Embodied Decision-Making Style: Below and Beyond Cognition

There is growing recognition of the essential role of sensorimotor processes as not just a supporter of the cognitive aspects of decision making, but rather as a foundation for all the coordinated physical and mental activities that go into how we make decisions. We illuminate concepts and methods for examining embodied decision making through the lens of Movement Pattern Analysis (MPA). MPA is as a prime example of a conceptually rooted observational methodology for deciphering embodied decision making and for decoding how people differ as decision makers with respect to cognitive motivational priorities. The historical origins of MPA that predated the formalized recognition of embodied cognition are presented, along with an overview of both the theoretical model and methodology. Advances in research on two psychometric benchmarks of observational research-inter-rater reliability and predictive validity-are highlighted as an empirical platform for the strong promise of MPA as a tool for understanding individual differences in embodied decision-making style. Future directions for research are considered-specifically with respect to the potential for utilizing automated coding, and the need for collaborative neuroscience research efforts-which would support further understanding of how decoding movement patterning captures human motivation at the level of sensory, motoric, cognitive and action integration which drives how people function as decision makers.

Beyond Self-Report: Emerging Methods for Capturing Individual Differences in Decision-Making Process

People vary in the way in which they approach decision-making, which impacts real-world behavior. There has been a surge of interest in moving beyond reliance on self-report measures to capture such individual differences. Particular emphasis has been placed on devising and applying a range of methodologies that include experimental, neuroscience, and observational paradigms. This paper provides a selective review of recent studies that illustrate the methods and yield of these approaches in terms of generating a deeper understanding of decision-making style and the notable differences that can be found across individuals.

Inter-rater reliability for movement pattern analysis (MPA): measuring patterning of behaviors versus discrete behavior counts as indicators of decision-making style

The unique yield of collecting observational data on human movement has received increasing attention in a number of domains, including the study of decision-making style. As such, interest has grown in the nuances of core methodological issues, including the best ways of assessing inter-rater reliability. In this paper we focus on one key topic – the distinction between establishing reliability for the patterning of behaviors as opposed to the computation of raw counts – and suggest that reliability for each be compared empirically rather than determined a priori. We illustrate by assessing inter-rater reliability for key outcome measures derived from movement pattern analysis (MPA), an observational methodology that records body movements as indicators of decision-making style with demonstrated predictive validity. While reliability ranged from moderate to good for raw counts of behaviors reflecting each of two Overall Factors generated within MPA (Assertion and Perspective), inter-rater reliability for patterning (proportional indicators of each factor) was significantly higher and excellent (ICC = 0.89). Furthermore, patterning, as compared to raw counts, provided better prediction of observable decision-making process assessed in the laboratory. These analyses support the utility of using an empirical approach to inform the consideration of measuring patterning versus discrete behavioral counts of behaviors when determining inter-rater reliability of observable behavior. They also speak to the substantial reliability that may be achieved via application of theoretically grounded observational systems such as MPA that reveal thinking and action motivations via visible movement patterns.

Parental smoking exposure and adolescent smoking trajectories

OBJECTIVE

In a multigenerational study of smoking risk, the objective was to investigate the intergenerational transmission of smoking by examining if exposure to parental smoking and nicotine dependence predicts prospective smoking trajectories among adolescent offspring.

METHODS

Adolescents (n = 406) ages 12 to 17 and a parent completed baseline interviews (2001-2004), and adolescents completed up to 2 follow-up interviews 1 and 5 years later. Baseline interviews gathered detailed information on parental smoking history, including timing and duration, current smoking, and nicotine dependence. Adolescent smoking and nicotine dependence were assessed at each time point. Latent Class Growth Analysis identified prospective smoking trajectory classes from adolescence into young adulthood. Logistic regression was used to examine relationships between parental smoking and adolescent smoking trajectories.

RESULTS

Four adolescent smoking trajectory classes were identified: early regular smokers (6%), early experimenters (23%), late experimenters (41%), and nonsmokers (30%). Adolescents with parents who were nicotine-dependent smokers at baseline were more likely to be early regular smokers (odds ratio 1.18, 95% confidence interval 1.05-1.33) and early experimenters (odds ratio 1.04, 95% confidence interval 1.04-1.25) with each additional year of previous exposure to parental smoking. Parents' current non-nicotine-dependent and former smoking were not associated with adolescent smoking trajectories.

CONCLUSIONS

Exposure to parental nicotine dependence is a critical factor influencing intergenerational transmission of smoking. Adolescents with nicotine-dependent parents are susceptible to more intense smoking patterns and this risk increases with longer duration of exposure. Research is needed to optimize interventions to help nicotine-dependent parents quit smoking early in their children's lifetime to reduce these risks.

Influences of tobacco advertising exposure and conduct problems on smoking behaviors among adolescent males and females

INTRODUCTION

Adolescents with conduct problems are more likely to smoke, and tobacco advertising exposure may exacerbate this risk. Males' excess risk for conduct problems and females' susceptibility to advertising suggest gender-specific pathways to smoking. We investigated the associations between gender, conduct problems, and lifetime smoking and adolescents' exposure to tobacco advertising, and we examined prospective relationships with smoking behaviors.

