Volatile substance misuse among high school students in South America

Repeated toluene and cyclohexane inhalation produces differential effects on HPA and HPT axes in adolescent male rats

Misused volatile solvents typically contain toluene (TOL) as the main psychoactive ingredient. Cyclohexane (CHX) can also be present and is considered a safer alternative. Solvent misuse often occurs at early stages of life, leading to permanent neurobehavioral impairment and growth retardation. However, a comprehensive examination of the effects of TOL and CHX on stress regulation and energy balance is lacking. Here, we compared the effect of a binge-pattern exposure to TOL or CHX (4,000 or 8,000 ppm) on body weight, food intake, the hypothalamus-pituitary-adrenal (HPA) and hypothalamus-pituitary-thyroid (HPT) axes in male adolescent Wistar rats. At 8,000 ppm, TOL decreased body weight gain without affecting food intake. In addition, TOL and CHX altered the HPA and HPT axes' function in a solvent- and concentration-dependent manner. The highest TOL concentration produced HPA axis hyperactivation in animals not subjected to stress, which was evidenced by increased corticotropin-releasing-factor (CRF) release from the median eminence (ME), elevated adrenocorticotropin hormone (ACTH) and corticosterone serum levels, and decreased CRF mRNA levels in the hypothalamic paraventricular nucleus (PVN). TOL (8,000 ppm) also increased triiodothyronine (T3) serum levels, decreased pro-thyrotropin-releasing-hormone (pro-TRH) mRNA transcription in the PVN, pro-TRH content in the ME, and serum thyroid stimulating hormone (TSH) levels. CHX did not affect the HPA axis. We propose that the increased HPT axis activity induced by TOL can be related to the impaired body weight gain associated with inhalant misuse. These findings may contribute to a better understanding of the effects of the misused solvents TOL and CHX.

Minocycline prevents neuronal hyperexcitability and neuroinflammation in medial prefrontal cortex, as well as memory impairment caused by repeated toluene inhalation in adolescent rats

Toluene can be intentionally misused by adolescents to experience psychoactive effects. Toluene has a complex mechanism of action and broad behavioral effects, among which memory impairment is reported consistently. We have previously reported that repeated toluene inhalation (8000 ppm) increases layer 5 prelimbic pyramidal cells' excitability in the medial prefrontal cortex (mPFC) of adolescent rats. Toluene also produces reactive oxygen species (ROS), which activate glial cells. Here, we tested the hypothesis that the anti-inflammatory agent minocycline would decrease toluene's effects because it inhibits NF-κB (nuclear factor enhancer of the kappa light chains of activated B cells) and reduces pro-inflammatory cytokine and ROS production. Our results show that minocycline (50 mg/kg, ip, for 10 days) prevents the hyperexcitability of mPFC neurons observed after repeated 8000 ppm toluene exposure (30 min/day, 2×/day for 10 days). Minocycline prevents toluene-induced hyperexcitability by a mechanism that averts the loss of the slow calcium-dependent potassium current, and normalizes mPFC neurons' firing frequency. These effects are accompanied by significant decreased expression of astrocytes and activated microglia in the mPFC, reduced NLRP3 inflammasome activation and mRNA expression levels of the pro-inflammatory cytokine interleukin 1β (IL-1β), as well as increased mRNA expression of the anti-inflammatory cytokine transforming growth factor β (TGF-β). Minocycline also prevents toluene-induced memory impairment in adolescent rats in the passive avoidance task and the temporal order memory test in which the mPFC plays a central role. These results show that neuroinflammation produces several effects of repeated toluene administration at high concentrations, and minocycline can significantly prevent them.

