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.

Addendum to "Evaluating substance use outcomes of recreational cannabis legalization using a unique co-twin control design".

An earlier version of this article was published in error. Our prior publication was missing reference to a prior study on this topic. Our prior research has not found an association between recreational cannabis legalization (RCL) and negative psychosocial and psychiatric outcomes. We reported significant associations between RCL with greater cannabis frequency and fewer alcohol use disorder symptoms. The current study expands on our previous research by using a cross-sectional design and different measures of problems from cannabis and alcohol use and including additional substance use variables. The current study found similar results to our previous research.

Evaluating substance use outcomes of recreational cannabis legalization using a unique co-twin control design.

Background: As more states pass recreational cannabis legalization (RCL), we must understand how RCL affects substance use.Objectives: The current study aims to examine the effect of RCL on lifetime and past-year use of cannabis, alcohol, tobacco, and other drugs, frequency of cannabis, alcohol, and tobacco use, co-use of cannabis with alcohol and tobacco, and consequences from cannabis and alcohol use.Methods: We used a unique, co-twin control design of twin pairs who were discordant for living in a state with RCL between 2018 and 2021. The sample consisted of 3,830 adult twins (41% male), including 232 twin pairs discordant for RCL. Problems from alcohol and cannabis use were assessed via the Brief Marijuana Consequences Questionnaire and the Brief Young Adult Alcohol Consequences Questionnaire.Results: Results indicated that the twin living in an RCL state was more likely to endorse past-year cannabis use (OR = 1.56, p = .009), greater number of cannabis use days in the past 6 months (ß = 0.47, p = .019), but not more negative consequences from cannabis use (ß = 0.21, p = .456) compared to their co-twin in a non-RCL state. There were no differences within-twin pairs in frequency of alcohol use (ß=-0.05, p = .601), but the RCL twin reported fewer negative consequences from alcohol use (ß=-0.29, p = .016) compared to their co-twin in a non-RCL state. We did not observe any other differences within-twin pairs on other outcomes.Conclusion: These results suggest that living in an RCL state is associated with greater cannabis frequency but not more negative consequences from cannabis use than living in a non-RCL state.

Children's Knowledge of Cannabis and Other Substances in States with Different Cannabis Use Regulations.

Background: Public acceptance of cannabis continues to increase across the US, yet there has been little research on how cannabis legalization affects young children. The present study compared knowledge of cannabis and other substances among children living in states with different cannabis laws and examined whether the association between such substance knowledge and externalizing behavior varies by state cannabis regulations. Methods: Participants were from the Adolescent Brain Cognitive DevelopmentSM Study (ABCD Study®) at the baseline assessment (N = 11,875, ages 9-11, collected from 2016 to 2018). Chi-square difference tests were used to compare nested models testing group differences in knowledge of substances and the association between externalizing disorder/behavior and substance knowledge as a function of state legality of cannabis use (recreational, medical, low THC/CBD, none). Results: Children living in states with more permissive cannabis laws had a greater knowledge of cannabis and reported more alcohol experimentation. In contrast, knowledge regarding alcohol, tobacco, and other illicit drugs was not greater in children from states with more permissive cannabis laws. Externalizing disorder/behavior was not significantly associated with cannabis knowledge in any group and not significantly different across groups. The association between externalizing disorder/behavior and illicit drug knowledge was significant only in states with the recreational and medical use laws but did not differ significantly across groups. Conclusion: Children living in environments with more permissive cannabis regulations have greater knowledge of cannabis, but not other substances, and report more experimentation with alcohol.

Effects of Behavioral Treatment Modified to Fit Children with Conduct Problems and Callous-Unemotional (CU) Traits.

