Neurobehavior disinhibition in childhood predicts suicide potential and substance use disorder by young adulthood

Substance use disorder is the outcome of deviant socialization: A prospective investigation spanning childhood to adulthood

OBJECTIVE

Disinhibitory behavior during childhood and adolescence has been frequently shown to amplify the risk for substance use disorder (SUD) in adulthood. This prospective study examined the hypothesis that poor communication with parents and association with deviant peers comprise an SUD-promoting environtype which catalyzes transition of disinhibitory behavior toward SUD.

METHOD

Male (N = 499) and female (N = 195) youths were tracked from 10 to 12 to 30 years of age. Path analysis evaluated the patterning of disinhibitory behavior and social environment during childhood on substance use during adolescence, and antisocial personality without co-occurring SUD in early adulthood and subsequently substance use disorder (SUD).

RESULTS

Disinhibitory behavior (SUD vulnerability) in childhood predicts antisociality without SUD (age 22) that segues to SUD (age 23-30) whereas the environtype (parents and peers) predicts substance use during adolescence which predicts antisocial personality leading to SUD. Antisociality without SUD in early adulthood mediates the association of substance use during adolescence and SUD.

CONCLUSION

Disinhibitory behavior and deviance-promoting social environment conjointly promote development of SUD via deviant socialization.

Transition to substance use disorders: impulsivity for reward and learning from reward

Substance dependence constitutes a profound societal burden. Although large numbers of individuals use licit or illicit substances, few transition to dependence. The specific factors influencing this transition are not well understood. Substance-dependent individuals tend to be swayed by the immediate rewards of drug taking, but are often insensitive to delayed negative consequences of their behavior. Dependence is consequently associated with impulsivity for reward and atypical learning from feedback. Behavioral impulsivity is indexed using tasks measuring spontaneous decision-making and capacity to control impulses. While evidence indicates drug taking exacerbates behavioral impulsivity for reward, animal and human studies of drug naïve populations demonstrate it might precede any drug-related problems. Research suggests dependent individuals are also more likely to learn from rewarding (relative to punishing) feedback. This may partly explain why substance-dependent individuals fail to modify their behavior in response to negative outcomes. This enhanced learning from reward may constitute a further pre-existing risk factor for substance dependence. Although impulsivity for reward and preferential learning from rewarding feedback are both underpinned by a compromised dopaminergic system, few studies have examined the relationship between these two mechanisms. The interplay of these processes may help enrich understanding of why some individuals transition to substance dependence.

Sensation seeking versus alcohol use: Evaluating temporal precedence using cross-lagged panel models

BACKGROUND

Sensation seeking has been theoretically conceptualized as the personality trait for novel and complex experiences responsible for the predilection of engaging in risky activities. The study evaluated several cross-lagged panel models premised on various measurement variations of sensation seeking to determine the extent that each representation operates as the temporal antecedent or consequent of alcohol use.

METHODS

Participants (N = 201) were United States college students under 21 years of age. The measures, completed in two assessments separated by a month, included the Sensation Seeking Scale-V (SSS-V) and its subscales of boredom susceptibility, disinhibition, experience seeking, thrill & adventure seeking; the Brief Sensation Seeking Scale (BSSS); and the frequency and quantity of alcoholic drinks. Cross-lagged panel models containing synchronous correlations, auto-regressive paths, and cross-lagged paths were estimated in path analysis using structural equation modeling.

RESULTS

The cross-lagged panel model results varied depending on the measurement variant of sensation seeking. The SSS-V emerged as a longitudinal precursor to both drink frequency and quantity. Thrill & adventure seeking longitudinally anticipated drink frequency and quantity. However, disinhibition and drink quantity reciprocally reinforced one another across time. Boredom susceptibility and experience seeking did not exhibit any temporal directionality with alcohol behaviors. Furthermore, the BSSS operated as a longitudinal precursor of drink quantity.

CONCLUSIONS

Findings help to unravel the temporal precedent of sensation seeking versus alcohol behaviors based on the scrutiny of various sensation seeking measurement approaches.

Active and Passive Attentional Processing in Adolescent Suicide Attempters: An Event-Related Potential Study

INTRODUCTION

Suicide is the second leading cause of death among adolescents. Suicidal behavior is associated with impairments in attention. Attention can be directed toward relevant events in the environment either actively, under voluntary control, or passively, by external salient events. The extent to which the risk for suicidal behavior affects active and passive attention is largely unknown.

METHODS

Event-related potentials (ERPs) were recorded while 14 adolescents with acute suicidal behavior and 14 healthy controls performed an auditory 3-stimulus oddball task. The task consisted of standard (80%), target (10%), and novel (10%) stimuli. The participants were instructed to press a button upon presentation of the target. The novel stimuli were unexpected and irrelevant to the target detection task.

