and anxiety symptoms. Results Results suggest that dyadic adjustment was significantly and negatively associated with depressive symptoms and anxiety symptoms in twins, and nonshared environmental influences largely accounted for this association. Furthermore, results obtained from partners’ reports of dyadic adjustment were largely consistent with those obtained from twins’ reports, suggesting that results were not a function of shared method variance. Limitations Longitudinal research in genetically informative samples would provide a stronger test of the causal association between dyadic adjustment and psychopathology. Conclusions The pattern of findings suggest that common nonshared environmental influences, such as partners’ characteristics, may lead to poorer dyadic adjustment and depression and anxiety. Therefore, couple-based interventions that improve dyadic adjustment may be effective in preventing and treating psychopathology in relationship partners.

Internalizing and externalizing behaviors are heritable, and show genetic stability during childhood and adolescence. Less work has explored how genes influence individual differences in developmental trajectories. We estimated ACE biometrical latent growth curve models for the Teacher Report Form (TRF) and parent Child Behavior Checklist (CBCL) internalizing and externalizing scales from ages 7 to 16 years in 408 twin pairs from the Colorado Longitudinal Twin Study. We found that Intercept factors were highly heritable for both internalizing and externalizing behaviors (a2 = .61–.92), with small and nonsignificant environmental influences for teacher-rated data but significant nonshared environmental influences for parent-rated data. There was some evidence of heritability of decline in internalizing behavior (Slopes for teacher and parent ratings), but the Slope genetic variance was almost entirely shared with that for the Intercept when different than zero. These results suggest that genetic effects on these developmental trajectories operate primarily on initial levels and stability, with no significant unique genetic influences for change. Finally, cross-rater analyses of the growth factor scores revealed moderate to large genetic and environmental associations between growth factors derived from parents' and teachers' ratings, particularly the Intercepts.

Adolescents with conduct and substance use problems are at increased risk for premature mortality, but the extent to which these risk factors reflect family- or individual-level differences and account for shared or unique variance is unknown. This study examined common and independent contributions to mortality hazard in adolescents ascertained for conduct disorder (CD) and substance use disorder (SUD), their siblings and community controls, hypothesizing that individual differences in CD and SUD severity would explain unique variation in mortality risk beyond that due to clinical/control status and demographic factors.Mortality analysis in a prospective study (Genetics of Antisocial Drug Dependence Study) that began in 1993.Multi-site sample recruited in San Diego, California and Denver, Colorado, USA.A total of 1463 clinical probands were recruited through the juvenile correctional system, court-mandated substance abuse treatment programs and correctional schools, along with 1399 of their siblings, and 904 controls.Mortality and cause-of-death were assessed via National Death Index search (released October, 2017).There were 104 deaths documented among 3766 (1168 female) adolescents and young adults (average age 16.79 years at assessment, 32.69 years at death/censoring). Mortality hazard for clinical probands and their siblings was 4.99 times greater than that of controls (95% confidence interval = 2.40-10.40; P 0.001). After accounting for demographic characteristics, site, clinical status, familial dependence and shared contributions of CD and SUD, CD independently predicted mortality hazard, whereas SUD severity did not.In the United States, youth with conduct and substance use disorders and their siblings face far greater risk of premature death than demographically similar community controls. In contrast to substance use disorder severity, conduct disorder is a robust predictor of unique variance in all-cause mortality hazard beyond other risk factors.

