Nearly half of 12 th graders have tried marijuana, and 6% use daily. This paper reviews studies on neuropsychological functioning, brain structure, brain function, and subjective and objective measures of sleep in relation to adolescent marijuana use. Adolescents who use marijuana heavily tend to show disadvantaged attention, learning, and processing speed; subtle abnormalities in brain structure; increased activation during cognitive tasks despite intact performance; and compromised objective indicators of sleep quality. Some abnormalities appear to persist beyond a month of abstinence, but may resolve within three months if cessation is maintained. Recommendations for future studies include characterizing these indices in youth prior to the onset of marijuana use then examining change after chronic use has started, and using large samples of youth with varying degrees of involvement with marijuana as well as alcohol, nicotine, and other drugs to characterize the interactive influences on neurocognition and neural health. KeywordsMarijuana; Cannabis; Adolescence; THC; Drug abuse; Neuropsychological assessment; Magnetic resonance imaging; Sleep Worldwide, recreational use of marijuana (including other cannabis products like hashish) is relatively common during adolescence, a period marked by important brain developments. In adults, chronic heavy marijuana use has been associated with alterations in brain structure, function, and behavior. Any cognitive deficits resulting from adolescent marijuana-related insults would have unfavorable implications for subsequent academic, occupational, and social functioning, extending into adulthood. Given the prevalence of marijuana use, elucidating the neurocognitive sequelae is vital.

Background Deficient behavioral regulation may be a risk factor for substance use disorders in adolescents. Abnormalities in brain regions critical to cognitive control have been linked to more intense and problematic future substance use (e.g., (Durazzo, Gazdzinski, Mon, & Meyerhoff, 2010; Falk, Berkman, Whalen, & Lieberman, 2011; Paulus, Tapert, & Schuckit, 2005). The goal of this study was to examine the degree to which brain response to an inhibition task measured in mid-adolescence can predict substance use 18 months later. Method Adolescents aged 16–19 (N=80) performed a go/no-go response inhibition task during fMRI at project baseline, and were followed 18 months later with a detailed interview on substance use and dependence symptoms. Participants were 39 high frequency users and 41 demographically similar low frequency users (458 versus 2 average lifetime drug use occasions at baseline, respectively). Results Across all subjects, no-go trials produced significant increases in neural response in the ventromedial prefrontal cortex and a region including the left angular and supramarginal gyri (p(FWE)<.01, cluster threshold ≥30 voxels). Less ventromedial prefrontal activation but more left angular gyrus activation predicted higher levels of substance use and dependence symptoms in the following 18 months, particularly for those who were high frequency users in mid-adolescence (p<.05). Conclusions These findings are consistent with studies showing that impairments in cognitive control have strong associations with substance use. We found a predictive relationship between atypical activation patterns at baseline and substance use behavior 18 months later, particularly among adolescents with histories of previous heavy use.

Sleep disturbance among patients with TBI may be associated with a particular constellation of neuropsychological abilities. These issues are discussed in relation to prior findings that indicate the involvement of additional neuropsychiatric factors associated with sleep disturbance in mild TBI.

Background Progressive myelination during adolescence implicates an increased vulnerability to neurotoxic substances and enduring neurocognitive consequences. This study examined the cognitive manifestations of altered white matter microstructure in chronic marijuana and alcohol-using (MJ+ALC) adolescents. Methods Thirty-six MJ+ALC adolescents (ages 16-19) and 36 demographically similar controls were evaluated with diffusion tensor imaging (Bava et al., 2009) and neurocognitive tests. Regions of group difference in fractional anisotropy (FA) and mean diffusivity (MD) were analyzed in relation to cognitive performance. Results In users, lower FA in temporal areas related to poorer performance on attention, working memory, and speeded processing tasks. Among regions where users had higher FA than controls, occipital FA was positively associated with working memory and complex visuomotor sequencing, whereas FA in anterior regions was negatively associated with verbal memory performance. Conclusions Findings suggest differential influences of white matter development on cognition in MJ+ALC using adolescents than in non-using peers. Neuroadaptation may reflect additive and subtractive responses to substance use that are complicated by competing maturational processes.

No abstract

ABSTRACT. Objective: Lifetime alcohol hangover and withdrawal symptoms in youth have been shown to predict poorer recall of verbal and nonverbal information, as well as reduced visuospatial skills. Some evidence has suggested that negative effects of alcohol on the brain may be buffered in part by potential neuroprotective properties of cannabinoids. We hypothesized that a history of more alcohol hangover symptoms would predict worse performances on measures of verbal and visual memory, and that this relationship would be moderated by marijuana involvement. Method: Participants were 130 adolescents (65 with histories of heavy marijuana use, and 65 non-marijuana-using controls), ranging in age from 15.7 to 19.1 years. Neuropsychological tests for visual and verbal memory and interviews assessing lifetime and recent substance use, hangover/withdrawal symptoms, and abuse and dependence criteria were administered. Results: Regression models revealed that greater alcohol hangover symptoms predicted worse verbal learning (p < .05) and memory (p < .05) (California Verbal Learning Test, Second Edition) scores for non-marijuana users, but alcohol hangover symptoms were not linked to performance among marijuana users. Alcohol hangover symptoms did not predict visual memory in either group. Conclusions: Results confi rm previous studies linking adolescent heavy drinking to reduced verbal learning and memory performance. However, this relationship is not seen in adolescents with similar levels of alcohol involvement who also are heavy users of marijuana. (J. Stud. Alcohol Drugs, 71, 885-894, 2010)

Objective: To identify culturally appropriate psychological screening measures for children and adolescents with type 1 diabetes in Qatar, determine rates of depressive and anxiety symptoms in a clinical sample, and examine associations between screening measures, demographic variables, medical characteristics, and diabetes treatment outcomes, specifically HbA1c. Methods: A total of 150 participants with type 1 diabetes aged 10-17 were recruited. Participants were Arabic or English speaking and of Qatari and non-Qatari nationality. Participants completed the Mood and Feelings Questionnaire (child and parent proxy form), the Spence Children's Anxiety Scale, and the Pediatric Quality of Life, Diabetes version (child and parent proxy form). Glycosylated hemoglobin (HbA1c) on the date of the testing was recorded.Results: Approximately ten percent (10.2%) of children and adolescents scored above the cutoff score of 27 indicating clinically significant depressive symptoms, and 12.8% of parents rated their child above the respective cutoff score of 21 for the parent proxy form. Further, 36% of the sample reported clinically significant anxiety symptoms, scoring above the cutoff score of 50. Parent report on their child's quality of life predicted HbA1c (F[6, 140] = 5.42, p = 0.000); B = −0.05, p = 0.002).Conclusions: Rates of depressive and anxiety symptoms are comparable to those observed in western countries. Thus, systematic screening for depression and anxiety in children and adolescents with type 1 diabetes should be implemented in Qatar. This will help inform decisions to refer to mental health services and thus provide more integrated care, possibly improving treatment outcomes.

No abstract