Research suggests that children with conduct problems (CP) and callous-unemotional (CU) traits show a diminished response to behavior therapy, perhaps due to a reward-oriented, punishment insensitive learning style. Children with CP and CU may benefit from personalizing behavioral treatment for them by emphasizing rewards and de-emphasizing punishments. This hypothesis was tested in a sample of 46 children (78.3% boys), ages 7.0 to 12.6 years (M = 9.3, SD = 1.4). All participants met criteria for ODD and ADHD and 63% also met criteria for CD. Participants were oversampled for high CU, but CU scores ranged from average to high. Children received four weeks of modified behavior therapy that emphasized rewards and de-emphasized punishments and four weeks of treatment as usual, which was standard behavior therapy that balanced rewards and punishments. Treatments were implemented in a summer treatment program and compared using a within-subjects design, with order of treatment counterbalanced. Disruptive behavior was equal or slightly higher in modified behavior therapy than in standard behavior therapy on point system measures, but lower on parent weekly ratings. End of treatment ratings showed both treatments produced significant improvements compared to pre-treatment ratings but did not differ from each other. Personalizing behavior therapy for children with CP and CU produced inconsistent findings relative to standard behavior therapy. Behavior therapy is likely to be a necessary part of treatment for children with CP and CU, but treatment personalization efforts may provide some benefit by addressing other deficits shown by these children.

Exploring Cannabis and Alcohol Co-Use in Adolescents: A Narrative Review of the Evidence.

Objective: Amidst the evolving policy surrounding cannabis legalization in the United States, cannabis use is becoming increasingly prevalent as perceptions of harm decrease, particularly among adolescents. Cannabis and alcohol are commonly used by adolescents and are often used together. However, developmental research has historically taken a "single substance" approach to examine the association of substance use and adolescent brain and behavior rather than examining co-(or poly-substance) use of multiple substances, such as cannabis and alcohol. Thus, the acute effects of cannabis and alcohol, and the impact of co-use of cannabis and alcohol on the adolescent brain, cognitive function and subsequent psychosocial outcomes remains understudied. This narrative review aims to examine the effects of cannabis and alcohol on adolescents across a number of behavioral and neurobiological outcomes. Methods: The PubMed and Google Scholar databases were searched for the last 10 years to identify articles reporting on acute effects of cannabis and alcohol administration, and the effects of cannabis and alcohol on neuropsychological, neurodevelopmental, neural (e.g., structural and functional neuroimaging), and psychosocial outcomes in adolescents. When adolescent data were not available, adult studies were included as support for potential areas of future direction in adolescent work. Results: Current studies of the impact of cannabis and alcohol on adolescent brain and behavior have yielded a complicated pattern. Some suggest that the use of cannabis in addition to alcohol during adolescence may have a "protective" effect, yielding neuropsychological and structural brain outcomes that are better than those for adolescents who use only alcohol. However, other adolescent studies suggest that cannabis and alcohol co-use is associated with negative health and social outcomes such as poorer academic performance and impaired driving. Conclusion: Variation in study methodologies, policy-level limitations and our limited understanding of the developmental neurobiological effects of cannabis preclude the straightforward interpretation of the existing data on adolescent cannabis and alcohol use. Further research on this topic is requisite to inform the development of effective intervention and prevention programs for adolescent substance users, which hinge on a more comprehensive understanding of how cannabis-and its intersection with alcohol-impacts the developing brain and behavior.

Is Cannabis Use Associated with Various Indices of Motivation among Adolescents?

Decreased motivation is often noted as a consequence of cannabis use (CU). Previous work has yielded mixed findings, relied mostly on adult samples, and varied to the extent that it accounted for potential confounds. This study examines associations between CU and several motivation indices among adolescents. We hypothesized that regular cannabis users would report lower motivation than light users, and that greater lifetime and past 30-day CU amounts would be associated with decreased motivation. Participants were 79 adolescents, ages 14-18, classified as recent regular cannabis users (n = 36) or light users (n = 43). Frequency and amount of substance use were assessed across participants' lifetime and during the past 30 days. Motivation was measured through the Apathy Evaluation Scale and Motivation and Engagement Scale. To examine associations between CU and our motivation indices, we conducted a series of two-step hierarchical multiple regressions. Variables found to correlate with any motivation measure were entered on step 1 (e.g., mental health, other substance use) and the relevant CU variable was entered on step 2. After controlling for confounds, no significant differences were observed between regular and light users on any motivation index, p > .01. Similarly, no associations between motivation and lifetime or past 30-day CU amount were observed, p > .01. Our findings do not support a link between reduced motivation and CU among adolescents after controlling for relevant confounds. Future studies will examine the levels of CU which influence motivation in adolescents, and the conditions under which this link becomes manifest.

