Publications by authors named "Jonathan D Schaefer"

Article Synopsis
  • - The study explored the relationship between adverse childhood experiences (ACEs) and mental health issues, noting that supportive adult relationships can help mitigate these problems.
  • - Using a twin-difference design, researchers analyzed data from a UK twin study to determine whether the protective effects of maternal warmth and adult support on mental health were truly causal, controlling for genetic and environmental factors.
  • - Results indicated that while children with more supportive adult relationships showed lower levels of mental health problems, these protective effects were significantly reduced when accounting for genetic and environmental factors, suggesting interventions should be more multifaceted.
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Psychophysiology can help elucidate the structure and developmental mechanisms of psychopathology, consistent with the Research Domain Criteria initiative. Cross-sectional research using categorical diagnoses indicates that P300 is an electrocortical endophenotype indexing genetic vulnerability to externalizing problems. However, current diagnostic systems' limitations impede a precise understanding of risk.

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Background: Cannabis use is associated with outcomes like income, legal problems, and psychopathology. This finding rests largely on correlational research designs, which rely at best on statistical controls for confounding. Here, we control for unmeasured confounders using a longitudinal study of twins.

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Although observational studies have shown that adolescent cannabis use is associated with impairments in important psychosocial domains, including peer, romantic, and parent-child relationships, educational outcomes, adult socioeconomic status, and legal consequences, mechanisms underlying these associations remain largely unclear. Cannabis use may have a deleterious causal effect on functioning, but it is also possible the association may be due to reverse causation or confounding by shared vulnerability factors that account for both cannabis use in adolescence and concurrent and subsequent psychosocial impairment. Causally informative studies that delineate these possibilities, including research using epidemiologic samples and quasi-experimental designs, are critical to move the field forward.

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Background: Military services provide a unique opportunity for studying resilience, a dynamic process of successful adaptation (ie, doing well in terms of functioning and symptoms) in response to significant adversity. Despite the tremendous interest in positive adaptation among military service members, little is known about the processes underlying their resilience. Understanding the neurobiological, cognitive, and social mechanisms underlying adaptive functioning following military stressor exposure is essential for enhancing the resilience of military service members.

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Background: Military service provides a unique opportunity for studying resilience, a dynamic process of successful adaptation (i.e., doing well in terms of functioning and symptoms) in response to significant adversity.

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Article Synopsis
  • - Researchers studied the contribution of polygenic scores (PGSs) for substance use (alcohol, cannabis, nicotine) in predicting outcomes beyond just family history of substance use disorders.
  • - The study found that while PGSs were generally effective predictors, their predictive power was influenced by demographic factors and genetic effects from parents, indicating less reliability in twin comparisons.
  • - The analysis showed that both PGSs and family history impacts on substance use were mediated by behavioral disinhibition observed in preadolescence, suggesting that disinhibition plays a key role in the relationship between genetics and substance use.
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Background: Psychopathology and risky behaviors increase during adolescence, and understanding which adolescents are most at risk informs prevention and intervention efforts. Pubertal timing relative to same-sex, same-age peers is a known correlate of adolescent outcomes among both boys and girls. However, it remains unclear whether this relation is better explained by a plausible causal process or unobserved familial liability.

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Although observational studies have shown that adolescent cannabis use is associated with impairments in important psychosocial domains, including peer, romantic, and parent-child relationships, educational outcomes, adult socioeconomic status, and legal consequences, mechanisms underlying these associations remain largely unclear. Cannabis use may have a deleterious causal effect on functioning, but it is also possible the association may be due to reverse causation or confounding by shared vulnerability factors that account for both cannabis use in adolescence and concurrent and subsequent psychosocial impairment. Causally informative studies that delineate these possibilities, including research using epidemiologic samples and quasi-experimental designs, are critical to move the field forward.

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Variation in the mental health of people who have experienced childhood maltreatment is substantial. One hypothesis is that this variation is attributable, in part, to the timing of maltreatment-specifically, whether maltreatment occurs during sensitive periods in development when the brain is maximally sensitive to particular types of environmental input. To determine whether there is scientific consensus around when periods of peak sensitivity occur, we did a systematic review of human observational studies.

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We examined whether a polygenic score (PGS) for smoking measured genetic risk for general behavioral disinhibition by estimating its associations with externalizing and internalizing psychopathology and related personality traits at multiple time points in adolescence (ages 11, 14, and 17 years; = 3225). The smoking PGS had strong associations with the stable variance across time for all the externalizing measures (mean standardized = .27), agreeableness ( = -.

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Psychological resilience as a longitudinal process is highly relevant for understanding the functioning outcomes of military populations. Here, we review the extant literature on resilience among military service members, focusing on National Guard Soldiers. Our specific project (Advancing Research on Mechanisms of Resilience, "ARMOR") aims to develop a comprehensive model of resilience using a multilevel perspective.

