Who are the new amphetamine users? A 10-year prospective study of young Australians

Understanding the complexity, patterns, and correlates of alcohol and other substance use among young people seeking help for mental ill-health

PURPOSE

Use of alcohol and other substances is a multifaceted issue impacting young people across multiple life domains. This paper aims to elucidate patterns of substance use and associated demographic and clinical factors among young people seeking treatment for their mental health.

METHODS

Young people (12-25 years old) were recruited from five youth-specific primary mental health ("headspace") services in Australia. Self-reported substance use and harms in the past 3 months were measured using WHO-ASSIST. Network analyses were conducted to evaluate interrelationships between use and harms associated with different substances. Subgroups were then identified based on whether participants reported using high centrality substances, and associated demographic and clinical factors were assessed with multinomial logistic regression.

RESULTS

1107 youth participated. 70% reported use of at least one substance in the past 3 months, with around 30% of those reporting related health, social, legal or financial problems. Network analysis highlighted substantial interconnections between use and harm indicators for all substances, with amphetamine-type stimulants (ATS) and cannabis being high central substances. Higher levels of substance use and harms were reported in subgroups with ATS or cannabis use and different risk factors were associated with these subgroups.

CONCLUSIONS

Findings highlight the importance of screening for substance use in youth primary mental healthcare settings, offering a key opportunity for early intervention. Clinicians should be aware of the inner connections of use and harms of different drugs and the role of cannabis and amphetamine use as a marker for more substance use profiles.

Substance Use, Health, and Adverse Life Events amongst Amphetamine-Type Stimulant Users in North East England: A Cross-Sectional Study

Amphetamine-type stimulants (ATS) are the second most commonly used class of illicit drugs globally, yet there is limited understanding of which factors contribute to different pathways of ATS use. We sought to compare current, former, and exposed non-ATS users’ substance use, mental/physical health, and adverse life experiences. A cross-sectional survey, using computer-assisted personal interview software, was conducted between June 2018 and March 2019 in North East England. Quota-based sampling was used to recruit 389 individuals (aged 18 to 68; 52.6% male): 137 current ATS users; 174 former users; and 78 exposed non-users. Standardized screening questionnaires captured current/prior substance use. Participants self-reported diagnoses of selected physical and mental health disorders and specific adverse life experiences. Analysis used descriptive statistics and comparative tests (including chi-square, Kruskal–Wallis and Mann–Whitney U). Early exposure to illicit substances, challenging mental health, and certain adverse life experiences (such as growing up in statutory care) were more common in individuals currently using ATS compared to those who had never used or stopped using stimulants. Multi-level interventions are needed that address the mental health, social, and economic needs of people with dependent drug use. These could include targeted efforts to support children growing up under care, integrated mental health and substance use support, and joined-up substance use interventions reflective of wider structural factors.

Adolescent cocaine differentially impacts psychomotor sensitization and epigenetic profiles in adult male rats with divergent affective phenotypes

Adolescent drug use reliably predicts increased addiction liability in adulthood, but not all individuals are equally impacted. To explore the biological bases of this differential reactivity to early life drug experience, we used a genetic rat model of temperament and evaluated the impact of adolescent cocaine exposure on adult psychomotor sensitization. Relative to adult bred low-responder (bLR) rats, bred high-responders (bHR) are more sensitive to the psychomotor-activating effects of cocaine and reinstate drug-seeking behavior more readily following prolonged cocaine exposure and/or abstinence. We found that a 7-day sensitizing cocaine regimen (15 mg/kg/day) during either adolescence or adulthood produced psychomotor sensitization in bHRs only, while a dual cocaine exposure prevented further sensitization, suggesting limits on neuroplasticity. By contrast, adolescent cocaine in bLRs shifted their resilient phenotype, rendering them more responsive to cocaine in adulthood following adolescent cocaine. To begin to explore the neural correlates of these behavioral phenotypes, we assessed two functionally opposite epigenetic chromatin modifications implicated in addiction liability, permissive acetylation (ac) and repressive tri-methylation (me3) on Histone 3 Lysine 9 (H3K9), in four striatal sub-regions. In bHRs, decreased H3K9me3 and increased acH3K9 in the nucleus accumbens (NAc) core associated with cocaine sensitization. In bLRs, the combination of cocaine exposure in adolescence and adulthood, which lead to an increased response to a cocaine challenge, also increased acH3K9 in the core. Thus, adolescent cocaine experience interacts with genetic background to elicit different behavioral profiles relevant to addiction in adulthood, with concurrent modifications in the epigenetic histone profiles in the NAc that associate with cocaine sensitization and with metaplasticity.

