Publications by authors named "Gretchen Saunders"

17 Publications

  • Page 1 of 1

Genetic association study of childhood aggression across raters, instruments, and age.

Transl Psychiatry 2021 07 30;11(1):413. Epub 2021 Jul 30.

Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.

Childhood aggressive behavior (AGG) has a substantial heritability of around 50%. Here we present a genome-wide association meta-analysis (GWAMA) of childhood AGG, in which all phenotype measures across childhood ages from multiple assessors were included. We analyzed phenotype assessments for a total of 328 935 observations from 87 485 children aged between 1.5 and 18 years, while accounting for sample overlap. We also meta-analyzed within subsets of the data, i.e., within rater, instrument and age. SNP-heritability for the overall meta-analysis (AGG) was 3.31% (SE = 0.0038). We found no genome-wide significant SNPs for AGG. The gene-based analysis returned three significant genes: ST3GAL3 (P = 1.6E-06), PCDH7 (P = 2.0E-06), and IPO13 (P = 2.5E-06). All three genes have previously been associated with educational traits. Polygenic scores based on our GWAMA significantly predicted aggression in a holdout sample of children (variance explained = 0.44%) and in retrospectively assessed childhood aggression (variance explained = 0.20%). Genetic correlations (r) among rater-specific assessment of AGG ranged from r = 0.46 between self- and teacher-assessment to r = 0.81 between mother- and teacher-assessment. We obtained moderate-to-strong rs with selected phenotypes from multiple domains, but hardly with any of the classical biomarkers thought to be associated with AGG. Significant genetic correlations were observed with most psychiatric and psychological traits (range [Formula: see text]: 0.19-1.00), except for obsessive-compulsive disorder. Aggression had a negative genetic correlation (r = ~-0.5) with cognitive traits and age at first birth. Aggression was strongly genetically correlated with smoking phenotypes (range [Formula: see text]: 0.46-0.60). The genetic correlations between aggression and psychiatric disorders were weaker for teacher-reported AGG than for mother- and self-reported AGG. The current GWAMA of childhood aggression provides a powerful tool to interrogate the rater-specific genetic etiology of AGG.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41398-021-01480-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8324785PMC
July 2021

Mechanisms of parent-child transmission of tobacco and alcohol use with polygenic risk scores: Evidence for a genetic nurture effect.

Dev Psychol 2021 May;57(5):796-804

Department of Psychology, University of Minnesota.

Parent-child similarity is a function of genetic and environmental transmission. In addition, genetic effects not transmitted to offspring may drive parental behavior, thereby affecting the rearing environment of the child. Measuring genetic proclivity directly, through polygenic risk scores (PRSs), provides a way to test for the effect of nontransmitted parental genotype, on offspring outcome, termed a genetic nurture effect-in other words, if and how parental genomes might affect their children through the environment. The current study used polygenic risk scores for smoking initiation, cigarettes per day, and drinks per week to predict substance use in a sample of 3,008 twins, assessed prospectively from age 17-29, and their parents, from the Minnesota Center for Twin and Family Research. Mixed-effects models were used to test for a genetic nurture effect whereby parental PRSs predict offspring tobacco and alcohol use after statistically adjusting for offspring's own PRS. Parental smoking initiation PRS predicted offspring cigarettes per day at age 24 (β = .103, 95% CI [.03, .17]) and alcohol use at age 17 (β = .091, 95% CI [.04, .14]) independent of shared genetics. There was also a suggestive independent association between the parent PRS and offspring smoking at age 17 (β = .096; 95% CI [.02, .17]). Mediation analyses provided some evidence for environmental effects of parental smoking, alcohol use, and family socioeconomic status. These findings, and more broadly the molecular genetic method used, have implications on the identification of environmental effects on developmental outcomes such as substance use. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1037/dev0001028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8238311PMC
May 2021

The role of the shared environment in college attainment: An adoption study.

J Pers 2021 05 27;89(3):580-593. Epub 2020 Oct 27.

Department of Psychology, University of Minnesota Twin Cities, Minneapolis, MN, USA.

