Developmental sources of variation in liability to adolescent substance use disorders

Therapeutic effect of implanted and non-invasive vagus nerve stimulation on heroin-induced anxiety

Substance addiction causes anxiety, which in turn reinforces the maintaining of substance use, resulting in a vicious circle. And this circle is one of the reasons why addiction is so hard to cure. However, there is no treatment involved in addiction-induced anxiety at present. We tested whether VNS (vagus nerve stimulation) can improve heroin-induced anxiety, and made a comparison between nVNS (transcervical vagus nerve stimulation) and taVNS (transauricular vagus nerve stimulation) on therapeutic effect. Mice were subjected to nVNS or taVNS before heroin administration. By observing c-Fos expression in the NTS (nucleus of the solitary tract), we assessed vagal fiber activation. Using the OFT (open field test) and the EPM (elevated cross maze test), we evaluated the anxiety-like behaviors of the mice. Using immunofluorescence, we observed the proliferation and activation of microglia in the hippocampus. And ELISA was used to measure the levels of proinflammatory factors in the hippocampus. Both nVNS and taVNS significantly increased the expression of c-Fos in the nucleus of solitary tract, suggesting the feasibility of nVNS and taVNS. The anxiety level of heroin-treated mice was significantly increased, microglia in the hippocampus was significantly proliferated and activated, and the proinflammatory factors (IL-1β, IL-6, TNF-α) in the hippocampus were significantly up-regulated. Crucially, both nVNS and taVNS reversed the above changes caused by heroin addiction. SIGNIFICANCE: It was confirmed that the therapeutic effect of VNS on heroin-induced anxiety may be an effective treatment method to break the "addiction-anxiety" cycle and provides some insights for subsequent treatment of addiction.

Social Support Protects Against Symptoms of Anxiety and Depression: Key Variations in Latinx and Non-Latinx White College Students

Social support protects against perceived stress and its harmful effects on psychological well-being. College students in general are at high risk for mental health disorders, and Latinx college students face unique stressors placing them at greater risk of psychological distress. Social support may be a key construct in improving outcomes for college students; however, few studies have empirically tested whether the protective effect of social support is equivalent across racial/ethnic groups. Using a series of regression models, we investigated whether social support moderates the relationship between perceived stress and endorsement of depression and anxiety symptoms in Latinx (n = 265) and non-Latinx White college students (n = 216) and whether this moderating effect varied by group membership. Participants completed a series of questionnaires measuring social support, perceived stress, and depression and anxiety symptoms. The moderating effects of social support varied by group membership and outcomes (i.e., depression and anxiety). Social support moderated the relationship between perceived stress and depression symptoms for both Latinx and non-Latinx White students. However, social support only buffered the effect of perceived stress on anxiety symptom endorsement for Latinx college students. These findings suggest that social support does not function uniformly across racial/ethnic groups or the endorsement of depression and anxiety symptoms. Social support may be particularly important for Latinx students by providing a buffer between perceived stress and symptoms of anxiety.

Understanding the Progression from Early Alcohol Use Experimentation to Alcohol Use Disorder: Testing Vulnerability by Experience Interactions Using a Two-Part Latent Growth Curve Model

Most adolescents experiment with alcohol, but a smaller percentage advance to heavy alcohol use (AU) and AU disorder (AUD). Understanding for whom and how early risk leads to AUD is of interest to prevention, treatment, and etiology of AUD. Informed by developmental and behavioral neuroscience theory, the current study tested whether temperament (effortful control, surgency, and negative affect), peer AU (multi-reporter), and AU with parents' permission interacted to distinguish youth who experiment with alcohol from those who escalate to AUD. Community adolescents (N = 765, 53% female) were assessed annually for seven years (M_age = 11.8, range: 10-13 at Year 1; M_age = 18.7; range = 17-20 at year 7). Temperament by early experience interactions were expected to predict amount of AU. Amount of AU was expected to mediate the relationship between the interactions and AUD symptoms (assessed at Years 3 and 7, M_age = 13.8 and 18.7) above and beyond a range of confounds (e.g., problem behavior and parental AU and AUD). Supporting hypotheses, effortful control and surgency interacted with AU with parents' permission and peer AU, respectively, to predict higher amount of AU (R² = 0.47) and AUD symptoms (R² = 0.03). Results support developmental and behavioral neuroscience theory. High surgency and low effortful control in conjunction with peer AU and AU with parents' permission were associated with large effects on AU and moderate mediated effects through AU to AUD. AU with parents' permission was risky at low and high effortful control and protective when peers used alcohol.

Pathological Gaming in Young Adolescents: A Longitudinal Study Focused on Academic Stress and Self-Control in South Korea

With the increase in social concern regarding pathological gaming among adolescents, the WHO (World Health Organization) included "gaming disorder" in the International Classification of Disorders, 11th version (ICD-11). However, little longitudinal research has been conducted examining social influences on pathological gaming, particularly in Asian countries (e.g., South Korea, China). With 4-year panel data from young adolescents (N = 968, 50.7% girls; M_age = 13.3 years) in South Korea, this study examined the effects of cultural environmental factors (parents' excessive interference, communication with parents, and friends' and teachers' support) on pathological gaming through academic stress and self-control. The results showed the critical role of academic stress and self-control in the effects of environmental factors on pathological gaming. Parents' excessive interference increased the degree to which youth experienced academic stress while the degree of communication with parents decreased this stress. Increased academic stress damaged self-control, which finally increased the degree of pathological gaming. Self-control affected the degree of pathological gaming stronger than gaming time did. The theoretical and practical implications from the study findings are discussed.

Sex and Trait Anxiety Differences in Psychological Stress are Modified by Environment

Evidence-based research has revealed how physiological and emotional responses to acute stress are adaptive. However, under conditions of unpredictable or protracted stress, health and drug vulnerability can be compromised. In this study, we examined anxiety-like behavioral responses of 4th generation adolescent male and female Long Evans rats selectively bred for high (HAn) and low (LAn) anxiety-like behavior when housed in an isolated environment (IE) versus a social environment (SE). After 35 days in IE or SE, animals were tested in the elevated plus maze (EPM), injected with amphetamine (AMPH: 0.5 mg/kg, IP) in the locomotor activity (LMA) chamber, measured for basal and post air puff-stressor core body temperature and blood pressure. Following select rearing, SE reduced the anxiogenic response in HAn rats with females displaying the lowest anxiety-like behavior in the EPM. During habituation in the LMA, IE rats remained active, while post-AMPH injection HAn females were hyperactive, followed closely by LAn females. Our findings from the post-stressor physiological measurements indicate that temperature differences due to environment are observed only in the SE females. We also observed group differences for diastolic (DBP) and systolic (SBP) blood pressure. HAn IE males experienced higher DBP and SBP but LAn IE females only experienced higher SBP. Not only do our findings corroborate earlier work on HAn/LAn lines but the findings obtained from this research offer new insights about the role of environment and the role of sex in (1) modulation of anxiety-like behavior, (2) AMPH sensitivity, and (3) basal and stress-induced physiological changes.