RESULTS

Accuracy of target detection was slightly but significantly reduced in the suicidal group. There were no significant differences in the amplitude of the target-N2 or -P3b between groups. There was a slight, but nonsignificant, increase in the amplitude of the novel-N2 and -P3 in the suicidal group.

CONCLUSIONS

This is the first study to explore both passive and controlled aspects of attention using ERPs in adolescents with acute suicidal behavior. Although there were no significant ERP group differences, this is an important step in identifying objective markers of suicide risk among adolescents.

Onset Age of Substance Use and Neuropsychological Performance in Hospital Patients

OBJECTIVE

Several studies have found neurocognitive deficits in adolescents following substance abuse. Predisposing risk factors may further impact vulnerability to neurocognitive deficits. Little is known about the cognitive performance of adult onset substance users compared to earlier onset users. This study aims to explore differences in neuropsychological functioning between early (EOAs) and late onset substance abusers (LOAs) when the effects of confounding factors are controlled.

METHOD

Data for this cross-sectional study was collected from hospital patients. A total of 164 patients with substance use disorder (SUD) aged 19 to 65, 76 with single-drug diagnosis and 88 with multidrug diagnosis, underwent neuropsychological tests for verbal capacity, attention, speed of processing, perceptual reasoning, memory and learning, executive functioning, and inhibitory capacity. Associations between regular onset age and neuropsychological measures were analysed using in multi-way ANCOVA, and the effect of age, multiple substance abuse, education level and learning difficulties were controlled.

RESULTS

Compared with LOAs, EOAs had weaker performance in the Digit Symbol test for mono-substance users. Meanwhile, compared with EOAs, LOAs had weaker performance in the Delayed Visual Memory test and the Raven test for mono-substance users, and the Block Design test for poly-substance users. From the confounding factors, early onset age of substance use is heightened among individuals with learning disabilities.

CONCLUSIONS

Onset age of substance use is related to the deterioration of performance in neuropsychological tests. Premorbid poor learning and inhibitory capacity may be important predisposing risk factors of SUD. Conversely, high level of education may be a protective factor for cognitive performance in patients with SUD.

Altered Static and Dynamic Functional Connectivity of Habenula Associated With Suicidal Ideation in First-Episode, Drug-Naïve Patients With Major Depressive Disorder

Investigating the neurobiological mechanism of suicidal ideation (SI) in major depressive disorder (MDD) may be beneficial to prevent the suicidal behavior. Mounting evidence showed that habenula contributed to the etiology of MDD. The habenula is a key brain region that links the forebrain to midbrain, crucial for the processing of reward and aversion. The aim of the present study was to identify whether first-episode, drug-naive MDD patients with SI displayed altered habenula neural circuitry. Forty-three and 38 drug-naïve patients with first-episode MDD with or without SI (SI+/- group) and 35 healthy control subjects (HC) underwent resting-state functional magnetic resonance imaging. The whole-brain habenula static (sFC) and dynamic functional connectivity (dFC) were calculated to identify regions showing significant difference among these three groups followed by region of interest to region of interest post hoc analysis. For sFC, compared with SI- and HC groups, SI+ group showed decreased sFC from habenula to the precuneus and the inferior frontal gyrus. Patients with MDD displayed increased sFC from habenula to the putamen but decreased sFC to the precentral gyrus. For dFC, SI+ group showed increased dFC from habenula to the superior temporal gyrus, the precuneus, but decreased dFC to the lingual gyrus, the postcentral gyrus, when comparing with SI- and HC groups. Patients with MDD, regardless of SI, displayed decreased dFC from the habenula to the angular gyrus. These findings provide evidence that SI in first-episode, drug-naïve patients with MDD may be related to an abnormality in habenula neural circuitry, which may provide the theoretical basis of novel treatments.

Childhood ADHD Symptoms and Future Illicit Drug Use: The Role of Adolescent Cigarette Use

Objectives

The aim of this study is to understand how early cigarette use might predict subsequent illicit drug use, especially among individuals with attention-deficit hyperactivity disorder (ADHD) symptoms during childhood.

Methods

Data were drawn from the National Longitudinal Study of Adolescent Health (Waves I-IV). The analysis sample involves participants who had not used illicit drugs at Wave I, with no missing responses for studied predictors (N = 7,332).

Results

Smoking status at Wave I (ever regular vs. never regular) and childhood ADHD symptoms predicted subsequent illicit drug use at Waves II to IV. No interaction effect of smoking status at Wave I and childhood ADHD symptoms was found. However, an indirect effect from childhood ADHD symptoms on illicit drug use was identified, through smoking status at Wave I. Similar results were observed for predicting illicit drug dependence.

Conclusions

The findings support the notion that smoking status during early adolescence may mediate the association between childhood ADHD symptoms and risk of later adult drug use. Interventions to prevent smoking among adolescents may be particularly effective at decreasing subsequent drug use, especially among children with ADHD symptoms.

