The Southern California Twin Register at the University of Southern California: III

Baker, Laura A.; Tuvblad, Catherine; Wang, Pan; Gomez, Karina; Bezdjian, Serena; Niv, Sharon; Raine, Adrian

doi:10.1017/thg.2012.127

Cited by 55 publications

(40 citation statements)

References 63 publications

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“…Participating families were socioeconomically and ethnically diverse and representative of the greater Los Angeles urban population (29) at the time of enrollment, including Hispanic (37%), Caucasian (27%), mixed ethnicity (17%), African American (14%), and Asian (5%) participants. For more details on study protocol and procedures, including zygosity determination, see Baker et al (30). MTFS.…”

Section: Methodsmentioning

confidence: 99%

Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies

Jackson

Isen

Khoddam

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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163

131

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Marijuana is one of the most commonly used drugs in the United States, and use during adolescence-when the brain is still developing-has been proposed as a cause of poorer neurocognitive outcome. Nonetheless, research on this topic is scarce and often shows conflicting results, with some studies showing detrimental effects of marijuana use on cognitive functioning and others showing no significant long-term effects. The purpose of the present study was to examine the associations of marijuana use with changes in intellectual performance in two longitudinal studies of adolescent twins (n = 789 and n = 2,277). We used a quasiexperimental approach to adjust for participants' family background characteristics and genetic propensities, helping us to assess the causal nature of any potential associations. Standardized measures of intelligence were administered at ages 9-12 y, before marijuana involvement, and again at ages 17-20 y. Marijuana use was self-reported at the time of each cognitive assessment as well as during the intervening period. Marijuana users had lower test scores relative to nonusers and showed a significant decline in crystallized intelligence between preadolescence and late adolescence. However, there was no evidence of a dose-response relationship between frequency of use and intelligence quotient (IQ) change. Furthermore, marijuana-using twins failed to show significantly greater IQ decline relative to their abstinent siblings. Evidence from these two samples suggests that observed declines in measured IQ may not be a direct result of marijuana exposure but rather attributable to familial factors that underlie both marijuana initiation and low intellectual attainment.M arijuana is one of the most commonly used drugs in the United States, with a lifetime use prevalence of 50% (1, 2). Despite this, research on the long-term effects of marijuana use is scarce compared with that of other illicit substances. Changing cultural attitudes toward marijuana have recently led to social and legal acceptance of recreational use (3, 4), making research on the potential consequences particularly salient.Previous research has shown that marijuana use can have a high societal cost through increased unemployment, absenteeism, decreased productivity, and increased rates of crime and incarceration (5-8). Given that about 19% of youth and young adults (ages 18-25 y) in the United States have used marijuana in the past month (9), the potential impact is nontrivial. There is evidence to suggest that the adolescent brain may be particularly vulnerable, especially with regard to neurocognitive functioning (10, 11). Marijuana use in adolescence, when the brain is still undergoing major developmental changes, has been associated with decreased intelligence (12, 13), reduced memory (13-15), poorer attention (16-18), and lower verbal ability (19-21). However, these findings come from cross-sectional studies, where the temporal ordering of cause and effect is uncertain. For longitudinal studies examining marijuana use and ch...

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Section: Methodsmentioning

confidence: 99%

Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies

Jackson

Isen

Khoddam

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

163

131

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“…Participating families were recruited from Los Angeles County and surrounding areas, representative of the ethnic and socioeconomic diversity of the greater Los Angeles area. 29 This ongoing cohort study includes over 780 monozygotic and dizygotic (same-sex and opposite-sex) twin pairs and triplets born between 1990–1995 and aged 9–10 years at study enrollment in 2000. The present study used data collected with up to 4 occasions of longitudinal assessments from childhood to adolescence.…”

Section: Methodsmentioning

confidence: 99%

Environmental Determinants of Aggression in Adolescents: Role of Urban Neighborhood Greenspace

Younan

Tuvblad

et al. 2016

Journal of the American Academy of Child & Adolescent Psych

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100

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Objective Neighborhood greenspace improves mental health of urban-dwelling populations, but its putative neurobehavioral benefits in adolescents remain unclear. We conducted a prospective study on urban-dwelling adolescents to examine the association between greenspace in residential neighborhood and aggressive behaviors. Method Participants (n = 1,287) of the Risk Factors for Antisocial Behavior Study, a multi-ethnic cohort of twins and triplets born in 1990–1995 and living in Southern California, were examined in 2000–2012 (aged 9 to 18 years) with repeated assessments of their aggressive behaviors by the parent-reported Child Behavior Checklist. Normalized Difference Vegetation Index (NDVI) derived from satellite imagery was used as a proxy for residential neighborhood greenspace aggregated over various spatiotemporal scales prior to each assessment. Multilevel mixed-effects models were used to estimate the effects of greenspace on aggressive behaviors, adjusting for within-family/within-individual correlations and other potential confounders. Results Both short-term (1- to 6-months) and long-term (1- to 3-years) exposures to greenspace within 1,000-meters surrounding residences were associated with reduced aggressive behaviors. The benefit of increasing vegetation over the range (~0.12 in NDVI) commonly seen in urban environments was equivalent to approximately 2 to 2.5 years of behavioral maturation. Sociodemographic factors (e.g., age, gender, race/ethnicity, and socioeconomic status) and neighborhood quality did not confound or modify these associations, and the benefits remained after accounting for temperature. Conclusion Our novel findings support the benefits of neighborhood greenspace in reducing aggressive behaviors of urban-dwelling adolescents. Community-based interventions are needed to determine the efficacy of greenspace as a preemptive strategy to reduce aggressive behaviors in urban environments.

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“…The adolescent twins and their families were originally recruited from Los Angeles County at ages 9–10, and were followed up at age 14 to obtain additional imaging and behavioral assessments. Participants were excluded if they had a history of significant head injury, major neurological, psychiatric illness, substance abuse, or contraindication to MRI (Baker et al, 2013; Yang, et al, 2012). The adolescent twins and their primary caregivers participated in 6–8 hours of laboratory assessment at USC including a one-hour scan.…”

Section: Methodsmentioning

confidence: 99%

Neural correlates of proactive and reactive aggression in adolescent twins

Yang

Joshi

Jahanshad

et al. 2016

Aggressive Behavior

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Verbal and physical aggression begin early in life and steadily decline thereafter in normal development. As a result, elevated aggressive behavior in adolescence may signal atypical development and greater vulnerability for negative mental and health outcomes. Converging evidence suggests that brain disturbances in regions involved in impulse control, emotional regulation, and sensation seeking may contribute to heightened aggression. However, little is known regarding the neural mechanisms underlying subtypes of aggression (i.e., proactive and reactive aggression) and whether they differ between males and females. Using a sample of 106 14-year-old adolescent twins, this study found that striatal enlargement was associated with both proactive and reactive aggression. We also found that volumetric alterations in several frontal regions including smaller middle frontal and larger orbitofrontal cortex were correlated with higher levels of aggression in adolescent twins. In addition, cortical thickness analysis showed that thickness alterations in many overlapping regions including middle frontal, superior frontal, and anterior cingulate cortex and temporal regions were associated with aggression in adolescent twins. Results support the involvement of fronto-limbic-striatal circuit in the etiology of aggression during adolescence.

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The Southern California Twin Register at the University of Southern California: III

Cited by 55 publications

References 63 publications

Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies

Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies

Environmental Determinants of Aggression in Adolescents: Role of Urban Neighborhood Greenspace

Neural correlates of proactive and reactive aggression in adolescent twins

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