A machine-learning approach for differentiating borderline personality disorder from community participants with brain-wide functional connectivity.

BACKGROUND: Functional connectivity has garnered interest as a potential biomarker of psychiatric disorders including borderline personality disorder (BPD). However, small sample sizes and lack of within-study replications have led to divergent findings with no clear spatial foci. AIMS: Evaluate discriminative performance and generalizability of functional connectivity markers for BPD. METHOD: Whole-brain fMRI resting state functional connectivity in matched subsamples of 116 BPD and 72 control individuals defined by three grouping strategies. We predicted BPD status using classifiers with repeated cross-validation based on multiscale functional connectivity within and between regions of interest (ROIs) covering the whole brain-global ROI-based network, seed-based ROI-connectivity, functional consistency, and voxel-to-voxel connectivity-and evaluated the generalizability of the classification in the left-out portion of non-matched data. RESULTS: Full-brain connectivity allowed classification (~70 %) of BPD patients vs. controls in matched inner cross-validation. The classification remained significant when applied to unmatched out-of-sample data (~61-70 %). Highest seed-based accuracies were in a similar range to global accuracies (~70-75 %), but spatially more specific. The most discriminative seed regions included midline, temporal and somatomotor regions. Univariate connectivity values were not predictive of BPD after multiple comparison corrections, but weak local effects coincided with the most discriminative seed-ROIs. Highest accuracies were achieved with a full clinical interview while self-report results remained at chance level. LIMITATIONS: The accuracies vary considerably between random sub-samples of the population, global signal and covariates limiting the practical applicability. CONCLUSIONS: Spatially distributed functional connectivity patterns are moderately predictive of BPD despite heterogeneity of the patient population.

Risk-related brain activation is linked to longitudinal changes in adolescent health risk behaviors.

Middle adolescence is the period of development during which youth begin to engage in health risk behaviors such as delinquent behavior and substance use. A promising mechanism for guiding adolescents away from risky choices is the extent to which adolescents are sensitive to the likelihood of receiving valued outcomes. Few studies have examined longitudinal change in adolescent risky decision making and its neural correlates. To this end, the present longitudinal three-wave study (Nw1 = 157, Mw1= 13.50 years; Nw2 = 148, Mw2= 14.52 years; Nw3 = 143, Mw3= 15.55 years) investigated the ontogeny of mid-adolescent behavioral and neural risk sensitivity, and their baseline relations to longitudinal self-reported health risk behaviors. Results showed that adolescents became more sensitive to risk both in behavior and the brain during middle adolescence. Across three years, we observed lower risk-taking and greater risk-related activation in the bilateral insular cortex. When examining how baseline levels of risk sensitivity were related to longitudinal changes in real-life health risk behaviors, we found that Wave 1 insular activity was related to increases in self-reported health risk behaviors over the three years. This research highlights the normative maturation of risk-related processes at the behavioral and neural levels during mid-adolescence.

Parenting, emotion regulation, and externalizing symptomatology as adolescent antecedents to young adult health risk behaviors.

This study used longitudinal data to elucidate how trajectories of negative parenting across adolescence are associated with young adult health risk behaviors (HRBs) by testing difficulties with emotion regulation and externalizing symptomatology as sequential underlying mediators. The sample included 167 adolescents (53% males, Mage  = 14 at Time 1 and Mage  = 18 at Time 5) who were assessed five times. Adolescents self-reported on negative parenting, emotion regulation, externalizing symptomatology, and engagement in HRBs. Results suggest that increasingly negative parenting across adolescence has adverse consequences for emotion regulation development and in turn, externalizing symptomatology, which confers risk for young adult HRBs. Results offer insights towards mechanisms for prevention and intervention and public health policy aimed at reducing the prevalence and consequences of engagement in HRBs.

Differential Associations of Adversity Profiles with Adolescent Cognitive Control and Psychopathology.