Association of opioid receptor gene polymorphisms with drinking severity and impulsivity related to alcohol use disorder in a Korean population

Aims

Recent evidence suggests that the opioid system is implicated in the pathophysiology of alcohol use disorder (AUD). We aimed to examine the genetic influence of opioid receptors on susceptibility to AUD and its clinical and psychological characteristics including harmful drinking behavior and various aspects of impulsivity in AUD patients.

Methods

Three μ‐opioid receptor gene (OPRM1) variants and two κ‐opioid receptor gene (OPRK1) variants were examined in 314 male patients with AUD and 324 male controls. We applied the Alcohol Use Disorders Identification Test (AUDIT), Obsessive Compulsive Drinking Scale (OCDS), and Alcohol Dependence Scale. AUD patients also completed the stop‐signal task, delay discounting task, balloon analogue risk task, and the Barratt Impulsiveness Scale version 11 (BIS‐11).

Results

No significant differences in genotype distributions or haplotype frequencies were found between AUD patients and controls. However, OPRK1 SNP rs6473797 was significantly related to the severity of alcohol‐related symptoms as measured by AUDIT and OCDS and a haplotype containing rs6473797 was also related to OCDS scores in AUD patients. For other psychological traits, OPRM1 SNP rs495491 was significantly associated with scores on the motor subfactor of the BIS‐11.

Conclusion

Genetic variations in opioid receptors may contribute to symptom severity and impulsivity in AUD patients.

Pharmacotherapeutic strategies for the treatment of attention-deficit hyperactivity (ADHD) disorder with comorbid substance-use disorder (SUD)

INTRODUCTION

Substance use disorder (SUD) is very common amongst patients with attention deficit hyperactivity disorder (ADHD). The two disorders share partially overlapping features and SUD in ADHD is characterized by an early age of onset, high likelihood of poly-substance use, increased risk of suicide attempts, more hospitalizations, and scarce treatment adherence.

AREAS COVERED

This paper reviews randomized active comparator-controlled or placebo-controlled trials evaluating the use of pharmacotherapy in patients with ADHD and SUD. The authors include open label and observational studies.

EXPERT OPINION

Stimulant and non-stimulant treatments should be used to aid ADHD symptomatology in patients with SUD. SUD seems to be less responsive, suggesting a relative independence of the two conditions. For this reason, the association of ADHD-specific drugs and SUD-treatments should be recommended in a large proportion of patients suffering from both disorders. The rate and the quality of ADHD response to specific pharmacological treatments is highly variable, depending on the dose and the duration of the treatment, the age of the patient, and the severity and the chronicity of addiction. Further research is necessary to explore the divergences in treatment response of different ADHD subtypes in different subtypes of SUD.

Hierarchical investigation of genetic influences on response inhibition in healthy young adults

Poor inhibitory control is a known risk factor for substance use disorders, making it a priority to identify the determinants of these deficits. The aim of the current study was to identify genetic associations with inhibitory control using the stop signal task in a large sample (n = 934) of healthy young adults of European ancestry. We genotyped the subjects genome-wide and then used a hierarchical approach in which we tested seven a priori single nucleotide polymorphisms (SNPs) previously associated with stop signal task performance, approximately 9,000 SNPs designated as high-value addiction (HVA) markers by the SmokeScreen array, and approximately five million genotyped and imputed SNPs, followed by a gene-based association analysis using the resultant p values. A priori SNP analyses revealed nominally significant associations between response inhibition and one locus in HTR2A (rs6313; p = .04, dominance model, uncorrected) in the same direction as prior findings. A nominally significant association was also found in one locus in ANKK1 (rs1800497; p = .03, uncorrected), although in the opposite direction of previous reports. After accounting for multiple comparisons, the HVA, genome-wide, and gene-based analyses yielded no significant findings. This study implicates variation in serotonergic and dopaminergic genes while underscoring the difficulty of detecting the influence of individual SNPs, even when biological information is used to prioritize testing. Although such small effect sizes suggest limited utility of individual SNPs in predicting risk for addiction or other impulse control disorders, they may nonetheless shed light on complex biological processes underlying poor inhibitory control. (PsycINFO Database Record

Sleep, Affect, and Social Competence from Preschool to Preadolescence: Distinct Pathways to Emotional and Social Adjustment for Boys and for Girls

Using a normative sample of 1,057 children studied across 4 waves over 6 years with multiple informants, we investigated transactional relations for sleep problems, anxious-depressed symptoms, and social functioning from preschool to preadolescence, assessing cumulative effects on children's emotional and social adjustment. To examine sex differences in the developmental processes, we conducted separate analyses for boys and girls. For both boys and girls, longitudinal cross-lagged panel analyses showed that preschool sleep problems directly predicted anxious-depressed symptoms 2 years later; indirect effects continued into preadolescence. For girls, early and later sleep problems directly or indirectly predicted a wide variety of preadolescent emotional and social adjustment domains (e.g., depressive symptoms, school competence, emotion regulation, risk-taking behaviors). For boys, social competence played a more important role than sleep problems in predicting preadolescent adjustment. Among the first set of findings that demonstrate longitudinal relations between sleep problems and social functioning in middle childhood and preadolescence, these results support Dahl's and Walker's neurological models of sleep and emotional functioning. We discuss these findings in light of relations between sleep and affect during pre-pubertal development and discuss differential findings for boys and girls.

