J Myers

Virginia Commonwealth University, Richmond, Virginia, United States

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Publications (14)102.69 Total impact

  • K S Kendler, J Myers
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    ABSTRACT: BACKGROUND: The distribution and co-morbidity of common psychiatric disorders can be largely explained as manifestations of two broad psychopathological spectra of internalizing and externalizing disorders. Twin studies suggest that these spectra arise from genetic factors. Method Structural equation twin modeling was applied to interview and questionnaire data on personality traits and lifetime psychiatric disorders on more than 5300 members of male-male (MM) and female-female (FF) twin pairs. RESULTS: The best-fitting models for both the externalizing and internalizing spectra differed significantly in males and females. In males, the externalizing genetic common factor was best indexed by four disorders in the following order: antisocial personality disorder (ASPD), drug abuse/dependence (DAD), alcohol abuse dependence (AAD) and conduct disorder (CD). In females, the four disorders most closely related to the externalizing common factor were, in order: DAD, AAD, nicotine dependence (ND) and ASPD. Personality traits of novelty seeking (NS) and extraversion (E) better indexed the genetic externalizing spectrum in females than in males. In both males and females, major depression (MD) and generalized anxiety disorder (GAD) best indexed the genetic internalizing common factor. Panic disorder (PD) and agoraphobia (AgP) better reflected the internalizing genetic common factor in women, and neuroticism (N) in men. Genetic correlations between the two spectra were estimated at + 0.53 in males and + 0.52 in females. CONCLUSIONS: The disorders that optimally index the genetic liability to externalizing and internalizing disorders in the general population differ meaningfully in men and women. In both sexes, these genetic spectra are better assessed by psychiatric disorders than by personality traits.
    Psychological Medicine 04/2013; · 5.59 Impact Factor
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    ABSTRACT: Gjerde LC, Czajkowski N, Røysamb E, Ørstavik RE, Knudsen GP, Østby K, Torgersen S, Myers J, Kendler KS, Reichborn-Kjennerud T. The heritability of avoidant and dependent personality disorder assessed by personal interview and questionnaire. Objective:  Personality disorders (PDs) have been shown to be modestly heritable. Accurate heritability estimates are, however, dependent on reliable measurement methods, as measurement error deflates heritability. The aim of this study was to estimate the heritability of DSM-IV avoidant and dependent personality disorder, by including two measures of the PDs at two time points. Method:  Data were obtained from a population-based cohort of young adult Norwegian twins, of whom 8045 had completed a self-report questionnaire assessing PD traits. 2794 of these twins subsequently underwent a structured diagnostic interview for DSM-IV PDs. Questionnaire items predicting interview results were selected by multiple regression, and measurement models of the PDs were fitted in Mx. Results:  The heritabilities of the PD factors were 0.64 for avoidant PD and 0.66 for dependent PD. No evidence of common environment, that is, environmental factors that are shared between twins and make them similar, was found. Genetic and environmental contributions to avoidant and dependent PD seemed to be the same across sexes. Conclusion:  The combination of both a questionnaire- and an interview assessment of avoidant and dependent PD results in substantially higher heritabilities than previously found using single-occasion interviews only.
    Acta Psychiatrica Scandinavica 04/2012; · 4.86 Impact Factor
  • C Blanco, J Myers, K S Kendler
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    ABSTRACT: Relatively little is known about the environmental and genetic contributions to gambling frequency and disordered gambling (DG), the full continuum of gambling-related problems that includes pathological gambling (PG). A web-based sample (n=43,799 including both members of 609 twin and 303 sibling pairs) completed assessments of number of lifetime gambling episodes, DSM-IV criteria for PG, alcohol, nicotine and caffeine intake, and nicotine dependence (ND) and DSM-III-R criteria for lifetime major depression (MD). Twin modeling was performed using Mx. In the entire cohort, symptoms of DG indexed a single dimension of liability. Symptoms of DG were weakly related to caffeine intake and moderately related to MD, consumption of cigarettes and alcohol, and ND. In twin and sibling pairs, familial resemblance for number of times gambled resulted from both familial-environmental (c²=42%) and genetic factors (a²=32%). For symptoms of DG, resemblance resulted solely from genetic factors (a²=83%). Bivariate analyses indicated a low genetic correlation between symptoms of DG and MD (r(a)=+0.14) whereas genetic correlations with DG symptoms were substantially higher with use of alcohol, caffeine and nicotine, and ND (ranging from +0.29 to +0.80). The results were invariant across genders. Whereas gambling participation is determined by shared environmental and genetic factors, DG constitutes a single latent dimension that is largely genetically determined and more closely related to externalizing than internalizing behaviors. Because these findings are invariant across genders, they suggest that the etiological factors of DG are likely to be similar in men and women.
