Adolescent inhalant use and executive cognitive functioning

Adolescent substance use and high school noncompletion: exploring the nature of the relationship using a discordant twin design

BACKGROUND AND AIMS

Previous studies have demonstrated associations between substance use and reduced educational attainment; however, many were unable to account for potential confounding factors like genetics and the rearing environment. In the few studies that controlled for these factors, the substances assessed were limited to alcohol, cannabis, and tobacco. To address these limitations, we examined the relationship between adolescent use of seven kinds of substances, the number of additional substances used, and high school noncompletion within a large sample of Australian twins.

DESIGN

A series of two-level generalized mixed effects logistic regressions were conducted to examine associations between adolescent substance use and high school noncompletion.

SETTING

Australia.

PARTICIPANTS

A total of 9579 adult Australian twins from two cohorts of the Australian Twin Registry.

MEASUREMENTS

Assessments of high school completion, childhood major depression, conduct disorder symptoms, substance use initiation, demographics, and parental educational attainment using the Australian version of the Semi-Structured Assessment for the Genetics of Alcoholism.

FINDINGS

There were unique within-twin-pair effects of use of sedatives (odds ratio [OR] = 22.39 [95% confidence interval (CI) = 1.18-423.48]) and inhalants/solvents (OR = 10.46 [95% CI = 1.30-84.16]) on high school noncompletion. The number of substances used in adolescence was strongly associated with high school noncompletion across all discordant twin models (ORs from 1.50-2.32, Ps < 0.03).

CONCLUSIONS

In Australia, adolescent substance use appears to be associated with early school dropout, with the effects of any given substance largely because of the confounding factors of parental education, childhood conduct disorder symptoms, and use of other substances. Sedatives and inhalants/solvents have effects on high school noncompletion that cannot be explained by polysubstance use or familial factors.

Default Mode Network Efficiency Is Correlated With Deficits in Inhibition in Adolescents With Inhalant Use Disorder

It is well established that alterations in cognitive function and damage to brain structures are often found in adolescents who have substance use disorder (SUD). However, deficits in executive cognitive functioning in adolescents related to the vulnerability and consumption of such substances are not well known. In this study, we use graph theoretic analysis to compare the network efficiency in the resting state for three networks-default mode network (DMN), salience network (SN) and fronto-parietal network (FPN)-between inhalant-consuming adolescents and a control group (12 to 17 years old). We analyzed whether the efficiency of these functional networks was related to working memory, mental flexibility, inhibition of response, and sequential planning. We found that, when compared to the control group, inhalant-consuming adolescents presented with important deficits in communication among brain regions that comprise the DMN, SN, and FPN networks. DMN is the most affected network by inhalant abuse during adolescence. The mediation analyses suggested that the relationship between inhalant abuse and inhibitory control and sequential planning was partly mediated by DMN efficiency.

The Abused Inhalant Toluene Impairs Medial Prefrontal Cortex Activity and Risk/Reward Decision-Making during a Probabilistic Discounting Task

Inhalant (e.g., toluene) misuse is linked to behavioral and cognitive deficits in humans, yet preclinical studies of the effect of inhalants on higher-order cognition are limited. We addressed this gap in the literature by examining the effect of toluene vapor exposure on risk/reward decision-making in male and female Sprague-Dawley rats using a probabilistic discounting task. In this task, rodents chose a risky/large reward or a safe/small reward, with the odds of risky reinforcement descending or ascending throughout the test session. We observed a dose-dependent, sex-independent deficit in behavioral flexibility during probabilistic discounting caused by acute toluene exposure. Rats exposed to toluene vapor during adolescence and tested as adults performed comparably to air-treated controls and were susceptible to the effects of an acute toluene challenge. These behavioral flexibility deficits observed suggests dysfunctional medial prefrontal cortex (mPFC) activity. To address this hypothesis, we virally expressed the genetically encoded calcium sensor GCaMP6f in glutamatergic mPFC neurons and monitored calcium transients in real-time using in vivo fiber photometry. mPFC activity peaked before either lever press during free-choice trials in toluene- and air-treated animals. During forced-choice trials, GCaMP6f transients shifted from pre-risky to pre-safe choice, an effect mitigated by acute toluene exposure. mPFC activity decreased during rewarded trials, with larger decreases following risky/large wins compared with safe/small wins. Toluene-treated animals also had decreased mPFC activity during rewarded trials, but there was no distinction between risky/large wins and safe/small wins. These results provide physiological evidence for mPFC-dependent behavioral deficits caused by toluene.SIGNIFICANCE STATEMENT Inhalants (e.g., toluene) are an understudied class of drugs of abuse that cause devastating behavioral and cognitive deficits in humans. Understanding the neurobiological interactions of toluene vapor using animal models is important for developing effective treatment strategies for inhalant addicts. Here we find that toluene vapor reduces behavioral flexibility in rodents making risk/reward-based decisions. The medial prefrontal cortex (mPFC) drives behavioral flexibility during this type of decision-making and we show that toluene reduces the ability of mPFC neurons to track optimal choices as reward probabilities change. Toluene also reduces these neurons' ability to distinguish between small and large rewards. A combination of these factors likely leads to the impaired performance in probabilistic discounting following acute toluene exposure.