Adverse childhood experiences are common and have long-term consequences for biological and psychosocial adjustment. We used a person-centered approach to characterize distinct profiles of adversity in early adolescence and examined associations with later cognitive control and psychopathology. The sample included 167 adolescents (47% female) and their primary caregivers who participated in a longitudinal study across four time points (approximately one year between assessments). At Time 1 (Mage = 14 years), we measured seven indicators of adversity: socioeconomic disadvantage, abuse, neglect, household chaos, parent substance use, parent depression, and negative life events. At Times 2-4, adolescents' behavioral performance and functional activation during a cognitive control task were measured. At Time 5, adolescents and their caregiver reported on adolescent internalizing and externalizing symptomatology. Using latent profile analysis, we identified four distinct adversity subgroups: a low exposure group, a neglect group, a household instability group, and a poly-adversity group. These groups significantly differed on subsequent levels of psychopathology, but not cognitive control. Specifically, the poly-adversity group reported significantly higher levels of both internalizing and externalizing symptomatology relative to the low exposure group, and the household instability group demonstrated elevated risk for externalizing symptomatology. When using a cumulative risk approach, higher levels of adversity exposure were associated with significantly worse cognitive control performance (but not neural activation). These results suggest that psychopathology outcomes may be differentially predicted by distinct patterns of risk, and that cognitive control impairment may be more strongly predicted by cumulative risk.

Development of cognitive control during adolescence: The integrative effects of family socioeconomic status and parenting behaviors.

Cognitive control is of great interest to researchers and practitioners. The concurrent association between family socioeconomic status (SES) and adolescent cognitive control is well-documented. However, little is known about whether and how SES relates to individual differences in the development of adolescent cognitive control. The current four-year longitudinal investigation (N = 167, 13-14 years at Wave 1) used multi-source interference task performance (reaction time in interference correct trials minus neutral correct trials) and corresponding neural activities (blood oxygen level dependent contrast of interference versus neutral conditions) as measures of cognitive control. SES and parenting behaviors (warmth, monitoring) were measured through surveys. We examined direct and indirect effects of earlier SES on the development of cognitive control via parenting behaviors; the moderating effect of parenting also was explored. Results of latent growth modeling (LGM) revealed significant interactive effects between SES and parenting predicting behavioral and neural measures of cognitive control. Lower family SES was associated with poorer cognitive performance when coupled with low parental warmth. In contrast, higher family SES was associated with greater improvement in performance, as well as a higher intercept and steeper decrease in frontoparietal activation over time, when coupled with high parental monitoring. These findings extend prior cross-sectional evidence to show the moderating effect of the parenting environment on the potential effects of SES on developmental changes in adolescent cognitive control.

Longitudinal Associations between Social Relationships and Alcohol Use from Adolescence into Young Adulthood: The Role of Religiousness.

As adolescence is a time characterized by rapid changes in social relationships as well as an increase in risk-taking behaviors, this prospective longitudinal study examined whether social involvement and social alienation are associated with changes in alcohol use from adolescence into young adulthood moderated by organizational and personal religiousness. Participants were 167 adolescents (53% male) assessed five times between ages 14 and 18 years old. Latent change score modeling analyses indicated that social alienation was positively associated with greater increases in alcohol use among those with low organizational religiousness and those with low personal religiousness in early adolescence and during the transition into young adulthood. The findings demonstrate the detrimental effects of social relationship risk factors that promote alcohol use during adolescence into young adulthood. The results further highlight the protective roles of organizational and personal religiousness acting as additional sources of social engagement experiences to modulate the effects of social alienation predicting alcohol use progression and provide evidence for the positive impact religiousness has on healthy adolescent development.

Neural cognitive control moderates the longitudinal link between hedonia and substance use across adolescence.

Hedonic dysregulation is evident in addiction and substance use disorders, but it is not clearly understood how hedonic processes may interact with brain development related to cognitive control to influence risky decision making and substance use during adolescence. The present study used prospective longitudinal data to clarify the role of cognitive control in the link between hedonic experiences and the development of substance use during adolescence. Participants included 167 adolescents (53% male) assessed at four time points, annually. Adolescents participated in a functional magnetic resonance imaging (fMRI) session where blood-oxygen level dependent (BOLD) response was monitored during the Multi-Source- Interference Task to assess cognitive control. Substance use and hedonia were assessed using self-report. A two-group growth curve model of substance use with hedonia as a time-varying covariate indicated that higher levels of hedonia predicted higher substance use, but only in adolescents with higher activation in the frontoparietal regions and in the rostral anterior cingulate cortex during cognitive control. Results elucidate the moderating effects of neural cognitive control on associations between hedonia and adolescent substance use, suggesting that lower cognitive control functioning in the brain may exacerbate risk for substance use promoted by hedonia.