Cannabis and amphetamine use and socio-ecological (proximal and distal) factors among school-going adolescents in four countries in the Caribbean and four countries in South America

The study aimed to assess the prevalence of cannabis and amphetamine use and socio-ecological (proximal and distal) factors among adolescents in eight countries of the Americas. We analysed cross-sectional survey data from 44,904 adolescents [mean age 14.6 years, standard deviation (SD) = 1.4] from Argentina, The Bahamas, Barbados, Belize, Bolivia, Chile, Peru and Trinidad and Tobago that participated in the Global School-Based Student Health Survey (GSHS) in 2011-2013. The prevalence of the past month's cannabis use was 8.3% and lifetime amphetamine use was 3.0%. In adjusted mixed-effects logistic regression analysis older age, male gender, personal attributes (anxiety, suicidal ideation, current tobacco use, current alcohol use, school truancy and sexual risk behaviour) and environmental stressors (having been in a physical fight, hunger, being bullied) were positively and parental support and peer support were negatively associated with the past month's cannabis and/or lifetime amphetamine use. Measures to prevent and control cannabis and amphetamine use in this adolescent population should include personal attributes (mental health, substance use, school truancy and sexual risk behaviour), environmental stressors and parental and peer support.

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.

Binge drinking and illicit drug use among adolescent students

OBJECTIVE

To estimate the prevalence of illicit drug use and its association with binge drinking and sociodemographic factors among adolescent students.

METHODS

This is a cross-sectional study with probabilistic conglomerate sampling, involving 1,154 students, aged 13 to 19 years old, from the public school system, in the city of Olinda, State of Pernambuco, Brazil, carried out in 2014. We used the Youth Risk Behavior Survey questionnaire, validated for use with Brazilian adolescents. The Chi-square test (≤ 0.05) and Poisson regression analysis were used to estimate the prevalence ratios, with 95% confidence intervals.

RESULTS

Use in life of illicit drugs was four times more prevalent among students who reported binge drinking (95%CI 3.19-5.45). Being in the age group of 16 to 19 years, being male, and having no religion were also significantly associated with illicit drug use.

CONCLUSIONS

The prevalence of use in life of illicit drugs was higher in this study than in other studies carried out in Brazil and it was strongly associated with binge drinking. This factor was associated with gender, age, and religion.

OBJETIVO

Estimar a prevalência do uso de drogas ilícitas e sua associação com binge drinking e fatores sociodemográficos entre estudantes adolescentes.

MÉTODOS

Estudo transversal com amostra probabilística por conglomerado, envolvendo 1.154 estudantes, de 13 a 19 anos de idade, da rede pública de ensino, no município de Olinda, PE, 2014. Foi utilizado o questionário Youth Risk Behavior Survey, validado para uso com adolescentes brasileiros. Para análise dos dados foi utilizado o teste do Qui-quadrado (≤ 0,05) e análise de regressão de Poisson, para estimar razões de prevalência, com intervalos com 95% de confiança.

RESULTADOS

O uso na vida de drogas ilícitas foi quatro vezes mais prevalente entre os estudantes que relataram o binge drinking (IC95% 3,19-5,45). Estar na faixa etária de 16 a 19 anos, ser do sexo masculino e não ter religião também foram significativamente associados ao uso de drogas ilícitas.

CONCLUSÕES

A prevalência do uso de drogas ilícitas na vida foi superior a outros estudos realizados no Brasil e esteve fortemente associado ao binge drinking. Esse fator mostrou associação com gênero, idade e religião.

Inhalant Abuse and Dextromethorphan

Inhalant abuse is the intentional inhalation of a volatile substance for the purpose of achieving an altered mental state. As an important, yet underrecognized form of substance abuse, inhalant abuse crosses all demographic, ethnic, and socioeconomic boundaries, causing significant morbidity and mortality in school-aged and older children. This review presents current perspectives on epidemiology, detection, and clinical challenges of inhalant abuse and offers advice regarding the medical and mental health providers' roles in the prevention and management of this substance abuse problem. Also discussed is the misuse of a specific "over-the-counter" dissociative, dextromethorphan.

