Prescription Opioid Decision-making and Use Behaviors in Adolescents With Acute Pain: A Qualitative Study.

OBJECTIVES: Understanding adolescent perspectives on prescribed opioids in the context of medical care for acute pain is needed to prevent opioid-related adverse outcomes. We explored factors that may influence opioid decision-making and use behaviors among adolescents prescribed opioids for acute pain. METHODS: We conducted semistructured interviews with 19 adolescents (63% females, ages 12 to 17) prescribed opioids upon discharge from surgery or intensive care unit admission. Interview transcripts were coded using inductive thematic analysis. RESULTS: Five themes were identified: "Opioid use to reduce extreme pain and facilitate acute recovery"; "Familiarity with risks and negative effects of opioids"; "Assessment of opioid risk based on individual characteristics and use behaviors"; "Careful balance of risks, benefits, and symptoms when taking opioids"; "Importance of trusted adults for adolescent opioid management". Adolescents commonly believe opioids are only appropriate for severe pain that cannot be managed with other strategies. Most (but not all) adolescents were aware of addiction and other potential opioid harms and generally disapproved of misuse. However, a few adolescents would consider taking unprescribed opioids for severe pain. Adolescents wanted to be well informed for opioid decision-making, considering guidance from trusted adults. DISCUSSION: Adolescents often demonstrated active and sound participation in shared opioid decision-making, influenced by complex integration of inputs and self-reflection. Conversely, potential factors that could contribute to risky behaviors included low personal risk perceptions, uncertainty about what constitutes opioid misuse, and avoidance of prescribed opioids despite extreme pain. Future studies may explore associations of adolescents' opioid decision-making with longer-term pain and opioid-related outcomes.

Exposure to non-persistent pesticides, BDNF, and behavioral function in adolescent males: Exploring a novel effect biomarker approach.

BACKGROUND: Numerous contemporary non-persistent pesticides may elicit neurodevelopmental impairments. Brain-derived neurotrophic factor (BDNF) has been proposed as a novel effect biomarker of neurological function that could help to understand the biological responses of some environmental exposures. OBJECTIVES: To investigate the relationship between exposure to various non-persistent pesticides, BDNF, and behavioral functioning among adolescents. METHODS: The concentrations of organophosphate (OP) insecticide metabolites 3,5,6-trichloro-2-pyridinol (TCPy), 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPy), malathion diacid (MDA), and diethyl thiophosphate (DETP); metabolites of pyrethroids 3-phenoxybenzoic acid (3-PBA) and dimethylcyclopropane carboxylic acid (DCCA), the metabolite of insecticide carbaryl 1-naphthol (1-N), and the metabolite of ethylene-bis-dithiocarbamate fungicides ethylene thiourea (ETU) were measured in spot urine samples, as well as serum BDNF protein levels and blood DNA methylation of Exon IV of BDNF gene in 15-17-year-old boys from the INMA-Granada cohort in Spain. Adolescents' behavior was reported by parents using the Child Behavior Check List (CBCL/6-18). This study included 140 adolescents of whom 118 had data on BDNF gene DNA methylation. Multivariable linear regression, weighted quantile sum (WQS) for mixture effects, and mediation models were fit. RESULTS: IMPy, MDA, DCCA, and ETU were detected in more than 70% of urine samples, DETP in 53%, and TCPy, 3-PBA, and 1-N in less than 50% of samples. Higher levels of IMPy, TCPy, and ETU were significantly associated with more behavioral problems as social, thought problems, and rule-breaking symptoms. IMPy, MDA, DETP, and 1-N were significantly associated with decreased serum BDNF levels, while MDA, 3-PBA, and ETU were associated with higher DNA methylation percentages at several CpGs. WQS models suggest a mixture effect on more behavioral problems and BDNF DNA methylation at several CpGs. A mediated effect of serum BDNF within IMPy-thought and IMPy-rule breaking associations was suggested. CONCLUSION: BDNF biomarkers measured at different levels of biological complexity provided novel information regarding the potential disruption of behavioral function due to contemporary pesticides, highlighting exposure to diazinon (IMPy) and the combined effect of IMPy, MDA, DCCA, and ETU. However, further research is warranted.