The Neuropsychology of Risky Sexual Behavior.

OBJECTIVES: Engagement in risky sexual behavior (RSB) is a significant public health concern. A growing body of literature is elucidating the role of brain systems and neuropsychological constructs implicated in RSB, which may pave the way for novel insights and prevention efforts. METHODS: In this article, we review studies incorporating neuropsychology into the study of RSB across the lifespan. The review of the literature on the neuropsychology of RSB is separated into three different sections by age of participants. Background is presented on research associating RSB with neurocognitive processes and the brain systems involved. Given the overlap between RSBs and substance use, studies addressing these problems in tandem are also discussed. RESULTS: Neurocognitive constructs are implicated in RSB, including impulsivity, decision-making, and working memory. DISCUSSION: Thus far, evidence suggest that neuropsychological factors are associated with engagement in RSB. More research on the influence of neuropsychological factors on engagement in RSB is necessary and may help inform future prevention efforts. (JINS, 2016, 22, 586-594).

Decision-Making Does not Moderate the Association between Cannabis Use and Body Mass Index among Adolescent Cannabis Users.

OBJECTIVES: Results from research conducted on the association between cannabis use and body mass index (BMI) reveal mixed findings. It is possible that individual differences in decision-making (DM) abilities may influence these associations. METHODS: This study analyzed how amount of cannabis use, DM performance, and the interaction of these variables influenced BMI and clinical classifications of weight among adolescents (ages 14 to 18 years; 56% male; 77% Hispanic). The sample consisted primarily of cannabis users (n=238) without a history of significant developmental disorders, birth complications, neurological conditions, or history of mood, thought, or attention deficit/hyperactivity disorder at screening. Furthermore, few participants engaged frequently in other drug use (except for alcohol and nicotine). RESULTS: Analyses revealed that more lifetime cannabis use was associated with a higher BMI and greater likelihood of being overweight/obese. Interactions between DM and cannabis use on BMI were not significant, and DM was not directly associated with BMI. DISCUSSION: Our findings suggest that among adolescents, cannabis use is associated with a greater BMI regardless of DM abilities and this association is not accounted for by other potential factors, including depression, alcohol use, nicotine use, race, ethnicity, or IQ. (JINS, 2016, 22, 944-949).

The effects of single versus mixed gender treatment for adolescent girls with ADHD.

This study evaluated the social behavior of adolescents with attention deficit hyperactivity disorder (ADHD) in single and mixed gender treatment settings. We collected ratings of social behavior (i.e., prosocial peer interactions, assertiveness, self-management, compliance, physical aggression, relational aggression) during single and mixed gender games within the Summer Treatment Program-Adolescent for 10 girls (M age = 13.17, 80% Hispanic) and 11 boys (M age = 12.89, 54.55% Hispanic). Counselors completed ratings immediately following 10 recreational periods for each adolescent they supervised (5 single gender games, 5 mixed gender games). Gender (female vs. male) × Setting (single vs. mixed gender) ANOVAs were conducted. If a significant interaction emerged, post hoc tests were also conducted. Several Gender × Setting interactions emerged, suggesting that girls benefit more from single gender formats than mixed gender formats. Girls showed more assertiveness, self-management, and compliance in single compared to mixed gender settings. A somewhat different pattern of results emerged for boys, which showed more appropriate social behavior (i.e., self-management, compliance) and less inappropriate social behavior (i.e., physical and relational aggression) in mixed gender settings compared to single gender settings. In contrast to previous ADHD treatment studies, these findings suggest that gender may impact treatment response for adolescents. Therefore, it is important that future studies evaluate whether current treatments for ADHD are appropriate for girls with ADHD and whether gender-specific treatments are necessary to address the unique difficulties of adolescent girls with ADHD.