Frustration stress (unexpected loss of alternative reinforcement) increases opioid self-administration in a model of recovery

PURPOSE

Engaging in alternative activities in the context where opioid use had occurred can constrain opioid use and helps to maintain recovery. However, "frustration stress" that occurs when contingencies on these alternative activities unexpectedly change (e.g., job loss or divorce) is thought to threaten recovery by prompting a return to drug use. Yet it remains unclear whether frustration stress can result in a return to drug use, and if so, whether it returns to prior levels or to even greater levels.

PROCEDURES

We examine the impact of unsignaled extinction of alternative reinforcement on opioid use. Rats were trained to respond for an etonitazene solution (5μg/ml, p.o.), then for food in alternating daily sessions. Subsequently, food and etonitazene were made concurrently available. Under concurrent availability conditions, rats were exposed to 1, 2, or 4 sessions of unsignaled food extinction, and effects on responding for etonitazene and food measured.

FINDINGS

When etonitazene was the only reinforcer available, rats earned 58.3±20.3μg/kg/session (mean±S.E.M.). When food was available in alternating sessions, etonitazene earned was unchanged (65.3±19.2μg/kg/session). Concurrent food availability decreased etonitazene earned (13.5±4.5μg/kg/session). Unsignaled food extinction returned etonitazene earnedto levels similar to (60.5±18.4μg/kg/session), but not greater than, those observed previously when etonitazene alone was available.

CONCLUSIONS

Unsignaled extinction of alternative behavior controlling opioid use can result in increased opioid use, but this use does not rise beyond previous levels observed when opioid use is unconstrained by alternative reinforced behavior.

Neurocognitive Characteristics of Early Marijuana Use Initiation in Adolescents: A Signature Mapping Analysis

OBJECTIVE

Prior studies of the association between neurocognitive functions and marijuana use among adolescents are mostly cross-sectional and conducted in adolescents who have already initiated marijuana use. The current study used a longitudinal design on a preadolescent, substance-naive sample. We sought to identify demographic factors associated with neurocognitive functions and the complement of neurocognitive function characteristics that predict marijuana initiation in adolescents.

METHOD

Substance-naive adolescents (n = 465) ages 10-12 years (51% male) were recruited from a community with high levels of adolescent marijuana use and prospectively followed to ages 12-15. Tasks measuring neurocognitive functions were administered and audio-assisted interviews were conducted. Two types of models were estimated for each outcome: forced-entry models and another using stepwise selection via bidirectional elimination with varying tolerance levels to account for selection misspecification.

RESULTS

About 10% (n = 49) initiated marijuana use over the study period. Child's age, academic achievement, and parental education were associated with baseline neurocognitive functions; namely, positive emotion attributions and lower impulsivity. Facial recognition-particularly misattribution of sad faces-was the strongest predictor of marijuana initiation, including in the stepwise model (partial OR = 1.3, 95% CI [1.03, 1.63], p < .05) that resulted in the best-fitting model.

CONCLUSIONS

Prediction of marijuana initiation was improved in stepwise models compared with forced-entry models. Emotion perception appears to be an early developmental risk factor that is prospectively associated with marijuana initiation; as expected, other neurocognitive functions did not play an interactive role. Future studies of the interrelationships between emotion perception and the myriad other factors implicated in marijuana initiation, including neurocognitive functions not measured here, will provide a more comprehensive understanding of risk for marijuana initiation.

Trajectories of marijuana use from late childhood to late adolescence: Can Temperament × Experience interactions discriminate different trajectories of marijuana use?

Informed by developmental ecological and epigenetic theory, the current study examined three aims concerning adolescent marijuana use with a large community sample (N = 755; gender = 53% female) and six annual assessments that spanned 11-18 years of age. First, the natural history of adolescent marijuana use was modeled using a two-part latent growth curve analysis. Second, the validity of the mixtures was examined with a broad array of known correlates of adolescent marijuana use. Third, temperament (e.g., surgency, effortful control, and negative affect) was tested as individual differences that would enter into statistical interactions with peer substance use and prior alcohol and cigarette use to distinguish trajectories of marijuana use. The results suggested that escalations in marijuana use were observed for some youth who initiated marijuana use early in adolescence. Youth whose marijuana use did escalate substantially (10%) were distinguished on temperament, conduct disorder, peer delinquency, and pubertal development at baseline. Furthermore, hypothesized interactions between surgency and both peer substance use and prior substance use discriminated different patterns of marijuana use. The findings are discussed with respect to strategies for timing and content of preventive interventions.

Differences between adolescents and adults in the acute effects of PCP and ketamine and in sensitization following intermittent administration

Adolescence is a phase of development during which many physiological and behavioral changes occur, including increased novelty seeking and risk taking. In humans, this is reflected in experimentation with drugs. Research demonstrates that drug use that begins during adolescence is more likely to lead to addiction than drug use that begins later in life. Despite this, relatively little is known of the effects of drugs in adolescence, and differences in response between adolescents and adults. PCP and ketamine are popular club drugs, both possessing rewarding properties that could lead to escalating use. Drug sensitization (or reverse tolerance), which refers to an increase in an effect of a drug following repeated use, has been linked with the development of drug cravings that is a hallmark of addiction. The current work investigated the acute response and the development of sensitization to PCP and ketamine in adolescent and adult rats. Periadolescent Sprague-Dawley rats (30days or 38days of age), and young adults (60days of age) received PCP (6mg/kg IP) or ketamine (20mg/kg IP) once every three days, for a total of five drug injections. Adolescents and adults showed a stimulant response to the first injection of either drug, however the response was considerably greater in the youngest adolescents and lowest in the adults. With repeated administration, adults showed a robust escalation in activity that was indicative of the development of sensitization. Adolescents showed a flatter trajectory, with similar high levels of activity following an acute treatment and after five drug treatments. The results demonstrate important distinctions between adolescents and adults in the acute and repeated effects of PCP and ketamine.