Reducing inhalant use in Latino adolescents through synchronized parent-adolescent interventions

This article presents the effects of a synchronized Latino youth/parent intervention on adolescent inhalant use. The analytic sample included only Latino adolescents (n = 487) between the ages of 12 and 14. Randomized at the school-level, the design included three possible conditions: (1) child and parent received the prevention interventions, (2) only the parent received the prevention intervention, (3) neither child or parent received the prevention interventions. Drawing from the eco-developmental perspective, the overall hypothesis was that youth randomly assigned to the condition with both interventions will report the strongest inhalant use prevention outcomes. Descriptive statistics and regression tests of significant group differences by treatment condition confirmed the overall hypothesis. Children receiving the youth intervention and whose parents received the synchronized parenting intervention reported the strongest desired inhalant prevention effects. The findings are interpreted from an eco-developmental perspective and implications for practice, policy, and future research are discussed.

Neuropsychiatric characterization of individuals with inhalant use disorder and polysubstance use according to latent profiles of executive functioning

BACKGROUND

Inhalant use disorder (IUD) is associated with deficits in executive functions (EFs). We described latent profiles of EFs and distribution of neuropsychiatric disorders and patterns of severity of use across these profiles.

METHODS

Individuals with IUD were recruited at community-based residential facilities for substance use treatment in Mexico City. Latent profile analysis was conducted with the following tasks: self-ordered pointing, Stroop, Iowa gambling, Wisconsin Card Sorting and Tower of Hanoi.

RESULTS

Three latent profiles were extracted from n = 165: lowest performances of inhibition of response and processing speed; lowest performance of self-monitoring, intermediate performance of inhibition of response and relatively spared processing speed; and intermediate performance of processing speed and self-monitoring, and relatively spared inhibition of response.

CONCLUSION

Between-group differences were observed mainly for antisocial personality disorder and lifetime suicidal. Findings remark the need for identifying distinct profiles of EFs within these populations to better understand the transdiagnostic heterogeneity of EFs.

Adolescent brain cognitive development (ABCD) study: Overview of substance use assessment methods

One of the objectives of the Adolescent Brain Cognitive Development (ABCD) Study (https://abcdstudy.org/) is to establish a national longitudinal cohort of 9 and 10 year olds that will be followed for 10 years in order to prospectively study the risk and protective factors influencing substance use and its consequences, examine the impact of substance use on neurocognitive, health and psychosocial outcomes, and to understand the relationship between substance use and psychopathology. This article provides an overview of the ABCD Study Substance Use Workgroup, provides the goals for the workgroup, rationale for the substance use battery, and includes details on the substance use module methods and measurement tools used during baseline, 6-month and 1-year follow-up assessment time-points. Prospective, longitudinal assessment of these substance use domains over a period of ten years in a nationwide sample of youth presents an unprecedented opportunity to further understand the timing and interactive relationships between substance use and neurocognitive, health, and psychopathology outcomes in youth living in the United States.

Inhalant use in adolescents in northern Russia

PURPOSE

To determine the prevalence of inhalant use in Russian adolescents and to investigate associated psychosocial problems from a gender perspective.

METHODS

Data on inhalant use and comorbid psychopathology were collected by means of self-reports from 2892 (42.4% boys) sixth to tenth grade students in public schools in Arkhangelsk, Russia. Multivariate analysis of covariance was used to assess differences in the levels of internalizing and externalizing problems in boys and girls, who were non-users and users of inhalants.

RESULTS

The prevalence of inhalant use was 6.1% among boys and 3.4% among girls. Compared with non-users, inhalant users scored significantly higher on internalizing and externalizing problems, functional impairment and lower on academic motivation, with psychopathology increasing with age. While there were no gender differences for internalizing problems, increased levels of externalizing problems in inhalant users were gender-specific (significantly higher in boys).

CONCLUSIONS

Inhalant use is related to significantly higher levels of comorbid psychopathology in Russian adolescents. Comprehensive, evidence-based prevention and intervention policies are needed to address inhalant use and its harmful effects.

Inhalant Use and Mental Health Problems in Russian Juvenile Delinquents

BACKGROUND

Inhalant use by children and adolescents has been linked to an increased risk of multiple drug use, mental health problems and antisocial behavior.

OBJECTIVES

The purpose of this study was to examine the association between the frequency of inhalant use and psychiatric diagnoses among incarcerated delinquent youths in Russia.

METHODS

A total of 370 incarcerated delinquents from a juvenile correction center in Northern Russia were assessed by means of a semi-structured psychiatric interview and by self-reports.

RESULTS

Compared to non-users (N = 266), inhalant users (N = 104) reported higher rates of PTSD, early onset conduct disorder, ADHD, alcohol abuse and dependence, as well as higher levels of antisocial behavior, impulsiveness and more psychopathic traits. Frequent inhalant users also reported the highest rates of co-occurring psychopathology.