A Review of the Effects of Adolescent Cannabis Use on Physical Health.

The current review highlights the available research related to cannabis and indicators of physical health in a variety of domains. Various studies have found associations between cannabis use with pulmonary, cardiovascular, gastrointestinal, and endocrine function as well as body mass index and sleep. At this time, more research is needed to understand the influence of cannabis use on physical health, particularly among adolescent samples.

A Review of the Effects of Adolescent Cannabis Use on Physical Health.

The current review highlights the available research related to cannabis and indicators of physical health in a variety of domains. Various studies have found associations between cannabis use with pulmonary, cardiovascular, gastrointestinal, and endocrine function as well as body mass index and sleep. At this time, more research is needed to understand the influence of cannabis use on physical health, particularly among adolescent samples.

An exploratory follow-up study of cannabis use and decision-making under various risk conditions within adolescence.

OBJECTIVE: Studies examining the associations between decision-making (DM) and cannabis use (CU) often use cross-sectional, adult samples, and composite scores or single tasks to assess DM. The present study explored differential associations between tasks assessing DM under various risk conditions (i.e., ambiguous vs. explicit; gain vs. loss) and CU frequency, CU-related problems, and CU disorder (CUD) onset across a 2-year period within adolescence. METHOD: Adolescents (n = 401, 90% Hispanic) aged 14-17 at baseline participated in five biannual assessments. CU frequency, CU-related problems, and CUD were assessed using the Drug Use History Questionnaire, Marijuana Problems Scale, and Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, fourth edition, respectively. DM was assessed using the Iowa gambling task (IGT), Game of Dice Task (GDT), and Cups Task. We used latent growth curve modeling to examine bidirectional associations between DM and escalation in CU frequency and CU-related problems, and discrete time survival analyses to determine whether baseline performance across DM tasks predicted CUD onset. RESULTS: Baseline performance on the GDT predicted greater escalation in CU (ß = .200, p = .008) and CU-related problems (ß = .388, p = .035). No other significant associations were found. CONCLUSIONS: DM under explicit risk may be a more salient risk factor for escalating CU and CU-related problems than DM under ambiguous risk. Deficits in executive functioning could partially explain the results. Findings suggest that neurocognitive development should inform prevention and intervention efforts focused on reducing CU. Given the exploratory nature of the present study, replication of findings is needed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

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.

The effects of cannabis use on physical health: A co-twin control study.

BACKGROUND: Research on the influence of cannabis use on anthropometrics, cardiovascular and pulmonary function, and other indicators of physical health has reported mixed results. We examined whether cannabis frequency is associated with physical health outcomes phenotypically and after controlling for shared genetic and environmental factors via a longitudinal co-twin control design. METHODS: We tested the phenotypic associations of adolescent, young adult, and adult cannabis frequency with adult physical health. Next, we ran multilevel models to test if significant phenotypic associations remained at the between-family and within-twin pair levels. Participants include 677 individual twins (308 twin pairs) aged 25-35. RESULTS: At the phenotypic level, adolescent cannabis use was associated with less adult exercise engagement (b = - 0.846 min, p = .000). Adult cannabis use was associated with a lower resting heart rate (HR; b = - 0.170 bpm, p = .001) and more frequent appetite loss (b = 0.018, p = .000). Only between-family effects were significant for adolescent cannabis use and exercise engagement (b = - 1.147 min, p = .000) and adult cannabis use and appetite loss frequency (b = 0.041, p = .002). The total within-twin (b = - 0.184, p = .014), MZ only (b = - 0.304, p = .003), and between-family effects (b = - 0.164, p = .025) were significant between adult cannabis use and a lower resting HR, which persisted after controlling for familial confounds and other substance use. CONCLUSIONS: The associations between cannabis use with exercise engagement and frequency of appetite loss are explained by familial confounding while the association between cannabis use and resting HR was not. These results do not support a causal association between cannabis use once a week and poorer physical health effects among adults aged 25-35.

Risky decision-making as an antecedent or consequence of adolescent cannabis use: findings from a 2-year longitudinal study.