Patients with longstanding trigger finger may develop flexion contracture at the proximal interphalangeal (PIP) joint that persists even after division of the A1 pulley. The purpose of this study was to explore the hypothesis that flexion deformity of the PIP joint in advanced trigger finger is caused by severe adhesion between the flexor digitorum superficialis (FDS) and the flexor digitorum profundus (FDP) tendons. Ten freshly frozen cadaveric hands were used in the experiments. After preparation of the extrinsic flexor, extrinsic extensor, and intrinsic muscle tendons, we applied weights to the flexor tendons and minimal tension to the extrinsic extensor and intrinsic muscle tendons. We then measured the initial flexion angles of the metacarpophalangeal (MCP) and PIP joints. Next, we measured the flexion angles of the MCP and PIP joints as increasing tension was applied to the extrinsic extensor and intrinsic muscle tendons, respectively. We repeated these experiments after constructing flexor tendon adhesion model. The initial flexion angles of the MCP and PIP joints were greater in the adhesion model, as were the average tensions required for full extension of these joints. Our results suggest that adhesion between two flexor tendons contributes to progression of flexion deformity in the PIP joint.

© 2015, Springer Science+Business Media New York. Behavioral disinhibition (BD) is a quantitative measure designed to capture the heritable variation encompassing risky and impulsive behaviors. As a result, BD represents an ideal target for discovering genetic loci that predispose individuals to a wide range of antisocial behaviors and substance misuse that together represent a large cost to society as a whole. Published genome-wide association studies (GWAS) have examined specific phenotypes that fall under the umbrella of BD (e.g. alcohol dependence, conduct disorder); however no GWAS has specifically examined the overall BD construct. We conducted a GWAS of BD using a sample of 1,901 adolescents over-selected for characteristics that define high BD, such as substance and antisocial behavior problems, finding no individual locus that surpassed genome-wide significance. Although no single SNP was significantly associated with BD, restricted maximum likelihood analysis estimated that 49.3 % of the variance in BD within the Caucasian sub-sample was accounted for by the genotyped SNPs (p = 0.06). Gene-based tests identified seven genes associated with BD (p ≤ 2.0 × 10−6). Although the current study was unable to identify specific SNPs or pathways with replicable effects on BD, the substantial sample variance that could be explained by all genotyped SNPs suggests that larger studies could successfully identify common variants associated with BD.

Existing literature on rumination has predominately focused on depressive rumination; thus, there is little research directly comparing different forms of rumination as correlates of psychopathological outcomes. In the present study the authors investigated anger and depressive rumination as correlates of internalizing and externalizing psychopathology. Cross-sectional confirmatory factor analyses on data from 764 young adults from the Colorado Longitudinal Twin Study indicated that anger and depressive rumination were separable at the latent variable level and were both associated with lifetime symptoms of internalizing and externalizing psychopathology. However, depressive rumination was more strongly associated with psychopathology than was anger rumination. Further analysis indicated that depressive rumination was independently associated with internalizing psychopathology, whereas associations between anger rumination and psychopathology were predominately due to shared variance with depressive rumination. Anger rumination was independently associated with externalizing psychopathology in women and was inversely associated with internalizing psychopathology in men. This result supports the clinical relevance of ruminative thought processes and the potential differential utility of anger and depressive content for understanding internalizing and externalizing psychopathology.

The present study examined the influence of maternal and child characteristics on parenting behaviors in a genetically informative study. The participants were 976 twins and their mothers from the Colorado Longitudinal Twin Study and the Twin Infant Project. Indicators of positive parenting were coded during parent–child interactions when twins were 7–36 months old. Child cognitive abilities and affection were independent correlates of positive parenting. There were significant gender differences in the magnitude of genetic and environmental influences on positive parenting, with shared environmental influences on parenting of girls and additive genetic influences on parenting of boys. Girls received significantly more positive parenting than boys. Differences in etiology of positive parenting may be explained by developmental gender differences in child cognitive abilities and affection, such that girls may have more rewarding interactions with parents, evoking more positive parenting.