Adult Attachment, Social Adjustment, and Well-Being in Drug-Addicted Inpatients

In recent years, attachment studies have gathered overwhelming evidence for a relation between insecure attachment and drug addiction. The existing literature predominantly addresses attachment styles and little attention is given to attachment-pattern-oriented studies. The current study explored how attachment, social adjustment, and well-being interact in 40 (28 men, 12 women; ages 20-52 years, M = 32.3, SD = 9.4) inpatients with drug addiction. The Adult Attachment Projective Picture System (AAP), the Social Adjustment Scale-Self-report (SAS-SR), and the General Health Questionnaire-28 (GHQ-28) were administered. Descriptive statistics were computed as well as differences between patterns of attachment in all variables were measured. None of the inpatients showed a secure attachment pattern: 7 scored as dismissing (18%), 5 preoccupied (12%) and 28 unresolved (70%). AAP stories were mainly connected with themes of danger, lack of protection, and helplessness. Inpatients classified as unresolved reported significantly higher maladjustment on the SAS-SR and GHQ-28 than those with resolved attachment patterns. Implications for clinicians and researchers are presented.

Exploring the Link among State of Mind Concerning Childhood Attachment, Attachment in Close Relationships, Parental Bonding, and Psychopathological Symptoms in Substance Users

Background: In the present study, we have explored the link among styles of attachment and psychopathology in drug users. We know that insecure attachment predisposes the individuals the development of drug-addiction and psychopathological symptoms. However, we do not know which attachment is more frequent in drug users and which is related to particular psychopathological symptoms. The aim of the present work is to explore the relationship between childhood attachment state of mind, attachment in close relationships, parental bonding and psychopathology in sample of Italian substance users.

Methods: We explored, in a sample of 70 drug users and drug-addicted patients, the childhood attachment state of mind measured by the Adult Attachment Interview, the attachment in close relationships by the Relationship Questionnaire and parental bonding measured by the Parental Bonding Instrument. The Symptom Check-List-90-R (SCL-90-R) measured psychopathological symptoms.

Results: We found that parental bonding, rather than state of mind concerning childhood attachment or attachment in close relationships, is related to the psychopathological manifestation of anxiety, hostility, depression, and paranoid ideation in the sample. The latter occurs frequently in our sample, independent of state of mind concerning child attachment, attachment in close relationships, and parental bonding, suggesting its role either as a factor that favors a bad image of the participants’ own relationships or as a direct effect of consuming drugs.

Conclusion: These results have clinical implications on suggesting ways of interventions that prevent drug-addiction, which should include the evaluation of attachment in the prodromic phases of substance use onset or rehabilitation programs to prevent and manage psychotic-like symptoms.

Overview on Prevalence and Recent Trends in Adolescent Substance Use and Abuse

Substance use and consequent disorders have burdened US health care, criminal justice, and society at large for centuries. Pathological substance use almost invariably begins before 25 years of age, demonstrating how critical adolescence is within the etiology, prevention, and treatment of substance use disorder. This article provides a high-level overview of the prevalence of substance use disorders to provide a context within which the remaining issue provides in-depth descriptions of the evidence on specific topics. Described herein are trends in substance use, substance use disorder, and demographic comparisons.

Hippocampal cell fate regulation by chronic cocaine during periods of adolescent vulnerability: Consequences of cocaine exposure during adolescence on behavioral despair in adulthood

Given that adolescence represents a critical moment for shaping adult behavior and may predispose to disease vulnerability later in life, the aim of this study was to find a vulnerable period during adolescence in which hippocampal cell fate regulation was altered by cocaine exposure, and to evaluate the long-term consequences of a cocaine experience during adolescence in affecting hippocampal plasticity and behavioral despair in adulthood. Study I: Male rats were treated with cocaine (15mg/kg, i.p.) or saline for 7 consecutive days during adolescence (early post-natal day (PND) 33-39, mid PND 40-46, late PND 47-53). Hippocampal plasticity (i.e., cell fate regulation, cell genesis) was evaluated 24h after the last treatment dose during the course of adolescence (PND 40, PND 47, PND 54). Study II: The consequences of cocaine exposure during adolescence (PND 33-39 or PND 33-46; 7 or 14days) were measured in adulthood at the behavioral (i.e., forced swim test, PND 62-63) and molecular (hippocampal cell markers, PND 64) levels. Chronic cocaine during early adolescence dysregulated FADD forms only in the hippocampus (HC), as compared to other brain regions, and during mid adolescence, impaired cell proliferation (Ki-67) and increased PARP-1 cleavage (a cell death maker) in the HC. Interestingly, chronic cocaine exposure during adolescence did not alter the time adult rats spent immobile in the forced swim test. These results suggest that this paradigm of chronic cocaine administration during adolescence did not contribute to the later manifestation of behavioral despair (i.e., one pro-depressive symptom) as measured by the forced swim test in adulthood.

Experimentation versus progression in adolescent drug use: A test of an emerging neurobehavioral imbalance model

Based on an emerging neuroscience model of addiction, this study examines how an imbalance between two neurobehavioral systems (reward motivation and executive control) can distinguish between early adolescent progressive drug use and mere experimentation with drugs. Data from four annual assessments of a community cohort (N = 382) of 11- to 13-year-olds were analyzed to model heterogeneity in patterns of early drug use. Baseline assessments of working memory (an indicator of the functional integrity of the executive control system) and three dimensions of impulsivity (characterizing the balance between reward seeking and executive control systems) were used to predict heterogeneous latent classes of drug use trajectories from early to midadolescence. Findings revealed that an imbalance resulting from weak executive control and heightened reward seeking was predictive of early progression in drug use, while heightened reward seeking balanced by a strong control system was predictive of occasional experimentation only. Implications of these results are discussed in terms of preventive interventions that can target underlying weaknesses in executive control during younger years, and potentially enable at-risk adolescents to exercise greater self-restraint in the context of rewarding drug-related cues.

Early-age clinical and developmental features associated to Substance Use Disorders in Attention-Deficit/Hyperactivity Disorder in Adults

OBJECTIVE

The main objective was to explore early-age conditions associated to Substance Use Disorders (SUD) in adults with Attention Deficit/Hyperactivity Disorder (ADHD); secondly, to determine which of those conditions are specific to ADHD subjects; and finally, to compare ADHD and non-ADHD subjects in terms of SUD lifetime prevalence and professional, social and personal adjustment.