BACKGROUND AND AIMS: Although poor decision-making (DM) has been correlated with problematic cannabis use (CU), cross-sectional designs make it difficult to determine whether poor DM represents an antecedent and/or consequence of CU. The current study measured bidirectional associations between CU and DM among adolescents over 2 years and compared these findings to those observed with episodic memory, which is consistently reported as a consequence of CU. We also measured the role of DM as a risk factor for cannabis use disorder (CUD) onset. DESIGN: Two-year longitudinal study with five bi-annual assessments. PARTICIPANTS: Participants were 401 adolescents aged 14-17 years at baseline. SETTING: Miami, Florida, USA. MEASUREMENTS: CU frequency and CUDs were assessed at each time-point through the Drug Use History Questionnaire and Structured Clinical Interview for DSM-IV, respectively. Neurocognition was assessed at odd time-points throughout the Iowa Gambling Task, Game of Dice Task and Cups Task [decision-making (DM)] and the Wechsler Memory Scale IV and California Verbal Learning Test II (episodic memory). We used latent growth curve modeling to examine bidirectional influences between CU and neurocognition over time. We applied discrete time survival analyses to determine whether baseline DM predicted CUD onset. FINDINGS: Greater lifetime CU frequency was associated with poorer episodic memory at baseline (bs = -14.84, -16.44, Ps = 0.038, 0.021). Greater CU escalation predicted lesser gains in immediate episodic memory (b = -0.05, P = 0.020). Baseline DM did not predict CU escalation (b = 0.07, P = 0.421), nor did escalation in CU predict changes in DM (b = 0.02, P = 0.352). Baseline DM also did not predict CUD onset (adjusted OR = 1.01, 95% confidence interval = 0.98-1.06). CONCLUSIONS: This study replicates findings that poorer episodic memory in adolescents appears to be a consequence of cannabis use, even among adolescents at earlier stages of use. Poor decision-making does not appear to be either a consequence of or a risk factor for escalating cannabis use or onset of cannabis use disorder among adolescents.

Substance use patterns in 9 to 13-year-olds: Longitudinal findings from the Adolescent Brain Cognitive Development (ABCD) study.

Background: Though largely substance-naïve at enrollment, a proportion of the youth in the Adolescent Brain Cognitive Development (ABCD) Study are expected to initiate substance use (SU) as they transition into later adolescence. With annual data from youth 9-13 years-old, this study aims to describe their SU patterns over time. Here, prevalence rates of use are reported, along with predicted odds of use while analyzing common risk-factors associated with youth SU. Methods: The ABCD Study® enrolled 11,876 participants at Baseline (ages 9-10) and has followed them annually. Data through half of the third follow-up visit are available (ages 12-13; n = 6,251). SU descriptives for al psychoactive substances over time are outlined. General estimating equations (GEEs) assessed whether sociodemographic factors, internalizing and externalizing symptoms, and parental SU problems were associated with SU between Baseline and Y2 follow-up. Results: Across time, alcohol and nicotine remain the most used substances. Yearly rates of any SU increased (past year use: 13.9% in Y1; 14% Y2, 18.4% Y3). Cumulatively, by Y3, 39.7% of the cohort reported experimenting (e.g., sipping alcohol) with SU within their lifetime, while 7.4% reported a "full use" (a full alcohol drink, nicotine use, cannabis use, or any other SU) in their lifetime (past-year: 1.9% alcohol, 2.1% nicotine, 1.1% cannabis, 1.2% other substances). GEEs revealed ongoing longitudinal associations between sociodemographic factors, greater externalizing symptoms, and parental drug problems with increased odds of initiating SU. Conclusions: As ABCD participants transition into their teenage years, the cohort is initiating SU at increasing (though still low) rates.

Individual-, peer-, and parent-level substance use-related factors among 9- and 10-year-olds from the ABCD Study: Prevalence rates and sociodemographic differences.