Objective: College attainment is one of the few phenotypes to have substantial variance accounted for by environmental factors shared by reared-together relatives. The shared environment is implicated by the consistently strong parent-to-offspring transmission of college attainment. The mechanisms underlying this relationship remain unclear. We use genetically informative methods with a longitudinal, adoption sample to identify possible environmental mechanisms underlying parent-offspring college transmission.

Method: Data were drawn from the Sibling Interaction and Behavior Study (SIBS), which includes 409 adoptive and 208 nonadoptive families, consisting of two offspring followed from adolescence into young adulthood and their rearing parents. Four domains of environmental mechanisms were examined: (a) skill enhancement; (b) academic support; (c) material advantage; and (d) supportive family environment.

Results: Both shared environmental and genetic factors contributed to the parent-offspring transmission of college attainment. However, highly educated parents did not appear to be increasing their adopted offspring's attainment through skill development. The environmental factors that were associated with increased odds of offspring college attainment were mother's academic expectations and family income.

Conclusions: While complete mediation of the parent-offspring transmission of college attainment was not identified, the results shed light on some of the mechanisms associated with the common environment variance in the college attainment phenotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jopy.12600DOI Listing
May 2021

Where Do Gambling Problems Fit in the Structure of Psychopathology During Emerging Adulthood?

Int Gambl Stud 2020 25;20(1):1-13. Epub 2019 Jul 25.

University of Minnesota, Department of Psychology.

Research suggests major mental disorders co-occur at higher than chance levels. In adult samples, a two factor structure emerges when modeling the higher order structure of psychopathology. Specifically, disorders tend to co-aggregate into two dimensions: Internalizing (depression and anxiety) and Externalizing (acting out, impulsive, and addictive) disorders. Despite this large body of evidence, few studies have integrated problem gambling into this overall model. We used confirmatory factor analysis to model how the symptom count of gambling fits into the structure of psychopathology in a large, community based young adult twin sample of men and women (age 24; N=1329). Twins were assessed via in-person, structured diagnostic interviews on disorders including: Major Depression, Phobias, Post-Traumatic Stress Disorder and Anxiety Disorders (internalizing) and Substance Use Disorders, Gambling Problems (self-report), and Antisocial Behaviors (externalizing). The data were fit to a two-factor structure, with gambling symptoms loading most highly on externalizing, rather than internalizing. The problem gambling loadings did not differ by sex. Implications of these findings suggest that during emerging adulthood gambling problems are best classified and conceptualized in the realm of externalizing disorders for both males and females. Results also suggest prevention and intervention efforts be aimed at young adults who exhibit commonly co-occurring psychopathology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/14459795.2019.1643901DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7540909PMC
July 2019

Genetic correlation, pleiotropy, and causal associations between substance use and psychiatric disorder.

Psychol Med 2020 Aug 7:1-11. Epub 2020 Aug 7.

Department of Psychology, University of Minnesota, Minneapolis, MN, USA.

Background: Substance use occurs at a high rate in persons with a psychiatric disorder. Genetically informative studies have the potential to elucidate the etiology of these phenomena. Recent developments in genome-wide association studies (GWAS) allow new avenues of investigation.

Method: Using results of GWAS meta-analyses, we performed a factor analysis of the genetic correlation structure, a genome-wide search of shared loci, and causally informative tests for six substance use phenotypes (four smoking, one alcohol, and one cannabis use) and five psychiatric disorders (ADHD, anorexia, depression, bipolar disorder, and schizophrenia).

Results: Two correlated externalizing and internalizing/psychosis factor were found, although model fit was beneath conventional standards. Of 458 loci reported in previous univariate GWAS of substance use and psychiatric disorders, about 50% (230 loci) were pleiotropic with additional 111 pleiotropic loci not reported from past GWAS. Of the 341 pleiotropic loci, 152 were associated with both substance use and psychiatric disorders, implicating neurodevelopment, cell morphogenesis, biological adhesion pathways, and enrichment in 13 different brain tissues. Seventy-five and 114 pleiotropic loci were specific to either psychiatric disorders or substance use phenotypes, implicating neuronal signaling pathway and clathrin-binding functions/structures, respectively. No consistent evidence for phenotypic causation was found across different Mendelian randomization methods.

