A robust brain network for sustained attention from adolescence to adulthood that predicts later substance use.

Substance use, including cigarettes and cannabis, is associated with poorer sustained attention in late adolescence and early adulthood. Previous studies were predominantly cross-sectional or under-powered and could not indicate if impairment in sustained attention was a consequence of substance-use or a marker of the inclination to engage in such behaviour. This study explored the relationship between sustained attention and substance use across a longitudinal span from ages 14 to 23 in over 1,000 participants. Behaviours and brain connectivity associated with diminished sustained attention at age 14 predicted subsequent increases in cannabis and cigarette smoking, establishing sustained attention as a robust biomarker for vulnerability to substance use. Individual differences in network strength relevant to sustained attention were preserved across developmental stages and sustained attention networks generalized to participants in an external dataset. In summary, brain networks of sustained attention are robust, consistent, and able to predict aspects of later substance use.

Trajectories of cortical structures associated with stress across adolescence: a bivariate latent change score approach.

BACKGROUND: Stress exposure in childhood and adolescence has been linked to reductions in cortical structures and cognitive functioning. However, to date, most of these studies have been cross-sectional, limiting the ability to make long-term inferences, given that most cortical structures continue to develop through adolescence. METHODS: Here, we used a subset of the IMAGEN population cohort sample (N = 502; assessment ages: 14, 19, and 22 years; mean age: 21.945 years; SD = 0.610) to understand longitudinally the long-term interrelations between stress, cortical development, and cognitive functioning. To these ends, we first used a latent change score model to examine four bivariate relations - assessing individual differences in change in the relations between adolescent stress exposure and volume, surface area, and cortical thickness of cortical structures, as well as cognitive outcomes. Second, we probed for indirect neurocognitive effects linking stress to cortical brain structures and cognitive functions using rich longitudinal mediation modeling. RESULTS: Latent change score modeling showed that greater baseline adolescence stress at age 14 predicted a small reduction in the right anterior cingulate volume (Std. ß = -.327, p = .042, 95% CI [-0.643, -0.012]) and right anterior cingulate surface area (Std. ß = -.274, p = .038, 95% CI [-0.533, -0.015]) across ages 14-22. These effects were very modest in nature and became nonsignificant after correcting for multiple comparisons. Our longitudinal analyses found no evidence of indirect effects in the two neurocognitive pathways linking adolescent stress to brain and cognitive outcomes. CONCLUSION: Findings shed light on the impact of stress on brain reductions, particularly in the prefrontal cortex that have consistently been implicated in the previous cross-sectional studies. However, the magnitude of effects observed in our study is smaller than that has been reported in past cross-sectional work. This suggests that the potential impact of stress during adolescence on brain structures may likely be more modest than previously noted.

Childhood mental health difficulties mediate the long-term association between early-life adversity at age 3 and poorer cognitive functioning at ages 11 and 14.

BACKGROUND: Early-life adversity is associated with adverse mental health outcomes and poorer cognitive functioning in later development. However, little is known about how early-life adversity, mental health, and cognition affect one another or how the effects unfold over time. Here, we test the hypothesis that early-life adversity may lead to mental health challenges which in turn have adverse consequences for the development of cognitive abilities. METHODS: In a large (N = 13,287) longitudinal (5 wave) sample assessed at ages 3, 5, 7, 11 and 14, we use both path analysis approach and latent growth curve mediation model to study whether poorer mental health in childhood may mediate the effects of early-life adversity on later working memory and vocabulary outcomes. RESULTS: We found a significant total association between early-life adversity and poorer performance on working memory (ß = .123, p < .001, [95% CI 0.106, 0.141]) and vocabulary scores (ß = -.111, p < .001, [95% CI -0.129, -0.093]). Notably, current and previous mental health mediated a substantial proportion (working memory: 59%; vocabulary: 70%) of these effects. Further longitudinal modeling showed that early-life adversity has an enduring adverse effect on mental health, and that poorer mental health is associated with poorer cognitive performance later on in development. In a complementary analysis using latent growth curve mediation model, we found indirect associations between early-life adversity and working memory through baseline mental health at age 3 (intercept: ß = .083, p < .001, [95% CI 0.072, 0.094]) and change in mental health across ages 3-11 (slope: ß = -.012, p = .001, [95% CI -0.019, -0.005]). Likewise, baseline mental health at age 3 (intercept: ß = -.095, p < .001, [95% CI -0.107, -0.083]) and change in mental health across ages 3-14 (slope: ß = .007, p = .001, [95% CI 0.003, 0.011]) significantly and completely mediated the relation between early-life adversity and vocabulary outcome. CONCLUSIONS: These findings have important potential clinical and educational implications, because they suggest that academic and cognitive resilience may be supported through early mental health interventions in vulnerable children.