    Psychological Medicine 08/2011; 42(3):497-508. · 5.59 Impact Factor
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    ABSTRACT: We make sense of human behavior using reasons, which produce understanding via a subjective empathy-based first-person perspective and causes, which leads to explanations utilizing objective facts about the world assessed scientifically. We evaluate the common sense hypothesis that for episodes of major depression (MD), reasons act as causes. That is, individuals who have highly understandable depressive episodes will have, on average, fewer objective scientifically validated causes than those who have un-understandable episodes. The understandability of a MD as defined by the Diagnostic and Statistical Manual, 4th Edition (DSM IV) experienced in the past year in 630 personally interviewed twins from a population-based registry was rated, with high reliability, from rich contextual information. We predicted, from these understandability ratings, via linear and logistic regression, 12 validated risk factors for MD reflecting genetic and long-term environmental liability. No significant association was observed between 11 of these indices and the understandability of the depressive episode. The only significant finding-higher cotwin risk for MD associated with greater understandability-was opposite that predicted by the reasons-as-causes hypothesis. Our results do not support the hypothesis that reasons for MD act as causes. These findings, unlikely to result from low power, may be explicable from an empirical and/or philosophical perspective. Our results are, however, consistent with 'the trap of meaning' hypothesis, which suggests that understanding does not equal explanation and that while reasons may be critical to help us empathize with our patients, they are unreliable indices of objective risk factors for illness.
    Molecular Psychiatry 03/2011; 16(6):626-33. · 15.15 Impact Factor
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    ABSTRACT: To describe the structure of genetic and environmental risk factors for four dimensions of borderline personality disorder (BPD) and to understand the source of resemblance of these dimensions and normal personality. A web-based sample (n = 44,112 including 542 twin pairs) completed items from 4 scales of the Dimensional Assessment of Personality Pathology Basic Questionnaire and the Big Five Inventory. A one-factor common pathway model best fits the 4 BPD scales producing a highly heritable latent liability (heritability = 60%) and strong loadings on all 4 dimensions. Affective instability had the lowest trait-specific genetic loading, suggesting that it was a core feature of BPD. A complex pattern of genetic and environmental associations was found between the big five personality traits and BPD dimensions. The strongest genetic correlations with the BPD traits were generally seen for neuroticism (positive), followed by conscientiousness and agreeableness, both negative. In the general population, these four BPD dimensions reflect one underlying highly heritable factor. The association between normative personality and dimensions of BPD is complex with high degrees of genetic correlation.
    Acta Psychiatrica Scandinavica 12/2010; 123(5):349-59. · 4.86 Impact Factor
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    K S Kendler, J Myers
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    ABSTRACT: Certain personality traits have long been suspected to reflect an enduring vulnerability to major depression (MD) in part because of shared genetic risk factors. Although many have agreed that normative personality is well captured by the 'Big-Five' personality traits of Openness (O), Conscientiousness (C), Extraversion (E), Agreeableness (A) and Neuroticism (N), to date genetically informative studies have only examined the relationship between MD and N and E. Questionnaires were completed on a website, yielding a sample of 44 112 subjects including both members of 542 same-sex twin pairs. Personality was measured by the Big Five Inventory. Structural modeling was performed by Mx. Three of the big-five personality traits--O, E and A--had small phenotypic associations with risk for MD and small genetic correlations. Two traits--N and C--had stronger phenotypic associations (positive for N and negative for C) with the following estimates of the genetic correlation with MD: +0.43 for N and -0.36 for C. N and C were moderately negatively correlated. Controlling for N reduced the genetic correlation between C and MD more than controlling for C reduced the genetic correlation between N and MD. A large proportion of the genetic risk for MD that is expressed via personality is captured by N, with a modest amount due to C, and small amounts from O, E and A.
    Psychological Medicine 10/2009; 40(5):801-6. · 5.59 Impact Factor
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    ABSTRACT: The diagnosis of certain psychiatric syndromes (e.g. panic attacks, post-traumatic stress disorder) is crucially dependent on the psychosocial context in which they arise. For other syndromes (e.g. schizophrenia), the context is generally irrelevant. Should the diagnosis of major depression (MD) be made dependent upon or independent of the psychosocial context in which it occurs? Twins were selected from a population-based registry who, on personal interview, reported developing a full depressive syndrome either 'out of the blue' or in response to stressful life events (SLEs) rated objectively as having mild, low moderate, high moderate or severe long-term contextual threat (LTCT). In these depressed subjects, no relationship was found between the level of adversity associated with onset and most indices of liability to depression, including risk of MD in co-twin and parents, level of neuroticism, risk for future depressive episodes, co-morbidity with other internalizing disorders and history of sexual abuse. Compared to the remainder of this epidemiologic cohort, subjects developing depression in response to the severe threat events had substantially elevated levels of all the examined indices of liability to MD. Individuals who develop a full depressive syndrome in response to high-threat events do not have an appreciably lower liability to MD than those developing depression after exposure to low adversity and have much higher liability to depression than observed in their population cohort. These results support the hypothesis that, in general, MD can be diagnosed independently of the psychosocial context in which it arises.
