Biomedical subjects

R C Kessler

Publications and source records attributed to R C Kessler.

At least 163 records · Page 9Linked to original sources

PubMed1993

Bulimia nervosa: a population-based study of purgers versus nonpurgers.

There has been recent interest in the possibility of dividing bulimia nervosa into two subtypes based on the method of weight prevention utilized by the individual. In an attempt to see if such a division is justified, this study compared 54 purging bulimics with 69 nonpurging bulimics ascertained from a population-based register of Virginia female twins. A bulimic was defined as a "purger" if she engaged in vomiting or laxative abuse. These two groups were examined on a variety of demographic, weight, and personality measures after controlling for the presence of obesity. No significant differences were found between the two groups on any of the variables examined.

Adult↗

PubMed1993

Primary prevention of secondary disorders: a proposal and agenda.

This paper calls for consideration of a new class of preventive interventions designed explicitly to prevent comorbidity of psychiatric disorders. Epidemiologic data show that successful interventions of this type could be extremely valuable, as up to half of lifetime psychiatric disorders and an even larger percent of chronic and seriously impairing disorders occur to people with a prior history of some other disorder. Furthermore, a review of etiologic hypotheses concerning the causes of comorbidity suggests that interventions aimed at primary prevention of secondary disorders might be feasible. However, more basic risk factor research is needed on the causes of comorbidity before we can make a clear assessment of feasibility and discover promising intervention targets. A number of methodological problems arise in carrying out this type of formative research. These problems are reviewed and suggestions are offered for solutions involving innovations in measurement, design, and data analysis.

Child of Impaired Parents↗

PubMed1993

A test of the equal-environment assumption in twin studies of psychiatric illness.

The traditional twin method is predicated on the equal-environment assumption (EEA)--that monozygotic (MZ) and dizygotic (DZ) twins are equally correlated in their exposure to environmental events of etiologic importance for the trait under study. In 1968, Scarr proposed a test of the EEA which examines the impact of phenotypic similarity in twins of perceived versus true zygosity. We apply this test for the EEA to five common psychiatric disorders (major depression, generalized anxiety disorder, phobia, bulimia, and alcoholism), as assessed by personal interview, in 1030 female-female twin pairs from the Virginia Twin Registry with known zygosity. We use a newly developed model-fitting approach which treats perceived zygosity as a form of specified familial environment. In 158 of the 1030 pairs (15.3%), one or both twins disagreed with the project-assigned zygosity. Model fitting provided no evidence for a significant influence of perceived zygosity on twin resemblance for any of the five disorders. Although limited in power, these results support the validity of the EEA in twin studies of psychiatric disorders.

Adult↗

PubMed1993

Testing hypotheses about direction of causation using cross-sectional family data.

We review the conditions under which cross-sectional family data (e.g., data on twin pairs or adoptees and their adoptive and biological relatives) are informative about direction of causation. When two correlated traits have rather different modes of inheritance (e.g., family resemblance is determined largely by family background for one trait and by genetic factors for the other trait), cross-sectional family data will allow tests of strong unidirectional causal hypotheses (A and B are correlated "because of the causal influence of A on B" versus "because of the causal influence of B on A") and, under some conditions, also of the hypothesis of reciprocal causation. Possible sources of errors of inference are considered. Power analyses are reported which suggest that multiple indicator variables will be needed to ensure adequate power of rejecting false models in the presence of realistic levels of measurement error. These methods may prove useful in cases where conventional methods to establish causality, by intervention, by prospective study, or by measurement of instrumental variables, are unfeasible economically, ethically or practically.

Adoption↗

PubMed1993

Social relationships of men at risk for AIDS.

Survey data collected in 1984-85 from a community sample of 637 gay and bisexual men were used to determine the features of social relationships that were most conductive to changes in both psychological health and AIDS-related sexual risk behavior. Multiple regression analyses showed that both the perceived availability of social support and the absence of conflicts in the social network were related to improve psychological health. At the same time, the subjective experience of integration into social networks was associated with increased psychological distress, and validation (the experience of being accepted by others) was related to a higher level of risk activity. These findings are discussed in terms of the social relationships among community members that share a common stressor--in this case the shared problem of being at risk for AIDS.

Acquired Immunodeficiency Syndrome↗

PubMed1993

Childhood adversities and adult depression: basic patterns of association in a US national survey.