Child maltreatment and risk behaviors: The roles of callous/unemotional traits and conscientiousness

Child maltreatment poses significant risk to the development of callous/unemotional traits as well as risk behaviors such as engaging in violence, having sex with strangers, and binge drinking. In the current study, the indirect pathway from child maltreatment to risk behaviors was examined via callous/unemotional traits; whereas the conscientious personality trait was tested as a moderator of this indirect pathway. Young adults and parents (N=361; Mage=19.14, SD=1.44) completed questionnaires on child maltreatment histories, callousness/unemotional traits, personality characteristics, and risk behaviors. Structural equation modeling was used to examine the hypothesized direct, indirect and conditional indirect effects. Findings showed indirect links between the child maltreatment latent factor and physical fighting, having sex with strangers, and binge drinking via callous/unemotional traits. Furthermore, the conscientiousness personality type significantly buffered the connection between callous/unemotional traits and physical fighting, supporting a conditional indirect effects. Callous/unemotional traits are important factors in the underlying mechanism between child maltreatment and risk behaviors among young adults, and conscientiousness serves as a protective factor against violence. Preventive intervention programs and clinicians may benefit from focusing in addressing callous/unemotional traits among youth who report childhood maltreatment experiences as well as targeting conscientiousness as a protective factor.

Youth Whose Weight Exceeds Healthy Guidelines Are High-Risk Targets for Tobacco Prevention Messaging and Close Monitoring of Cigarette Use

BACKGROUND

Adolescents are long-standing tobacco prevention targets, given that smoking patterns typically originate before adulthood. Pediatric overweight/obesity remains at epidemic levels. Links between these two biobehavioral risks are not well understood, yet of keen public health and pediatric care relevance. The aims of the present study were to examine smoking behaviors and attitudes of overweight (OV), obese (OB), and severely obese (SO) adolescents, compared to healthy weight (HW), utilizing the nationally representative sample, Monitoring the Future.

METHODS

Smoking behavior prevalence (ever, current, or age of initiation), perceived risk of harm, disapproval of others smoking, and peer smoking were determined for a pooled 2008-2009 sample of 19,678 10th graders (Mage=16.09±0.47 years) by CDC-defined BMI percentile-based categories within race/ethnic group (69.5% white, 14.5% African American, and 16.0% Hispanic). Logistic regression examined the impact of excess weight status on smoking behaviors and attitudes relative to HW.

RESULTS

Relative to HW of same race/ethnicity, white or African American OV, OB, and SO had higher odds of recent smoking, with the highest prevalence among SO. For white youth, excess weight increased odds of ever smoking, early daily smoking (before grade 9), perceiving low risk of harm, and not disapproving of others smoking. Findings varied for African American or Hispanic youth.

CONCLUSIONS

As we move toward fostering a tobacco-free generation, youth whose weight exceeds healthy guidelines are high-risk targets for tobacco prevention messaging and close monitoring of cigarette use, particularly those who are severely obese as well as white youth of excess weight, starting before adolescence.

Abnormal regional homogeneity in young adult suicide attempters with no diagnosable psychiatric disorder: a resting state functional magnetic imaging study

Many young adults who attempt suicide have no discernible mental illness, suggesting an etiology distinct from other psychiatric disorders. Neurological anomalies associated with a history of suicidal behavior may predict future risk. In the present study, we explored changes in neural circuit organization associated with suicidal behavior by comparing local synchronization of resting-state functional magnetic resonance imaging signals in suicide attempters without a psychiatric diagnosis (SA group, 19.84±1.61 years, n=19) with those in healthy controls (HC group, 20.30±1.72 years, n=20) using regional homogeneity (ReHo) analysis. The SA group exhibited significantly lower mean ReHo in the left (L) fusiform and supraorbital inferior frontal gyri, L hippocampus, bilateral parahippocampal and middle frontal gyri, right (R) angular gyrus, and cerebellar lobules RVIII, RII, and LVI compared with the HC group. Conversely, in the SA group, ReHo was higher in the R supraorbital middle frontal gyrus, R inferior parietal lobe, and L precuneus. The SA group also had significantly higher total Barratt Impulsiveness Scale scores compared with the HC group. Local functional connectivity is altered in multiple regions of the cerebral cortex, limbic system, and cerebellum of suicidal young adults. Elucidating the functional deficits associated with these ReHo changes may clarify the pathophysiological mechanisms of suicidal behavior and assist in identifying high-risk individuals.