Previous studies have established that personality traits related to emotionality are moderately heritable. However, the relative heritability of the strategies people use to regulate emotions is unknown. The present study compared the magnitude of additive genetic, shared environmental, and nonshared environmental influences on 2 commonly used emotion regulation strategies: cognitive reappraisal and expressive suppression. In 743 twin pairs (1,486 twins), we replicated previous estimates of heritability of neuroticism (a2 = .41). Furthermore, cognitive reappraisal was significantly less heritable and more influenced by nonshared environment (a2 = .20; e2 = .80) than either neuroticism or suppression (a2 = .35; e2 = .65), another emotion regulation strategy. Finally, Cholesky decomposition modeling suggested that while there were common genetic and environmental influences on neuroticism, reappraisal and suppression, there were also significant nonshared environmental influences common between reappraisal and adaptive emotional functioning after controlling for neuroticism and suppression. These findings highlight that different aspects of emotional processing, even the use of different emotion regulation strategies, are differentially heritable. The importance of the nonshared environmental influences specific to reappraisal and adaptive emotional functioning speaks to the potential impact of social context, social partners, and psychosocial interventions on reappraisal habits. (PsycINFO Database Record

This study examined the genetic and environmental influences on rumination and its associations with several forms of psychopathology in a sample of adult twins ( N = 744). Rumination was significantly associated with major depressive disorder, depressive symptoms, generalized anxiety disorder, eating pathology, and substance dependence symptoms. There were distinct patterns of etiological overlap between rumination and each form of psychopathology; rumination had considerable genetic overlap with depression, modest genetic overlap with eating pathology, and almost no genetic overlap with substance dependence. Findings further suggest considerable overlap between genetic and environmental influences on rumination and those contributing to the covariance between forms of psychopathology. Results were specific to ruminative thought and did not extend to self-reflection. These findings support the conceptualization of rumination as a transdiagnostic correlate and risk factor for psychopathology and also suggest that the biological and environmental mechanisms linking rumination to psychopathology may differ depending on the disorder.

Distal radius fracture is the most common fracture of the upper extremity, with an annual incidence of 2 to 4 per 1,000 persons.1) The annual incidence of distal radius fracture is increasing in elderly population, due to an increase in life expectancy, as well as in young population, due to sports activities. Approximately 60,000 distal radius fractures occur annually in Korea, and the residual lifetime risk is about 21.7% for women aged 50 years.2) Various treatment options are available for distal radius fractures. Stable distal radius fractures can be successfully treated by conservative methods, such as splinting or casting. However, some cases of unstable distal radius fractures and displaced intra-articular fractures require surgical treatment. Surgical options for the treatment of distal radius fractures include percutaneous pinning, internal fixation, and external fixation. Among these methods, the use of internal fixation using a volar locking plating system is the most common.3,4) At present, volar locking plate is generally used in the treatment of unstable distal radius fracture because of its advantages and the advancements presented with plate fixation systems. Various types of distal radius anatomical plates have been developed and are in widespread use. However, these anatomical plates were designed in Western countries, based on the anatomical characteristics of Western populations. Koreans have different anatomical features from those of the Western populations, such as a relatively small and short radius, especially in elderly women. And the angle of volar cortex is comparatively more acute than that of Western populations.5) Therefore, the conventional anatomical plate systems specific for the Western populations do not always anatomically fit in Korean patients. In some patients, although the smallest conventional anatomical plate system was chosen, the plate size was too large for small radius of elderly Korean women. And in some patients, the precontoured plates do not appropriately contact the volar cortex. These mismatches of the anatomically precontoured plate system may cause complications, such as failure to achieve anatomic reduction, failure to achieve firm contact of the plate on the cortex, and tendon or nerve irritation.6) Thus, Korean type of anatomical volar plate system was required to solve these problems. The Korean-type distal radius anatomical volar plate (K-DRAVP) system was designed and developed based on anatomical characteristics of distal radius of Koreans.5) The purpose of this study was to evaluate the preliminary results of the new K-DRAVP system, and to compare its radiologic and clinical results with those of the other systems.