Beyond the tip of the iceberg: A narrative review to identify research gaps on comorbid psychiatric disorders in adolescents with methamphetamine use disorder or chronic methamphetamine use

BACKGROUND

Methamphetamine use disorder (MUD) frequently begins in adolescence, often accompanied by other psychiatric or mental disorders. Up to now, no comprehensive review about MUD and comorbid disorders in adolescents is available. We thus aimed to review the literature on comorbid mental disorders and MUD in adolescents in order to identify future research topics. Method: A PubMed search was conducted in July 2019. Relevant comorbidities were defined as attention-deficit disorder with/without hyperactivity, anxiety disorders, depression, eating disorders, post-traumatic stress disorder, psychosis, borderline personality disorder, conduct disorder and antisocial personality disorder, as well as other substance use disorders. For each comorbidity, we summarized prevalence rates, findings on comorbidity mechanisms, and recommended treatment options, if applicable. Results: Few articles focused on MUD in adolescents. Prevalence rates differed largely between comorbid disorders, with tobacco use disorder, conduct disorder, post-traumatic stress disorder, anxiety disorders, and attention-deficit disorders being the most prevalent comorbidities while eating disorders were rare. Examined onset patterns and comorbidity mechanisms indicated three groups of comorbidities: preexisting disorders self-medicated with methamphetamine, disorders induced by chronic methamphetamine use, and disorders arising due to risk factors shared with MUD. Reviewed comorbidities were frequently associated with worse treatment outcomes. Conclusions: The limited evidence is in stark contrast to the presumably high prevalence and relevance of comorbid mental disorders in adolescents with MUD. Suggestions for future research topics, informed by adult findings, include genetic vulnerabilities, biological changes, and consequences of different use patterns. Surprisingly few MUD treatment programs explicitly integrate comorbid mental disorder modules.

Effects of Methamphetamine Exposure on Fear Learning and Memory in Adult and Adolescent Rats

Methamphetamine (meth) use is often comorbid with anxiety disorders, with both conditions predominant during adolescence. Conditioned fear extinction is the most widely used model to study the fear learning and regulation that are relevant for anxiety disorders. The present study investigates how meth binge injections or meth self-administration affect subsequent fear conditioning, extinction and retrieval in adult and adolescent rats. In experiment 1, postnatal day 35 (P35-adolescent) and P70 (adult) rats were intraperitoneally injected with increasing doses of meth across 9 days. At P50 or P85, they underwent fear conditioning followed by extinction and test. In experiments 2a-c, P35 or P70 rats self-administered meth for 11 days then received fear conditioning at P50 or P85, followed by extinction and test. We observed that meth binge exposure caused a significant disruption of extinction retrieval in adult but not adolescent rats. Interestingly, meth self-administration in adolescence or adulthood disrupted acquisition of conditioned freezing in adulthood. Meth self-administration in adolescence did not affect conditioned freezing in adolescence. These results suggest that intraperitoneal injections of high doses of meth and meth self-administration have dissociated effects on fear conditioning and extinction during adulthood, while adolescent fear conditioning and extinction are unaffected.

Amphetamine use in the fourth decade of life: Social profiles from a population-based Australian cohort

INTRODUCTION AND AIMS

To estimate the prevalence and frequency of amphetamine use in a cohort of Australians aged in their mid-30s.