METHOD

Comparison between ADHD adults with (n=236) and without lifetime SUD (n=309) regarding clinical characteristics of ADHD, externalization disorders, temperamental traits, environmental factors, academic history and family psychiatric history; secondly, ADHD subjects were compared to a non-ADHD group (n=177) concerning those variables.

RESULTS

The following variables were found to be positively associated to SUD in ADHD subjects: ADHD severity, CD and ODD comorbidities, temperamental characteristics ("fearful", "accident prone" and "frequent temper tantrums"), "sexual abuse", "be suspended from school", family history of SUD and ADHD, and male gender; ADHD inattentive subtype and "fearful" were inversely associated to SUD. From those variables, "frequent temper tantrums" was also associated to SUD in non-ADHD subjects. ADHD subjects had higher prevalence of lifetime SUD and greater professional, social and personal impairment than non-ADHD subjects.

CONCLUSION

Findings suggest a significant association between ADHD, SUD and early-age conditions, such as CD and ODD comorbidity; other variables from childhood, namely, ADHD subtype, temper characteristics ("fearful", "accident prone"), "sexual abuse", "be suspended from school" and family history of ADHD are associated to SUD in ADHD subjects, but not in non-ADHD subjects. Moreover, this study confirms both the higher prevalence of lifetime SUD and greater professional, social and personal impairment in ADHD subjects than in non-ADHD subjects.

A systematic review of the relationships between family functioning, pubertal timing and adolescent substance use

AIMS

Experiences linked to poor family functioning and pubertal timing have each been associated with increased risk of substance misuse in adolescence. However, it remains unclear to what extent family functioning and pubertal timing combine to put adolescents at particular risk.

METHOD

A systematic review was planned, undertaken and reported according to the 27 items of the PRISMA statement. Databases World of Knowledge, PsycINFO and PubMed were searched. Fifty-eight papers were retained and are discussed in this review after screening titles, abstracts and full papers against pre-established exclusion criteria.

RESULTS

The combination of off-time pubertal timing and poor parent-adolescent relationship quality has been related to higher levels of substance use. However, this is an under-studied area of research and the evidence is less strong for boys than girls.

CONCLUSIONS

Adolescents experiencing both poor parent-adolescent relationship quality and off-time pubertal timing may represent a high-risk group that can benefit from approaches aimed at reducing risk of substance misuse.

Hope and recovery from substance abuse for female drug offenders in Taiwan

This study was designed to fulfill a twofold purpose. First, based on the hope theory framework and previous research, a 16-session hope-based substance abuse treatment program to help female drug abusers achieve a better recovery was developed. Second, ANCOVA was used to test the effectiveness of this treatment model. The participants were 40 female drug offenders who were randomly assigned into experimental and control groups. The 20 experimental group participants received 16 sessions of hope-based substance abuse treatment whereas the 20 control group members were put on the waiting list for another term of treatment. The results indicated that the members of the two groups had significant differences in their posttest scores for recovery goal setting and pursuing, pathway controlling, adequate energy, knowledge of the changing process, ability to cope, adequate cognition, emotion regulation, and self-esteem.

Impulsivity differences in recreational cannabis users and binge drinkers in a university population

BACKGROUND

Recreational cannabis use and alcohol binge drinking are the most common drug consumption patterns in young adults. Impulsivity and several psychopathological signs are increased in chronic drug users, but the implications of recreational use are still poorly understood.

METHODS

We evaluated impulsivity, sensation-seeking traits, impulsive decision-making, inhibitory control and possible symptoms of depression, anxiety and psychosis in three groups of young university adults: recreational cannabis users (N=20), alcohol binge drinkers (N=22) and non-drug users (N=26).

RESULTS

The cannabis and binge drinking groups had increased scores for impulsivity and sensation-seeking traits. Both groups also exhibited increased impulsive decision-making on the two-choice task and the Iowa gambling task; however, only the cannabis group was significantly different from the non-drug group regarding inhibitory control (go/no-go and stop tasks). The cannabis and binge drinking groups did not show differences in the psychopathological symptoms evaluated.

CONCLUSIONS

Our observations of this population of non-dependent drug users are consistent with the increased impulsivity traits and behaviors that have been described previously in chronic drug abusers. In this study, compared to no drug use, the recreational use of cannabis was associated with a major dysfunction of the different facets of impulsive behaviors. However, alcohol binge drinking was related only to impulsive decision-making. These results suggest that impulsivity traits and behaviors are present not only in chronic drug abusers but also in recreational drug users. Future work should continue to investigate the long-term effects of these common consumption patterns on various impulsive behaviors and psychopathological symptoms.

Revisiting the concepts of risk and protective factors for understanding the etiology and development of substance use and substance use disorders: implications for prevention

Over the past 20 years we have accumulated a greater knowledge and understanding of the genetic, neurobiological, and behavioral factors that may be associated with young people initiating the use of drugs and other substances and to progressing from use to abuse and dependence. This knowledge suggests that individuals may be "predisposed" to substance use disorders (SUD) and that the actual engagement in these behaviors depends on their environmental experiences from micro to macro levels. This paper summarizes this knowledge base and supports a developmental framework that examines the interaction of posited genetic, psychological, and neurobiological "predispositions" to SUD and those environmental influences that exacerbate this vulnerability.

Bindungsmuster von Cannabis- und Ecstasykonsumenten

Fragestellung: Frühere Studien haben einen Zusammenhang zwischen Opiatabhängigkeit und dem ängstlich-vermeidenden Bindungsmuster aufgezeigt. In dieser Studie soll explorativ untersucht werden, ob sich dieser Zusammenhang auch bei anderen Konsumentengruppen findet. Methode: Mit dem Bindungsinterview nach Bartholomew wurden die Bindungsmuster zweier Gruppen abhängig oder missbräuchlich Cannabis (N = 19) bzw. Ecstasy (N = 31) konsumierender Jungerwachsener untersucht, die einen möglichst „reinen“ Konsum der jeweiligen Substanz betrieben. Ergebnisse: Die Cannabisgruppe wies überwiegend abweisende und unerwartet häufig auch sichere Bindungsmuster auf. In der Ecstasygruppe traten alle Formen unsicherer Bindung gleich häufig, aber kaum sichere Bindungsmuster auf. Schlussfolgerungen: Die deutlichen Unterschiede zwischen den Gruppen sprechen gegen einen allgemeinen Zusammenhang eines einzelnen Bindungsmusters mit Substanzstörungen. In der Cannabisgruppe finden sich eine sichere und eine unsichere, überwiegend abweisende Untergruppe. Die Ergebnisse der Ecstasygruppe sprechen gegen einen einfachen Zusammenhang zwischen dem Konsum von Stimulanzien und einem anklammernd-aktivierendem Bindungsmuster, aber für eine deutliche klinische Auffälligkeit der Ecstasygruppe. Aufgrund des kleinen Stichprobe und des explorativen Charakters der Studie müssen die Ergebnisse an einem größeren Kollektiv repliziert werden.