Inhibition during early adolescence predicts alcohol and marijuana use by late adolescence

OBJECTIVE

Adolescent substance use has been associated with poorer neuropsychological functioning, but it is unclear if deficits predate or follow the onset of use. The goal of this prospective study was to understand how neuropsychological functioning during early adolescence could predict substance use by late adolescence.

METHOD

At baseline, participants were 175 substance-use-naïve healthy 12- to 14-year-olds (41% female) recruited from local schools. Participants completed extensive interviews and neuropsychological tests. Each year, participants' substance use was assessed. By late adolescence (ages 17 to 18), 105 participants transitioned into substance use and 75 remained substance-naïve. Hierarchical linear regressions examined how baseline cognitive performance predicted subsequent substance use, controlling for common substance use risk factors (i.e., family history, externalizing behaviors, gender, pubertal development, and age).

RESULTS

Poorer baseline performance on tests of cognitive inhibition-interference predicted higher follow-up peak drinks on an occasion (β = -.15; p < .001), more days of drinking (β = -.15; p < .001), and more marijuana use days (β = -.17; p < .001) by ages 17 to 18, above and beyond covariates. Performances on short-term memory, sustained attention, verbal learning and memory, visuospatial functioning, and spatial planning did not predict subsequent substance involvement (ps > .05).

CONCLUSIONS

Compromised inhibitory functioning during early adolescence prior to the onset of substance use was related to more frequent and intense alcohol and marijuana use by late adolescence. Inhibition performance could help identify teens at risk for initiating heavy substance use during adolescence, and potentially could be modified to improve outcome.

Student assistance program outcomes for students at risk for suicide

Pennsylvania's response to adolescent suicide is its Student Assistance Program (SAP). SAP has been funded for 27 years although no statewide outcome studies using case-level data have been conducted. This study used logistic regression to examine drug-/alcohol-related behaviors and suspensions of suicidal students who participated in SAP. Of the 46 services, 10 best predicted (p<.01) that these undesirable outcomes would cease. Although no study subjects died by suicide, 42 of 374,626 referred students did die by suicide. Suicidal students who did not participate had double the rate of suicide of suicidal participants of SAP. Students referred for other reasons also killed themselves. Further work must be done to assess all referred students for suicide risk, examine educational outcomes, monitor substance-related crimes and overdoses, and examine school-related factors postmortem. Evidence from this study can be used by researchers to plan future studies and by Pennsylvania's school nurses when planning services.

Fluctuating disinhibition: implications for the understanding and treatment of alcohol and other substance use disorders

Disinhibition is present in various maladaptive behaviors, including substance use disorders. Most previous research has assumed that disinhibition is a psychological construct that is relatively stable within individuals. However, recent evidence suggests that the ability to inhibit behavior fluctuates in response to environmental and psychological triggers. In this review we discuss some of the factors that cause (dis)inhibition to fluctuate, we examine whether these fluctuations contribute to subjective craving and substance consumption, and we ask if they might increase the risk of relapse in those who are attempting to abstain. The research that we discuss has furthered our understanding of the causal relationships between disinhibition and substance use disorders, and it also highlights opportunities to develop novel treatment interventions. We conclude that substance misusers and their therapists should be made aware of the triggers that can cause disinhibition to fluctuate, and we highlight the need for more research to investigate the effectiveness of inhibitory control training in clinical settings.

Cognitive training for improving executive function in chemotherapy-treated breast cancer survivors

BACKGROUND

A majority of breast cancer (BC) survivors, particularly those treated with chemotherapy, experience long-term cognitive deficits that significantly reduce quality of life. Among the cognitive domains most commonly affected include executive functions (EF), such as working memory, cognitive flexibility, multitasking, planning, and attention. Previous studies in other populations have shown that cognitive training, a behavioral method for treating cognitive deficits, can result in significant improvements in a number of cognitive skills, including EF.

MATERIALS AND METHODS

In this study, we conducted a randomized controlled trial to investigate the feasibility and preliminary effectiveness of a novel, online EF training program in long-term BC survivors. A total of 41 BC survivors (21 active, 20 wait list) completed the 48 session training program over 12 weeks. The participants were, on average, 6 years after therapy.

RESULTS

Cognitive training led to significant improvements in cognitive flexibility, verbal fluency and processing speed, with marginally significant downstream improvements in verbal memory as assessed via standardized measures. Self-ratings of EF skills, including planning, organizing, and task monitoring, also were improved in the active group compared with the wait list group.