Effects of Yi-Gan-san on the psychiatric behavior of children and adolescents with Tourette's Syndrome: A randomized, double-blind, controlled preliminary study.

ETHNOPHARMACOLOGICAL RELEVANCE: Gilles de la Tourette's Syndrome (TS) is a childhood-onset disease with clinical features of motor and phonic tics. Yi-Gan-san (YGS) is a traditional Chinese medicine formula that can reduce aggressiveness and agitation and inhibit dopamine function. This study investigated the effects of YGS on the psychiatric behavior of children and adolescents with TS. METHODS: A double-blind, randomized, controlled preliminary study was conducted. A total of 38 patients with TS were assigned to the control group (CG, 19 patients) who received the oral administration of YGS placebo (90% starch and 10% YGS; 2.5 g thrice daily) or to a treatment group (TG, 19 patients) who received YGS for 4 weeks. The primary outcome measure was the change in Yale Global Tic Severity Scale (YGTSS) overall and subscale scores. RESULTS: The intensity score for phonic tics before oral administration of YGS, and after 2 weeks, 3 weeks and 4 weeks was not significantly different between CG and TG groups (2.94 ± 1.14 vs 2.79 ± 1.08, p = .686; 2.29 ± 1.21 vs 1.95 ± 1.08, p = .370; 2.41 ± 1.18 vs 2.05 ± 1.51, p = .435; and 2.29 ± 1.26 vs 1.84 ± 1.42, p = .323, respectively), while the intensity score for phonic tics after 1-week oral administration of YGS in the TG was 1.89 ± 1.10 lower than 3.06 ± 1.39 in the CG (p = .008). CONCLUSION: Oral administration of YGS for 1 week only reduced the intensity of phonic tics compared with oral administration of YGS placebo, suggesting that YGS can reduce their intensity for a short period, and the compliance of oral administration of YGS for 4 weeks can be accepted in children and adolescents with Tourette's Syndrome. However, because this study was preliminary, the selection of an appropriate placebo and dosage and long-term observations are crucial areas for future studies.

Voluntary alcohol binge-drinking in adolescent C57Bl6 mice induces delayed appearance of behavioural defects in both males and females.

Adolescence is a developmental period characterized by significant changes in brain architecture and behaviour. The immaturity of the adolescent brain is associated with heightened vulnerability to exogenous agents, including alcohol. Alcohol is the most consumed drug among teenagers, and binge-drinking during adolescence is a major public health concern. Studies have suggested that adolescent alcohol exposure may interfere with the maturation of frontal brain regions and lead to long-lasting behavioural consequences. In this study, by using a slightly modified version of the Drinking in the Dark paradigm, adolescent C57Bl6 mice reach high blood alcohol concentration after voluntary binge-drinking. In order to assess short- and long-term consequences of adolescent alcohol exposure (AAE), a battery of behavioural tests was performed during late adolescence and during adulthood. We showed that AAE had no short-term effect on young mice behaviour but rather increased anxiety- and depressive-like behaviours, as well as alcohol consumption during adulthood. Moreover, alcohol binge-drinking during adolescence dramatically decreased recognition memory performances and behavioural flexibility in both adult males and females. Furthermore, we showed that voluntary consumption of alcohol during adolescence did not trigger any major activation of the innate immune system in the prefrontal cortex. Together, our data suggest that voluntary alcohol binge-drinking in adolescent mice induces a delayed appearance of behavioural impairments in adulthood.

Prenatal drug exposure and executive function in early adolescence.