Characterization of South African adolescents with alcohol use disorders but without psychiatric or polysubstance comorbidity

BACKGROUND

Individuals who begin drinking during early adolescence and exhibit externalizing pathology and disinhibitory/dysregulatory tendencies are more vulnerable to developing alcohol use disorders (AUDs) in adulthood. Previous research has focused on in-treatment populations with substantial comorbid psychopathology and polysubstance use. Here, we characterize a unique sample of treatment-naïve adolescents without such comorbidity to help identify vulnerable youth who may benefit from early intervention.

METHODS

We compared externalizing propensity, disinhibitory characteristics, and school performance in adolescents with AUDs (but without comorbid psychopathology or other substance use; n = 70) to those of demographically matched controls (n = 70). Within the AUD group, we compared measures of substance use and the disinhibitory syndrome between boys and girls with differing severity of externalizing propensity.

RESULTS

Adolescents with AUDs demonstrated more externalizing propensity and disinhibitory personality traits (impulsivity, novelty seeking, and excitement seeking), poorer self-monitoring and response inhibition, more bullying and sexual risk-taking behavior, poorer first-language performance, and greater use of alcohol, cannabis, and nicotine (p < 0.05). Within the AUD group, participants with higher externalizing propensity began drinking earlier, more frequently, and for a longer duration than those with lower externalizing symptoms (p < 0.05). Disinhibitory features (personality, cognition, and behavior) were, however, not stronger in those with higher externalizing propensity.

CONCLUSIONS

We suggest that the constructs of externalizing propensity and disinhibitory syndrome are useful in characterizing treatment-naïve adolescents with AUDs but without comorbid psychopathology or polysubstance use. These results support the importance of these constructs in understanding adolescent AUDs, even when the frank externalizing diagnoses of childhood (oppositional defiant disorder and conduct disorder) are excluded.

Environmental stressors, low well-being, smoking, and alcohol use among South African adolescents

This is the first study to examine the pathways from environmental stressors to substance use among a sample of South African adolescents (N = 2195). The study objective was to assess how environmental stressors might affect cigarette smoking and alcohol use among South African adolescents, and to focus on one mechanism, low well-being, which might mediate this association. Participants consisted of 2195 Black, mixed ancestry ("Colored"), Indian, and White youth, aged 12-17 years old (mean age = 14.6; SD = 1.8), recruited via a multi-stage stratified sampling procedure in Durban, Cape Town, and Johannesburg, South Africa. Data were collected via individual in-person structured interviews, administered by trained interviewers in the participant's preferred language. Structural equation modeling was used to analyze the interrelationships of environmental stressors (violent victimisation, legal and illegal drug availability) and low well-being (depressive symptoms, low self-esteem, health problems) with respect to adolescent cigarette smoking and alcohol use. The results supported our hypotheses: Environmental stressors were related to low well-being which, in turn, was linked to both adolescent smoking and alcohol use. There were also direct pathways from environmental stressors to both adolescent smoking and alcohol use. Smoking and alcohol use were significantly correlated. The findings suggest that environmental stressors may be associated with diminished psychological and physical well-being, as well as smoking and alcohol use, among South African adolescents. Longitudinal research is warranted to further understand the interrelationship of environmental stressors, low well-being, and adolescent substance use, so that these issues may be addressed by South African programmes and policies.

Neuropsychological performance of South African treatment-naïve adolescents with alcohol dependence

BACKGROUND

Alcohol dependence (AD) in developmentally vulnerable adolescents is ubiquitous and confers a risk for long-term neurocognitive sequelae, yet comorbid substance use disorders and psychopathology can complicate interpretations. Here, we compare cognitive functioning in adolescents with and without AD, who are free from comorbid disorders.

METHODS

English- and Afrikaans-speaking adolescents (13-15 years) of mixed ancestry and low socio-economic status were recruited from the Cape Town region of South Africa. Adolescents with psychiatric, developmental, or other substance use disorders (SUDs) were excluded. AD (n=26) and control (n=26) groups were matched on age, gender, language, and level of education. Neuropsychological testing in participants' home language followed detailed medical/psychiatric evaluation.

RESULTS

Although our sample included participants who smoked tobacco, lifetime dosage of other drugs was negligible. When tobacco and other drug use as well as demographic variables were controlled, adolescents with AD performed more poorly on measures of Verbal Story Memory, Self-Monitoring, and Psychomotor Speed and Coordination.

CONCLUSIONS

These preliminary results, although relatively subtle, suggest that adolescents with AD may be at increased risk for failure to reach optimal levels of neuromaturation, and may be susceptible to cognitive problems associated with protracted alcohol consumption.

The emergence of gonadal hormone influences on dopaminergic function during puberty

Adolescence is the developmental epoch during which children become adults-intellectually, physically, hormonally and socially. Brain development in critical areas is ongoing. Adolescents are risk-taking and novelty-seeking and they weigh positive experiences more heavily and negative experiences less than adults. This inherent behavioral bias can lead to risky behaviors like drug taking. Most drug addictions start during adolescence and early drug-taking is associated with an increased rate of drug abuse and dependence. The hormonal changes of puberty contribute to physical, emotional, intellectual and social changes during adolescence. These hormonal events do not just cause maturation of reproductive function and the emergence of secondary sex characteristics. They contribute to the appearance of sex differences in non-reproductive behaviors as well. Sex differences in drug use behaviors are among the latter. The male predominance in overall drug use appears by the end of adolescence, while girls develop the rapid progression from first use to dependence (telescoping) that represent a female-biased vulnerability. Sex differences in many behaviors including drug use have been attributed to social and cultural factors. A narrowing gap in drug use between adolescent boys and girls supports this thesis. However, some sex differences in addiction vulnerability reflect biologic differences in brain circuits involved in addiction. The purpose of this review is to summarize the contribution of sex differences in the function of ascending dopamine systems that are critical to reinforcement, to briefly summarize the behavioral, neurochemical and anatomical changes in brain dopaminergic functions related to addiction that occur during adolescence and to present new findings about the emergence of sex differences in dopaminergic function during adolescence.