Preclinical characterization of toluene as a non-classical hallucinogen drug in rats: participation of 5-HT, dopamine and glutamate systems

RATIONALE

Toluene is a misused inhalant with hallucinogenic properties and complex effects. Toluene blocks N-methyl-D-aspartate (NMDA) receptors, releases dopamine (DA), and modifies several neurotransmitter levels; nonetheless, the mechanism by which it produces hallucinations is not well characterized.

OBJECTIVES

This study aims (a) to study toluene's effects on the 5-HT2A-mediated head-twitch response (HTR), dopamine (DA), and serotonin (5-HT) tissue levels in discrete brain regions; (b) to compare the actions of toluene, ketamine, and 1-[2,5-dimethoxy-4-iodophenyl]-2-aminopropane (DOI) on HTR; and (c) to study the pharmacological blockade of toluene's and ketamine's effects by selective drugs.

METHODS

Independent groups of rats inhaled toluene (500-12,000 ppm) for 30 min during which the occurrence of serotonergic signs was analyzed. Brains were obtained after exposure to determine DA and 5-HT levels by HPLC.

RESULTS

Toluene concentration-dependently induced HTR. Other serotonin syndrome signs were evident at high concentrations. Toluene (4000 and 8000 ppm), and ketamine (3 and 10 mg/kg), significantly increased 5-HT levels in the frontal cortex (FC) striatum, hippocampus, and brain stem, as well as DA levels in the striatum and FC. Pretreatment with ketanserin (5HT2A/2C receptor antagonist), M100907 (selective 5-HT2A receptor antagonist), D-serine (co-agonist of the NMDA receptor glycine site), and haloperidol (D2 receptor antagonist) significantly decreased toluene's and ketamine's actions. The 5HT1A receptor antagonist WAY100635 had no effect.

CONCLUSION

Toluene stimulates 5HT2A and 5HT2C receptors, and increases 5-HT and DA levels. These actions are similar to those produced by ketamine and involve activation of a complex neurotransmitter network that includes NMDA receptor antagonism.

Effects of lifetime tobacco, alcohol and drug use on psychological and behavioral problems among 10th grade students in Istanbul

AIMS

The aim of this study was to determine the effects of life-time tobacco, alcohol, and substance use on psychological and behavioral variables among 10th grade students in Istanbul/Turkey.

MATERIALS AND METHODS

This study employed a cross-sectional online self-report survey conducted in 45 schools from the 15 districts in Istanbul. The questionnaire featured a section about use of substances, including tobacco, alcohol, and drugs. The depression, anxiety, anger, assertiveness, sensation seeking and impulsiveness subscales of the Psychological Screening Test for Adolescents (PSTA) were used. The analyses were conducted based on 4957 subjects.

RESULTS

Logistic regression analyses were conducted with each school with the related and behavioral variables as the dependent variables. Gender, tobacco, alcohol, and drug use being the independent variables. All four independent variables predicted the dependent variables. Lifetime tobacco and drug use had significant effects on all the subscale score, whereas lifetime alcohol use had significant effects on all the subscale scores other than lack of assertiveness, and male gender was a significant covariant for all the subscale scores. Drug use showed the highest effect on dependent variables. Interaction was found between effects of tobacco and alcohol on anxiety, whereas interactions were found between effects of tobacco and drugs on lack of assertiveness and impulsiveness.

CONCLUSION

The findings suggested that male students with lifetime tobacco, alcohol or drug use have particularly high risk of psychological and behavioral problems. The unique effects of substance clusters on these problems may be useful in developing secondary preventive practices for substance use and abuse problems in Istanbul.