PURPOSE: Study of the relationship between prenatal cocaine exposure (PCE) and executive function (EF) has yielded inconsistent results. The purpose of the current study is to examine whether PCE, biological sex, environmental risk, and their interaction predicted EF in early adolescence. METHODS: 135 12-year-old adolescents (40.7% with PCE), who were followed prospectively from birth, attempted up to 8 Tower of Hanoi (ToH) puzzle trials of increasing complexity. The number of correctly completed puzzles served as the main outcome measure. Survival analysis was used to examine predictors of the number of successfully completed trials. RESULTS: As trial difficulty increased, fewer adolescents were able to solve the TOH puzzle. Adolescents from high risk environments and with either prenatal alcohol or prenatal cannabis exposure completed fewer puzzles (p < .05). In addition, a hypothesized 3-way interaction of PCE x sex x environmental risk was found such that cocaine-exposed males with high environmental risk had the worst performance (p < .01). CONCLUSIONS: The current findings are consistent with prior research indicating that males with PCE may be at particular risk of poorer functioning and highlight the potential importance of examining adolescent's sex and environmental risk as moderators of PCE effects.

A Phase 3, Placebo-Controlled Trial of Once-Daily Viloxazine Extended-Release Capsules in Adolescents With Attention-Deficit/Hyperactivity Disorder.

PURPOSE: This phase 3 clinical trial evaluated the efficacy and safety of viloxazine extended-release capsules (VLX-ER) as a monotherapy for attention-deficit/hyperactivity disorder (ADHD) in adolescents (12-17 years). METHODS: Eligible subjects (n = 310) were randomized to receive once-daily 200 and 400 mg VLX-ER, or placebo for 6 weeks. The primary efficacy end point was change from baseline (CFB) at the end of study (EOS) in ADHD Rating Scale-5 Total score. Key secondary end points were Clinical Global Impression-Improvement score at EOS, CFB at EOS in Conners 3-Parent Short Form Composite T-score, and CFB at EOS in Weiss Functional Impairment Rating Scale-Parent Total average score. RESULTS: In the 200-mg/d and 400-mg/d VLX-ER treatment groups, a significant improvement was found in the CFB at EOS in ADHD Rating Scale-5 Total (P = 0.0232, P = 0.0091) and Inattention (P = 0.0424, P = 0.0390) and Hyperactivity/Impulsivity (P = 0.0069, P = 0.0005) subscale scores versus placebo. The Clinical Global Impression-Improvement score was significantly improved at EOS in the 200-mg/d and 400-mg/d VLX-ER groups versus placebo (P = 0.0042, P = 0.0003). The Conners 3-Parent Short Form composite T-score and Weiss Functional Impairment Rating Scale-Parent Total average score exhibited improvement in both VLX-ER groups; however, the difference versus placebo was not statistically significant. The most common treatment-related adverse events were somnolence, headache, decreased appetite, nausea, and fatigue. The adverse event-related discontinuation rates were <5% in all groups. CONCLUSIONS: Viloxazine extended-release demonstrated statistically significant and clinically meaningful improvement in ADHD symptoms in adolescents and was generally well tolerated.

Reliability of a computer-based neurobehavioral assessment test battery for Bangladeshi adolescent children.

In developing countries, there is a need for low-cost neurobehavioral (NB) test batteries for vulnerable populations, particularly for children exposed to environmental neurotoxicants. The objective of the current study was to assess the feasibility and test-retest reliability of the Behavioral Assessment and Research System (BARS) in children from a rural community in Bangladesh. Fifty healthy adolescents living in the Health Effects of Arsenic Longitudinal Study (HEALS) area in Araihazar, Bangladesh completed all six tests from the BARS in two test sessions scheduled two weeks apart. The BARS tests evaluated NB functions such as motor coordination, attention, memory, and information processing speed. The reliability assessment, evaluated by test-retest correlations demonstrated moderate to strong correlations (i.e., correlation coefficients ranged from 0.43 to 0.85), which were statistically significant (p < 0.05). Paired t-tests for comparing the test and retest outcomes indicated significant improvement in NB performance, highlighting learning and practice effects. NB performance improved with increasing age in most cases. Adolescent boys performed better than the girls in Finger Tapping, Digit Span, and Simple Reaction Time, whereas the girls performed better in Continuous Performance and Symbol Digit tests. The reliability scores (Pearson's correlations 0.43-0.85) were consistent with other children studies in different cultural settings. The effects of age and sex on NB tests were also consistent with findings reported in other countries. Overall, the findings of the study support the feasibility of using this computer-based test system to assess vulnerability of brain health due to environmental exposures among rural Bangladeshi children.