DESIGN AND METHODS

Cross-sectional analysis of wave 10 data collected in 2014 from the Victorian Adolescent Health Cohort Study: a sample of 1435 persons originally selected in a stratified, random community survey of secondary school students from the state of Victoria that commenced in 1992. Weighted multinomial regression models were used to evaluate the social, health and other substance-use correlates of lifetime and current (12-month) amphetamine use and current frequency of use.

RESULTS

Lifetime amphetamine use was reported by 23.2% (95% confidence interval 21.0-25.5%) of respondents, and 6.5% (95% confidence interval 5.2-7.8%) reported current (12-month) use. A quarter (26%) of those currently using amphetamines, 1.7% (95% confidence interval 1.0-2.4%) of all respondents, reported frequent (at least weekly) use. Men reported greater amphetamine use than women. Current amphetamine use was associated with disrupted family circumstances, socioeconomic adversity, polydrug use and high levels of drug use within the social and familial environment. Frequent use was associated with greater likelihood of multiple adversity, unemployment, anxiety disorders and use of mental health services.

DISCUSSION AND CONCLUSIONS

The current results show that lifetime, current and frequent amphetamine use was common amongst adults in the fourth decade of life in this cohort, and associated with the experience of social disadvantage, poor mental health and living in a social context in which drug use is the norm.

Adolescence and Reward: Making Sense of Neural and Behavioral Changes Amid the Chaos

Adolescence is a time of significant neural and behavioral change with remarkable development in social, emotional, and cognitive skills. It is also a time of increased exploration and risk-taking (e.g., drug use). Many of these changes are thought to be the result of increased reward-value coupled with an underdeveloped inhibitory control, and thus a hypersensitivity to reward. Perturbations during adolescence can alter the developmental trajectory of the brain, resulting in long-term alterations in reward-associated behaviors. This review highlights recent developments in our understanding of how neural circuits, pubertal hormones, and environmental factors contribute to adolescent-typical reward-associated behaviors with a particular focus on sex differences, the medial prefrontal cortex, social reward, social isolation, and drug use. We then introduce a new approach that makes use of natural adaptations of seasonally breeding species to investigate the role of pubertal hormones in adolescent development. This research has only begun to parse out contributions of the many neural, endocrine, and environmental changes to the heightened reward sensitivity and increased vulnerability to mental health disorders that characterize this life stage.

Development and Validation of the Amphetamine-Type Stimulants Motive Questionnaire in a Clinical Population

Approximately 35.7 million people world-wide use amphetamine-type stimulants (ATS) leading to a high demand for effective treatment. Understanding the motives behind ATS use is a necessary basis for preventive and therapeutic treatment. The objective of this study is to develop the Amphetamine-Type stimulants Motive Questionnaire (AMQ) and to confirm its construct and concurrent validity in respect to the first and the latest month of ATS use based on answers of 233 patients with ATS disorders (74.2% male; mean age: 31.1 years). Confirmatory factor analyses were employed to test for the construct validity of the AMQ. Nested models of confirmatory factor analyses with increasing constraints for gender and age were estimated to test the equivalence of the factor structure in different subgroups. Independent sample t-tests were conducted to test for mean differences in the motive dimensions. A structural equation model was estimated to confirm the concurrent validity using the latent four motive factors (i.e., enhancement, coping, social, and conformity motives) as independent variables and frequency of ATS use in the first and the latest month of use as a dependent variable. The results confirmed the AMQ's four-dimensional factor structure in general, and across gender and age groups for both periods of time. Men (first month: M = 4.21, SD = 0.75; latest month: M = 3.86, SD = 0.93) use ATS more frequently due to enhancement motives than women (first month: M = 3.85, SD = 1.12; latest month: M = 3.46, SD = 1.29) at both periods of time [first month: t(77) = -2.33, p = 0.022; latest month: t(80) = -2.19, p = 0.031]. Structural equation modeling confirmed an association between coping motives and use frequency, for both periods of time (first and latest month: β = 0.32, p < 0.001), as well as between social motives and frequency of use for the latest month of use (β = 0.30, p < 0.01). To conclude, the AMQ is a valid and reliable instrument for assessing motives of ATS use in a clinical population. It can provide important insights into the motivational structure of the first and latest months of ATS use which are useful for preventive and therapeutic treatments as well as the development of abstinence skills.