Conclusions: Genetic etiology of substance use and psychiatric disorders is highly pleiotropic and involves shared neurodevelopmental path, neurotransmission, and intracellular trafficking. In aggregate, the patterns are not consistent with vertical pleiotropy, more likely reflecting horizontal pleiotropy or more complex forms of phenotypic causation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1017/S003329172000272XDOI Listing
August 2020

Differential implications of persistent, remitted, and late-onset ADHD symptoms for substance abuse in women and men: A twin study from ages 11 to 24.

Drug Alcohol Depend 2020 07 27;212:107947. Epub 2020 Feb 27.

University of Minnesota, Twin Cities: Department of Psychology, 75 E. River Rd, Minneapolis, MN, 55455, United States.

Background: Persistence and emergence of ADHD in adulthood are associated with substance problems. We investigate differential implications of ADHD course for tobacco, alcohol, or marijuana problems by sex, then whether substance misuse results from ADHD or contributes to it, through a twin differences design.

Methods: A population-based cohort of 998 twins (61 % monozygotic; 52 % female), born in Minnesota from 1988 to 1994, was prospectively assessed from ages 11-24. Childhood ADHD was oversampled. At age 24, 255 had a history of childhood-onset ADHD (160 persistent, 95 remitted); 93 had late-onset ADHD symptoms identified in late-adolescence/adulthood. Persistent, remitted, and late-onset groups were compared to those without ADHD (N = 459) on childhood characteristics and age-24 substance problems.

Results: Persistent and late-onset groups differed in childhood; twin concordances suggested greater genetic etiology for persistent ADHD. As adolescents, however, both groups were high in conduct problems; by adulthood, they were comparably high in substance problems. In particular, women whose ADHD persisted were 5 times more likely to develop tobacco use disorder than women without ADHD. Remitted ADHD was associated with less-increased risk, except for alcohol problems among women. Consistent with possible causality, monozygotic female twins with more age-17 ADHD symptoms than co-twins had more age-24 tobacco symptoms; a similar association was found for alcohol.

Conclusions: Presence or emergence of ADHD in early adulthood increases substance problems to a greater degree for women than men. While effects of substances on later ADHD were not statistically significant, detection was limited by the relative rarity of late-adolescent substance symptoms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.drugalcdep.2020.107947DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293951PMC
July 2020

Sibling Comparison Designs: Addressing Confounding Bias with Inclusion of Measured Confounders.

Twin Res Hum Genet 2019 10 27;22(5):290-296. Epub 2019 Sep 27.

Department of Psychology, University of Minnesota, Minneapolis, MN, USA.

Genetically informative research designs are becoming increasingly popular as a way to strengthen causal inference with their ability to control for genetic and shared environmental confounding. Co-twin control (CTC) models, a special case of these designs using twin samples, decompose the overall effect of exposure on outcome into a within- and between-twin-pair term. Ideally, the within-twin-pair term would serve as an estimate of the exposure effect controlling for genetic and shared environmental factors, but it is often confounded by factors not shared within a twin-pair. Previous simulation work has shown that if twins are less similar on an unmeasured confounder than they are on an exposure, the within-twin-pair estimate will be a biased estimate of the exposure effect, even more biased than the individual, unpaired estimate. The current study uses simulation and analytical derivations to show that while incorporating a covariate related to the nonshared confounder in CTC models always reduces bias in the within-pair estimate, it will be less biased than the individual estimate only in a narrow set of circumstances. The best case for bias reduction in the within-pair estimate occurs when the within-twin-pair correlation in exposure is less than the correlation in the confounder and the twin-pair correlation in the covariate is high. Additionally, the form of covariate inclusion is compared between adjustment for only one's own covariate value and adjustment for the deviation of one's own value from the covariate twin-pair mean. Results show that adjusting for the deviation from the twin-pair mean results in equal or reduced bias.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1017/thg.2019.67DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7170177PMC
October 2019

Mediating pathways from childhood ADHD to adolescent tobacco and marijuana problems: roles of peer impairment, internalizing, adolescent ADHD symptoms, and gender.

J Child Psychol Psychiatry 2018 10;59(10):1083-1093

Department of Psychology, University of Minnesota, Minneapolis, MN, USA.