Caffeine enhances sustained attention among adolescents.

Despite the growing interest in caffeine use and its effects among adolescents, and a large literature on caffeine and attention among adults, there is a lack of experimental work examining the impact of caffeine on sustained attention among adolescents. We evaluated the acute effects of caffeine (vs. placebo) during a long (33-min) classic vigilance task among 31 adolescents (aged 12-17; 15 female; median caffeine use = 28 mg/day). We predicted a dose-dependent effect of caffeine, which would attenuate declines in target detection over time (i.e., a vigilance decrement). In each of 3 visits, participants completed an identical pairs continuous performance task beginning ∼25 min after consumption of noncaloric flavored water containing placebo, 1 mg/kg, or 3 mg/kg caffeine (order counterbalanced). Percent hits for low probability targets across 12 100-trial blocks was the primary outcome measure. As predicted, the linear decline in hits across trial blocks was attenuated by caffeine (Caffeine vs. Placebo × Block Linear, p = .01), with significant improvements in Blocks 9-12 (ps < .03). Compared to 1 mg/kg, 3 mg/kg caffeine resulted in earlier improvement in target detection (Drug Dose × Block Quadratic, p = .001). This study demonstrated that caffeine acutely and dose-dependently improves sustained attention among adolescents. These results were likely due to the attention-enhancing effect of caffeine, rather than withdrawal reversal, as our sample was characterized by light to moderate caffeine use. This study provides the foundation for further work on the impact of chronic caffeine consumption on cognitive function during adolescence. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Molecular and neuronal mechanisms underlying the effects of adolescent nicotine exposure on anxiety and mood disorders.

Tobacco addiction is highly co-morbid with a variety of mental health conditions, including schizophrenia, mood and anxiety disorders. Nicotine, the primary psychoactive compound in tobacco-related products is known to functionally modulate brain circuits that are disturbed in these disorders. Nicotine can potently regulate the transmission of various neurochemicals, including dopamine (DA), γ-amino-butyric acid (GABA) and glutamate, within various mesocorticolimbic structures, such as the ventral tegmental area (VTA), nucleus accumbens (NAc) and prefrontal cortex (PFC), all of which show pathologies in these disorders. Many neuropsychiatric diseases have etiological origins during neurodevelopment, typically occurring during vulnerable periods of adolescent or pre-natal brain development. During these neurodevelopmental periods, exposure to extrinsic drug insults can induce enduring and long-term pathophysiological sequelae that ultimately increase the risk of developing chronic mental health disorders in later life. These vulnerability factors are of growing concern given rising rates of adolescent nicotine exposure via traditional tobacco use and the increasing use of alternative nicotine delivery formats such as vaping and e-cigarettes. A large body of clinical and pre-clinical evidence points to an important role for adolescent exposure to nicotine and increased vulnerability to developing mood and anxiety disorders in later life. This review will examine current clinical and pre-clinical evidence that pinpoints specific mechanisms within the mesocorticolimbic circuitry and molecular biomarkers linked to the association between adolescent nicotine exposure and increased risk of developing mood and anxiety-related disorders. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

Experiences of parents with an adolescent abusing substances admitted to a mental health institution in Giyani, South Africa.

BACKGROUND: Substance abuse by adolescents may be a problem that contributes to their mental illness. Substance abuse does affect not only the individual who is abusing it but also friends, family and the whole community. The adolescent abusing substances may be mentally unstable and have unpredictable behaviour. There is no research on the experiences of parents with adolescents abusing substances in Giyani, South Africa. OBJECTIVE: The purpose of the study was to explore and describe the experiences of parents with adolescents abusing substances admitted to a mental health institution in Giyani. METHOD: A qualitative, exploratory, descriptive and contextual research design was used. Data were collected by means of conducting individual, in-depth, phenomenological interviews, observations and field notes. The following central question was asked to the participants: 'How is it for you to have an adolescent who is abusing substances'. Data were analysed by using a thematic method of coding. An independent coder analysed data together with the researcher, and consensus was reached. RESULTS: Four themes emerged from the data: parents experienced uncontrolled thoughts regarding their adolescent abusing substances, not being able to control their adolescent abusing substances through discipline, negative feelings regarding their adolescent abusing substances and negative consequences regarding their adolescents abusing substances. CONCLUSION: From the study result, it is clear that parents with adolescent abusing substances need professional assistance and support as evidenced by the challenges faced in terms of promoting, maintaining and restoring their mental health. Psychiatric nurses should take responsibility to educate the community about substance abuse, for example offering school health programmes. Further research studies can also be conducted in other villages to gain a greater understanding of those parents' experiences with an adolescent abusing substances.