Protective effects of physical exercise on MDMA-induced cognitive and mitochondrial impairment

Debate continues about the effect of 3, 4-methylenedioxymethamphetamine (MDMA) on cognitive and mitochondrial function through the CNS. It has been shown that physical exercise has an important protective effect on cellular damage and death. Therefore, we investigated the effect of physical exercise on MDMA-induced impairments of spatial learning and memory as well as MDMA effects on brain mitochondrial function in rats. Male wistar rats underwent short-term (2 weeks) or long-term (4 weeks) treadmill exercise. After completion of exercise duration, acquisition and retention of spatial memory were evaluated by Morris water maze (MWM) test. Rats were intraperitoneally (I.P) injected with MDMA (5, 10, and 15mg/kg) 30min before the first training trial in 4 training days of MWM. Different parameters of brain mitochondrial function were measured including the level of ROS production, mitochondrial membrane potential (MMP), mitochondrial swelling, mitochondrial outermembrane damage, the amount of cytochrome c release from the mitochondria, and ADP/ATP ratio. MDMA damaged the spatial learning and memory in a dose-dependent manner. Brain mitochondria isolated from the rats treated with MDMA showed significant increase in ROS formation, collapse of MMP, mitochondrial swelling, and outer membrane damage, cytochrome c release from the mitochondria, and finally increased ADP/ATP ratio. This study also found that physical exercise significantly decreased the MDMA-induced impairments of spatial learning and memory and also mitochondrial dysfunction. The results indicated that MDMA-induced neurotoxicity leads to brain mitochondrial dysfunction and subsequent oxidative stress is followed by cognitive impairments. However, physical exercise could reduce these deleterious effects of MDMA through protective effects on brain mitochondrial function.

Methamphetamine use in Central Germany: protocol for a qualitative study exploring requirements and challenges in healthcare from the professionals' perspective

INTRODUCTION

The synthetic drug methamphetamine with its high addiction potential is associated with substantial adverse health effects. In Germany, especially Central Germany, the increase in the consumption of methamphetamine has exceeded that of other illegal drugs. The treatment system and service providers are facing new challenges due to this rise in consumption. This qualitative study will explore the demand created by the increasing healthcare needs of methamphetamine-addicted persons in Central Germany, and the difficulty of rehabilitating addicted people.

METHODS AND ANALYSIS

The collection of empirical data will take place in a consecutive, two-stage process. In the first part of data collection, the experiences and perspectives of 40 professionals from numerous healthcare sectors for methamphetamine-addicted persons will be explored with the help of semistructured face-to-face interviews and probed by the research team. These findings will be discussed in 2 focus groups consisting of the participants of the face-to-face interviews; these group discussions comprise the second part of the data collection process. The interviews will be audio recorded, transcribed, and then subjected to qualitative content analysis.

ETHICS AND DISSEMINATION

All interviewees will receive comprehensive written information about the study, and sign a declaration of consent prior to the interview. The study will comply rigorously with data protection legislation. The research team has obtained the approval of the Ethical Review Committee at the Martin Luther University Halle-Wittenberg, Germany. The results of the study will be published in high-quality, peer-reviewed international journals, presented at several congresses and used to design follow-up research projects.

TRIAL REGISTRATION NUMBER

VfD_METH_MD_15_003600.

Stimulant use disorders in people with psychosis: a meta-analysis of rate and factors affecting variation

OBJECTIVE

Stimulant abuse and dependence often complicate the care of people with psychotic disorders. This study systematically reviews the prevalence estimates reported for stimulant abuse and dependence in people with psychotic disorders, and examines personal, clinical, regional and methodological factors which explain variation in these rates.