The role of first use of inhalants within sequencing pattern of first use of drugs among Brazilian university students

The present study investigated the role of first use of inhalants within a first drug sequencing pattern. In a representative sample of university students from 27 Brazilian capitals (n = 12,711), we analyzed the patterns of transition from/to first use of inhalants to/from the first use of alcohol, tobacco, cannabis, cocaine, hallucinogens, ecstasy, amphetamines, prescription opioids, and tranquilizers. Cox proportional hazards models were used to analyze data. Drugs that were not specified as the pair of drugs tested in each model were included as time-varying covariates in all models. In this sample, first use of inhalants was preceded only by the first use of alcohol and tobacco. However, first use of inhalants preceded first use of cannabis, amphetamines, cocaine, and tranquilizers. First use of inhalants preceded the first use of prescription opioids, and vice versa. This study highlights the need to intervene early with youths who are at risk of or just beginning to use inhalants, because this class of drugs seems to be the first illegal drug in Brazil to be experimented by respondents in our sample. There is also a call for attention to individuals who have already first used inhalants because of their higher chance to experiment with other drugs such as cannabis, cocaine, and prescription drugs. All these findings show an in-transition culture of drug use, which should be tracked through time, because some classical models (i.e., gateway model) might be outdated and might also not fit within different settings.

Profile of inhalant users seeking treatment at a de-addiction centre in north India

BACKGROUND & OBJECTIVES

Inhalants are substances whose chemical vapors are inhaled to produce euphoric, disinhibiting, and exciting effects. Data on inhalant abuse in India are relatively scarce. We report the demographic and clinical profile of inhalant users among the treatment seekers at a Drug De-addiction and Treatment Centre in north India.

METHODS

The records of treatment seekers at the Drug De-addiction and Treatment Centre, over 10 years (2002-2011) were scanned to identify 92 cases reporting inhalant use. Of these 92 cases, the complete record files were available for 87 (94.6%) cases. These case files were reviewed and the relevant data were collected and analyzed.

RESULTS

Over the study period of 10 years, the number of cases with inhalant abuse per year rose steadily to peak at 20 cases (4.08% of new cases) in 2006 and then stabilized at 1-3 per cent of new cases annually. Of the 87 cases studied, all were males with a mean age of 18.9±4.12 yr, mean education of 9.8±3.42 yr and mean family income of Rs. 7676±7343.15 (median: Rs. 5000). Majority of subjects were unmarried (89.7%), urban resident (79.3%), and from a nuclear family (78.2%). About half of the subjects were students (50.6%). The most common inhalant used was typewriter correction fluid (73.6%) followed by typewriter diluent fluid (19.5%) and glue (6.9%). The most common reason for initiation was curiosity. The mean age of onset of inhalant use was 16.3±4.22 yr. Most subjects fulfilled the criteria for inhalant dependence (85.1%). Psychiatric co-morbidity and the family history of substance dependence were present in 26.4 and 32.9 per cent subjects, respectively. Majority of the subjects reported drug related problems, occupation and finance being the worst affected. Interpretations & conclusions: Our results showed that the inhalant users were mostly urban youth belonging to middle socio-economic class families. The principal sources of inhalant abuse were the commonly available substances like typewriter correction fluids and majority of the subjects initiated it out of curiosity. Nearly three-fourth of the subjects used some other substance of abuse in addition, tobacco being the most common. In view of associated drug related problems, there is a need for strategies to prevent this emerging health care problem.

Use transition between illegal drugs among Brazilian university students

PURPOSE

The aim of the present study was to test whether the first use of an illicit drug increases the chance of first use of other illicit drugs.

METHOD

The transitions from the first use of a drug to the first use of another drug were analyzed. Comparisons were made between first drug users and non-users. Survival analysis methods were used to compare the cumulative probability of second drug use after adjusting for socio-demographic covariates and the intermediate use of alcohol and/or tobacco. A total of 12,721 Brazilian university students participated in this study.

RESULTS

Inhalants and marijuana were used prior to the use of several other drugs, whereas the opposite pattern was not found. Ecstasy was used before other drugs in several instances. Other well-examined drugs, such as amphetamines, cocaine and hallucinogens, were used both before and after other illicit drugs without any marked predominance for either of the two roles.

CONCLUSIONS

This study supports the role of the use of marijuana and inhalants almost exclusively before the use of other illicit drugs, whereas the use of ecstasy has an opposite role. These roles could be linked to the prevalence of lifetime use and whether individuals were at an earlier or later age during experimentation.