METHODS

Adolescents completed baseline (2001-2004; n = 541) and 5-year follow-up (2007-2009; n =320) interviews for a family study of smoking risk. Baseline interviews assessed conduct problems and tobacco advertising exposure; smoking behavior was assessed at both timepoints. Generalized linear models analyzed gender differences in the relationship between conduct problems, advertising exposure, and smoking behavior at baseline and longitudinally.

RESULTS

At baseline, among males, conduct problems were associated with greater advertising exposure independent of demographics and lifetime smoking. Among females at baseline, conduct problems were associated with greater advertising exposure only among never-smokers after adjusting for demographics. In longitudinal analyses, baseline advertising exposure predicted subsequent smoking initiation (i.e., smoking their first cigarette between baseline and follow-up) for females but not for males. Baseline conduct problems predicted current (i.e., daily or weekly) smoking at follow-up for all adolescents in adjusted models.

CONCLUSIONS

The findings of this study reinforce that conduct problems are a strong predictor of subsequent current smoking for all adolescents and reveal important differences between adolescent males and females in the relationship between conduct problems, tobacco advertising behavior, and smoking behavior. The findings suggest gender-specific preventive interventions targeting advertising exposure may be warranted.

Predicting individual differences in decision-making process from signature movement styles: an illustrative study of leaders

There has been a surge of interest in examining the utility of methods for capturing individual differences in decision-making style. We illustrate the potential offered by Movement Pattern Analysis (MPA), an observational methodology that has been used in business and by the US Department of Defense to record body movements that provide predictive insight into individual differences in decision-making motivations and actions. Twelve military officers participated in an intensive 2-h interview that permitted detailed and fine-grained observation and coding of signature movements by trained practitioners using MPA. Three months later, these subjects completed four hypothetical decision-making tasks in which the amount of information sought out before coming to a decision, as well as the time spent on the tasks, were under the partial control of the subject. A composite MPA indicator of how a person allocates decision-making actions and motivations to balance both Assertion (exertion of tangible movement effort on the environment to make something occur) and Perspective (through movements that support shaping in the body to perceive and create a suitable viewpoint for action) was highly correlated with the total number of information draws and total response time-individuals high on Assertion reached for less information and had faster response times than those high on Perspective. Discussion focuses on the utility of using movement-based observational measures to capture individual differences in decision-making style and the implications for application in applied settings geared toward investigations of experienced leaders and world statesmen where individuality rules the day.

Behavioral resilience in the post-genomic era: emerging models linking genes with environment

One of the most important deliverables of the post-genomic era has been a new and nuanced appreciation of how the environment shapes—and holds potential to alter—the expression of susceptibility genes for behavioral dimensions and disorders. This paper will consider three themes that have emerged from cutting-edge research studies that utilize newer molecular genetic approaches as well as tried-and-true genetic epidemiological methodologies, with particular reference to evolving perspectives on resilience and plasticity. These themes are: (1) evidence for replicable and robust shared environmental effects on a number of clinically relevant behaviors in childhood and adolescence; (2) evolving research on gene-environment interaction; and (3) a newer focus on differential susceptibility and plasticity. The net sum of these themes is that consideration of genetic effects on behavioral dimensions and disorders needs to be connected to thinking about the role of environment as a potent source for promoting resilience and change.

Randomized Prospective Study on the Use of Eufiss in the Prevention of Infections in Patients Treated with External Fixation

Percutaneous synthesis using K-wires or external fixation in orthopedics and traumatology is extremely common. Postoperative management of external fixation includes frequent wound care which is demanding for both the patient and the healthcare professionals. In literature the most frequently reported complication is infection. The use of ionic silver goes back to the beginning of the last century and there are many articles describing its antimicrobial efficacy even for antibiotic-resistant bacteria. In this study we assess the reduction in both superficial and deep infections by using ionic silver in patients with external fixation for orthopedic diseases or traumatology. Furthermore, we show how this method could also contribute to reducing wound care costs. The data collected shows an overall infection incidence of 10%, concordant with data in literature. There appears to be no correlation between the probability of superficial infections and predisposing diseases, such as diabetes, nor the fracture site or position. The presence of loose pins increases the probability of infection. There appears to be no correlation between the clinical examination and the microbiological culture. The data analysis shows that wound care with ionic silver reduces the incidence of superficial infection of the pins. Furthermore, this method guarantees greater cleanliness of the skin and the external fixator which increases patient satisfaction in the management of the external fixation. To date, an insufficient number of patients have been studied to gather enough data to establish which wound care method is the most economical. Certainly, we can state that treatment with ionic silver reduces infection incidence and enables better management of the external fixators and percutaneous synthesis in orthopedics and traumatology.