The long-term relationships between various forms of childhood adversity and adult episodes of major depression are explored in a representative household survey of the United States adult (age 25+) population. Seven of the eight childhood adversities considered are significantly associated with recent (12-month) episodes of depression. These effects are largely indirect consequences of some childhood adversities leading to a life history of depression and prior depression leading to new episodes. Only three of the eight childhood adversities directly affect recent onset or recurrence. The paper closes with a discussion of implications for future research on the long-term effects of childhood adversities.

Adult↗

PubMed1993

Major depression and phobias: the genetic and environmental sources of comorbidity.

In a population based sample of 2163 personally interviewed female twins, substantial comorbidity was observed between DSM-III-R defined major depression (MD) and 4 subtypes of phobia: agoraphobia, social phobia, animal phobia and situational phobia. However, the level of comorbidity of MD with agoraphobia was much greater than that found with the other phobic subtypes. We concluded bivariate twin analyses to decompose the genetic and environmental sources of comorbidity between MD and the phobias. Our results suggest that a modest proportion of the genetic vulnerability to MD also influences the risk for all phobic subtypes, with the possible exception of situational phobias. Furthermore, the magnitude of comorbidity resulting from this shared genetic vulnerability is similar across the phobic subtypes. By contrast, the non-familial environmental experiences which predispose to depression substantially increase the vulnerability to agoraphobia, have a modest impact on the risk for social and situational phobias and no effect on the risk for animal phobias. The increased comorbidity between MD and agoraphobia results, nearly entirely, from individual-specific environmental risk factors for MD which also increase the risk for agoraphobia but not for other phobias.

Adult↗

PubMed1993

Panic disorder in women: a population-based twin study.

Previous studies based on probands from clinical samples suggest that panic disorder aggregates strongly in families and may be due to a highly penetrant single major locus. In this study we examine panic disorder as assessed at blind, structured psychiatric interview in 2163 women from a population-based twin registry. DSM-III-R diagnoses were assigned at a narrow and at a broad level both by clinician review and by computer algorithm. The familial aggregation of panic disorder in this sample was only modest. The relatively small number of affected individuals prevented a definitive resolution of competing genetic and non-genetic models of familial transmission. Although there was some inconsistency across diagnostic approaches, most results suggested that the familial aggregation of panic disorder was due largely to genetic factors. Using a multifactorial-threshold model, the best estimates of the heritability of liability ranged from 30 to 40%. From a familial perspective, panic disorder with phobic avoidance appears to represent a more severe form of the syndrome than panic disorder without avoidance. Our results, which suggest that in the general population panic disorder is only a moderately heritable condition, are at variance with results from several previous investigations based on clinically ascertained samples.

Adult↗

PubMed1993

A longitudinal study of psychological distress in a cohort of gay men. Effects of social support and coping strategies.

This study presents analyses on questionnaire data collected from a panel of 520 gay men at risk for acquired immune deficiency syndrome, enrolled in the Coping and Change Study (1985-1987). The data were assessed to determine the association of social support and coping styles with subsequent depression and global distress and to investigate whether these predictors of mental health are stable or transient over time. Three different measures of the subjective, qualitative nature of social support were significantly associated with subsequent mental health. Those who reported a subjective sense of isolation experienced significantly more adverse mental health 6 months later at all three measurement periods. Scattered effects were found for perceived social conflict and perceived social support from others. These results indicate that certain types of social support appear to influence mental health in this cohort and, furthermore, that some associations are transient and others more stable over time.

Acquired Immunodeficiency Syndrome↗

PubMed1993

The prediction of major depression in women: toward an integrated etiologic model.

OBJECTIVE: The authors develop an exploratory, integrated etiologic model for the prediction of episodes of major depression in an epidemiologic sample of women. METHOD: Both members of 680 female-female twin pairs of known zygosity from a population-based register were assessed three times at greater than 1-year intervals. The last two assessments included a structured interview evaluation for presence of episodes of major depression, defined by DSM-III-R, in the preceding year. The final structural equation model contained nine predictor variables: genetic factors, parental warmth, childhood parental loss, lifetime traumas, neuroticism, social support, past depressive episodes, recent difficulties, and recent stressful life events. RESULTS: The best-fitting model predicted 50.1% of the variance in the liability to major depression. The strongest predictors of this liability were, in descending order, 1) stressful life events, 2) genetic factors, 3) previous history of major depression, and 4) neuroticism. While 60% of the effect of genetic factors on the liability to major depression was direct, the remaining 40% was indirect and mediated largely by a history of prior depressive episodes, stressful life events, lifetime traumas, and neuroticism. The model suggested that at least four major and interacting risk factor domains are needed to understand the etiology of major depression: traumatic experiences, genetic factors, temperament, and interpersonal relations. CONCLUSIONS: Major depression is a multifactorial disorder, and understanding its etiology will require the rigorous integration of genetic, temperamental, and environmental risk factors.