Summary Background and aim The purpose of this study was to evaluate the anatomical constancy of the direct small branches of the proper digital nerve. Methods A total of 208 digital nerves of the index, long, ring, and little fingers from 13 cadavers were studied. For each digital nerve, the number of direct small branches was counted at the proximal and middle phalanx levels. In addition, the diameter of these branches was measured at the level of the branch bifurcation. We also measured the diameter of the proper digital nerve at the level of the distal interphalangeal (DIP) joint. Results The direct small branches of the proper digital nerve were anatomically constant among the index, long, and ring fingers. The average number of direct small branches was 2.7 at the proximal phalanx level and 2.3 at the middle phalanx level. At the level of the DIP joint, the average thickness of the proper digital nerve was 0.85 mm in the index finger, 0.84 mm in the long finger, 0.72 mm in the ring finger, and 0.49 mm in the little finger. Conclusion In this study, we verified the anatomical constancy of the direct small branches of the proper digital nerve. The size of these branches at the proximal phalanx level was similar to that of the corresponding proper digital nerve at the level of the DIP joint. Therefore, these nerve branches at the proximal phalanx could be applied to the creation of various sensate flaps for the reconstruction of the fingertip injuries.

Studies have reported an inverse association between language development and behavioral inhibition or shyness across childhood, but the direction of this association is unclear. The present study tested alternative hypotheses regarding this association in a large sample of toddlers. Data on behavioral inhibition and expressive and receptive language abilities were collected from 816 twins at ages 14, 20, and 24 months. Growth and regression models were fit to the data to assess the longitudinal associations between behavioral inhibition and language development from 14 to 24 months. Overall, there were significant associations between behavioral inhibition and expressive language, and minimal associations with receptive language, indicating that the association is better explained by reticence to respond rather than deficient language development.

This study was conducted to estimate the magnitude of genetic and environmental influences on the association between three indices of subjective well-being (i.e., life satisfaction, positive affect, negative affect) and positive and negative components of marital adjustment (i.e., spousal support, spousal strain) in a sample of adult married twin pairs (N = 453 pairs). Results indicated that subjective well-being and marital adjustment were significantly associated (particularly in women), that there were gender differences in the magnitude of genetic and environmental influences on this covariation, and that this association was largely influenced by genetic factors in women and genetic and nonshared environmental factors in men. These findings highlight the importance of using genetically informed research to evaluate the genetic and environmental influences on the covariation between marital adjustment and individual outcomes such as subjective well-being.

Background: We identified a subset of patients who had posterolateral rotatory instability (PLRI) following corrective osteotomy for asymptomatic cubitus varus deformity. We aimed to identify risk factors for PLRI in such patients by comparing this subgroup to patients who did not demonstrate PLRI following osteotomy.Methods: We retrospectively reviewed the medical records and radiographs of 22 patients with cubitus varus that underwent corrective osteotomy at our institution between 2003 and 2010. All patients underwent surgery for cosmetic reasons, and no patient reported functional problems such as PLRI or ulnar nerve symptoms pre-operatively. We sought to identify differences between those that experienced an increase in PLRI after osteotomy (PLRI group) and those that did not (non-PLRI group) with regard to demographics, degree of deformity, amount of surgical correction, and final outcomes.Results: Five patients had PLRI after osteotomy, and all five subsequently underwent lateral ulnar collateral ligament reconstruction using a triceps tendon graft. No statistically significant difference was observed between the PLRI and non-PLRI groups in terms of demographics, degree of deformity, amount of surgical correction, range of motion, and final Mayo Elbow Performance Index (MEPI) and the Disabilities of Arm, Shoulder, and Hand (DASH) scores. However, the PLRI group had marginally greater medial displacement of the distal fragment.Conclusions: This study demonstrates that PLRI can become apparent after corrective osteotomy for cubitus varus in the absence of clinical symptoms of instability preoperatively. We suggest that careful examination for PLRI should be performed after surgical correction for cubitus varus deformity, and surgeons should be prepared to proceed with simultaneous reconstruction of the lateral ligaments of the elbow.