Genetic and environmental influences upon the CBCL/6-18 DSM-oriented scales: similarities and differences across three different computational approaches and two age ranges

Inasmuch as the newly established DSM-oriented CBCL/6-18 scales are to be increasingly employed to assess clinical/high-risk populations, it becomes important to explore their aetiology both within the normal- and the extreme range of variation in general population samples and to compare the results obtained in different age groups. We investigated by the Quantitative Maximum Likelihood, the De Fries-Fulker, and the Ordinal Maximum Likelihood methods the genetic and environmental influences upon the five DSM-oriented CBCL/6-18 scales in 796 twins aged 8-17 years belonging to the general population-based Italian Twin Registry. When children were analysed together regardless of age, most best-fitting solutions yielded genetic and non-shared environmental factors as the sole influences for DSM-oriented CBCL/6-18 behaviours, both for the normal and the extreme variations. When analyses were conducted separately for two age groups, shared environmental influences emerged consistently for Affective and Anxiety Problems in children aged 8-11. Oppositional-Defiant, Attention Deficit/Hyperactivity, and Conduct Problems appeared-with few exceptions-influenced only by genetic and non-shared environmental factors in both age groups, according to all three computational approaches. The De Fries-Fulker method appeared to be more sensitive in detecting shared environmental effects. Analysing the same set of data with different analytic approaches leads to better-balanced views on the aetiology of psychopathological behaviours in the developmental years.

Sibling Contagion for Drinking in Adolescence: A Micro Process Framework

Siblings represent an important social influence on alcohol use in adolescence. That said, there is a need for studies that examine potential mechanisms by which siblings exert an influence on the likelihood of drinking in adolescence. This paper illustrates a method that utilizes videotaped interaction between sibling dyads along with a micro social coding system that captures rule break behavior between siblings. Sibling interaction was observed in sibling pairs participating in the Iowa Youth and Families Project (IYFP) at baseline; younger sibling use of alcohol was tracked for 3 additional annual assessments. Exposure to older sibling rule break at baseline was associated with later use of alcohol by younger siblings across the 3 annual assessments. Micro social methods hold promise for uncovering processes that underlie sibling contagion for alcohol use in adolescence.

Anxiety in middle adulthood: effects of age and time on the 14-year course of panic disorder, social phobia and generalized anxiety disorder

BACKGROUND

Much about the long-term course of anxiety disorders is unknown. The present study utilizes a naturalistic, longitudinal, short-interval follow-up design to elucidate the course of anxiety disorders over 14 years in a largely middle-aged adult sample recruited from out-patient psychiatry and primary care facilities.

METHOD

The sample consisted of 453 participants with a diagnosis of panic disorder (PD), social phobia (SP) and/or generalized anxiety disorder (GAD). Anxiety symptom ratings were tracked using weekly psychiatric status ratings (PSRs). Controlling for demographic and clinical variables, the course of PD, GAD and SP were examined using longitudinal growth models, with the most severe PSR at each follow-up point as the main outcome variable.

RESULTS

PSRs significantly decreased in severity over time in each of the three disorders. In the interaction effects models, age x time had a significant effect on course for PD and GAD, but not for SP, in that older age was associated with lower PSRs over time.

CONCLUSIONS

The present findings suggest that the severity of anxiety disorders declines over time, although this decline is modest and depends on the specific disorder being assessed. Older individuals with PD and GAD have a better prognosis than their younger counterparts, as their course is characterized by a steeper decline in severity. The present findings provide important information about the course of anxiety disorders in mid-life.

Parental smoking and adolescent smoking initiation: an intergenerational perspective on tobacco control

OBJECTIVE

Adolescence is an important period of risk for the development of lifelong smoking behaviors. Compelling, although inconsistent, evidence suggests a relationship between parental smoking and the risk of smoking initiation during adolescence. This study investigates unresolved issues concerning the strength and nature of the association between parent smoking and offspring smoking initiation.

METHODS

We enrolled 564 adolescents aged 12 to 17, along with 1 of their parents, into the New England Family Study between 2001 and 2004. Lifetime smoking histories were obtained from parents and their adolescent offspring. Discrete-time survival analysis was used to investigate the influence of parental smoking histories on the risk of adolescent smoking initiation.

RESULTS

Parental smoking was associated with a significantly higher risk of smoking initiation in adolescent offspring. In addition, the likelihood of offspring smoking initiation increased with the number of smoking parents and the duration of exposure to parental smoking, suggesting a dose-response relationship between parental smoking and offspring smoking. Offspring of parents who had quit smoking were no more likely to smoke than offspring of parents who had never smoked. The effects of parental smoking on offspring initiation differed by sex (with a stronger effect of fathers' smoking on boys than girls), developmental period (with a stronger effect of parental smoking before the adolescent was age 13 than afterward), and residence of parents (with effects of fathers' smoking being dependent on living in the same household as the adolescent). Parental smoking was also associated with stronger negative reactions to adolescents' first cigarette, a potential marker of the risk of progression to higher levels of use.

CONCLUSIONS

Parental smoking is an important source of vulnerability to smoking initiation among adolescents, and parental smoking cessation might attenuate this vulnerability.

