A longitudinal twin study of personality and major depression in women.
ABSTRACT To elucidate the nature of the etiologic relationship between personality and major depression in women.
A longitudinal twin design in which twins completed a time 1 questionnaire and, 15 months later, were personally interviewed for the occurrence of major depression during the last year and completed a time 2-questionnaire. Both questionnaires contained short forms assessing neuroticism and extraversion.
1733 twins from female-female pairs ascertained from the population-based Virginia Twin Registry.
Extraversion was unrelated to lifetime or 1-year prevalence of major depression. Neuroticism was strongly related to lifetime prevalence of major depression and robustly predicted the prospective 1-year prevalence of major depression in those who, at time 1, denied previous depressive episodes. However, controlling for levels of neuroticism at time 1, levels of neuroticism at time 2 were moderately elevated in those who had had an episode of major depression between times 1 and 2 ("scar" effect) and substantially elevated in those experiencing an episode of major depression at time 2 ("state" effect). In those who developed major depression, levels of neuroticism did not predict time to onset. In the best-fit longitudinal twin model, the proportion of the observed correlation between neuroticism and the liability to major depression that is due to shared genetic risk factors was estimated at around 70%, that due to shared environmental risk factors at around 20%, and that due to a direct causal effect of major depression on neuroticism (via both "scar" and "state" effects) at around 10%. Approximately 55% of the genetic liability of major depression appeared to be shared with neuroticism, while 45% was unique to major depression.
In women, the relationship between neuroticism and the liability to major depression is substantial and largely the result of genetic factors that predispose to both neuroticism and major depression.
- [Show abstract] [Hide abstract]
ABSTRACT: Previous studies have showed some evidences about the relationship between personality traits particularly neuroticism and extroversion, separately, with psychological stress and anxiety. In the current study, we clarified the magnitude of joint interdependence (co-morbidity) of anxiety (continuous) and Psychological stress (dichotomous) as dependent variables of mixed type with five-factor personality traits as independent variables. Data from 3180 participants who attended in the cross-sectional population-based "study on the epidemiology of psychological, alimentary health and nutrition" and completed self-administered questionnaires about demographic and life style, gastrointestinal disorders, personality traits, perceived intensity of stress, social support, and psychological outcome was analyzed using shared random effect approach in R Free software. The results indicated high scores of neuroticism increase the chance of high psychological stress (odds ratio [OR] = 5.1; P < 0.001) and anxiety score (B = 1.73; P < 0.001) after adjustment for the probable confounders. In contrast, those who had higher scores of extraversion and conscientiousness experienced lower levels of anxiety score (B = -0.54 and -0.23, respectively, P < 0.001) and psychological stress (OR = 0.36 and 0.65, respectively, P < 0.001). Furthermore, higher score of agreeableness had significant negative relationship with anxiety (B = -0.32, P < 0.001). The present study indicated that the scores of neuroticism, extraversion, agreeableness and conscientiousness strongly predict both anxiety and psychological stress in Iranian adult population. Due to likely mechanism of genetic and environmental factors on the relationships between personality traits and psychological disorders, it is suggested to perform longitudinal studies focusing on both genetic and environmental factors in Iranian population.Journal of research in medical sciences : the official journal of Isfahan University of Medical Sciences. 09/2014; 19(9):834-43.
- [Show abstract] [Hide abstract]
ABSTRACT: Identifying the factors that influence stability and change in chronic posttraumatic stress disorder (PTSD) is important for improving clinical outcomes. Using a cross-lagged design, we analyzed the reciprocal effects of personality and PTSD symptoms over time and their effects on stress exposure in a sample of 222 trauma-exposed veterans (ages 23–68; 90.5% male). Personality functioning and PTSD were measured approximately 4 years apart, and self-reported exposure to major adverse life events during the interim was also assessed. Negative emotionality positively predicted future PTSD symptoms, and this effect was partially mediated by exposure to new events. Constraint (negatively) indirectly affected PTSD via its association with exposure to new events. There were no significant effects of positive emotionality nor did PTSD symptom severity exert influences on personality over time. Results indicate that high negative affect and disconstraint influence the course of PTSD symptoms by increasing exposure to stressful life events.Journal of Anxiety Disorders 01/2015; 31C. · 2.96 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: An external or internal “predictive adaptive response” (PAR) can be defined as an adaptive change in long-term behavior or development due to an environmental exposure that triggers it. A PAR can lead to differential development among initially similar individuals, and increase evolutionary fitness. Despite many theories and empirical observations of PAR-like changes in depressive tendencies, clear empirical findings on human personality changes following depressive symptoms are lacking, possibly because these changes take a long time to develop and most follow up studies have been short. Here we show that in sufficiently long (5- and 15-year) clinical and general-population follow ups, increases can be observed in the Temperament and Character Inventory’s personality trait Harm avoidance as a function of temporally accumulating Major Depressive Episodes (132 Depression patients from Vantaa Depression Study) and depressive symptoms (3105 participants from Young Finns general-population sample). Personality changes did not occur in the other six personality traits of the inventory, but did in a highly similar Neuroticism trait from another inventory. Even when controlling for concurrent changes in depressive symptoms from the baseline to the endpoint, depressive symptoms that occurred during the follow-up period associated with Harm-avoidance changes, rendering individuals more fearful and anticipating harm. This study provides consistent, specific, and plausible dose–response and temporal gradients between accumulated depressive episodes and personality change. Effect sizes were between small to moderate, though. Altogether, the findings support the feasibility of using existing systems of personality assessment (i.e., self-report questionnaires) to study PARs, despite the multiplicity of the systems.Evolution and Human Behavior 01/2015; · 2.87 Impact Factor