CONCLUSIONS

Our findings suggest that EF skills may be improved even in long-term survivors by using a computerized, home-based intervention program. These improvements may potentially include subjective EF skills, which suggest a transfer of the training program to real-world behaviors.

Risk-taking behaviors of adolescents with extreme obesity: normative or not?

OBJECTIVE

Present first published data detailing high-risk behaviors of adolescent high school students (HSS) with extreme obesity (BMI ≥ 99th percentile for age and gender) compared with healthy weight peers (5th-84th percentile).

METHODS

The 2007 Youth Risk Behavior Survey was used to compare HSS with extreme obesity (N = 410) and healthy weight peers (N = 8669) in their engagement in (1) tobacco use, (2) alcohol/other drug use, (3) high-risk sexual behaviors, and (4) suicidal behaviors. Logistic regression was used to calculate gender-stratified odds ratios (OR) and 95% confidence intervals (CI), controlling for age and race.

RESULTS

HSS with extreme obesity were similar to healthy weight peers in the prevalence of most behaviors related to alcohol/drug use, high-risk sexual activities, and suicide, with the following exceptions: relative to healthy weight HSS, both male and female students with extreme obesity more frequently reported ever trying cigarettes (female students, adjusted OR: 2.0 [95% CI: 1.3-3.2]; male students, OR: 1.5 [CI: 1.2-2.0]). Compared with healthy weight female students, female students with extreme obesity had lower odds of ever having sex (OR: 0.5 [CI: 0.3-0.9]), but greater odds of drinking alcohol/using drugs before their last sexual encounter (OR: 4.6 [CI: 1.2-17.6]), currently smoking (OR: 2.3 [CI: 1.2-4.4]), and using smokeless tobacco (OR: 4.6 [CI: 1.2-17.2]). Compared with healthy weight male students, male students with extreme obesity had greater odds of smoking before age 13 (OR: 1.4 [CI: 1.0-2.0]).

CONCLUSIONS

With few exceptions, HSS with extreme obesity engage in high-risk behaviors at rates comparable with healthy weight peers, sometimes in even more dangerous ways. Health care providers should assess risk-taking behaviors in this cohort.

Substance use/abuse and suicidal behavior in young adult women: a population-based study

Associations between substance use variables and suicidal behavior were analyzed in an urban population sample from ("the Women and Alcohol in Gothenburg" study). In Phase I, 20-year-old women (n = 2,069) completed a screening questionnaire. Interviews were carried out with a stratified sample (n = 560). Data, collected in 1995 and 2000, were analyzed using logistic regression to generate odds ratios. Drug use, but not risky alcohol consumption, was associated with suicidal thoughts after adjusting for current depression. Study limitations and implications for suicide prevention are discussed. The study was funded by the Swedish Research Council and the Alcohol Research Council of Sweden.

Evidence for genes on chromosome 2 contributing to alcohol dependence with conduct disorder and suicide attempts

Twin studies provide strong evidence that there is a shared genetic liability that predisposes to a number of different psychiatric outcomes related to behavioral disinhibition. Further, alcohol dependence comorbid with other disinhibitory disorders is particularly heritable. Chromosome 2p14-2q14.3 has been linked to multiple psychiatric conditions related to behavioral undercontrol. In the Collaborative Study on the Genetics of Alcoholism (COGA), we previously reported linkage to this region with alcohol dependence (AD), suicide attempts (SUI), and conduct disorder (CD). In this study, we follow-up on these previous reports of linkage by combining the phenotypes in analyses that jointly consider the presence of multiple conditions. Linkage analyses of the combined phenotype of AD with CD or SUI results in a maximum LOD score of 5.4 in this region. In addition to this primary linkage peak, independent samples have reported linkage to other alcohol-related phenotypes across chromosome 2. Accordingly, we followed-up these linkage signals by testing for association with SNPs across chromosome 2 in a case-control sample, in which a subset of the cases consisted of alcohol-dependent probands from the linkage sample. We find evidence of association with the combined AD with CD or SUI phenotype, with 23 genes surviving permutation testing. The number of associated genes across the chromosome may explain the persistent linkage findings reported on chromosome 2 across a number of independent studies of alcohol and disinhibitory phenotypes. Further, none of the genes were located directly under the primary COGA linkage peak, which has implications for association tests following-up linkage peaks.