Anxiety sensitivity as a predictor of the clinical course of panic disorder: a 1-year follow-up study

BACKGROUND

There is evidence that negative affect (NA) and anxiety sensitivity (AS) predict the development of anxiety disorders, particularly panic disorder (PD). The main purpose of this study was to examine whether NA and AS will also predict the clinical course of PD.

METHODS

Participants were 136 individuals with a DSM-III-R diagnosis of PD (with or without agoraphobia) enrolled in a naturalistic and longitudinal study of anxiety disorders, the Harvard/Brown Anxiety Research Project (HARP). Participants were administered the Anxiety Sensitivity Index and the Negative Affect Scales of the Positive and Negative Affect Schedule-Expanded Form (PANAS-X-NA) and their percentage of time in PD episode was followed for 1 year after the administration of the measures.

RESULTS

Multiple regression analyses indicated that AS, but not NA, was a significant predictor of percentage of time in PD episode after controlling for previous time in PD episodes, comorbid depression, other anxiety disorders, and exposure to psychopharmacological and behavioral treatments. As expected, the Physical Concerns subscale of the Anxiety Sensitivity Index had a significant independent contribution in predicting the course of the disorder.

CONCLUSIONS

Overall, these findings suggest that AS, as a unique construct, may be predictive of the amount of time patients are in episode of PD.

A twin study of smoking, nicotine dependence, and major depression in men

This study examined the nature of the relationship among lifetime major depression, smoking, and nicotine dependence. Subjects were 8,169 male twins from the Vietnam Era Twin Registry. Biometrical modeling demonstrated a genetic influence on daily smoking, nicotine dependence, and major depression, and a family environmental influence on daily smoking. Genetic factors influencing nicotine dependence also strongly influenced major depression. We also compared probands with a history of major depression (n = 398) from pairs discordant for major depression, their nondepressed cotwins (n = 364), and controls (n = 1,863) on a number of secondary smoking outcomes. Major depression was associated with current daily smoking and certain nicotine withdrawal symptoms. Individuals with a familial vulnerability for major depression, even without a personal history of major depression, were more likely to smoke despite a serious illness and to report nervousness, restlessness, difficulty concentrating, and depressed mood during past quit attempts. Among the 237 monozygotic pairs discordant for major depression, depressed probands were more likely to have a lifetime history of nicotine dependence than were cotwins. Findings extend Kendler and colleague's (1993) study of female twins by demonstrating in men that shared genetic factors predispose not only to major depression and daily smoking but also to major depression and nicotine dependence.

Incorporating the family as a critical context in genetic studies of children: implications for understanding pathways to risky behavior and substance use

The availability of candidate gene markers for biobehavioral traits will undoubtedly result in increasing attention to genetic influences in studies of childhood risk factors for health behaviors. However, a strict emphasis on genomics without consideration of the social contexts that give rise to risky behaviors will miss opportunities to understand more fully the powerful effect of the family on childhood development. This article discusses the rationale for using the family as a critical context for studying the translation of genetic propensity for risky behavior into developmental pathways that span childhood and adolescence. Attention is given to the importance of family environmental factors; the emerging literature on genetic influences on potential intermediate phenotypes; the need for rich and detailed characterizations of both phenotypes and environmental risk factors embedded within genomic studies of children; and implications for interventions and preventions aimed at risky behaviors. Via discussion of these issues, pragmatic considerations of how studying families as a context may facilitate the thoughtful inclusion of children into genetic paradigms are emphasized.

Educational attainment and cigarette smoking: a causal association?

BACKGROUND

Despite abundant evidence that lower education is associated with a higher risk of smoking, whether the association is causal has not been convincingly established.

METHODS

We investigated the association between education and lifetime smoking patterns in a birth cohort established in 1959 and followed through adulthood (n = 1311). We controlled for a wide range of potential confounders that were measured prior to school entry, and also estimated sibling fixed effects models to control for unmeasured familial vulnerability to smoking.

RESULTS

In the full sample of participants, regression analyses adjusting for multiple childhood factors (including socioeconomic status, IQ, behavioural problems, and medical conditions) indicated that the number of pack-years smoked was higher among individuals with less than high school education [rate ratio (RR) = 1.58, confidence interval (CI) = 1.31, 1.91]. However, in the sibling fixed effects analysis the RR was 1.23 (CI = 0.80, 1.93). Similarly, adjusted models estimated in the full sample showed that individuals with less than high school education had fewer short-term (RR = 0.40; CI = 0.23, 0.69) and long-term (RR = 0.59; CI = 0.42, 0.83) quit attempts, and were less likely to quit smoking (odds ratio = 0.34; CI = 0.19, 0.62). The effects of education on quitting smoking were attenuated in the sibling fixed effects models that controlled for familial vulnerability to smoking.

CONCLUSIONS

A substantial portion of the education differential in smoking that has been repeatedly observed is attributable to factors shared by siblings that contribute to shortened educational careers and to lifetime smoking trajectories. Reducing disparities in cigarette smoking, including educational disparities, may therefore require approaches that focus on factors early in life that influence smoking risk over the adult life span.