    Psychological Medicine 09/2009; 40(5):771-80. · 5.59 Impact Factor
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    ABSTRACT: While the role of genetic factors in self-report measures of emotion has been frequently studied, we know little about the degree to which genetic factors influence emotional facial expressions. Twenty-eight pairs of monozygotic (MZ) and dizygotic (DZ) twins from the Minnesota Study of Twins Reared Apart were shown three emotion-inducing films and their facial responses recorded. These recordings were blindly scored by trained raters. Ranked correlations between twins were calculated controlling for age and sex. Twin pairs were significantly correlated for facial expressions of general positive emotions, happiness, surprise and anger, but not for general negative emotions, sadness, or disgust or average emotional intensity. MZ pairs (n=18) were more correlated than DZ pairs (n=10) for most but not all emotional expressions. Since these twin pairs had minimal contact with each other prior to testing, these results support significant genetic effects on the facial display of at least some human emotions in response to standardized stimuli. The small sample size resulted in estimated twin correlations with very wide confidence intervals.
    Psychological Medicine 11/2007; 38(10):1475-83. · 5.59 Impact Factor
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    ABSTRACT: Psychiatric diagnoses obtained at personal interview are only moderately reliable and depend critically on accurate self-observation. Reports by family members provide additional information but may be biased. It is unclear how best to combine these two sources of diagnostic data. Using complete data on lifetime prevalence for six disorders in approximately 1200 male-male twin pairs from a population based registry, we first applied a standard bivariate twin model--which treats self-diagnoses and informant-diagnoses as separate phenotypes--and then examined a 'multiple-rater' model--which assumes that self-report and co-twin-report are fallible indices of one underlying disease liability. Best-fit models were chosen using Akaike's information criterion. Standard bivariate analyses indicated that the same genetic factors accounted for variation in self-reported and co-twin-reported diagnoses. The multiple-rater model produced a substantial decrease in variance attributed to individual-specific environment and a proportional increase in heritability of liability for major depression, generalized anxiety disorder, alcohol dependence and adult antisocial behaviour, but not for drug abuse/dependence or regular tobacco use. The best-fit model consistently included either a 'bias' or a 'correlated error' path. No evidence for family environmental risk factors was found for any disorder. The genetic factors that influence self-report psychiatric illness also influence psychiatric illness as described by relatives. For many psychiatric disorders, incorporation of self-report and family history data in a single model may reduce measurement error and increase estimates of heritability. However, account must be taken of the fact that family history reports are systematically biased. While promising, these results are preliminary and require replication.
    Psychological Medicine 08/2002; 32(5):829-42. · 5.59 Impact Factor
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    ABSTRACT: For irrational fears and their associated phobias, epidemiological studies suggest sex differences in prevalence and twin studies report significant genetic effects. How does sex impact on the familial transmission of liability to fears and phobias? In personal interviews with over 3000 complete pairs (of whom 1058 were opposite-sex dizygotic pairs), ascertained from a population-based registry, we assessed the lifetime prevalence of five phobias and their associated irrational fears analysed using a multiple threshold model. Twin resemblance was assessed by polychoric correlations and biometrical model-fitting incorporating sex-specific effects. For agoraphobia, situational and blood/injury fear/phobia, the best fit model suggested equal heritability in males and females and genetic correlations between the sexes of less than +0.50. For animal fear/phobias by contrast, the best fit model suggested equal heritability in males and females and a genetic correlation of unity. No evidence was found for an impact of family environment on liability to these fears or phobias. For social phobias, twin resemblance in males was explained by genetic factors and in females by familial-environmental factors. The impact of sex on genetic risk may differ meaningfully across phobia subtypes. Sex-specific genetic risk factors may exist for agoraphobia, social, situational and blood-injury phobias but not for animal fear/phobia. These results should be interpreted in the context of the limited power of twin studies, even with large sample sizes, to resolve sex-specific genetic effects.