Adult↗

PubMed1993

Marital disruption and depression in a community sample.

The extent to which marital disruption causes poor mental health is not well characterized even after 20 years of research. This is due in large part to the fact that previous research has ignored the possibility of selection. The present analysis is based on a representative community sample and was designed to take a step toward correcting these problems and to explore a number of specifications overlooked in previous research. The aggregate results show that marital disruption is associated with an increase of approximately one-third of a standard deviation on a screening scale of depression over a three-year interval between waves of data collection. The effect is more pronounced among women than men and is confined to people other than those who are escaping marriages with serious long-term problems. No evidence is found that the depressogenic effect of marital disruption can be explained by increased financial pressures or other secondary changes in roles. However, increased emotional reactivity to these changes is shown to play a powerful role in promoting depression among the recently divorced. The implications and limitations of these results are discussed.

Adaptation, Psychological↗

PubMed1992

A population-based twin study of alcoholism in women.

OBJECTIVE: To clarify the role of genetic factors in the etiology of alcoholism in women. DESIGN AND SETTING: Personal structured psychiatric interviews conducted by researchers "blinded" to the status of the co-twin in an epidemiologic sample of 1030 female-female twin pairs of known zygosity from the population-based Virginia Twin Registry. MEASURES: Three definitions of lifetime prevalence of alcoholism based on Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised criteria: (1) alcoholism with tolerance or dependence; (2) alcoholism with or without tolerance-dependence; and (3) alcoholism with or without tolerance-dependence or problem drinking. RESULTS: Using narrow, intermediate, or broad definitions, the probandwise concordance for alcoholism was consistently higher in monozygotic than in dizygotic twin pairs. Multifactorial threshold models suggested that the heritability of liability to alcoholism in women is in the range of 50% to 60%. CONCLUSIONS: The results support the hypothesis that genetic factors play a major role in the etiology of alcoholism in women. Women should be well represented in the efforts currently under way to elucidate the molecular basis of the genetic susceptibility to alcoholism.

Alcoholism↗

PubMed1992

Childhood parental loss and adult psychopathology in women. A twin study perspective.

We examine the relationship between parental loss prior to age 17 years and adult psychopathology in 1018 pairs of female twins from a population-based registry. The relationship between loss and adult psychopathology varied as a function of the kind of loss (death vs separation), the parent involved, and the form of psychopathology. Increased risk for major depression and generalized anxiety disorder was associated with parental separation but not parental death and with separation from either mother or father. Panic disorder was associated with parental death and maternal, but not paternal, separation. Increased risk for phobia was associated with parental death and not parental separation. Risk for eating disorder was unrelated to the experience of parental loss. A model that includes parental loss as a form of "specified" family environment shows that, if it is truly an environmental risk factor for adult psychopathologic conditions, it can account for between 1.5% and 5.1% of the total variance in liability to these disorders and is responsible for between 7.0% and 20.5% of the tendency for these disorders to aggregate in siblings.

Adolescent↗

PubMed1992

A population-based twin study of major depression in women. The impact of varying definitions of illness.

Although depression aggregates in families, the degree to which this aggregation results from genetic vs environmental factors remains uncertain. We examined this question in 1033 female-female twin pairs from a population-based registry. Both members of each twin pair were "blindly" assessed by structured psychiatric interview. Nine commonly used definitions of major depression, which produced life-time prevalence rates ranging from 12% to 33%, were examined. For all definitions, the results of model fitting to twin correlations suggested that the liability to depression results from genetic factors and environmental experiences unique to the individual. For seven of the definitions, the estimated heritability of liability was similar, ranging from 33% to 45%. For the two definitions that included only primary cases of depression, the heritability was lower (21% to 24%). The results document that in women (1) genetic factors play a substantial, but not overwhelming, role in the cause of depression; (2) the tendency for depression to aggregate in families results largely from shared genetic and not from shared environmental factors; (3) except for definitions that exclude secondary cases, the magnitude of genetic influence is similar in broadly and narrowly defined forms of major depression; and (4) most environmental experiences of causative importance for depression are those not shared by members of an adult twin pair.

Adolescent↗

PubMed1992

Generalized anxiety disorder in women. A population-based twin study.