Effects of progression to cigarette smoking on depressed mood in adolescents: evidence from the National Longitudinal Study of Adolescent Health

AIMS

To investigate the relationship between smoking status and continuously distributed depressed mood among a cohort of adolescents.

DESIGN

Quasi-experimental design, selecting the subset of adolescents who reported never having smoked a cigarette at baseline, some of whom progressed subsequently to smoking at follow-up approximately 1 year later.

SETTING

Data were drawn from the National Longitudinal Study of Adolescent Health, an ongoing study designed to assess the health status of adolescents, and explore the causes of adolescent health-related behaviours.

PARTICIPANTS

Nationally representative sample of adolescents from the USA (n = 12 149), including a subsample who reported never having smoked a cigarette at baseline (n = 5475), aged on average 15 years at baseline and of predominantly European ancestry.

MEASUREMENTS

Logistic and linear regression models controlling for potential confounders to explore the relationship between smoking status and depressed mood measured using the Centers for Epidemiological Studies Depression Scale (CES-D).

FINDINGS

Various relationships between smoking status and depressed mood were observed, with a general trend for these effects to be greater among females. Smoking status at baseline did not significantly predict CES-D score at follow-up, although this effect approached significance in females (P = 0.077). Among never smokers at baseline, level of depressed mood at baseline predicted subsequent progression to smoking initiation (P = 0.022) but not progression to regular smoking (P = 0.229). Among never smokers at baseline, progression to smoking initiation during the follow-up period was associated with higher CES-D scores at follow-up, even after adjusting for baseline depressed mood (P < 0.001), with this effect greater for females than for males. Among those who initiated smoking, progression to regular smoking was associated with higher CES-D score at follow-up among females (P = 0.001), but not males (P = 0.966).

CONCLUSIONS

These data appear to support a complex model of the relationship between depressed mood and smoking status which includes elements of both confounding and causal models. The relationship between cigarette smoking and depression may be a factor in the development of subsequent dependence.

Impact of parental history of substance use disorders on the clinical course of anxiety disorders

Background

Among the psychological difficulties seen in children of parents with substance use problems, the anxiety disorders are among the most chronic conditions. Although children of alcoholic parents often struggle with the effects of parental substance use problems long into adulthood, empirical investigations of the influence of parental substance use disorders on the course of anxiety disorders in adult offspring are rare. The purpose of this study was to examine prospectively the relationship between parental substance use disorders and the course of anxiety disorders in adulthood over the course of 12 years.

Methods

Data on 618 subjects were derived from the Harvard/Brown Anxiety Research Project (HARP), a longitudinal naturalistic investigation of the clinical course of multiple anxiety disorders. Kaplan-Meier survival estimates were used to calculate probabilities of time to anxiety disorder remission and relapse. Proportional hazards regressions were conducted to determine whether the likelihood of remission and relapse for specific anxiety disorders was lower for those who had a history of parental substance use disorders than for individuals without this parental history.

Results

Adults with a history of parental substance use disorders were significantly more likely to be divorced and to have a high school level of education. History of parental substance use disorder was a significant predictor of relapse of social phobia and panic disorders.

Conclusion

These findings provide compelling evidence that adult children of parents with substance use disorders are more likely to have relapses of social phobia and panic disorders. Clinicians who treat adults with anxiety disorders should assess parental substance use disorders and dependence histories. Such information may facilitate treatment planning with regards to their patients' level of vulnerability to perceive scrutiny by others in social situations, and ability to maintain a long-term panic-free state.

Childhood-onset bipolar disorder: Evidence for increased familial loading of psychiatric illness

OBJECTIVE

To determine whether childhood-onset bipolar disorder (BP) is associated with an increased psychiatric family history compared with adolescent-onset BP.

METHOD

Semistructured psychiatric interviews were conducted for 438 youth with BP spectrum disorders. To evaluate the effects of age at onset and psychiatric family history, the sample was divided into childhood-onset BP (age and BP onset <12 years; n = 192), adolescents with early-onset BP (age > or =12 years and BP onset <12 years; n = 136), and adolescents with late-onset BP (age and BP onset > or =12 years; n = 110). Lifetime family history of psychiatric illness was ascertained for first- and second-degree relatives through both direct interview of caretakers and the Family History Screen.

RESULTS

After significant demographic and clinical factors were controlled for, children and adolescents with childhood-onset BP showed higher percentages of positive first-degree family history for depression, anxiety, attention-deficit/hyperactivity, conduct, and substance dependence disorders and suicidal behaviors compared with adolescents with late onset. Subjects with childhood-onset BP also showed elevated familial loading for depression and attention-deficit/hyperactive disorder in second-degree relatives.

CONCLUSIONS

These data support a model that postulates a higher density of familial risk for a broad range of psychopathology in childhood-onset BP.

Psychotic symptoms in pediatric bipolar disorder and family history of psychiatric illness

BACKGROUND

Few studies have examined the specificity and non-specificity in patterns of familial loading for presentation of psychotic symptoms in pediatric bipolar disorder (BP).