Cognitive variations following exposure to childhood adversity: Evidence from a pre-registered, longitudinal study.

Background: Different methodological approaches to studying the effects and timing of childhood adversity have been proposed and tested. While childhood adversity has primarily been operationalized through specificity (effects of individual adversity types) and cumulative risk (sum of all adversities reported by an individual) models, dimensional models (probeable through latent class and other cluster analyses) have recently gained traction given that it can overcome some of the limitations of the specificity and cumulative risk approaches. On the other hand, structured lifecourse modelling is a new statistical approach that examines the effects of the timing of adversity exposure on health outcomes by comparing sensitive periods and accumulation hypotheses. In this study, we apply these sets of methodological approaches and theoretical models to better understand the complex effects of childhood adversity on cognitive outcomes. Methods: We analysed data obtained from the Avon Longitudinal Study of Parents and Children for 2965 participants (Male = 1125; Female = 1840). This included parental report of 11 types of childhood adversity when participants were between 8 months and 8.7 years, and performance on inhibition, working memory and emotion recognition neurocognitive tasks when participants were 24 years of age (April 1, 1992-October 31, 2017). We used latent class analysis to classify the participants into subgroups, while we used Kruskal-Wallis test to examine differences in cognitive performance among the adversity subgroups. Additionally, to test whether sensitive period or accumulation models better explain the effects of childhood adversity on cognitive functioning, we carried out separate analyses using structured lifecourse modelling approaches. Findings: Latent class analysis showed evidence of 5 classes, namely: low adversity (71.6%), dysfunctional family (9.58%); parental deprivation (9.65%); family poverty (6.07%) and global adversity (3.1%). We observed group differences in cognitive performance among the adversity classes in an inhibition control task, χ2(4) = 15.624, p = 0.003 and working memory task, χ2(4) = 15.986, p = 0.003. Pairwise comparison tests showed that participants in the family poverty class performed significantly worse than those in the low adversity class, for the inhibition control task (p = 0.007) while participants in the global adversity class significantly performed worse than participants in the low adversity class (p = 0.026) and dysfunctional family class (p = 0.034) on the working memory task. A further analysis revealed that the associations between each individual adversity type and cognitive outcomes were mostly consistent with the observed class performance in which they co-occurred. Follow-up analyses suggested that adversity during specific sensitive periods, namely very early childhood and early childhood, explained more variability in these observed associations, compared to the accumulation of adversities. Interpretation: These findings suggest that dimensional approaches e.g., latent class analysis or cluster analysis could be good alternatives to studying childhood adversity. Using latent class analysis for example, can help reveal the population distribution of co-occurring adversity patterns among participants who may be at the greatest health risk and thus, enable a targeted intervention. In addition, this approach could be used to investigate specific pathways that link adversity classes to different developmental outcomes that could further complement the specificity or cumulative risk approaches to adversity. On the other hand, findings from a separate analysis using structured lifecourse modelling approaches also highlight the vital developmental timeframes in childhood during which the impact of adversity exposure on cognitive outcomes is greatest, suggesting the need to provide comprehensive academic and mental health support to individuals exposed during those specific timeframes. Funding: T.N. received funding from Cambridge Trust (University of Cambridge).

Working for the future: parentally deprived Nigerian Children have enhanced working memory ability.