Little is known about the role of familial and genetic factors in the etiology of generalized anxiety disorder (GAD), a new disorder first proposed in DSM-III. We examine this question in 1033 female-female twin pairs from a population-based registry. Both members in each twin pair were "blindly" assessed by structured psychiatric interview. Our results suggest the following: (1) GAD is a moderately familial disorder; (2) the tendency for GAD to run in families seems to be due largely or entirely to genetic factors shared between relatives rather than to the effects of the familial environment; (3) the heritability of GAD, estimated at around 30%, is modest, with the remainder of the variance in liability resulting from environmental factors not shared by adult twins; (4) the heritability of GAD cannot be explained solely by the occurrence of GAD only during episodes of major depression or panic disorder; and (5) the etiologic role of genetic factors is probably similar in GAD with a 1- vs a 6-month minimum duration of illness.

Adult↗

PubMed1992

The genetic epidemiology of phobias in women. The interrelationship of agoraphobia, social phobia, situational phobia, and simple phobia.

In 2163 personally interviewed female twins from a population-based registry, the pattern of age at onset and comorbidity of the simple phobias (animal and situational)--early onset and low rates of comorbidity--differed significantly from that of agoraphobia--later onset and high rates of comorbidity. Consistent with an inherited "phobia proneness" but not a "social learning" model of phobias, the familial aggregation of any phobia, agoraphobia, social phobia, and animal phobia appeared to result from genetic and not from familial-environmental factors, with estimates of heritability of liability ranging from 30% to 40%. The best-fitting multivariate genetic model indicated the existence of genetic and individual-specific environmental etiologic factors common to all four phobia subtypes and others specific for each of the individual subtypes. This model suggested that (1) environmental experiences that predisposed to all phobias were most important for agoraphobia and social phobia and relatively unimportant for the simple phobias, (2) environmental experiences that uniquely predisposed to only one phobia subtype had a major impact on simple phobias, had a modest impact on social phobia, and were unimportant for agoraphobia, and (3) genetic factors that predisposed to all phobias were most important for animal phobia and least important for agoraphobia. Simple phobias appear to arise from the joint effect of a modest genetic vulnerability and phobia-specific traumatic events in childhood, while agoraphobia and, to a somewhat lesser extent, social phobia result from the combined effect of a slightly stronger genetic influence and nonspecific environmental experiences.

Adolescent↗

PubMed1992

Major depression and generalized anxiety disorder. Same genes, (partly) different environments?

Bivariate twin analysis can determine the extent to which two disorders share common genetic, familial environmental, or individual-specific environmental risk factors. We applied this method to lifetime diagnoses of major depression and generalized anxiety disorder as assessed at personal interview in a population-based sample of 1033 pairs of female same-sex twins. Three definitions of generalized anxiety disorder were used that varied in minimum duration (1 vs 6 months) and in the presence or absence of a diagnostic hierarchy. For all definitions of generalized anxiety disorder, the best-fitting twin model was the same. Familial environment played no role in the etiology of either condition. Genetic factors were important for both major depression and generalized anxiety disorder and were completely shared between the two disorders. A modest proportion of the nonfamilial environmental risk factors were shared between major depression and generalized anxiety disorder. Within the limits of our statistical power, our findings suggest that in women, the liability to major depression and generalized anxiety disorder is influenced by the same genetic factors, so that whether a vulnerable woman develops major depression or generalized anxiety disorder is a result of her environmental experiences.

Adult↗

PubMed1992

Genetic and environmental factors in the aetiology of menstrual, premenstrual and neurotic symptoms: a population-based twin study.

Symptoms during the premenstrual and menstrual phases of the female reproductive cycle were assessed in 827 pairs of female same-sex twins from a population-based registry. By conventional factor analysis, premenstrual and menstrual symptoms were relatively independent of one another and of baseline 'neurotic' symptoms (i.e. anxiety, depression and somatization). Familial resemblance for menstrual and premenstrual symptoms was due solely to genetic factors with heritability estimates of 39.2% and 35.1%, respectively. Multivariate genetic analysis revealed distinct genetic and environmental factors for menstrual, premenstrual and neurotic symptoms. The genes and individual-specific experiences that predispose to premenstrual symptoms appear to be largely distinct from those which predispose either to menstrual or to neurotic symptoms. The generalizability of these results may be limited because only a modest number of premenstrual and menstrual symptoms were assessed, all by retrospective self-report.

Adult↗