Cortical and subcortical abnormalities in late-onset depression with history of suicide attempts investigated with MRI and voxel-based morphometry

Late-onset major depression is thought to have a biological (vascular) basis, which could be a result of brain structure change. Vascular lesions can affect both the gray matter (GM) and white matter (WM), while most previous studies addressed WM abnormality. This study explored the disease- and symptom (history of suicide attempt) -related GM morphometry in elderly male patients with late-onset depression. A total of 70 patients with depression admitted to our geriatric psychiatric ward were investigated, and 26 age-matched males were recruited as controls. We used T1-weighted magnetic resonance imaging (MRI) to obtain cerebral structural information and adopted voxel-based morphometry (VBM) to investigate brain volume change related to disease (depression vs control) and symptom (depression with history of suicide attempt vs depression without history of suicide attempt). Late-onset depression was associated with smaller volumes in several regions of GM (insula and the posterior cingulate region) and WM (subcallosal cingulate cortex, floor of lateral ventricles, parahippocampal region, insula, and the cerebellum). Compared with nonsuicidal counterpart, suicidal depression was associated with decreased GM and WM volume in the frontal, parietal, and temporal regions, and the insula, lentiform nucleus, midbrain, and the cerebellum. Marked regional volume reduction was noticed at dorsal medial prefrontal cortex. Our results demonstrate that the development of suicidal behaviors in major depression is related to widespread but discrete volume reduction in several cortical and subcortical structures, fitting with the hypothesis that decreased cerebral volume in certain regions renders biological susceptibility to attempt suicide during depressive states.

Neural circuitry associated with risk for alcohol use disorders

The core features of risk for alcohol use disorders (AUD), including behavioral disinhibition, affective dysregulation, and executive dysfunction, map onto distinct neural circuits that have been found to be abnormal in the offspring of alcohol dependent individuals. Components of the cerebellothalamocortical system and the extended limbic network may provide the underpinnings for the behavioral and emotional dysfunction observed in individuals at heightened risk for AUD. In addition, abnormalities in these structures appear to be altered in individuals with the predisposition for other psychiatric conditions that may share a similar genetic diathesis. This review proposes several neurobehavioral mechanisms of genetic vulnerability that may account for phenotypic characteristics in individuals at risk for AUD.

Infant neurobehavioral dysregulation: behavior problems in children with prenatal substance exposure

OBJECTIVE

The objective of this study was to test a developmental model of neurobehavioral dysregulation relating prenatal substance exposure to behavior problems at age 7.

METHODS

The sample included 360 cocaine-exposed and 480 unexposed children from lower to lower middle class families of which 78% were black. Structural equation modeling was used to test models whereby prenatal exposure to cocaine and other substances would result in neurobehavioral dysregulation in infancy, which would predict externalizing and internalizing behavior problems in early childhood. Structural equation models were developed for individual and combined parent and teacher report for externalizing, internalizing, and total problem scores on the Child Behavior Checklist.

RESULTS

The goodness-of-fit statistics indicated that all of the models met criteria for adequate fit with 7 of the 9 models explaining 18% to 60% of the variance in behavior problems at age 7. The paths in the models indicate that there are direct effects of prenatal substance exposure on 7-year behavior problems as well as indirect effects, including neurobehavioral dysregulation.

CONCLUSIONS

Prenatal substance exposure affects behavior problems at age 7 through 2 mechanisms. The direct pathway is consistent with a teratogenic effect. Indirect pathways suggest cascading effects whereby prenatal substance exposure results in neurobehavioral dysregulation manifesting as deviations in later behavioral expression. Developmental models provide an understanding of pathways that describe how prenatal substance exposure affects child outcome and have significant implications for early identification and prevention.

Suicide ideation among college students: a multivariate analysis

The goal of this study was to develop a multi-dimensional model that might explain suicide ideation among college students. Face-to-face interviews were conducted with 1,249 first-year college students. An estimated 6%(wt) of first-year students at this university had current suicide ideation. Depressive symptoms, low social support, affective dysregulation, and father-child conflict were each independently associated with suicide ideation. Only 40%(wt) of individuals with suicide ideation were classified as depressed according to standard criteria. In the group who reported low levels of depressive symptoms, low social support and affective dysregulation were important predictors of suicide ideation. Alcohol use disorder was also independently associated with suicide ideation, while parental conflict was not. Results highlight potential targets for early intervention among college students.

Novelty-induced locomotion is positively associated with cocaine ingestion in adolescent rats; anxiety is correlated in adults

The present studies assessed the roles of sex, age, novelty-seeking and plus-maze behavior on cocaine drinking in rats. Cocaine/saccharin solution was available in three daily, 5-hour sessions then a saccharin-only solution was also available in following sessions. In the one-bottle drinking phase, early and late adolescent males, post-natal day 28 (PN28) and PN42, consumed more cocaine/saccharin solution than young adults (PN65), but females did not exhibit significant age differences. Adolescents of both sexes consumed more cocaine/saccharin than adults during choice drinking. Saccharin availability in the two-bottle trials decreased cocaine/saccharin consumption in PN28 and PN65 rats. After a drug-free period, cocaine-stimulated locomotion was lower in cocaine/saccharin drinking than saccharin-only males, indicating tolerance. We tested the hypothesis that individual differences in pre-screened behavioral traits would correlate with cocaine/saccharin consumption in PN28 and PN65 male rats. High locomotor responses to novelty were associated with greater cocaine/saccharin drinking in adults in one-bottle sessions. In the subsequent choice drinking phase, correlations were age-specific. Adolescents with high novelty-induced locomotion and adults that spent less time on open arms of the elevated plus-maze drank more cocaine/saccharin. Thus, behavioral phenotypes correlated with individual differences in cocaine/saccharin consumption in an age-related manner.