    Psychological Medicine 03/2002; 32(2):209-17. · 5.59 Impact Factor
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    ABSTRACT: Much of our knowledge of the role of genetic factors in the etiology of phobias comes from one population-based sample of female twins. We examined the sources of individual differences in the risks for phobias and their associated irrational fears in male twins. In personal interviews with both members of 1198 male-male twin pairs (707 monozygotic [MZ] and 491 dizygotic [DZ]) ascertained from a population-based registry, we assessed the lifetime history of agoraphobia and social, animal, situational, and blood/injury phobias as well as their associated irrational fears. Twin resemblance was assessed by means of probandwise concordance, odds ratios, tetrachoric correlations, and univariate and multivariate biometrical model fitting. The suggestive results obtained by analysis of phobias only were supported by analyzing both fears and phobias. All 5 phobia subtypes aggregate within twin-pairs. This aggregation is due largely or solely to genetic factors with heritability of liabilities ranging from 25% to 37%. Multivariate analysis revealed a common genetic factor, genetic factors specific to each subtype, and a common familial-environmental factor. In male subjects, genetic risk factors, which are partially common across all subtypes and partially subtype specific, play a moderate role in the etiology of phobias and their associated irrational fears. Family environment probably has an impact on risk for agoraphobia and social phobia. The genetic liability to blood/injury phobias is not distinct from those of the more typical phobias.
    Archives of General Psychiatry 04/2001; 58(3):257-65. · 13.77 Impact Factor
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    ABSTRACT: Women who report childhood sexual abuse (CSA) are at increased risk for developing psychiatric disorders in adulthood. What is the diagnostic specificity and cause of this association? In a population-based sample of 1411 female adult twins, 3 levels of CSA were assessed by self-report and cotwin report: nongenital, genital, and intercourse. Interviews with twins and parents assessed family background and diagnoses of psychiatric and substance dependence disorders. Odds ratios (ORs) were calculated by logistic regression. By self-report, 30.4% reported any CSA and 8.4% reported intercourse. Self-reported CSA was positively associated with all disorders, the highest ORs being seen with bulimia and alcohol and other drug dependence. The ORs were modest and often nonsignificant with nongenital CSA and increased with genital CSA and especially intercourse, where most ORs exceeded 3.0. A similar pattern of findings was seen with CSA as reported by the cotwin, although many ORs were smaller. Controlling for family background factors and parental psychopathology produced a small to modest reduction in ORs. In twin pairs discordant for CSA, the exposed twin was at consistently higher risk of illness. Women with CSA have a substantially increased risk for developing a wide range of psychopathology. Most of this association is due to more severe forms of CSA and cannot be explained by background familial factors. Although other biases cannot be ruled out, these results are consistent with the hypothesis that CSA is causally related to an increased risk for psychiatric and substance abuse disorders.
    Archives of General Psychiatry 11/2000; 57(10):953-9. · 13.77 Impact Factor
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    ABSTRACT: Although parenting has long been considered an important risk factor for subsequent psychopathology, most investigations of this question have studied a single informant, clinical populations, one or a few disorders and did not consider relevant covariates. Three dimensions of parenting (coldness, protectiveness and authoritarianism) were measured by combining the retrospective reports from adult female twins, their co-twins, and their mothers and fathers. We assessed by personal interview, lifetime history in the twins of eight common psychiatric and substance abuse disorders and a range of predictors of parenting. Analyses were performed using logistic regression. Examined individually, high levels of coldness and authoritarianism were modestly but significantly associated with increased risk for nearly all disorders, while the impact of protectiveness was more variable. These associations declined modestly when putative predictors of parenting were added as covariates. Maternal and paternal parenting were equally associated with outcomes in adult daughters. When coldness, protectiveness and authoritarianism were examined together, nearly all significant associations were seen solely with coldness. Few significant interactions were found between maternal and paternal parenting or between coldness, protectiveness and authoritarianism. The shared experience of these three dimensions of parenting predicts a quite small correlation in liability to these disorders in dizygotic twin pairs (e.g. r < 0.04). In women, parenting behaviour, especially levels of coldness, is probably causally related to risk for a broad range of adult psychiatric disorders. The impact of parenting on substance use disorders may be largely mediated through their co-morbidity with major depression, phobias and generalized anxiety disorder. In general population samples, the association of poor parenting with psychiatric illness is modest, largely non-specific and explains little of the observed aggregation of these disorders in families.
    Psychological Medicine 03/2000; 30(2):281-94. · 5.59 Impact Factor
  • J.  MYERS , C. A.  PRESCOTT 
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    ABSTRACT: Background. Although parenting has long been considered an important risk factor for subsequent psychopathology, most investigations of this question have studied a single informant, clinical populations, one or a few disorders and did not consider relevant covariates.
    Psychological Medicine 02/2000; 30(02):281 - 294. · 5.59 Impact Factor