METHODS

Diagnostic assessment of 263 pediatric BP probands included lifetime history of psychotic symptoms as well as longitudinal follow-up; family history of psychiatric illness was determined for 1st degree relatives.

RESULTS

Pediatric BP probands with lifetime history of psychosis had a higher percentage of positive family history of anxiety disorders and suicide attempts as compared to probands with no history of psychosis.

DISCUSSION

Familial loading for a spectrum of internalizing disorders is associated with presentation of psychotic symptoms in pediatric BP.

Estimating genetic and environmental influences on depressive symptoms in adolescence: differing effects on higher and lower levels of symptoms

We estimate the relative effect sizes of genetic and environmental influences on both higher and lower levels of depressive symptoms with attention to persistence over a 1-year period in the genetically informative subsample of adolescents participating in the National Longitudinal Study of Adolescent Health (Add Health). Shared environmental effects were significant for persistent higher levels of depressive symptoms but not nonpersistent symptoms. Genetic effects were significant for both persistent and nonpersistent lower levels of depressive symptoms. Nongenetic factors that promote similarity between siblings for high levels of depressive symptoms are important and should be considered in both etiological and applied research. Genetic contributions to lack of susceptibility to depression should be considered in biological models of depression suppression.

A twin-sibling study of tobacco use in adolescence: etiology of individual differences and extreme scores

A database is emerging that examines the relative contributions of genes and the environment to the etiology of smoking in adolescence. We present analyses derived from a genetically informative subsample of sibling pairs (monozygotic and dizygotic twins, full siblings, and half-siblings) participating in two waves of the National Longitudinal Study of Adolescent Health to estimate these parameters on both individual differences in smoking and extreme levels of smoking. Evidence indicated both genetic and shared environmental influences on high levels of smoking frequency, as well as on individual differences in smoking. No notable gender differences in these parameters emerged. Shared environmental effects were especially notable for high levels of smoking frequency and significantly greater than those found for individual differences. These findings were compatible with prior studies of both adolescent and adult smoking and reinforce the importance of familial influences on high levels of smoking frequency in adolescence.

Sibling effects on substance use in adolescence: social contagion and genetic relatedness

Prior research on sibling contagion for substance use has not attended to individual differences in the sibling relationship that may be influenced by genetic similarity. The authors utilizing data on a sample of twin and nontwin siblings participating in the National Longitudinal Study of Adolescent Health (Add Health). Although monozygotic twins had the highest levels of sibling contact and mutual friendships, the pattern of results for other sibling types were not consistent with genetic models, and biometric analysis indicated that shared environmental factors influenced these sibling relationship features. Application of DeFries-Fulker regression models provided evidence that sibling contact and mutual friendships represent a source of social contagion for adolescent smoking and drinking independent of genetic relatedness. The results are interpreted using a social contagion framework and contrasted with other competing models such as those focused on the equal environments assumption and niche selection.

Sibling effects on smoking in adolescence: evidence for social influence from a genetically informative design

AIMS

Behavioral genetic research has suggested that sibling effects on smoking may reflect social rather than genetic processes. We utilize a genetically informative sample of adolescents to test this proposition, focusing on sibling relationship processes (social connectedness) shown to be influential in studies of deviancy.

DESIGN

A combined twin-sibling design was employed to disentangle genetic and non-genetic effects.

PARTICIPANTS

We utilized a sample of 1421 adolescent sibling pairs participating in the US National Longitudinal Study of Adolescent Health (Add Health). These sibling pairs represent a spectrum of genetic relatedness and include monozygotic twins, dizygotic twins, biological siblings, half-siblings and unrelated siblings.

MEASUREMENTS

Participants completed self-report questionnaires on smoking behavior, quality of relationship with their sibling (social connectedness) and peer and parental smoking.

FINDINGS

Main effects of both shared environment and genetics were found on adolescent smoking frequency. Social connectedness between siblings moderated shared environmental influences on smoking frequency at each time period, as well as on change in smoking frequency. Shared environmental effects were more pronounced when siblings reported high levels of social connectedness. These environmental sibling effects on smoking were significant after controlling for parent and peer smoking.

CONCLUSIONS

This report extends prior research on sibling effects on smoking by identifying specific relationship dynamics that underlie transmission of risk within sibships and providing evidence that such relationship dynamics represent social rather than genetic processes.

Familial overlap between bipolar disorder and psychotic symptoms in a Canadian cohort

BACKGROUND

Although they were once considered separate nosologic entities, there is current interest in the etiologic overlap between bipolar disorder (BD) and schizophrenia. A critical issue concerns the familial basis of the overlap, specifically, the possibility of a distinct familial subtype of BD with psychotic features.

METHODS

We recruited individuals with BD from the community and compared them with a matched group diagnosed with no mental disorder to confirm familial aggregation for BD, schizophrenia, and psychotic symptoms. We then compared BD probands both with and without first-degree relatives with psychotic symptoms on several clinical indicators to determine the specificity of the familial aggregation.