Background: We examined whether increased risk for adolescent tobacco and marijuana problems associated with childhood ADHD is explained by key intermediary influences during adolescence and differs by gender.

Methods: Longitudinal structural equation models examined mediating effects on problems with both substances (or each substance separately) through age-14 peer impairment, internalizing, and adolescent ADHD symptoms in two twin samples, prospectively assessed since age 11 (N = 2,164). Whether these mediators contributed beyond mediating effects of early-adolescent substance use was also considered. Twin difference analyses further illuminated which mediators might be potentially causal.

Results: Direct effects of childhood ADHD on age-17 tobacco and marijuana problems (i.e., independent of included mediators) as well as effects of adolescent ADHD symptoms were significant only for females. By contrast, mediation by peer impairment, evident particularly for marijuana, was relatively stronger for males than females. Depression and anxiety were not prospectively associated with age-17 substance problems when earlier substance problems were considered. Consistent with causal influence of early substance use on later problems, monozygotic twins with more severe tobacco or marijuana problems at age 14 than their co-twins were also more likely to have substance problems later in adolescence.

Conclusions: Mediation through peer impairment, continued presence of ADHD symptoms, and early substance use may alter development so that childhood ADHD indirectly contributes to problems with tobacco and marijuana. Targeting gender-sensitive interventions prior to mid-adolescence, before these patterns become established, is essential.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcpp.12977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6169803PMC
October 2018

The relationship between subjective well-being and mortality within discordant twin pairs from two independent samples.

Psychol Aging 2018 05;33(3):439-447

Department of Psychology, University of Minnesota.

Prior research has shown robust associations between greater subjective well-being (SWB) and reduced mortality. Whether this observed association is causal in nature or due instead to confounding genetic or environmental factors affecting both SWB and mortality is not well understood. We used a combined sample of 6,802 twins drawn from two cohorts: the Longitudinal Study of Middle-Aged Danish Twins (MADT; N = 2,815, baseline age between 45 and 69 years, M = 56.8, SD = 6.4) and the Longitudinal Study of Aging Danish Twins (LSADT; N = 3,987, baseline age between 70 and 97 years, M = 76.6, SD = 4.9). The relationship between SWB, encompassing measures of life satisfaction and affect, and all-cause mortality was evaluated using survival analyses at both the individual level and within twin pairs. Twin difference analyses were completed within 1,053 monozygotic (MZ) twin pairs and 1,143 dizygotic (DZ) twin pairs to control for genetic and shared environmental confounding. As expected, the individual-level results showed that higher levels of SWB were associated with reduced mortality: affect hazard ratio (HR) = .90, 95% confidence interval (CI) [.87, .94]; life satisfaction HR = .88, 95% CI [.84, .92]. The effect of SWB on reduced mortality remained significant within both MZ and DZ pairs, suggesting that the association is independent of genetic and nonshared environmental confounding factors. These findings, which generalized across both younger (MADT) and older (LSADT) cohorts of adults, remained significant when accounting for demographic factors, physical health, and cognitive functioning. (PsycINFO Database Record
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1037/pag0000248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5963536PMC
May 2018

Associations between childhood ADHD, gender, and adolescent alcohol and marijuana involvement: A causally informative design.

Drug Alcohol Depend 2018 03 27;184:33-41. Epub 2017 Dec 27.

Department of Psychology, University of Minnesota, Twin Cities, United States.

Background: We report whether the etiology underlying associations of childhood ADHD with adolescent alcohol and marijuana involvement is consistent with causal relationships or shared predispositions, and whether it differs by gender.

Methods: In three population-based twin samples (N = 3762; 64% monozygotic), including one oversampling females with ADHD, regressions were conducted with childhood inattentive or hyperactive-impulsive symptoms predicting alcohol and marijuana outcomes by age 17. To determine whether ADHD effects were consistent with causality, twin difference analyses divided effects into those shared between twins in the pair and those differing within pairs.