The mediating role of attachment and mentalising in the relationship between childhood maltreatment, self-harm and suicidality.

BACKGROUND: Although the relationship between childhood maltreatment, self-harm and suicidality is well-established, less is known about the mediating mechanisms explaining it. Based on a developmental mentalisation-based theoretical framework, childhood adversity compromises mentalising ability and attachment security, which in turn increase vulnerability to later stressors in adulthood. OBJECTIVE: This study aimed to investigate the role of attachment and mentalising as potential mechanisms in the relationship between childhood maltreatment, self-harm and suicidality. PARTICIPANTS AND SETTING: We recruited 907 adults from clinical and community settings in Greater London. METHODS: The study design was cross-sectional. Participants completed self-report questionnaires on retrospectively rated childhood trauma, and current attachment to the romantic partner, mentalising, self-harm, suicidal ideation and attempt. We used structural equation modelling to examine the data and conceptualized childhood maltreatment as a general factor in a confirmatory bifactor model. RESULTS: The results showed that childhood maltreatment was both directly associated with self-harm and suicidality and indirectly via the pathways of attachment and mentalising. CONCLUSIONS: These findings indicate that insecure attachment and impaired mentalising partially explain the association between childhood maltreatment, self-harm and suicidality. Clinically, they provide support for the potential of mentalisation-based therapy or other psychosocial interventions that aim to mitigate the risk of self-harm and suicidality among individuals who have experienced childhood maltreatment via increasing understanding of self and other mental states.

Do early responders and treatment non-responders offer guidance to make CPT group a more effective treatment?

BACKGROUND: Treatment dropout has been problematic with evidence-based treatments for posttraumatic stress disorder (PTSD), including cognitive processing therapy (CPT). This study sought to evaluate whether CPT group contributed to symptom improvement among treatment completers and non-completers. METHODS: Sixty-one Iraq and Afghanistan combat Veterans self-selected CPT group or treatment as usual (TAU) forming a convenience sample. Defining treatment completion as attending at least nine sessions: 18 completed treatment, 20 dropped-out (DOs); 20 completed TAU, 3 lost to TAU follow-up. RESULTS: Multiple Regression revealed significant pre-post-treatment improvement, the Clinician-Administered PTSD Scale (CAPS-IV, F(5, 40.1) = 2.53, p = 0.0436). Reviewing DOs' last available PTSD Checklist-Military Version scores before leaving treatment, six achieved clinically significant improvement of >10 points; seven a clinically reliable change of 5-10 points. CONCLUSION: These findings highlight that CPT group may be effective at reducing trauma-related symptoms among treatment completers and dropouts and point to the utility of a clinical definition of good treatment end-state.

Transactional relations between developmental trajectories of executive functioning and internalizing and externalizing symptomatology in adolescence.

Adolescence is a period of social, physical, and neurobiological transitions that may leave individuals more vulnerable to the development of internalizing and externalizing symptomatology. Extant research demonstrates that executive functioning (EF) is associated with psychopathology outcomes in adolescence; however, it has yet to be examined how EF and psychopathology develop transactionally over time. Data were collected from 167 adolescents (47% female, 13-14 years old at Time 1) and their primary caregiver over 4 years. At each time point, adolescents completed three behavioral tasks that capture the underlying dimensions of EF, and both adolescents and their primary caregiver completed measures of adolescent psychopathology. Latent growth curve modeling was used to test the associations between initial levels and trajectories of EF and psychopathology. Results indicated that higher initial levels of internalizing and externalizing symptomatology were associated with lower EF at Time 4 (controlling for Time 1 EF). Initial levels of EF did not predict changes in internalizing and externalizing symptomatology. These findings suggest that early psychopathology may be a risk factor for maladaptive EF development in adolescence.

Associations between developmental patterns of negative parenting and emotion regulation development across adolescence.

