Recreational cannabis legalization has had limited effects on a wide range of adult psychiatric and psychosocial outcomes.

BACKGROUND: The causal impacts of recreational cannabis legalization are not well understood due to the number of potential confounds. We sought to quantify possible causal effects of recreational cannabis legalization on substance use, substance use disorder, and psychosocial functioning, and whether vulnerable individuals are more susceptible to the effects of cannabis legalization than others. METHODS: We used a longitudinal, co-twin control design in 4043 twins (N = 240 pairs discordant on residence), first assessed in adolescence and now age 24-49, currently residing in states with different cannabis policies (40% resided in a recreationally legal state). We tested the effect of legalization on outcomes of interest and whether legalization interacts with established vulnerability factors (age, sex, or externalizing psychopathology). RESULTS: In the co-twin control design accounting for earlier cannabis frequency and alcohol use disorder (AUD) symptoms respectively, the twin living in a recreational state used cannabis on average more often (ßw = 0.11, p = 1.3 × 10-3), and had fewer AUD symptoms (ßw = -0.11, p = 6.7 × 10-3) than their co-twin living in an non-recreational state. Cannabis legalization was associated with no other adverse outcome in the co-twin design, including cannabis use disorder. No risk factor significantly interacted with legalization status to predict any outcome. CONCLUSIONS: Recreational legalization was associated with increased cannabis use and decreased AUD symptoms but was not associated with other maladaptations. These effects were maintained within twin pairs discordant for residence. Moreover, vulnerabilities to cannabis use were not exacerbated by the legal cannabis environment. Future research may investigate causal links between cannabis consumption and outcomes.

The creation and validation of the Developmental Emotional Faces Stimulus Set.

The Developmental Emotional Faces Stimulus Set (DEFSS) is designed to provide a standardized set of emotional stimuli that includes both child and adult faces and that has been validated by participants across a wide range of ages. This article describes the creation and validation of the DEFSS, which includes 404 validated facial photographs of people between 8 and 30 years old displaying five different emotional expressions: happy, angry, fearful, sad, and neutral. The emotions in all photographs were identified correctly by 86 % of the raters (minimum 55 %), and validity did not vary as a function of the age group of the model or of the raters, indicating that the pictures are equally appropriate for use across the entire age range. Strengths and limitations of the DEFSS are discussed.

NIH Toolbox Cognition Battery (CB): validation of executive function measures in adults.

This study describes psychometric properties of the NIH Toolbox Cognition Battery (NIHTB-CB) executive function measures in an adult sample. The NIHTB-CB was designed for use in epidemiologic studies and clinical trials for ages 3 to 85. A total of 268 self-described healthy adults were recruited at four university-based sites, using stratified sampling guidelines to target demographic variability for age (20-85 years), gender, education and ethnicity. The NIHTB-CB contains two computer-based instruments assessing executive function: the Dimensional Change Card Sort (a measure of cognitive flexibility) and a flanker task (a measure of inhibitory control and selective attention). Participants completed the NIHTB-CB, corresponding gold standard convergent and discriminant measures, and sociodemographic questionnaires. A subset of participants (N=89) was retested 7 to 21 days later. Results reveal excellent sensitivity to age-related changes during adulthood, excellent test-retest reliability, and adequate to good convergent and discriminant validity. The NIH Toolbox EF measures can be used effectively in epidemiologic and clinical studies.

Associations between executive functions assessed in different contexts in a genetically informative sample.

Executive functions (EFs) are cognitive functions that help direct goal-related behavior. EFs are usually measured via behavioral tasks assessed in highly controlled laboratory settings under the supervision of a research assistant. Online versions of EF tasks are an increasingly popular alternative to in-lab testing. However, researchers do not have the same control over the testing environment during online EF assessments. To assess the extent to which EFs assessed in-lab and online are related, we used data from the Colorado Online Twin Study (CoTwins; 887 individual twins aged 13.98-19.05) and constructed an Lab Common EF factor and an Online Common EF factor from four EF tasks assessed in-lab and online. The Lab Common and Online Common EF factors were genetically identical (rA = 1.00) but phenotypically separable (r = .77, 95% confidence interval [0.59, 0.94]) indicating that these EF factors have the same genetic underpinnings but may be differentially influenced by environmental factors. We examined phenotypic, genetic, and environmental correlations between the EF factors and a general cognitive ability factor (g) assessed in the lab and found similar relationships between Lab Common EF and g and Online Common EF and g. Overall, these results suggest that Common EF factors assessed in different contexts are highly related to each other and similarly related to other cognitive outcomes. These findings indicate that online task-based EF assessments could be a viable strategy for increasing sample sizes in large-scale studies, particularly genetically informed studies. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

II. NIH Toolbox Cognition Battery (CB): measuring executive function and attention.

In this chapter, we discuss two measures designed to assess executive function (EF) as part of the NIH Toolbox Cognition Battery (CB) and report pediatric data from the validation study. EF refers to the goal-directed cognitive control of thought, action, and emotion. Two measures were adapted for standardized computer administration: the Dimensional Change Card Sort (a measure of cognitive flexibility) and a flanker task (a measure of inhibitory control in the context of selective visual attention). Results reveal excellent developmental sensitivity across childhood, excellent reliability, and (in most cases) excellent convergent validity. Correlations between the new NIH Toolbox measures and age were higher for younger children (3-6 years) than for older children (8-15 years), and evidence of increasing differentiation of EF from other aspects of cognition (indexed by receptive vocabulary) was obtained.

Impacts of recreational cannabis legalization on cannabis use: a longitudinal discordant twin study.