Volatile solvents as drugs of abuse: focus on the cortico-mesolimbic circuitry

Volatile solvents such as those found in fuels, paints, and thinners are found throughout the world and are used in a variety of industrial applications. However, these compounds are also often intentionally inhaled at high concentrations to produce intoxication. While solvent use has been recognized as a potential drug problem for many years, research on the sites and mechanisms of action of these compounds lags behind that of other drugs of abuse. In this review, we first discuss the epidemiology of voluntary solvent use throughout the world and then consider what is known about their basic pharmacology and how this may explain their use as drugs of abuse. We next present data from preclinical and clinical studies indicating that these substances induce common addiction sequelae such as dependence, withdrawal, and cognitive impairments. We describe how toluene, the most commonly studied psychoactive volatile solvent, alters synaptic transmission in key brain circuits such as the mesolimbic dopamine system and medial prefrontal cortex (mPFC) that are thought to underlie addiction pathology. Finally, we make the case that activity in mPFC circuits is a critical regulator of the mesolimbic dopamine system's ability to respond to volatile solvents like toluene. Overall, this review provides evidence that volatile solvents have high abuse liability because of their selective effects on critical nodes of the addiction neurocircuitry, and underscores the need for more research into how these compounds induce adaptations in neural circuits that underlie addiction pathology.

Volatile substance misuse : clinical considerations, neuropsychopharmacology and potential role of pharmacotherapy in management

Volatile substance misuse is among the most prevalent and toxic forms of psychoactive drug use, and often results in highly deleterious social, psychological and medical consequences. The prevalence of this pernicious form of substance misuse owes in part to the fact that volatile substances of misuse are ubiquitous in the natural environment. Commonly misused commercial products include glue, shoe polish, nail polish remover, butane lighter fluid, gasoline and computer duster spray. National samples of volatile substance misusers tend to exhibit high rates of psychiatric problems and antisocial behaviour. In addition, cognitive impairments and affective dysregulation are often observed among these individuals. Volatile substances exert their complex neuropharmacological effects on dopaminergic, glutamatergic, GABAergic and serotoninergic receptor systems, as well as on cell membranes and ion channels. Concomitantly, pharmacotherapies for volatile substance abuse might profitably target a number of mechanisms, including reward circuitry in the brain, symptoms of craving and withdrawal, neuropsychiatric and emotional impairments that promote volatile substance abuse, and cognitive enhancement to rectify deficits in executive function. This review details the modes of use, subjective effects, epidemiology, adverse consequences, neuropsychopharmacology and drug treatment of volatile substance misuse, and discusses the potential role of novel forms of pharmacological intervention for this oft-overlooked public health threat of epidemic proportions.

Inhalant abuse: An exploratory study

BACKGROUND

Inhalants are being abused by large numbers of people throughout the world, particularly children and adolescents. It is also an often overlooked form of ubstance abuse in adolescents.

AIMS

The current study explored the inhalant abuse among adolescents seeking treatment from a tertiary care drug de-addiction clinic.

SETTINGS AND DESIGN

The study was conducted at a tertiary level multispecialty hospital.

MATERIALS AND METHODS

The current study was a chart review of the cases with inhalant abuse/dependence presenting to the clinic over a 1-year period. All the treatment records of the de-addiction clinic were reviewed, and information was gathered regarding patients with inhalant abuse/dependence.

STATISTICAL ANALYSIS

Descriptive statistics with frequency distribution was carried out by using SPSS version 10.0.

RESULTS

The mean age of the subjects was 16.24 years (SD±1.9 years; range 12-18 years). Twenty-two percent of the subjects were illiterate. Forty percent of the adolescents had a family history of alcohol use problems and 48% that of tobacco use. The mean age of the initiation of inhalant use was 11.6 years (SD±2.17 years). It varied from 9 to 18 years. Forty percent of the adolescents had made a previous abstinence attempt.

CONCLUSIONS

The findings provide important information on an underresearched area in psychiatry.