RESULTS

As expected, there was evidence for familial aggregation of schizophrenia and psychotic symptoms in families having probands with BD. Familial loading for schizophrenia and psychotic symptoms was especially notable in male relatives of female probands with BD. We found no differences in the clinical profile of probands with BD stratified for familial loading for psychotic symptoms.

CONCLUSIONS

Findings from this sample support etiologic theories arguing for a shared but nonspecific genetic etiology for BD and schizophrenia, with psychotic symptoms being a potential key indicator for genetic studies.

Sisters, brothers, and delinquency: evaluating social influence during early and middle adolescence

Although a number of studies have shown that brothers are highly correlated for delinquent behavior, much less research has been conducted on sisters. We propose that sisters, like brothers, show notable similarity for delinquent behavior, and also promote each other's delinquency through direct interaction. We examined these issues in 164 brother and sister pairs studied over a 4-year period (from early to middle adolescence) in a study of intact families in the rural Midwest. Sibling similarity for self-reports of delinquent behavior were highly correlated for both brothers and sisters. Conditional effects of high levels of hostile-coercive sibling relationships and older sibling delinquency predicted younger sibling delinquency in both brother and sister pairs. For brothers, conditional effects were also detected for high levels of warmth-support, in contrast to sisters. The conditional effects of older sibling delinquency and relationship quality were shown to predict change in younger sibling delinquency through adolescence. The results add to a growing literature on sibling effects as well as theoretical models that emphasize the role of social interaction between siblings as a risk factor for the development of delinquent activity in adolescence.

Sibling aggregation for psychiatric disorders in offspring at high and low risk for depression: 10-year follow-up

BACKGROUND

A unique way of determining patterns of parent-offspring transmission of risk to affective disorders is to focus on aggregation within sibling pairs. We attempt to extend our previous finding that sibling aggregation is notable for anxiety disorders in a 10-year follow-up of siblings at high and low risk for depression, by virtue of parental diagnosis.

METHODS

The sample, which included 173 unique sibling pairs in the high risk cohort, and 83 pairs in the low risk cohort, had been assessed using semi-structured clinical interviews three times over a 10-year period, spanning from childhood to adulthood. Sibling aggregation was quantified using pairwise odds ratios.

RESULTS

Sibling aggregation in the high risk cohort was greater than aggregation in the low risk cohort for anxiety disorders, especially those that emerged in childhood, and later co-morbid disorders, especially major depressive disorder and suicide attempts.

CONCLUSIONS

Familial liability to affective disorders may be reflected most strongly by a developmental sequence of anxiety disorders in childhood followed by later depressive and suicidal in adolescence and adulthood.

Sibling aggregation for psychopathology in offspring of opiate addicts: effects of parental comorbidity

Applied a new analytic approach within the high-risk paradigm, the analysis of sibling aggregation, to identify homogeneous subtypes of familial risk for psychopathology and addiction. All sibling pairs participating in a study of offspring of opiate-addicted parents were identified and their aggregation for psychiatric disorders was determined using pairwise odds ratios, an analytic technique used in genetic epidemiology. Sibling aggregation was most notable for depressive and anxiety disorders but only in the presence of comorbid depressive disorders in the parents. Parental comorbid alcoholism did not impact sibling aggregation. We emphasize methodological implications of this approach for addressing issues of phenotypic and etiologic heterogeneity in the study of developmental risk for substance abuse.

A new instrument to assess sibling relationships in antisocial youth: the social interaction between siblings (SIBS) interview: a research note

This paper presents psychometric information on a new interview (SIBS) designed to examine sibling influences on antisocial behavior. The feasibility of the instrument and internal consistency of the SIBS scales was documented in a sample of 29 children (ages 6-11) with a delinquent older brother. In addition, adequate to excellent test-retest reliability of the SIBS scales was demonstrated in an unselected sample. The potential utility of the SIBS interview for assessing the role of siblings in the development of antisocial behavior is discussed.

Psychiatric disorders in the relatives of depressed probands. II. Familial loading for comorbid non-depressive disorders based upon proband age of onset

This study examined familial loading for non-depressive disorders in first-degree relatives (FDRs) of early-(< 20 years of age) and adult-onset (> or = 20 years of age) depressed probands. Our previous work, which demonstrated that FDRs of early-onset probands have higher rates of major depression as compared to FDRs of adult-onset probands, has not yet examined risk for non-depressive disorders in FDRs. In this paper, we focus on best-estimate diagnoses of anxiety disorders, alcoholism, and antisocial personality conducted on 639 first-degree relatives. The FDRs of early-onset probands had significantly higher rates of comorbid transmission of alcoholism and depression, and antisocial personality and depression, respectively. Significant co-transmission of anxiety disorders and depression was found in the FDRs of both early- and adult-onset probands. Future genetic studies of depression, especially early-onset depression, should hence broaden their definitions of phenotypes to include comorbid disorders when searching for the etiology of this complex disorder.