Results: Adolescents with more severe childhood ADHD were more likely to initiate alcohol and marijuana use earlier, escalate to frequent or heavy use, and develop symptoms. While risks were similar across genders, females with more hyperactivity-impulsivity had higher alcohol consumption and progressed further toward daily marijuana use than did males. Monozygotic twins with more severe ADHD than their co-twins did not differ significantly on alcohol or marijuana outcomes, however, suggesting a non-causal relationship. When co-occurring use of other substances and conduct/oppositional defiant disorders were considered, hyperactivity-impulsivity remained significantly associated with both substances, as did inattention with marijuana, but not alcohol.

Conclusions: Childhood ADHD predicts when alcohol and marijuana use are initiated and how quickly use escalates. Shared familial environment and genetics, rather than causal influences, primarily account for these associations. Stronger relationships between hyperactivity-impulsivity and heavy drinking/frequent marijuana use among adolescent females than males, as well as the greater salience of inattention for marijuana, merit further investigation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.drugalcdep.2017.11.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5818293PMC
March 2018

Increased Risk of Smoking in Female Adolescents Who Had Childhood ADHD.

Am J Psychiatry 2018 01 25;175(1):63-70. Epub 2017 Aug 25.

From the Department of Psychology, University of Minnesota, Twin Cities; and the Department of Human Development and Family Studies, Auburn University, Auburn, Ala.

Objective: This study examined the effects of childhood attention deficit hyperactivity disorder (ADHD) symptoms, both inattention and hyperactivity-impulsivity, on the development of smoking in male and female adolescents.

Method: Twin difference methods were used to control for shared genetic and environmental confounders in three population-based, same-sex twin samples (N=3,762; 64% monozygotic). One cohort oversampled female adolescents with ADHD beginning in childhood. Regressions of childhood inattentive and hyperactive-impulsive symptoms were conducted to predict smoking outcomes by age 17. ADHD effects were divided into those shared between twins in the pair and those nonshared, or different within pairs.

Results: Adolescents who had more severe ADHD symptoms as children were more likely to initiate smoking and to start smoking younger. The association of ADHD symptoms with daily smoking, number of cigarettes per day, and nicotine dependence was greater in females than in males. Monozygotic female twins with greater attentional problems than their co-twins had greater nicotine involvement, consistent with possible causal influence. These effects remained when co-occurring externalizing behaviors and stimulant medication were considered. Hyperactivity-impulsivity, while also more strongly related to smoking for female adolescents, appeared primarily noncausal.

Conclusions: Smoking initiation and escalation are affected differentially by ADHD subtype and gender. The association of inattention with smoking in female adolescents may be causal, whereas hyperactivity-impulsivity appears to act indirectly, through shared propensities for both ADHD and smoking.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1176/appi.ajp.2017.17010009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5756118PMC
January 2018

Parent-Offspring Resemblance for Drinking Behaviors in a Longitudinal Twin Sample.

J Stud Alcohol Drugs 2017 01;78(1):49-58

Department of Psychology, University of Minnesota, Minneapolis, Minnesota.

Objective: The purpose of the current study was to evaluate parent-offspring resemblance for alcohol consumption and dependence symptoms, including sex-specific effects, and how these patterns change across adolescence and early adulthood.

Method: Three cohorts of twins were assessed longitudinally at five time points between ages 14 and 29 years, with parents directly assessed at intake, using structured interviews. Twin offspring and parents from the population-based Minnesota Twin Family Study were included for a total sample size of 3,762 offspring (52% female) and their parents. Alcohol use was measured using an index based on drinking quantity, frequency, maximum drinks, and number of intoxications. Alcohol dependence symptom counts were also used.

Results: Parent-offspring correlations for alcohol consumption increased from age 14 (r = .12) to age 17 (r = .25), remained stable from ages 17 through 24, and then decreased slightly by age 29 (r = .19). Familial resemblance for symptoms of alcohol dependence peaked at age 17 (r = .18) then decreased through age 29 (r = .11). Parent-offspring correlations of both measures did not vary significantly by sex of offspring or sex of parent.

Conclusions: Overall, parent-offspring resemblance for alcohol use and problems is relatively stable after early adulthood, with resemblance for alcohol use at higher magnitudes across offspring development. Evidence for differential resemblance based on sex of offspring or parents was lacking.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5148749PMC
http://dx.doi.org/10.15288/jsad.2017.78.49DOI Listing
January 2017

The impact of focusing a program to prevent heavier drinking on a pre-existing phenotype, the low level of response to alcohol.