AIMS: To estimate the effect of recreational legalization on cannabis use frequency and sources of variance across legal environments. DESIGN: Longitudinal discordant twin and gene-environment interaction models in twins recruited from birth records and assessed prospectively. SETTING: The United States, including states with different recreational cannabis policies before and after 2014, when recreational cannabis was first legalized. PARTICIPANTS: Two longitudinal, prospectively assessed samples of American twins aged 24-47 (n = 1425 in legal states, n = 1996 in illegal states), including 111 monozygotic pairs discordant for residence. MEASUREMENTS: Current cannabis use frequency (measured continuously and ordinally) was the primary outcome, and the predictor was recreational status of cannabis (legal/illegal) in the participant's state of residence at the time of assessment. Covariates include age, sex and cannabis use frequency prior to 2014. FINDINGS: Accounting for pre-2014 use, residents of legal states used cannabis more frequently than residents of illegal states (b = 0.21, P = 8.08 × 10-5 ). Comparing 111 pairs of monozygotic twins discordant for residence confirmed the effect (b = 0.18, P = 0.014). There was inconclusive evidence for genetic influences on cannabis use frequency that were specific to the legal environment [χ2  = 2.9 × 10-9 , degrees of freedom (d.f.) = 1, P > 0.999]. Existing genetic influences were moderated by the legal environment, as the genetic correlation between marijuana use before and after legalization was lower in states that legalized (rgenetic  = 0.24) compared with states that did not (rgenetic  = 0.78, Pdifference  = 0.016). CONCLUSIONS: In the United States, there appears to be a ~ 20% average increase in cannabis use frequency attributable to recreational legalization, consistent across increasingly rigorous designs. In addition, the heritability of cannabis use frequency appears to be moderated by legalization.

Maternal sensitivity during the first 3½ years of life predicts electrophysiological responding to and cognitive appraisals of infant crying at midlife.

This study examined the predictive significance of maternal sensitivity in early childhood for electrophysiological responding to and cognitive appraisals of infant crying at midlife in a sample of 73 adults (age = 39 years; 43 females; 58 parents) from the Minnesota Longitudinal Study of Risk and Adaptation. When listening to an infant crying, both parents and nonparents who had experienced higher levels of maternal sensitivity in early childhood (between 3 and 42 months of age) exhibited larger changes from rest toward greater relative left (vs. right) frontal EEG activation, reflecting an approach-oriented response to distress. Parents who had experienced greater maternal sensitivity in early childhood also made fewer negative causal attributions about the infant's crying; the association between sensitivity and attributions for infant crying was nonsignificant for nonparents. The current findings demonstrate that experiencing maternal sensitivity during the first 3½ years of life has long-term predictive significance for adults' processing of infant distress signals more than three decades later. (PsycINFO Database Record

Reflection training improves executive function in preschool-age children: behavioral and neural effects.

To assess the role of reflection in executive function, preschool-age children who perseverated (failed) on a pre-training version of the Dimensional Change Card Sort (DCCS) were given training with a different version (different stimuli) in which they were provided with corrective feedback and taught to reflect on the conflicting rule representations involved in the task. In Exp. 1, reflection training was based closely on Kloo and Perner (2003). Exp. 2 used a shortened (15min) version of the training protocol. In Exp. 3, this version of reflection training was compared to corrective feedback alone or mere practice with the task (without feedback). In all 3 experiments, children who received reflection training showed substantial improvements in performance on the pre-training version of the DCCS, whereas children in control conditions did not. In Exp. 3, these improvements were accompanied by a reduction from pre- to post-training in the amplitude of the N2 component of the ERP, an index of conflict detection. Results suggest not only that EF can be trained using a brief intervention targeting reflection, but also that training-related improvements in performance are associated with the down-regulation of ACC-mediated conflict detection. Implications for education are discussed.

Cognition assessment using the NIH Toolbox.

Cognition is 1 of 4 domains measured by the NIH Toolbox for the Assessment of Neurological and Behavioral Function (NIH-TB), and complements modules testing motor function, sensation, and emotion. On the basis of expert panels, the cognition subdomains identified as most important for health, success in school and work, and independence in daily functioning were Executive Function, Episodic Memory, Language, Processing Speed, Working Memory, and Attention. Seven measures were designed to tap constructs within these subdomains. The instruments were validated in English, in a sample of 476 participants ranging in age from 3 to 85 years, with representation from both sexes, 3 racial/ethnic categories, and 3 levels of education. This report describes the development of the Cognition Battery and presents results on test-retest reliability, age effects on performance, and convergent and discriminant construct validity. The NIH-TB Cognition Battery is intended to serve as a brief, convenient set of measures to supplement other outcome measures in epidemiologic and longitudinal research and clinical trials. With a computerized format and national standardization, this battery will provide a "common currency" among researchers for comparisons across a wide range of studies and populations.

N2 amplitude as a neural marker of executive function in young children: an ERP study of children who switch versus perseverate on the Dimensional Change Card Sort.

To explore the neurocognitive mechanisms underlying individual differences in executive function during the preschool years, high-density electroencephalography (EEG) was used to record event-related potentials (ERPs) from 99 children (between 35 and 54 months of age) during performance on the Dimensional Change Card Sort (DCCS), a widely used measure of executive function in which participants are required to sort bivalent stimuli first by one dimension and then by another. ERP analyses comparing children who switched flexibly (passed) to those who perseverated on post-switch trials (failed) focused on the N2 component, which was maximal over fronto-central sites. N2 amplitude was smaller (less negative) for children who passed the DCCS than for children who failed, suggesting that the N2, often associated with conflict monitoring, may serve as a neural marker of individual differences in executive function. Implications for learning and education are discussed.