BACKGROUND: The dominant view based on the deficit model of developmental psychopathology is that early adverse rearing impairs cognition. In contrast, an emerging evolutionary-developmental model argues that individuals exposed to early-life stress may have improved cognitive abilities that are adapted to harsh environments. We set out to test this hypothesis by examining cognitive functions in parentally deprived children in Nigeria. METHODS: Cognitive performance was compared between 53 deprived children who currently live in institutional homes and foster families and 51 nondeprived control participants. We used a multifaceted neurocognitive test battery for the assessment of inhibition, set-shifting and working memory. RESULTS: Results showed that the deprived and nondeprived group did not significantly differ in their performance on set-shifting and inhibition tasks. Conversely, the deprived group performed significantly better than the nondeprived group in the working memory task. DISCUSSION: We interpret the enhanced working memory ability of the deprived group as a correlate of its ecological relevance. In Nigeria, underprivileged children may need to rely to a larger extent on working memory abilities to attain success through academic work. This study provides further evidence that exposure to early adversity does not necessarily impair cognitive functions but can even enhance it under some conditions and in some domains.

Contributions of Working Memory and Inhibition to Cognitive Flexibility in Nigerian Adolescents.

This study used a novel approach that combined the latency and accuracy scores to examine the relative involvement of inhibition and working memory in two measures of cognitive flexibility - mixing cost and switch cost in 110 Nigerian adolescents. Results showed that inhibition was significantly associated with switch cost. On the other hand, working memory was negatively associated with mixing cost. These findings support the assumption that cognitive flexibility skills are dependent on inputs from inhibition and working memory processes. Inhibition is involved in the deactivation of irrelevant stimuli during switching trials while working memory is essential to maintain the current rule in sets that require no shifting.

Risky decision making and cognitive flexibility among online sports bettors in Nigeria.

Online sports betting is a popular recreational activity in Nigeria. Like other forms of gambling, risk of pathological progression exists for gamblers who continue betting despite severe financial and psychosocial consequences. In the present study, we examined whether this population of gamblers shows deficits in decision making and cognitive flexibility that have been documented in Western gambling populations. Thirty-six online sports bettors and 42 non-gambling participants completed a version of the Iowa gambling task (IGT) and an established set-shifting task for the assessment of cognitive flexibility. The two groups did not differ significantly in the selection of disadvantageous decks on the IGT. In contrast, sports bettors committed significantly more errors on the set-shifting task than non-gambling control participants. As this performance deficit was not specific to trials requiring a set shift, it most likely resulted from gambling-related changes in general cognitive or motivational abilities that are required to successfully complete challenging mental tasks. While our results illustrate that findings from Western populations cannot automatically be generalised to other contexts, it should be noted that we focused on only one particular type of gambling and included mostly participants with mild gambling-related problems.

Perseverative Responding in Nigerian Chronic Alcohol and Marijuana Users.

Background: Chronic consumption of alcohol and marijuana, especially when initiated at an early age, has been implicated in cognitive alterations in the domain of executive functioning. Despite the robustness of this finding in Western populations, its generalizability to other cultural contexts is largely unknown. In this study, we examined whether the regular use of alcohol or marijuana use relates to impaired executive functioning in male students of a Nigerian university. Methods: Chronic alcohol users (n = 39), chronic marijuana users (n = 35) and drug-abstinent control participants (n = 40) recruited through snow-ball sampling technique completed a computerized version of the Wisconsin Card Sorting Test (cWCST). As an established measure of executive functioning, the cWCST allows for the simultaneous assessment of three distinct executive processes: set shifting, rule inference, and set maintenance. Results revealed a selective set-shifting deficit in both alcohol and marijuana users. Results: Both groups committed significantly more perseverative errors than the control group, and group differences were significantly stronger on this indicator of set shifting than on indicators of rule inference or set maintenance. Conclusions: Our findings support the generalizability of drug-related deficits in executive functioning and contribute to the characterization of executive dysfunction in non-Western populations. Future longitudinal studies are required to clarify whether executive dysfunction is an antecedent or consequence of alcohol and marijuana use in young Nigerians.