Alcohol Clin Exp Res 2015 Feb 6;39(2):308-16. Epub 2015 Feb 6.

Department of Psychiatry, University of California, San Diego, La Jolla, California.

Background: Heavy drinking is common during transitions from high school to college. Optimal programs for diminishing risks for high alcohol consumption often tailor the approach to the specific needs of students. This study describes the results of an Internet-based prevention protocol that tailors the information to the risk associated with a pre-existing phenotype, the Low level of Response (Low LR) to alcohol.

Methods: Using stratified random assignment, 454 freshmen with Low and High LR values were assigned to 2 education groups (LR-based where all examples were given the context of the Low LR model of heavy drinking or a State Of The Art (SOTA) Group where the same lessons were taught but without an emphasis on LR) or a no-intervention Control Group. Individuals in the 2 education groups viewed 50-minute online videos once per week for 4 weeks. Changes in drinking patterns were assessed at Baseline, 4 weeks, and 8 weeks using a 2 (LR status) by 3 (education group) by 3 (time points) analysis of variance, with additional tests for ethnicity and sex.

Results: Low LR participants tended to decrease their usual (p < 0.06) and maximum (p < 0.05) drinks per occasion most prominently when assigned to the LR-based protocol, while those with High LRs improved more in the SOTA Group. The most robust differences were seen when controlling for ethnicity. The effect sizes were small to medium.

Conclusions: These results support the advantages of carrying out prevention via the Internet and in tailoring the approach to a pre-existing phenotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/acer.12620DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4331238PMC
February 2015

Predictors of subgroups based on maximum drinks per occasion over six years for 833 adolescents and young adults in COGA.

J Stud Alcohol Drugs 2014 Jan;75(1):24-34

University of Connecticut, Storrs, Connecticut.

Objective: A person's pattern of heavier drinking often changes over time, especially during the early drinking years, and reflects complex relationships among a wide range of characteristics. Optimal understanding of the predictors of drinking during times of change might come from studies of trajectories of alcohol intake rather than cross-sectional evaluations.

Method: The patterns of maximum drinks per occasion were evaluated every 2 years between the average ages of 18 and 24 years for 833 subjects from the Collaborative Study on the Genetics of Alcoholism. Latent class growth analysis identified latent classes for the trajectories of maximum drinks, and then logistic regression analyses highlighted variables that best predicted class membership.

Results: Four latent classes were found, including Class 1 (69%), with about 5 maximum drinks per occasion across time; Class 2 (15%), with about 9 drinks at baseline that increased to 18 across time; Class 3 (10%), who began with a maximum of 18 drinks per occasion but decreased to 9 over time; and Class 4 (6%), with a maximum of about 22 drinks across time. The most consistent predictors of higher drinking classes were female sex, a low baseline level of response to alcohol, externalizing characteristics, prior alcohol and tobacco use, and heavier drinking peers.

Conclusions: Four trajectory classes were observed and were best predicted by a combination of items that reflected demography, substance use, level of response and externalizing phenotypes, and baseline environment and attitudes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3893632PMC
http://dx.doi.org/10.15288/jsad.2014.75.24DOI Listing
January 2014

Sex differences in how a low sensitivity to alcohol relates to later heavy drinking.

Drug Alcohol Rev 2012 Nov 18;31(7):871-80. Epub 2012 Jun 18.

Department of Psychiatry, University of California, San Diego, La Jolla, USA.

Introduction And Aims: A low level of response (LR), or low sensitivity, to alcohol is a genetically influenced characteristic that predicts future heavy drinking and alcohol problems. While previous analyses of how LR relates to heavier drinking reported the process is similar in males and females, some potential sex differences have been identified. This difference is further explored in these analyses.

Design And Methods: Prospective structural equation models (SEMs) were evaluated for 183 young adult females and 162 males, none of Asian background, from the Collaborative Study on the Genetics of Alcoholism. Invariance analyses and SEM evaluations by sex were used to compare across females and males for these primarily Caucasian (75%), non-Asian young (mean age 19) subjects.