Treatment seeking adults with autism or ADHD and co-morbid substance use disorder: prevalence, risk factors and functional disability

BACKGROUND

Little is known about Autism Spectrum Disorder (ASD) in adults, especially not about ASD with co-morbid Substance Use Disorder (SUD). We wanted to examine how adults with ASD compare to adults with ADHD on prevalence and risk factors for co-morbid SUD, and on disability levels associated with SUD.

METHODS

We stratified 123 treatment seeking adults with ASD (n=70) or ADHD (n=53), into current, former and no history of SUD (SUD+, SUD(wedge), and SUD-), and conducted interviews to explore associated risk factors and current levels of disability.

RESULTS

Prevalence of co-morbid SUD was higher in ADHD than in ASD in our sample (58% versus 30%, p=0.001). There was no statistically significant difference between ASD and ADHD in risk factors or disability scores. Patients with lifetime SUD started regular smoking earlier in life (OR=5.69, C(95%) 2.3-13.8), reported more adverse family events (OR=2.68; CI(95%) 1.2-6.1), and had more parental SUD (OR=5.36; CI(95%) 1.0-14.5). Disability scores were significantly lower in SUD- and SUD(wedge) groups compared to the SUD+ group.

DISCUSSION

These findings suggest that ASD and ADHD share similar risk factors for SUD. High disability in ASD and ADHD with SUD may normalize after prolonged abstinence. Early onset of SUD was not associated with more severe disability scores than later onset. Results suggest that a subgroup of patients with former SUD may have a higher level of functioning before the onset of SUD in comparison to those without lifetime SUD.

Deployment and the use of mental health services among U.S. Army wives

BACKGROUND

Military operations in Iraq and Afghanistan have involved the frequent and extended deployment of military personnel, many of whom are married. The effect of deployment on mental health in military spouses is largely unstudied.

METHODS

We examined electronic medical-record data for outpatient care received between 2003 and 2006 by 250,626 wives of active-duty U.S. Army soldiers. After adjustment for the sociodemographic characteristics and the mental health history of the wives, as well as the number of deployments of the personnel, we compared mental health diagnoses according to the number of months of deployment in Operation Iraqi Freedom in the Iraq-Kuwait region and Operation Enduring Freedom in Afghanistan during the same period.

RESULTS

The deployment of spouses and the length of deployment were associated with mental health diagnoses. In adjusted analyses, as compared with wives of personnel who were not deployed, women whose husbands were deployed for 1 to 11 months received more diagnoses of depressive disorders (27.4 excess cases per 1000 women; 95% confidence interval [CI], 22.4 to 32.3), sleep disorders (11.6 excess cases per 1000; 95% CI, 8.3 to 14.8), anxiety (15.7 excess cases per 1000; 95% CI, 11.8 to 19.6), and acute stress reaction and adjustment disorders (12.0 excess cases per 1000; 95% CI, 8.6 to 15.4). Deployment for more than 11 months was associated with 39.3 excess cases of depressive disorders (95% CI, 33.2 to 45.4), 23.5 excess cases of sleep disorders (95% CI, 19.4 to 27.6), 18.7 excess cases of anxiety (95% CI, 13.9 to 23.5), and 16.4 excess cases of acute stress reaction and adjustment disorders (95% CI, 12.2 to 20.6).

CONCLUSIONS

Prolonged deployment was associated with more mental health diagnoses among U.S. Army wives, and these findings may have relevance for prevention and treatment efforts.

Deficits in behavioral inhibition predict treatment engagement in prison inmates

Many inmates do not respond favorably to standard treatments routinely offered in prison. Executive cognitive functioning and emotional regulation may play a key role in treatment responsivity. During intake into treatment, inmates (N = 224) were evaluated for executive functioning, emotional perception, stress reactivity (salivary cortisol), IQ, psychological and behavioral traits, prior drug use, child and family background, and criminal histories and institutional behavior. Outcome measures included program completion, treatment readiness, responsivity and gain, and the Novaco Reaction to Provocation Questionnaire. Relative deficits in behavioral inhibition significantly predicted treatment outcomes, more so than background, psychological, or behavioral variables, and other neurocognitive and emotional regulatory measures. Future replications of these results have potential to improve assessment and treatment of offenders who are otherwise intractable.

Are adolescents more vulnerable to drug addiction than adults? Evidence from animal models

BACKGROUND AND RATIONALE

Epidemiological evidence suggests that people who begin experimenting with drugs of abuse during early adolescence are more likely to develop substance use disorders (SUDs), but this correlation does not guarantee causation. Animal models, in which age of onset can be tightly controlled, offer a platform for testing causality. Many animal models address drug effects that might promote or discourage drug intake and drug-induced neuroplasticity.

METHODS

We have reviewed the preclinical literature to investigate whether adolescent rodents are differentially sensitive to rewarding, reinforcing, aversive, locomotor, and withdrawal-induced effects of drugs of abuse.

RESULTS AND CONCLUSIONS

The rodent model literature consistently suggests that the balance of rewarding and aversive effects of drugs of abuse is tipped toward reward in adolescence. However, increased reward does not consistently lead to increased voluntary intake: age effects on voluntary intake are drug and method specific. On the other hand, adolescents are consistently less sensitive to withdrawal effects, which could protect against compulsive drug seeking. Studies examining neuronal function have revealed several age-related effects but have yet to link these effects to vulnerability to SUDs. Taken together, the findings suggest factors which may promote recreational drug use in adolescents, but evidence relating to pathological drug-seeking behavior is lacking. A call is made for future studies to address this gap using behavioral models of pathological drug seeking and for neurobiologic studies to more directly link age effects to SUD vulnerability.