AMPed-up adolescents: The role of age in the abuse of amphetamines and its consequences on cognition and prefrontal cortex development.

Adolescent use of amphetamine and its closely related, methylated version methamphetamine, is alarmingly high in those who use drugs for nonmedical purposes. This raises serious concerns about the potential for this drug use to have a long-lasting, detrimental impact on the normal development of the brain and behavior that is ongoing during adolescence. In this review, we explore recent findings from both human and laboratory animal studies that investigate the consequences of amphetamine and methamphetamine exposure during this stage of life. We highlight studies that assess sex differences in adolescence, as well as those that are designed specifically to address the potential unique effects of adolescent exposure by including groups at other life stages (typically young adulthood). We consider epidemiological studies on age and sex as vulnerability factors for developing problems with the use of amphetamines, as well as human and animal laboratory studies that tap into age differences in use, its short-term effects on behavior, and the long-lasting consequences of this exposure on cognition. We also focus on studies of drug effects in the prefrontal cortex, which is known to be critically important for cognition and is among the later maturing brain regions. Finally, we discuss important issues that should be addressed in future studies so that the field can further our understanding of the mechanisms underlying adolescent use of amphetamines and its outcomes on the developing brain and behavior.

Associations of the Behavioral Assessment and Research System (BARS) neurobehavioral outcomes with attention problems in children living near coal ash storage sites.

Environmental exposures have been linked to childhood problems with overactivity, attention, and impulse control, and an increased risk of attention deficit hyperactivity disorder (ADHD) diagnosis. Two approaches to identify these types of exposure-related neurobehavioral problems include the use of computerized tests, such as the Behavioral Assessment and Research System (BARS), as well as the use of behavior rating scales. To assess comparability of these two types of measures, we analyzed data from 281 children aged 6 to 14 years enrolled in a 5-year research study investigating coal ash exposure and neurobehavioral health. All children lived in proximity of coal ash storage sites. We administered six computer tests from the BARS and obtained behavior measures from the parent-completed Child Behavior Checklist (CBCL) ADHD DSM oriented scale. BARS test performance was associated with age indicating that the tests could be used to evaluate neurodevelopmental changes over time or across a wide age range. Tests within the BARS including Continuous Performance (CPT) false alarm (standardized estimate 1.57, 95% confidence interval (CI) (0.67, 2.48), adjusted p = 0.006), Selective Attention (SAT) wrong count (standardized estimate 2.8, 95% CI (1.17, 4.44), adjusted p = 0.006), and SAT proportion correct (standardized estimate -2.45, 95% CI (-4.01, -0.88), adjusted p = 0.01) were associated with attention and impulse control problems on the CBCL after adjustment for multiple comparisons. Findings support that the BARS can contribute to research on environmental exposures by assessing subclinical behaviors related to ADHD such as sustained attention, impulse control, response inhibition, associative learning, and short-term memory. Future research can examine relationships of these BARS measures with biomarkers of neurotoxic exposures related to living near coal ash storage sites to better identify the potential risk for ADHD-related behaviors among children living near coal ash storage sites.

Recent Advances in the Pharmacological Management of Behavioral Disturbances Associated with Autism Spectrum Disorder in Children and Adolescents.