Background: Although a relatively large body of research has identified multiple factors associated with adolescent substance use, less is known about earlier substance-related factors during preadolescence, including curiosity to use substances. The present study examined individual-, peer-, and parent-level domains pertaining to substance use and how these domains vary by sociodemographic subgroups and substance type. Methods: Participants were 11,864 9- and 10-year-olds from the baseline sample of the Adolescent Brain Cognitive Development (ABCD) Study. Youth-reported measures were curiosity to use substances and perceived peer substance use. Parent-reported measures were availability of and rules about substances. Generalized logistic mixed models (GLMM) were used to compare these measures across alcohol, nicotine, and marijuana and across sociodemographic subgroupings (sex, race/ethnicity, household income, and family history of alcohol problems). GLMM was then used to examine predictors of curiosity to use by substance type. Results: The most striking descriptive differences were found between race/ethnicity and income categories (e.g., positive associations between greater income and greater availability of alcohol). In multivariable analyses, greater curiosity to use alcohol was associated with being male, higher household income, perceived peer alcohol use, and easy alcohol availability; greater curiosity to use nicotine was associated with being male, perceived peer cigarette use, easy availability of cigarettes, and no parental rules about cigarette use. Conclusions: This study identified substance use-related individual-, peer-, and parent-level factors among a diverse, national sample. Findings highlight the importance of considering sociodemographic and substance-specific variability and may help identify risk and protective factors preceding adolescent substance use.

Screen time and early adolescent mental health, academic, and social outcomes in 9- and 10- year old children: Utilizing the Adolescent Brain Cognitive Development ℠(ABCD) Study.

In a technology-driven society, screens are being used more than ever. The high rate of electronic media use among children and adolescents begs the question: is screen time harming our youth? The current study draws from a nationwide sample of 11,875 participants in the United States, aged 9 to 10 years, from the Adolescent Brain Cognitive Development Study (ABCD Study®). We investigate relationships between screen time and mental health, behavioral problems, academic performance, sleep habits, and peer relationships by conducting a series of correlation and regression analyses, controlling for SES and race/ethnicity. We find that more screen time is moderately associated with worse mental health, increased behavioral problems, decreased academic performance, and poorer sleep, but heightened quality of peer relationships. However, effect sizes associated with screen time and the various outcomes were modest; SES was more strongly associated with each outcome measure. Our analyses do not establish causality and the small effect sizes observed suggest that increased screen time is unlikely to be directly harmful to 9-and-10-year-old children.

Genetic and environmental relations of executive functions to antisocial personality disorder symptoms and psychopathy.

Meta-analytic findings suggest that antisocial behavior, broadly defined, may relate to a Common Executive Function (EF) factor that captures covariance across response inhibition, working memory updating, and mental set shifting tasks. However, it is unclear whether this common factor, which is isomorphic with individual differences in response inhibition, accounts for all of the EF variance in antisocial behavior and psychopathy, or if they also relate to updating- and shifting-specific abilities. Moreover, findings that antisocial behavior and lower cognitive ability are particularly associated with the psychopathy dimension reflecting impulsivity and irresponsibility, compared to the dimension reflecting affective-interpersonal functioning, raise the possibility that EF relates to the variance shared between the impulsive-irresponsible psychopathy dimension and antisocial personality disorder. We examined these questions in a young adult twin sample (N = 765) with measures of multiple EF latent variables, Levenson Self-Report Psychopathy (LSRP) Primary (affective-interpersonal) and Secondary (impulsive-irresponsible) scales, and antisocial personality disorder symptoms (ASPDsx). Phenotypically, higher ASPDsx and LSRP Secondary psychopathy, but not LSRP Primary psychopathy, were associated with lower Common EF. Moreover, both psychopathy dimensions were negatively correlated with Updating-Specific ability, which was unrelated to ASPDsx. Results from twin models indicated that the association between LSRP Secondary psychopathy and ASPDsx was due to both genetic and nonshared environmental influences; however, Common EF's association with ASPDsx was primarily genetic, whereas its association with LSRP Secondary psychopathy had a significant environmental component. Thus, the interrelations among these constructs may reflect heterogeneous etiological pathways.