Distinctions in Behavioral Impulsivity: Implications for Substance Abuse Research

OBJECTIVES: Researchers have clearly implicated impulsivity as having a key role in substance use disorders, and comparisons of self-report measures suggest there are measurably different components of impulsive behavior. However comparatively little research has been devoted to understanding the multidimensional nature of this construct using laboratory measures of impulsivity that may be more sensitive to tracking changes across time. Many studies have measured impulsivity, but this construct has been measured using methodologically different types of laboratory impulsivity paradigms that are often used in isolation. As a result, it is important to determine whether some of the most frequently used types of behavioral measures of impulsivity account for unique variance. METHODS: Here, we used factor analytical techniques in two studies to evaluate the independence of three of the most commonly used behavioral impulsivity paradigms. First, a factor analysis was conducted using previously collected data (n = 204), and second, data was gathered specifically to replicate and extend the results of our original analysis (n = 198). RESULTS: Both studies revealed three distinct factors, confirming our hypothesis of at least three components of impulsive behavior that can be measured by these methodological approaches. CONCLUSIONS: These findings suggest that researchers should carefully consider their selection of laboratory-behavioral impulsivity measures, and that the measure(s) selected should be related to the particular underlying processes relevant to substance use disorders and treatment success.

Multiple adverse outcomes over 30 years following adolescent substance misuse treatment

OBJECTIVE

To compare outcomes over 30 years experienced by individuals who as adolescents entered substance misuse treatment and a general population sample.

METHOD

All 1992 individuals seen at the only clinic for substance misusing adolescents in Stockholm from 1968 to 1971 were compared to 1992 individuals randomly selected from the Swedish population, matched for sex, age and birthplace. Death, hospitalization for physical illness related to substance misuse, hospitalization for mental illness, substance misuse, criminal convictions and poverty were documented from national registers.

RESULTS

Relative risks of death, physical illness, mental illness, substance misuse, criminal convictions and poverty were significantly elevated in the clinic compared to the general population sample. After adjustment for substance misuse in adulthood, the risks of death, physical and mental illness, criminality and poverty remained elevated.

CONCLUSION

Adolescents who consult for substance misuse problems are at high risk for multiple adverse outcomes over the subsequent 30 years.

Moderate adolescent drug use and the development of substance use self-regulation

This article presents a re-conceptualization of moderate adolescent drug use. It is argued that experimentation with alcohol and other drugs during the teenage years may play an important role in the development of regulatory competency in relation to drug consumption in adulthood. When such regulatory skills fail to emerge in young people, during the transition to adulthood, the likelihood of serious alcohol- or drug-related harm is increased. The article reviews the empirical evidence of poor self-regulation as a predictor of long-term alcohol- and drug-related problems, places self-regulation within a broader theoretical framework, and considers the policy and practice implications of this conceptualization.

Spirituality, sense of coherence, and coping responses in women receiving treatment for alcohol and drug addiction

PURPOSE

To examine the role of spirituality, sense of coherence, and coping responses in relation to stress and trauma symptoms among women in substance abuse treatment.

DATA SOURCES/STUDY SETTING

Data for the present analyses were obtained from baseline interviews of 393 women in an urban area of Massachusetts. Interviews were conducted from April 2003 to September 2006. Participants came from four substance abuse treatment programs (three residential and one outpatient) participating in the Mother's Hope, Mind and Spirit Study, an evaluation of an intervention funded by the Substance Abuse and Mental Health Services Administration (SAMSHA).

PRINCIPAL FINDINGS

Stress was significantly associated with drug addiction severity and trauma symptoms were significantly related to alcohol addiction severity. Spirituality, sense of coherence, and coping responses did not mediate the relationship between perceived stress, and posttraumatic stress, and alcohol and drug addiction severity. However, negative and significant associations were found between perceived stress and spirituality, sense of coherence and coping responses, and between posttraumatic stress symptomatology and sense of coherence.

CONCLUSION

Enhanced substance abuse treatments that increase spirituality, sense of coherence, and coping responses may be beneficial in helping women in substance abuse treatment to manage stress and posttraumatic stress symptoms. However, further research is needed to identify the pathways through which spirituality, sense of coherence and coping responses may mediate the effects of stress and posttraumatic stress symptoms on alcohol and drug addiction severity.

The development of alcohol use disorders

Pathological alcohol use is a complex and costly problem. This chapter focuses on recent developments in the etiology of alcohol use disorders. Literature is reviewed from the fields of epidemiology, genetics, personality, neuropsychology, parenting, and social influences. In addition, theoretical models that describe pathways to the development of alcohol use disorders are presented. Particular emphasis is given to ways in which genetic, environmental, psychopharmacological, and personological literatures can inform one another.

Misuse of methamphetamine and prescription stimulants among youths and young adults in the community

BACKGROUND

Gender differences in the prevalence and characteristics of misuse of methamphetamine (meth) and prescription stimulants were examined in a representative US sample of youths and young adults aged 16-25 (N=24,409).

METHODS

Stimulant misusers were categorized into three mutually exclusive subgroups: meth users only, meth and prescription stimulant users, and prescription stimulant users only (e.g., Benzedrine, Ritalin, or Dexedrine). Multinominal logistic regression analyses identified the characteristics associated with misuse of meth and prescription stimulants.

RESULTS

About 1 in 10 youths reported any misuse of stimulants in their lifetime. Prescription stimulant misuse occurred earlier and was more frequent than meth misuse. About 47% of meth misusers also reported prescription stimulant misuse. Among misusers of meth and prescription stimulants, males were more likely than females to misuse methylphenidate (82% versus 65%) but were less likely to misuse diet pills or amphetamines (37% versus 49%). Multinominal logistic regression analyses indicated that all subgroups of lifetime stimulant misuse were associated with past year substance abuse. The characteristics of meth misusers differed slightly from prescription stimulants misusers.

CONCLUSIONS

Multidrug use is common among stimulant misusers. Parents should be informed about the risk of prescription stimulant misuse by their youths.

Testosterone levels and sexual maturation predict substance use disorders in adolescent boys: a prospective study

BACKGROUND

This investigation determined whether testosterone level and sexual maturation in boys biased development of socially nonnormative behavior culminating in a substance use disorder (SUD).

METHODS

The subjects were 179 boys recruited in late childhood through a high-risk paradigm. Path analysis was used to evaluate the influence of testosterone level and sexual maturation in early adolescence (age 12-14) on attitudes toward antisociality, affiliation with deviant peers, and social potency in middle adolescence (age 16), illicit drug use by late adolescence (age 19), and SUD in young adulthood (age 22).