Attention deficit in depressed suicide attempters

Attention is typically impaired in depression and may play a role in risk for suicidal behavior. In this study, 66 non-patients, 83 depressed subjects with no past history of suicide attempt, 53 depressed subjects with one or more low lethality suicide attempts, and 42 depressed subjects with at least one high lethality attempt were compared on two computerized measures of attention, a continuous performance test (CPT) and a Stroop task. All subjects were medication free at the time of assessment. Attention was impaired in all depressed subjects but worse in those with a past history of suicidal behavior. CPT performance did not differ among the groups, but Stroop interference was significantly poorer in all depressed subjects relative to non-patients, and poorer still in high lethality suicide attempters relative to all other groups. Interference scores correlated modestly with subjective depression, functional level, suicide ideation, number of past suicide attempts, and lethality of past attempts. Depression-related impairments of attention, especially susceptibility to interference, are accentuated in those with a past history of suicidal behavior. Fundamental deficits in attentional control may play a role in risk for suicidal behavior, and may contribute to a variety of cognitive deficits in suicidal patients. Brain regions subserving attentional control, which overlap considerably with regions implicated in affective disorders, may be a useful target for studies seeking to characterize neuropsychological factors associated with suicidal behavior.

Brain activation, response inhibition, and increased risk for substance use disorder

BACKGROUND

Youth at high risk for developing substance use disorders (SUDs) often exhibit differences which suggest inhibitory impairments when compared to average risk youth.

METHODS

To examine the underlying neural activity related to these impairments, functional MRI (fMRI) was employed in adolescents during an antisaccade task requiring inhibition of an eye movement response. Each subject's level of neurobehavioral disinhibition (ND) was assessed using a multi-informant, multi-method approach, which has been shown to be highly predictive of SUD onset. The fMRI data was categorized into neural regions of interest according to total frontal, parietal, occipital, and temporal lobe activation.

RESULTS

Results demonstrated that ND score was negatively correlated with total amount of frontal activation, but was not significantly correlated with total activation in any other neural region.

CONCLUSIONS

These results indicate deficits in frontal activation in youth with high amounts of ND, suggesting a possible developmental delay of executive processes in high-risk youth.

Impulsivity as a vulnerability marker for substance-use disorders: review of findings from high-risk research, problem gamblers and genetic association studies

There is a longstanding association between substance-use disorders (SUDs) and the psychological construct of impulsivity. In the first section of this review, personality and neurocognitive data pertaining to impulsivity will be summarised in regular users of four classes of substance: stimulants, opiates, alcohol and 3,4-methylenedioxymethamphetamine (MDMA). Impulsivity in these groups may arise via two alternative mechanisms, which are not mutually exclusive. By one account, impulsivity may occur as a consequence of chronic exposure to substances causing harmful effects on the brain. By the alternative account, impulsivity pre-dates SUDs and is associated with the vulnerability to addiction. We will review the evidence that impulsivity is associated with addiction vulnerability by considering three lines of evidence: (i) studies of groups at high-risk for development of SUDs; (ii) studies of pathological gamblers, where the harmful consequences of the addiction on brain structure are minimised, and (iii) genetic association studies linking impulsivity to genetic risk factors for addiction. Within each of these three lines of enquiry, there is accumulating evidence that impulsivity is a pre-existing vulnerability marker for SUDs.

Conceptual issues in understanding the relationship between suicidal behavior and substance use during adolescence

Alcohol and drug use are considered to be risk factors for suicidal behaviors in adolescence, but the precise nature of the relationship between suicidality and substance abuse, and the implications of this relationship for prevention and treatment interventions remain elusive. There are several conceptual issues that need to be addressed when considering the substance abuse-suicidality relationship. What are the most appropriate ways of defining suicidal behaviors? What are the best ways of assessing suicidal behavior and characterizing its course over time? Should adolescents who are suicidal be considered to be a single homogeneous population? What are the possible ways in which the course of substance abuse and suicidality over time are related? What factors potentially affect the trajectories of both substance abuse and suicidality? Does the relationship between substance abuse and suicidality change over time? And, to what extent can our knowledge of factors precipitating and maintaining the joint outcomes of suicidal and substance abuse behaviors be incorporated into interventions that target both? Careful consideration and exploration of these issues hopefully should improve our understanding the substance abuse-suicidality interrelationship, and ultimately the development of more effective prevention efforts and treatments for youths with both problems.