Research has documented changes in parenting practices and in emotion regulation (ER) during adolescence. However, developmental trajectories of these constructs and how they may be linked are not clearly known. The present study examined longitudinal associations between developmental trajectories of negative parenting and developmental trajectories of ER (e.g., abilities and strategy use, including cognitive reappraisal and suppression). The sample included 167 adolescents (53% males) who were first recruited at age 13 or 14 years and assessed annually four times. Adolescents self-reported on the perceived degree of their parent's negative parenting and ER. Growth mixture modeling revealed two distinct trajectories of negative parenting across adolescence: Class 1 contained the majority of adolescents (84%), with moderate initial levels of negative parenting that decreased across adolescence; Class 2 contained a smaller group of adolescents (16%), reporting moderate initial levels of negative parenting that increased across adolescence. Though growth curve modeling did not reveal significant growth in ER across time in the sample as a whole, results from a two-group model demonstrated that ER development significantly differs depending on adolescents' experiences of negative parenting trajectories. Adolescents experiencing decreases in negative parenting showed significant increases in ER abilities and no significant changes in suppression. Adolescents experiencing increases in negative parenting exhibited significant decreases in ER abilities. Adolescent's cognitive reappraisal was unaffected by negative parenting. The findings underscore the significant role of differential parenting environments in the development of ER abilities during adolescence. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Reinforcement Learning Disruptions in Individuals With Depression and Sensitivity to Symptom Change Following Cognitive Behavioral Therapy.

Importance: Major depressive disorder is prevalent and impairing. Parsing neurocomputational substrates of reinforcement learning in individuals with depression may facilitate a mechanistic understanding of the disorder and suggest new cognitive therapeutic targets. Objective: To determine associations among computational model-derived reinforcement learning parameters, depression symptoms, and symptom changes after treatment. Design, Setting, and Participants: In this mixed cross-sectional-cohort study, individuals performed reward and loss variants of a probabilistic learning task during functional magnetic resonance imaging at baseline and follow-up. A volunteer sample with and without a depression diagnosis was recruited from the community. Participants were assessed from July 2011 to February 2017, and data were analyzed from May 2017 to May 2021. Main Outcomes and Measures: Computational model-based analyses of participants' choices assessed a priori hypotheses about associations between components of reward-based and loss-based learning with depression symptoms. Changes in both learning parameters and symptoms were then assessed in a subset of participants who received cognitive behavioral therapy (CBT). Results: Of 101 included adults, 69 (68.3%) were female, and the mean (SD) age was 34.4 (11.2) years. A total of 69 participants with a depression diagnosis and 32 participants without a depression diagnosis were included at baseline; 48 participants (28 with depression who received CBT and 20 without depression) were included at follow-up (mean [SD] of 115.1 [15.6] days). Computational model-based analyses of behavioral choices and neural data identified associations of learning with symptoms during reward learning and loss learning, respectively. During reward learning only, anhedonia (and not negative affect or arousal) was associated with model-derived learning parameters (learning rate: posterior mean regression ß = -0.14; 95% credible interval [CrI], -0.12 to -0.03; outcome sensitivity: posterior mean regression ß = 0.18; 95% CrI, 0.02 to 0.37) and neural learning signals (moderation of association between striatal prediction error and expected value signals: t97 = -2.10; P = .04). During loss learning only, negative affect (and not anhedonia or arousal) was associated with learning parameters (outcome shift: posterior mean regression ß = -0.11; 95% CrI, -0.20 to -0.01) and disrupted neural encoding of learning signals (association with subgenual anterior cingulate prediction error signals: r = -0.28; P = .005). Symptom improvement following CBT was associated with normalization of learning parameters that were disrupted at baseline (reward learning rate: posterior mean regression ß = 0.15; 90% CrI, 0.001 to 0.41; loss outcome shift: posterior mean regression ß = 0.42; 90% CrI, 0.09 to 0.77). Conclusions and Relevance: In this study, the mapping of reinforcement learning components to symptoms of major depression revealed mechanistic features associated with these symptoms and points to possible learning-based therapeutic processes and targets.

Impaired mentalizing in depression and the effects of borderline personality disorder on this relationship.