RESULTS

Testosterone level predicted social potency and approval of aggressive/antisocial behavior. Sexual maturation mediated the relation between testosterone level in early adolescence and later affiliation with deviant peers. Social potency, approval of aggressive/antisocial behavior, and deviant peer affiliations predicted illicit drug use by late adolescence that in turn predicted SUD in young adulthood.

CONCLUSIONS

This study demonstrated that pubertal processes in early adolescence influence the risk for SUD via effects on psychosocial functioning.

Risk and protective factors for adolescent substance use: findings from a study in selected Central American countries

PURPOSE

To identify the prevalence of substance use and problems with use, and risk and protective factors at different levels of the adolescent's ecology associated with substance use among adolescents in selected Central American countries.

METHODS

Results of a survey of 17,215 students from Panama, Costa Rica, and Guatemala conducted in 2000-2001 served as the basis for the analyses. Lifetime use of alcohol, tobacco, marijuana, and five other drugs (inhalants, tranquilizers, cocaine, crack, and ecstasy), and problems with drugs and alcohol were the outcome variables. Risk factors included dysregulation, family problems with drugs/alcohol, negative family interactions, school disengagement, peer deviance, and exposure to community violence. Protective factors included a personal belief in God, positive family interactions, parent religiosity, and positive student-teacher interaction. Both hierarchical linear regression and logistic regression analyses were used to model main and interaction effects of risk and protective factors.

RESULTS

There was a linear association between number of risk and protective factors and substance use, however, risk factors were more strongly associated with substance use than were protective factors. There were significant risk-by-protective-factor interactions for alcohol and marijuana use, and for problems with drugs and alcohol. Risk interacted most consistently with a personal belief in God, but also with parent religiosity and with student-teacher communication.

CONCLUSIONS

It is important to consider risk and protective factors at different levels of an adolescent's ecology. Prevention and intervention efforts should focus on interactions adolescents have in different microsystems (e.g., with parents, teachers, and peers).

Hispanic drug abuse in an evolving cultural context: an agenda for research

Drug abuse in the U.S. Hispanic population appears to be in a dynamic state of acceleration, although there are differences in drug use patterns between U.S.-born and foreign-born Hispanics, and across Hispanic subgroups (i.e., Mexican, Cuban, Puerto Rican, and Central or South American). An understanding of the consequences of cultural adjustments for drug use is needed to effectively anticipate the scope and dimensions of illicit drug use in the largest, rapidly growing, minority group in the U.S. This paper provides an epidemiologic overview of current Hispanic drug use, summarizes research on the relationship between culture change and drug use, organized according to individual, social (i.e., family and peer group), and community level influences on drug use, and offers a systematic agenda for future research.

Correlates of subjective stress among drug court clients

Psychosocial stress is consistently found to promote initiation, intensification, and relapse in drug abuse. It would, therefore, be desirable to identify characteristics of offenders who are at heightened risk for stress-induced exacerbations of addictive behavior. In this cross-sectional, correlational, interview study, 500 clients of two Kentucky drug courts averaged 30 years of age and were predominantly male, White, employed, high school educated, single, and adjudicated in small- and medium-size cities. Five independent correlates of greater subjective stress emerged in stepwise multiple regression analysis (R2 = .395): use of escape-avoidance coping, positive reappraisal coping (inversely associated), more negative life events, better self-rated health (inversely associated), and access to social support related to work problems (inversely associated). Treatment interventions emphasizing effective coping styles and building of social support as well as managing of negative life events and perceptions of health may serve to lessen subjective stress and its consequences in drug-abusing criminal populations.

Neurocognitive skills moderate urban male adolescents' responses to preventive intervention materials

The present experiment was designed to determine whether individual variation in neurobiological mechanisms associated with substance abuse risk moderated effects of a brief preventive intervention on social competency skills. This study was conducted in collaboration with the ongoing preventive intervention study at Johns Hopkins University Prevention Intervention Research Center (JHU PIRC) within the Baltimore City Public Schools. A subsample (N = 120) of male 9th grade students was recruited from the larger JHU study population. Approximately half of the participants had a current or lifetime diagnosis of CD while the other half had no diagnosis of CD or other reported problem behaviors. Measures of executive cognitive function (ECF), emotional perception and intelligence were administered. In a later session, participants were randomly assigned to either an experimental or control group. The experimental group underwent a facilitated session using excerpted materials from a model preventive intervention, Positive Adolescent Choices Training (PACT), and controls received no intervention. Outcomes (i.e., social competency skills) were assessed using virtual reality vignettes involving behavioral choices as well as three social cognition questionnaires. Poor cognitive and emotional performance and a diagnosis of CD predicted less favorable change in social competency skills in response to the prevention curriculum. This study provides evidence for the moderating effects of neurocognitive and emotional regulatory functions on ability of urban male youth to respond to preventive intervention materials.

Cocaine addiction and family dysfunction: a case-control study in southern Brazil

Family-related factors play a crucial role in the onset, development, and maintenance of drug misuse and addiction. To investigate the hypothesis that families with a cocaine addicted son display more dysfunction than control families, we applied the Personal Authority in the Family System and the Self-Report Measure of Family Functioning to 67 case triads (child-father-mother) in which the son was an inpatient with a primary diagnosis of cocaine abuse or dependence and to 67 matched control triads from the community (Pelotas, Brazil) in 2000. Case children, mothers, and fathers were significantly more likely to present nuclear family triangulation than their matched control subjects. In addition, case triads had a significantly greater chance of perceiving family functioning as enmeshment. These results suggest both structural and functional differences in these families. We argue for the need of interventions in the family as a whole and for further research in this area.

Attachment and substance use disorders: A review of the literature and a study in drug dependent adolescents

Earlier studies on attachment and substance use disorders using the Hazan and Shaver (1987) self-report mainly indicate a link with "avoidant" attachment styles. Studies working with the Adult Attachment Interview (Main & Goldwyn, 1998) have produced inconsistent results. The present study used the Bartholomew (1990) interview coding system to assess attachment in a sample of 71 German opiate using, drug dependent adolescents (DDAs, age 14 - 25) and 39 non-clinical controls. Fearful attachment was predominant in DDAs, while controls were predominantly secure. Severity of drug use, as assessed with the European Addiction Severity Index (Gsellhofer, Fahrner, & Platt, 1994) and urinalyses, was positively correlated with fearful attachment, but negatively correlated with dismissing attachment. The presence of comorbid psychiatric disorders was associated with fearful attachment but not with addiction severity.