Autism spectrum disorder (ASD) is a heterogeneous neuropsychiatric condition affecting an estimated one in 36 children. Youth with ASD may have severe behavioral disturbances including irritability, aggression, and hyperactivity. Currently, there are only two medications (risperidone and aripiprazole) approved by the US Food and Drug Administration (FDA) for the treatment of irritability associated with ASD. Pharmacologic treatments are commonly used to target ASD-associated symptoms including irritability, mood lability, anxiety, and hyperactivity. However, evidence for the efficacy of many commonly used treatments is limited by the lack of large placebo-controlled trials of these medications in this population. Research into the pathophysiology of ASD has led to new targets for pharmacologic therapy including the neuroimmune system, the endocannabinoid system, and the glutamatergic neurotransmitter system. The goal of this review is to provide an overview of the current evidence base for commonly used treatments, as well as emerging treatment options for common behavioral disturbances seen in youth with ASD.

Marijuana and the Pediatric Population.

Cannabinoids, the psychoactive compounds in marijuana, are one of the most commonly used substances in the United States. In this review, we summarize the impact of marijuana on child and adolescent health and discuss the implications of marijuana use for pediatric practice. We review the changing epidemiology of cannabis use and provide an update on medical use, routes of administration, synthetic marijuana and other novel products, the effect of cannabis on the developing brain, other health and social consequences of use, and issues related to marijuana legalization.

This is your teen brain on drugs: In search of biological factors unique to dependence toxicity in adolescence.

Response variability across the lifespan is an important consideration in toxicology and risk assessment, and the toxic effects of drugs and chemicals during adolescence need more research. This paper summarizes a workshop presented in March 2019, at the Society of Toxicology Annual Meeting in Baltimore, Maryland, that brought together experts in research on drug dependence and toxicity related to nicotine, cannabis, cocaine, and other illicit drugs during adolescence. The goal of the workshop was to address the following issues: (1) Do the effects of adolescent exposure differ from the same exposure in adults? (2) Are there unique biological markers of adolescent brain development? If so, what are they and how reliable are they? (3) Since multiple factors influence substance use disorder, can we disentangle risk factors for abuse and/or toxicity? What are the underlying biological susceptibilities that lead to dependence and neurotoxicity? What are the social, psychosocial and environmental factors that contribute to abuse susceptibilities? This paper reviews drug policy and national trends in adolescent substance use; the public health consequences of e-cigarettes; rat models of adolescent-onset nicotine self-administration and persisting effects of gestational nicotine; sex-dependent effects of delta-9-tetrahydrocannabinol on adolescent brain-behavior relationships; and translational approaches for identifying adolescent risk factors for transition to drug dependence. There is strong evidence that drug exposure prior to adulthood has longer lasting effects on behavior and the underlying neural circuitry. These effects, which are sex-dependent and influenced by stress, may be candidates as predictors of adolescent vulnerability. A major challenge to determining if adolescents have a unique susceptibility to dependence is whether and to what extent the human data allow distinction between the increased risk due to biological immaturity, an underlying biological susceptibility to dependence, or psychosocial and environmental factors for substance dependence. Factors important to consider for development of animal models include the timing and pattern of exposure as it relates to adolescence; age of assessment, and direct comparison with similar effects following exposures to adults to demonstrate that these effects are unique to adolescence. Here we provide a roadmap for further research into what makes adolescent brain development unique.

Risk taking, sensation seeking and personality as related to changes in substance use from adolescence to young adulthood.

INTRODUCTION: This study examined changes in substance use from adolescence to young adulthood as related to adolescents' risk taking, sensation seeking, antisocial activities, and personality traits. METHODS: Chilean youth (N = 890, 52% female) were studied in adolescence (14.5 and 16.2 years) and young adulthood (M age 21.3 years). Risk taking was assessed via a laboratory-based performance task (Balloon Analogue Risk Task), and self-administered questionnaires assessed sensation seeking, antisocial behaviors, personality and substance use. RESULTS: Frequent involvement in sensation seeking and antisocial activities were associated with increased odds of continued marijuana use from adolescence to young adulthood and of illicit substance use at young adulthood. High risk taking was associated with a reduced likelihood of discontinuing marijuana use at young adulthood, and high agreeableness and conscientiousness were associated with reduced likelihood of new onset marijuana use and illicit substance use at young adulthood. CONCLUSIONS: Results highlight specific risk-taking tendencies and personality characteristics that relate to initiating, continuing, or discontinuing substance use at entry into adulthood. Sensation seeking and involvement in antisocial activities were the two foremost risk factors for continued use, which is a forecaster of drug dependence. Findings suggest potential prevention and intervention targets for abstaining from or discontinuing substance use as youth transition to adulthood.