BACKGROUND: Mentalizing, the ability to understand the self and others as well as behaviour in terms of intentional mental states, is impaired in Borderline Personality Disorder (BPD). Evidence for mentalizing deficits in other mental disorders, such as depression, is less robust and these links have never been explored while accounting for the effects of BPD on mentalizing. Additionally, it is unknown whether BPD symptoms might moderate any relationship between depressive symptoms and mentalizing. METHODS: Using multivariate regression modelling on cross-sectional data obtained from a sample of 274 participants recruited from clinical settings, we investigated the association between mentalizing impairment and depression and examined whether this was moderated by the presence and number of concurrent BPD symptoms, while adjusting for socio-demographic confounders. RESULTS: Impaired mentalizing was associated with depressive symptoms, after adjustment for socio-demographic confounders and BPD symptoms (p = 0.002, ß = - 0.18). BPD symptoms significantly moderated the association between impaired mentalizing and depressive symptoms (p = 0.003), with more severe borderline symptoms associated with a stronger effect of poor mentalization on increased depressive symptoms. CONCLUSION: Mentalizing impairments occur in depression even after adjusting for the effect of BPD symptoms. Our findings help further characterise mentalizing impairments in depression, as well as the moderating effect of BPD symptoms on this association.. Further longitudinal work is required to investigate the direction of association.

A 4-year longitudinal neuroimaging study of cognitive control using latent growth modeling: developmental changes and brain-behavior associations.

Despite theoretical models suggesting developmental changes in neural substrates of cognitive control in adolescence, empirical research has rarely examined intraindividual changes in cognitive control-related brain activation using multi-wave multivariate longitudinal data. We used longitudinal repeated measures of brain activation and behavioral performance during the multi-source interference task (MSIT) from 167 adolescents (53% male) who were assessed annually over four years from ages 13 to 17 years. We applied latent growth modeling to delineate the pattern of brain activation changes over time and to examine longitudinal associations between brain activation and behavioral performance. We identified brain regions that showed differential change patterns: (1) the fronto-parietal regions that involved bilateral insula, bilateral middle frontal gyrus, left pre-supplementary motor area, left inferior parietal lobule, and right precuneus; and (2) the rostral anterior cingulate cortex (rACC) region. Longitudinal confirmatory factor analyses of the fronto-parietal regions revealed strong measurement invariance across time implying that multivariate functional magnetic resonance imaging data during cognitive control can be measured reliably over time. Latent basis growth models indicated that fronto-parietal activation decreased over time, whereas rACC activation increased over time. In addition, behavioral performance data, age-related improvement was indicated by a decreasing trajectory of intraindividual variability in response time across four years. Testing longitudinal brain-behavior associations using multivariate growth models revealed that better behavioral cognitive control was associated with lower fronto-parietal activation, but the change in behavioral performance was not related to the change in brain activation. The current findings suggest that reduced effects of cognitive interference indicated by fronto-parietal recruitment may be a marker of a maturing brain that underlies better cognitive control performance during adolescence.

Probing commitment in individuals with borderline personality disorder.

Interpersonal problems are a core symptom of borderline personality disorder (BPD). In particular, patients with BPD exhibit a heightened sensitivity to cues of acceptance or rejection in their relationships. The current study investigated the psychological processes underpinning this heightened responsiveness. In a between-subjects design, we implemented a reactivity induction designed to trigger either acceptance or rejection of a partner in two separate groups, and measured the effects which this manipulation had upon 49 patients with BPD, as well as 52 control participants. The experimental paradigm required participants to repeatedly choose whether to coordinate with their partner on a decision-making task. When both players coordinate on the same option, both are rewarded. The experiment probed participants' commitment to their partners: participants were sometimes presented with tempting opportunities to unilaterally defect from the coordination. The results show that participants in the BPD group were less committed than participants in the control group when exposed to the rejection manipulation.

Maltreatment and brain development: The effects of abuse and neglect on longitudinal trajectories of neural activation during risk processing and cognitive control.

The profound effects of child maltreatment on brain functioning have been documented. Yet, little is known about whether distinct maltreatment experiences are differentially related to underlying neural processes of risky decision making: valuation and control. Using conditional growth curve modeling, we compared a cumulative approach versus a dimensional approach (relative effects of abuse and neglect) to examine the link between child maltreatment and brain development. The sample included 167 adolescents (13-14 years at Time 1, 53 % male), assessed annually four times. Risk processing was assessed by blood-oxygen-level-dependent responses (BOLD) during a lottery choice task, and cognitive control by BOLD responses during the Multi-Source Interference Task. Cumulative maltreatment effects on insula and dorsolateral anterior cingulate cortex (dACC) activation during risk processing were not significant. However, neglect (but not abuse) was associated with slower developmental increases in insula and dACC activation. In contrast, cumulative maltreatment effects on fronto-parietal activation during cognitive control were significant, and abuse (but not neglect) was associated with steeper developmental decreases in fronto-parietal activation. The results suggest neglect effects on detrimental neurodevelopment of the valuation system and abuse effects on accelerated neurodevelopment of the control system, highlighting differential effects of distinct neglect versus abuse adverse experiences on neurodevelopment.