CONCLUSIONS

Our findings suggest that inhalant use in delinquents is frequent and may require additional clinical measures to address the issue of psychiatric comorbidity.

Approach Behaviour, Stress and Substance Use in Young Adults

We investigated the interaction between approach behaviours (measured through performance on a resource-gathering task) and self-reported global life stress to predict substance use. Our hypothesis that high levels of approach behaviour in combination with high life stress would predict elevated substance use was guided by the reinforcement sensitivity theory (Gray & McNaughton, ). Ninety-three young adult students (61 women and 32 men) completed a computerized resource-gathering task and questionnaires assessing global life stress and substance use. Consistent with the hypothesis, approach behaviour was positively related to substance use for individuals with high life stress. The findings suggest that person by environment interactions are useful in understanding substance use and we discuss how approach-motivated individuals may arrive at different substance use outcomes as a function of stressful contexts. Copyright © 2016 John Wiley & Sons, Ltd.

Effectiveness of Inhalant Abuse Legislation

BACKGROUND

Since peaking in the 1990s, inhalant abuse has steadily decreased over the past two decades. Concurrently, nearly every state has passed legislation aimed at minimizing inhalant abuse. While males have historically been more likely to abuse inhalants than females, there is no longer a sex effect in self-reported rates of inhalant abuse.

OBJECTIVES

The objective of the present study is to evaluate the effect of anti-inhalant abuse legislation on self-reported rates of inhalant abuse, in high school age males and females.

METHODS

Beginning in 1993, the CDC's biannual Youth Risk Behavior Surveillance Survey asked respondents if they have ever used inhalants to get high. Data from these surveys were collected, along with the date of passage of anti-inhalant abuse legislation in 46 of 50 states. ANOVAs were conducted to assess the effect of legislation on self-reported inhalant abuse rates.

RESULTS

There were no significant main effects or interactions that demonstrated that inhalant abuse rates decreased in males or females following passage of legislation aimed at decreasing inhalant abuse. Conclusion/Importance: To date, 46 of 50 states have passed laws aimed at minimizing inhalant abuse, and while inhalant abuse rates have been decreasing for the past two decades, there is no evidence that this decline is related to enactment of these laws. Further research is needed to determine the cause of the decrease in inhalant abuse. The laws may benefit from amendments to include options for treatment.

Serial neuropsychological assessment of an adolescent girl after suffering a sudden out-of-hospital-cardiac-arrest following recreational inhalant use

Sudden out-of-hospital-cardiac-arrest (OHCA) following recreational inhalant use is well documented in the literature. The present case study reports the long-term neuropsychological sequelae of a 14-year-old girl who suffered an OHCA secondary to recreational butane gas inhalation. The patient was assessed on day-13 as an inpatient, and again at 3- and 12-month outpatient follow-ups. Acutely the patient demonstrated significant impairment on tasks associated with verbal and non-verbal memory and executive functioning. Re-testing at 3-months post-acute state suggested improved executive and non-verbal functions while showing continued deficits in verbal memory. At 12-months she was cognitively performing at levels expected for her age. This case is reported for its rarity in successfully being able to track the patient's clinical course from hospital discharge to the successful reintegration back into school and community settings.

Patterns of substance use, delinquency, and risk factors among adolescent inhalant users

BACKGROUND

Despite insidious effects, use of inhalant substances by adolescents remains an understudied phenomenon.

OBJECTIVE

This research was designed to identify patterns of past year substance use and delinquency among adolescent inhalant users.

METHOD

The study used a sample of adolescent inhalant users (ages ranged from 12-17 years, n = 7,476) taken from a pooled sample of the 2002 through 2012 National Survey of Drug Use and Health (NSDUH). Three-step latent class analyses were conducted with past year substance use and delinquency behaviors as class indicators. Demographic and social covariates were included in the analyses.

RESULTS

Analyses yielded a six-class solution comprised of classes of users characterized by low substance use/low delinquency, high substance use/low delinquency, low substance use/fighting, cigarettes/alcohol/marijuana, high substance use/high delinquency, and cigarettes/alcohol/ marijuana/opioids/moderate delinquency.

CONCLUSIONS

Findings provide insight into the taxonomy of adolescent inhalant user heterogeneity, and may inform future efforts at detection and prevention of inhalant use by suggesting warning signs of co-occurring externalizing behaviors and possible indications of underlying internalized issues.

A signal detection analysis of executive control performance among adolescent inhalant and cannabis users

BACKGROUND

Inhalant users have multiple comorbid issues (e.g., polydrug use) that complicate identifying inhalant-specific cognitive deficits.

OBJECTIVES

The aim of the present study was to use signal detection theory to identify inhalant-specific differences in executive control.

METHODS

We examined three well-matched groups: 19 inhalant users, 19 cannabis users, and 19 controls using Stroop and Go/No-Go tasks.

RESULTS

Inhalant users demonstrated significantly lower d-prime scores relative to controls, but not cannabis users, on both tasks, suggesting possible executive deficits relative to controls. CONCLUSIONS/IMPORTANCE: The results of this study raise questions regarding inhalant toxicity and the vulnerability of the adolescent brain to drugs of abuse.