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OBJECTIVE Stressful life events are associated with the onset of episodes of major depression. However, exposure to stressful life events is influenced by genetic factors, and these factors are correlated with those that predispose to major depression. The aim of this study was to clarify the degree to which stressful life events cause major depression. (More)
BACKGROUND Patterns of comorbidity suggest that the common psychiatric and substance use syndromes may be divisible into 2 broad groups of internalizing and externalizing disorders. We do not know how genetic and environmental risk factors contribute to this pattern of comorbidity or whether the etiologic structure of these groups differ in men and women.(More)
OBJECTIVE The rate of cannabis use by women has been increasing in recent decades. This study examined the etiology of cannabis use and abuse among women and the possible role of genetic risk factors. METHOD Unselected individual twins (N=1,934) from female-female pairs ascertained through a population-based registry, including both members of 485(More)
BACKGROUND The development of drug dependence requires prior initiation. What is the relationship between the risk factors for initiation and dependence? METHODS Using smoking as a model addiction, we assessed smoking initiation (SI) and nicotine dependence (ND) by personal interview in 1898 female twins from the population-based Virginia Twin Registry.(More)
BACKGROUND 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? METHODS 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(More)
OBJECTIVE Data on use and misuse of six classes of illicit substances by male twin pairs were used to examine whether genetic and shared environmental risk factors for substance use disorders are substance-specific or -nonspecific in their effect. METHOD Lifetime history of use and abuse/dependence of cannabis, cocaine, hallucinogens, sedatives,(More)
BACKGROUND In order to develop informed approaches to prevention and treatment of illicit psychoactive substance use, abuse, and dependence, we need to understand the sources of individual differences in risk. METHODS In personal interviews with 1198 male-male twin pairs (708 monozygotic and 490 dizygotic) ascertained from a population-based registry, we(More)
OBJECTIVE Major depression is a multifactorial disorder with many etiologic variables that are interrelated through developmental pathways. The authors used structural equation modeling to generate a developmental model for the etiology of major depression in women. METHOD Data from 1,942 adult female twins, interviewed up to four times over a 9-year(More)
CONTEXT Prior evidence from twin studies suggested genetic moderation of the depressogenic effects of stressful life events (SLEs). Can the specific genes involved in this effect be identified? OBJECTIVE To replicate and extend a recent study that a functional variant in the serotonin transporter (5-HTT) might in part explain these findings. DESIGN(More)
OBJECTIVE Three potent risk factors for major depression are female sex, the personality trait of neuroticism, and adversity resulting from exposure to stressful life events. Little is known about how they interrelate in the etiology of depressive illness. METHOD In over 7,500 individual twins from a population-based sample, the authors used a Cox(More)