Processes linking socioeconomic disadvantage and neural correlates of cognitive control in adolescence.

Socioeconomic status (SES) is broadly associated with self-regulatory abilities across childhood and adolescence. However, there is limited understanding of the mechanisms underlying this association, especially during adolescence when individuals are particularly sensitive to environmental influences. The current study tested perceived stress, household chaos, parent cognitive control, and parent-adolescent relationship quality as potential proximal mediators of the association between family SES and neural correlates of cognitive control. A sample of 167 adolescents and their primary caregivers participated in a longitudinal study across four years. SES was indexed by caregivers' education and income-to-needs ratio at Time 1. At Time 2, adolescents reported on their perceived stress, household chaos, and relationship with parents, and parents completed a cognitive control task. Two years later, adolescents completed the same cognitive control task while blood-oxygenation-level-dependent (BOLD) response was monitored with functional magnetic resonance imaging (fMRI). A parallel mediation model indicated that parent cognitive control, but not other proximal factors, explained the relation between SES and adolescents' activation in the middle frontal gyrus during a cognitive control task. The results suggest potential targets for intervention and prevention efforts that may positively alter neurocognitive outcomes related to socioeconomic disadvantage.

Socioeconomic Risk for Adolescent Cognitive Control and Emerging Risk-Taking Behaviors.

This study examined whether cognitive control mediated the association between socioeconomic status (SES; composite of income-to-needs ratio and parent education) and changes in risk-taking behaviors. The sample included 167 dyads of adolescents (53% male; Mage  = 14.07 years at Time 1) and their parents, assessed annually across 4 years. Parents reported socioeconomic variables at Time 1. Adolescents reported risk-taking behaviors at Times 1 and 4, and completed a functional magnetic resonance imaging cognitive control task at Times 2 and 3. Lower SES was associated with lower behavioral (but not neural) cognitive control, which was associated with increases in risk-taking behaviors. The findings suggest that elevated socioeconomic risk may compromise cognitive control which can cascade into maladaptive behaviors in adolescence.

Bidirectional links between adolescent brain function and substance use moderated by cognitive control.

BACKGROUND: No clear consensus exists as to whether neurodevelopmental abnormalities among substance users reflect predisposing neural risk factors, neurotoxic effects of substances, or both. Using a longitudinal design, we examined developmental patterns of the bidirectional links between neural mechanisms and substance use throughout adolescence. METHOD: 167 adolescents (aged 13-14 years at Time 1, 53% male) were assessed annually four times. Risk-related neural processing was assessed by blood-oxygen-level-dependent responses in the insula during a lottery choice task, cognitive control by behavioral performance during the Multi-Source Interference Task, and substance use by adolescents' self-reported cigarette, alcohol, and marijuana use. RESULTS: Latent change score modeling indicated that greater substance use predicted increased insula activation during risk processing, but the effects of insula activation on changes in substance use were not significant. The coupling effect from substance use to insula activation was particularly strong for adolescents with low cognitive control, which supports the theorized moderating role of cognitive control. CONCLUSIONS: Our results elucidate how substance use may alter brain development to be biased toward maladaptive decision-making, particularly among adolescents with poor cognitive control. Furthermore, the current findings underscore that cognitive control may be an important target in the prevention and treatment of adolescent substance use given its moderating role in the neuroadaptive effects of substance use on brain development.

Valuation of peers' safe choices is associated with substance-naïveté in adolescents.

Social influences on decision-making are particularly pronounced during adolescence and have both protective and detrimental effects. To evaluate how responsiveness to social signals may be linked to substance use in adolescents, we used functional neuroimaging and a gambling task in which adolescents who have and have not used substances (substance-exposed and substance-naïve, respectively) made choices alone and after observing peers' decisions. Using quantitative model-based analyses, we identify behavioral and neural evidence that observing others' safe choices increases the subjective value and selection of safe options for substance-naïve relative to substance-exposed adolescents. Moreover, the effects of observing others' risky choices do not vary by substance exposure. These results provide neurobehavioral evidence for a role of positive peers (here, those who make safer choices) in guiding adolescent real-world risky decision-making.