Results: The prospective SEM for the full set of 345 subjects had good fit characteristics and explained 37% of the variance. While the initial invariance analyses identified few sex differences, comparisons of correlations and direct evaluations of path coefficients across males and females indicated that only females showed a link between a low LR and future alcohol problems that was partially mediated by more positive alcohol expectancies and drinking to cope. These sex differences were reflected in the different structures of the SEM results for female versus male subjects.

Discussion And Conclusions: These prospective results indicate that there might be some important sex differences regarding how a lower LR relates to alcohol outcomes that should be considered in protocols focusing on preventing the impact of LR on future drinking problems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1465-3362.2012.00469.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3459074PMC
November 2012

Comparison across two generations of prospective models of how the low level of response to alcohol affects alcohol outcomes.

J Stud Alcohol Drugs 2012 Mar;73(2):195-204

Department of Psychiatry, University of California, San Diego School of Medicine, La Jolla, California 92037, USA.

Objective: This article presents the first direct comparison of level of response (LR)-based prospective models in two generations of the same families. To accomplish this, we describe results from the first prospective evaluation of potential mediators of how an earlier low LR to alcohol relates to adverse alcohol outcomes in offspring from the San Diego Prospective Study (SDPS).

Method: To compare with data from probands in the SDPS, new data were gathered from 86 drinking offspring (age ~20 years) during the 25-year follow-up of these families. Consistent with the usual effect of a low LR, outcomes 5 years later for both generations focused on drinking quantities as well as alcohol problems during the follow-up. A structural equation model (SEM) was used to analyze the relationships among variables, and the models in proband and offspring generations were compared using direct observations of the model results and through invariance procedures.

Results: In these drinking offspring, LR correlated with 5-year outcomes (r = .48, p < .001) and the SEM R² was .48, with good fit statistics. As predicted, the LR relationship to alcohol-related outcomes was both direct and partially mediated by heavier peer drinking, positive alcohol expectancies, and using alcohol to cope with stress. These results were similar to a previously published prospective model in SDPS probands, although path coefficients were generally higher in the younger group.

Conclusions: The LR-based model of heavier drinking operated similarly across generations, with some modest differences. These results indicate that the model may be meaningful in both younger and middle-age groups.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3281979PMC
http://dx.doi.org/10.15288/jsad.2012.73.195DOI Listing
March 2012

Structuring a college alcohol prevention program on the low level of response to alcohol model: a pilot study.

Alcohol Clin Exp Res 2012 Jul 6;36(7):1244-52. Epub 2012 Feb 6.

Department of Psychiatry, University of California, San Diego, La Jolla, CA 92037, USA.

Background: New approaches are needed to bolster the modest effects of campus drinking prevention programs. However, more definitive research on new paradigms is very expensive, and in the current economic climate, progress can be made by evaluating smaller pilot studies. This study describes one such approach.

Methods: A sample of 18-year-old or older, healthy, drinking freshmen at our university was assigned to 2 groups stratified to be similar on demography, drinking histories, and their level of response (LR) to alcohol. In the spring quarter of the school year, the 32 subjects in each of 2 groups viewed four 45-minute Internet-based videotapes as part of 4 prevention sessions. All 8 modules were based on the same techniques and general content, but the 4 videos for the first group were structured around the validated model of how a low LR affects heavy drinking (the low level of response-based [LRB] Group), with partial mediation by heavier drinking peers, positive alcohol expectancies, and drinking to cope with stress. Videos for the state-of-the-art (SOTA) comparison group did not place the similar prevention messages into the low LR framework. Changes in drinking were evaluated at 3 times: before Module 1, before Module 4, and 1 month after Module 4.

Results: Usual and maximum drinks per occasion decreased over time for both high and low LR subjects in both LRB and SOTA groups. As predicted, the low LR students showed greater decreases in the LRB Group, while high LR students showed greater decreases in the more generic SOTA Group.

Conclusions: The results support the hypothesis that tailoring prevention efforts to address specific predisposing factors, such as a low LR, may be associated with beneficial effects on drinking quantity. We hope that these data will encourage additional efforts to validate the low LR-based prevention paradigm and test other interventions that are targeted toward predisposing phenotypes such as impulsivity and negative affect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1530-0277.2011.01723.xDOI Listing
July 2012
-->