Objective To identify robust predictors of drug dependence. Methods This longitudinal study included 2361 male and female twins from an ongoing longitudinal study at the Center for Antisocial Drug Dependence (CADD) at the University of Colorado Boulder and Denver campuses. Twins were recruited for the CADD project while they were between the ages of 12 and 18. Participants in the current study were on average approximately 15 years of age during the first wave of assessment and approximately 20 years of age at the second wave of assessment. The average time between assessments was five years. A structured interview was administered at each assessment to determine patterns of substance use and Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; Fourth Edition) attention deficit hyperactivity disorder (ADHD), conduct disorder (CD), and drug dependence symptoms. Cloninger's Tridimensional Personality Questionnaire was also used to assess novelty seeking tendencies (NS). At the second wave of assessment, DSM-IV dependence symptoms were reassessed using the same interview. Path analyses were used to examine direct and indirect mechanisms linking psychopathology and drug outcomes. Results Adolescent substance use, CD, and NS predicted young adult substance dependence, whereas the predictive effects of ADHD were few and inconsistent. Furthermore, CD and NS effects were partially mediated by adolescent substance use. Conclusions Adolescent conduct problems, novelty seeking, and drug use are important indices of future drug problems. The strongest predictor was novelty seeking.

Although integrin-linked kinase (ILK) has been suggested to play a role in the tumorigenesis of a number of human epithelial carcinomas, little is known of its role in musculoskeletal sarcoma. The authors studied ILK expression by immunohistochemistry using osteosarcoma prechemotherapy specimens from 56 patients, and investigated the prognostic implications of the findings obtained. It was found that ILK overexpression was significantly correlated with the presence of distant metastasis (p = 0.008) and that it was an independent prognostic factor for both poor overall survival and poor event-free survival (p = 0.015 and 0.010, respectively). During a transfection experiment conducted by transfecting osteosarcoma cells with ILK siRNA, VEGF concentrations were measured using an ELISA kit, and then compared with those of untransfected controls to evaluate its angiogenic effects. In addition, apoptotic percentages were measured by Annexin-V flow cytometry, and invasive properties were evaluated by measuring the numbers of non-migrating cells in a Boyden chamber. It was found that ILK downregulation significantly decreased angiogenesis, increased apoptosis, and decreased invasiveness of osteosarcoma cells. These results show that ILK is a promising prognostic factor in osteosarcoma and a novel potential therapeutic target for the treatment of osteosarcoma. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1668–1675, 2013

We examined the associations between language skills and concern and disregard for others in young children assessed longitudinally at ages 14, 20, 24, and 36 months, testing the hypothesis that language skills have a specific role (distinct from that of general cognitive ability) in the development of concern and disregard for others. We found that higher language skills predicted higher concern for others and lower disregard for others even after controlling for general cognitive ability, whereas the association between general cognitive ability and concern/disregard for others was not significant after controlling for language skills. Language skills at 14 months predicted concern for others at 36 months, and results suggested that the relations between language skills and concern and disregard for others begin early in development. Gender differences in concern and disregard for others were at least partially explained by differences in language skills. These results support the specific role of language skills in concern and disregard for others.

Background: Prediction of antisocial behavior is important, given its adverse impact on both the individuals engaging in antisocial behavior and society. Additional research identifying early predictors of future antisocial behavior, or antisocial propensity, is needed. The present study tested the hypothesis that both concern for others and active disregard for others in distress in toddlers and young children predict antisocial behavior during middle childhood and adolescence. Methods: A representative sample of same-sex twins (N = 956) recruited in Colorado was examined. Mother-rated and researcher-observed concern and disregard for others assessed at age 14–36 months were examined as predictors of parent- (age 4–12), teacher- (age 7–12), and self-reported (age 17) antisocial behavior. Results: Observed disregard for others predicted antisocial behavior assessed by three different informants (parents, teachers, and self), including antisocial behavior assessed 14 years later. It also predicted a higher order antisocial behavior factor (β = .58, p