Psychiatric disorders in the relatives of depressed probands. I. Comparison of prepubertal, adolescent and early adult onset cases

Research with adults suggests that early onset of depression is associated with increased rates of depression among relatives. This paper presents results, of a family study that tested the hypothesis that prepubertal depression was associated with a greater familial loading of depression than the postpubertal form, which in turn had a greater familial loading than adult onset depression. Probands were from a child to adult longitudinal study. Psychiatric disorders among relatives were assessed with family interview and family history methods 'blind' to all findings regarding the proband. Contrary to expectation, familial rates of depression did not differ significantly between the groups. However, manic disorders tended to be more common among the relatives of postpubertal depressed cases than among the relatives of adult onset cases. Moreover, relatives of prepubertal depressed subjects had higher rates of criminality and family discord than postpubertal subjects. Prepubertal onset depressive disorders appear to be relatively distinct from postpubertal forms.

Sibling resemblance for psychiatric disorders in offspring at high and low risk for depression

This study examined sibling resemblance for major depressive disorder, anxiety disorder, and conduct disorder, in offspring at high and low risk for depression by virtue of parental diagnosis. The sample, which ranged in age from 6 to 23 years, included 164 sibling pairs at high risk, and 68 sibling pairs at low risk. Each cohort was assessed at two waves separated by a 2-year period. Sibling resemblance in the high risk cohort was substantially greater than resemblance in the low risk cohort for anxiety disorder (and comorbid conditions including anxiety disorder), but not depression. Discussion focused on the possibility that anxiety disorder may reflect the most pronounced familial influences common to siblings at high risk for depression.

A twin study of competence and problem behavior in childhood and early adolescence

The Child Behavior Checklist (CBCL) was completed by parents of 181 pairs of same-sex twins ages 7-15 (mean age = 11.0 years). Correlations between scores on the CBCL scales for 99 pairs of monozygotic twins and 82 pairs of dizygotic twins indicated significant genetic influences that varied according to the specific area of competence and problem behavior. Model-fitting estimates derived from multiple regression analyses indicated significant genetic influence on competence in school and on all areas of problem behavior. In addition, significant shared environmental influence was detected for amount and quality of participation in activities, quality of social relationships, performance in school, anxiety/depression, and delinquent behaviour. Implications for future work on the mechanisms underlying these effects are discussed.

Adjustment in middle childhood and early adolescence: links with earlier and contemporary sibling relationships

The relation of individual differences in internalizing and externalizing behavior in middle childhood and early adolescence to children's concurrent sibling relationships and their mothers' mood, and to their sibling and mother-child relationships in the preschool period was studied. Thirty-nine younger and 39 older siblings observed at home in the preschool period were studied 5 and 7 years later. Differences in adjustment were related to contemporary sibling relationships and maternal mood, and to sibling and mother-child interaction in the preschool period, even when mothers' current mood was taken into account.

Genes, environment, and addictive behavior: etiology of individual differences and extreme cases

There is considerable interest in assessing the role of genetic factors in the aetiology of addiction. This paper reviews the possible contribution of a new quantitative technique, termed DF analysis after its originators DeFries & Fulker. DF analysis provides a way of examining whether aetiological factors relating to addiction as a discrete disorder (manifest as extreme scores on a diagnostic instrument) are similar to or different from those that relate to it as a continuum. For example, it is possible to estimate the contribution of familial factors to the development of a clinical condition defined in terms of an extreme score on an instrument by examining the extent of regression towards the unselected population mean of siblings' scores on that instrument. At the same time it is possible to estimate familial influences on the full range of values by examining the correlation between the scores of siblings. Insofar as the two methods produce different estimates, it is possible to infer different levels of involvement of familial factors for extreme cases than for the continuum as a whole. Information provided by such analyses could be critical when constructing models of addictive disorders and help direct more specific studies isolating particular mechanisms.

HLA-JY328: mapping studies and expression of a polymorphic HLA class I gene

The JY328 clone was identified in a human genomic library using cDNA corresponding to mRNA for HLA-B7 as a probe. The L/328 cell line was established by cotransformation of mouse Ltk- cells with the herpes thymidine kinase gene and clone JY328. On Northern blots, RNA from L/328 strongly hybridized to an HLA class I probe, and an antigen was recognized by an anti-HLA class I framework antibody on the cell surface. A DNA probe corresponding to a segment of intron 7 was developed by comparing the nucleotide sequence of clone JY328 with that of other HLA class I-type genes. Using the radiolabeled probe to screen Southern blots of DNA from families with siblings exhibiting intra-HLA recombinations, a restriction fragment length polymorphism was revealed--a 1.4 kb BstE II band not present in all individuals. A corresponding fragment was apparent in the base sequence of clone JY328. The occurrence of this band on Southern blots established that JY328 maps distinct from and centromeric to the HLA-C locus and near to the HLA-B locus. Antibody absorption studies and cytotoxicity tests indicated that the JY328 gene product was not an HLA-B antigen but that it did specifically absorb CW7-specific antibody. In sum, these results suggest a novel, polymorphic HLA class I gene which expresses a product serologically similar to HLA-Cw7 but which does not map within the corresponding locus.