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Article Synopsis
  • Molecular genetic studies have discovered numerous genome-wide association study (GWAS) loci linked to alcohol and nicotine use, allowing researchers to assess relationships between polygenic scores (PGS) and substance use patterns from late childhood to early adulthood.
  • The study utilized latent growth curve models to analyze data from the Minnesota Twin Family Study, examining how PGSs for alcohol and nicotine influenced initial usage and change over time, while controlling for demographic factors.
  • Results indicated that PGSs were associated with specific substance use trajectories, with significant cross-substance effects observed, highlighting that PGSs can serve as predictors of both alcohol and nicotine consumption behaviors.
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Article Synopsis
  • Observational studies have shown a link between cannabis use and a higher risk of psychosis, raising questions about whether this relationship is causal or influenced by other factors.
  • Analyzing data from twin cohorts, the researchers found that while higher cannabis use in adolescence was related to increased Psychoticism in adulthood, there was no clear causal effect when comparing cannabis use between twins.
  • The findings suggest that the observed association between cannabis use and psychosis may stem from shared family traits rather than direct effects of cannabis itself, highlighting the need to focus on other factors in addressing psychotic disorders.
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Educational success is associated with greater quality of life and depends, in part, on heritable cognitive and non-cognitive traits. We used polygenic scores (PGS) for smoking and educational attainment to examine different genetic influences on facets of academic adjustment in adolescence and educational attainment in adulthood. PGSs were calculated for participants of the Minnesota Twin Family Study (N = 3225) and included as predictors of grades, academic motivation, and discipline problems at ages 11, 14, and 17 years-old, cigarettes per day from ages 14 to 24 years old, and educational attainment in adulthood (mean age 29.

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Importance: Air pollution exposure damages the brain, but its associations with the development of psychopathology are not fully characterized.

Objective: To assess whether air pollution exposure in childhood and adolescence is associated with greater psychopathology at 18 years of age.

Design, Setting, And Participants: The Environmental-Risk Longitudinal Twin Study is a population-based cohort study of 2232 children born from January 1, 1994, to December 4, 1995, across England and Wales and followed up to 18 years of age.

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Observational studies have linked cannabis use to an array of negative outcomes, including psychiatric symptoms, cognitive impairment, and educational and occupational underachievement. These associations are particularly strong when cannabis use occurs in adolescence. Nevertheless, causality remains unclear.

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Just how common are "common" mental health problems? For much of the 20 century, psychiatric research and the US health care system seemed to proceed under the assumption that the answer is "not very." It was not until the early 1990s that the United States conducted its first nation-wide survey of mental health problems, the National Comorbidity Survey, which revealed that about half of all adult participants had experienced at least one diagnosable psychiatric disorder in their lifetime, and close to 1 in 3 participants had met criteria for a psychiatric diagnosis in the past 12 months. Subsequent longitudinal studies showed that these estimates-although initially surprising-were still too low, and that, with repeated assessments over long follow-up periods, the proportion of people who report at least 1 diagnosable brush with a psychiatric disorder can exceed 80%.

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Objective: To evaluate the difference in the rectal-interdigital temperature gradient (RITG) between dogs that were presented to an emergency room with clinical signs of shock compared to those without signs of shock, and if this gradient can be used as a diagnostic marker for shock.

Design: Prospective, single center, observational study conducted from 2014 to 2015.

Setting: University veterinary teaching hospital.

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Childhood maltreatment is associated with increased risk for most forms of psychopathology. We examine emotion dysregulation as a transdiagnostic mechanism linking maltreatment with general psychopathology. A sample of 262 children and adolescents participated; 162 (61.

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Importance: Millions of adults now entering middle age were exposed to high levels of lead, a developmental neurotoxin, as children. Although childhood lead exposure has been linked to disrupted behavioral development, the long-term consequences for adult mental and behavioral health have not been fully characterized.

Objective: To examine whether childhood lead exposure is associated with greater psychopathology across the life course and difficult adult personality traits.

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Adolescence is the peak age for both victimization and mental disorder onset. Previous research has reported associations between victimization exposure and many psychiatric conditions. However, causality remains controversial.

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Cognitive impairment has been identified as an important aspect of major depressive disorder (MDD). We tested two theories regarding the association between MDD and cognitive functioning using data from longitudinal cohort studies. One theory, the cognitive reserve hypothesis, suggests that higher cognitive ability in childhood decreases risk of later MDD.

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We review epidemiological evidence indicating that most people will develop a diagnosable mental disorder, suggesting that only a minority experience enduring mental health. This minority has received little empirical study, leaving the prevalence and predictors of enduring mental health unknown. We turn to the population-representative Dunedin cohort, followed from birth to midlife, to compare people never-diagnosed with mental disorder (N = 171; 17% prevalence) to those diagnosed at 1-2 study waves, the cohort mode (N = 409).

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