Neuropsychological Effects of Mercury Exposure in Children and Adolescents of the Amazon Region, Brazil.

BACKGROUND: Studies with children exposed to methylmercury (MeHg) through fish consumption in the Brazilian Amazon region report that the high levels of hair Hg are associated with significant decreases in intelligence, memory, attention, and visuospatial processing. OBJECTIVE: To investigate the relationship between mercury exposure and neuropsychological functions in riverside communities of the Brazilian Amazon. METHOD: 263 participants aged 6 to 14 years old were assessed, from resettlement regions, near the Madeira river, Rondônia, Brazil. To assess the neuropsychological functions we used the following instruments: intelligence (WASI), working memory (Corsi Block-Tapping Task and Digit Span), verbal fluency (Word Generation - NEPSY II), inhibitory control (Inhibition Errors - NEPSY II), shifting (Trail Making Test) and manual motor dexterity (Grooved PegBoard Test). Socioeconomic status was obtained through household surveys. Total Hg levels were quantified hair samples (Total HgH) collected from the occipital region of the scalp and analyzed by Cold Vapor Atomic Absorption Spectrometry. RESULTS: The group in the upper quartile of Total HgH levels presented lower scores on the tasks that assessed estimated IQ, visuospatial working memory, semantic knowledge and phonological verbal fluency, when compared to the group in the lower quartile level. A regression analysis controlled for age, sex, and maternal education showed that for each increase of 10 µg/g of Total HgH, there was a decrease around half standard deviation in Verbal IQ, estimated IQ scores, semantic knowledge, phonological verbal fluency and for verbal and visuospatial working memory. CONCLUSIONS: High concentrations of Total Hg in hair were associated with a lower performance in neuropsychological functions tests. The results show that environmental exposure to Hg is associated to children and adolescents' lower neuropsychological performance in the riverine and resettled areas of the Brazilian Amazon region.

Adolescent cannabis use, cognition, brain health and educational outcomes: A review of the evidence.

We review the findings of systematic reviews and meta-analyses of case-control studies that examine brain functioning and cognitive correlates of adolescent cannabis use using structural and functional neuroimaging tools and standardised neuropsychological tests. We also examine prospective epidemiological studies on the possible effects of adolescent and young adult cannabis use on cognitive performance in adult life and the completion of secondary education. We summarize the findings of studies in each of these areas that have been published since the most recent systematic review. Systematic reviews find that adolescent cannabis use is inconsistently associated with alterations in the structure of prefrontal and temporal brain regions. Meta-analyses reveal functional alterations in the parietal cortex and putamen. Differences in the orbitofrontal cortex predate cannabis use; it is unclear if they are affected by continued cannabis use and prolonged abstinence. Longitudinal and twin studies report larger declines in IQ among cannabis users than their non-using peers but it is unclear whether these findings can be attributed to cannabis use or to genetic, mental health and environmental factors. Several longitudinal studies and a meta-analysis of cross-sectional studies suggest that there is some cognitive recovery after abstinence from cannabis. Longitudinal studies and some twin studies have found that cannabis users are less likely to complete secondary school than their non-using controls. This association might reflect an effect of cannabis use and/or the social environment of cannabis users and their cannabis using peers. Cognitive performance is altered in some domains (e.g. IQ, verbal learning) in young people while they are regularly using cannabis. There are two important messages to adolescents and young adults: First, cannabis has potentially detrimental effects on cognition, brain and educational outcomes that persist beyond acute intoxication. Second, impaired cognitive function in cannabis users appears to improve with sustained abstinence.