METHODS

PsychINFO, EMBASE and MEDLINE (1946-2013) were searched systematically for studies reporting on stimulant drug use disorders in representative samples of people with psychotic disorders. Random effects models estimated the pooled rate of a stimulant use disorder, defined to include stimulant abuse and stimulant dependence. Study characteristics associated with heterogeneity in rates of stimulant use disorder were examined by subgroup analyses for categorical variables, by meta-regression for continuous independent variables and by multiple meta-regression.

RESULTS

Sixty-four studies provided 68 estimates of lifetime or recent stimulant use disorders in 22,500 people with psychosis. The pooled rate of stimulant use disorder was 8.9% (95% CI 7.4%, 10.5%). Higher rates of stimulant use disorders were reported in studies of affective psychosis, studies from inpatient settings, studies from the USA and Australia, and studies with higher rates of cannabis disorder; in multiple meta-regression analysis these factors explained 68% of between-study variance. Rates of stimulant use disorder were stable over time, and unrelated to age, sex, stage of psychosis, type of stimulant drug or study methodology factors.

CONCLUSIONS

Reported rates of stimulant use disorder in people with psychosis are much higher than in the general population but vary widely and are associated with regional, service setting and clinical differences between studies. It is likely that stimulants contribute to the overall burden of psychosis, and that social and environmental factors combine with drug and illness-related factors to influence stimulant use in psychosis.

Stimulant and other substance use disorders in schizophrenia: prevalence, correlates and impacts in a population sample

OBJECTIVES

Stimulants may worsen psychotic symptoms but there is limited evidence about the impact of stimulant abuse in people with schizophrenia. This study examined the prevalence and correlates of stimulant and other drug disorders in a population-based sample of people with schizophrenia, examining associations with frequent service use, physical health comorbidities and accommodation instability.

METHODS

New South Wales (NSW) hospital, community mental health and emergency department data were used to examine health service contact over 5 years in 13,624 people with a diagnosis of schizophrenia. Associations of stimulant disorders were examined with multinomial logistic regression, comparing people with no substance disorders to those with cannabis disorders, stimulant disorders or both.

RESULTS

Of people with schizophrenia, 51% had substance disorders, including 14% with stimulant disorders. Stimulant disorders were more common in young adults and in urban areas, less common in migrants, and unrelated to initial social disadvantage. More than 80% of those with stimulant disorders also had cannabis disorders. Service use and harms were most common in this group, including frequent mental health admissions (59%), frequent emergency department presentations (52%), admissions with injury or self-harm (44%), infectious disease diagnoses (22%), multiple changes of residence (61%), movement to more disadvantaged locations (42%) and periods of homelessness (18%). People with stimulant disorders alone had higher rates of self-harm, infectious disease and non-mental health admissions than people with cannabis disorders alone.

CONCLUSIONS

Stimulant disorders occur in people with schizophrenia and in first-episode psychosis at rates more than 10 times that of the broader population. Stimulant disorders are likely to worsen the burden of psychosis, and strategies are needed to engage and support the highly disadvantaged group of people with schizophrenia who have cannabis and stimulant disorders.

Crystal methamphetamine initiation among street-involved youth

BACKGROUND

Although many settings have recently documented a substantial increase in the use of methamphetamine-type stimulants, recent reviews have underscored the dearth of prospective studies that have examined risk factors associated with the initiation of crystal methamphetamine use.

OBJECTIVES

Our objectives were to examine rates and risk factors for the initiation of crystal methamphetamine use in a cohort of street-involved youth.

METHODS

Street-involved youth in Vancouver, Canada, were enrolled in a prospective cohort known as the At-Risk Youth Study (ARYS). A total of 205 crystal methamphetamine-naïve participants were assessed semi-annually and Cox regression analyses were used to identify factors independently associated with the initiation of crystal methamphetamine use.

RESULTS

Among 205 youth prospectively followed from 2005 to 2012, the incidence density of crystal methamphetamine initiation was 12.2 per 100 person years. In Cox regression analyses, initiation of crystal methamphetamine use was independently associated with previous crack cocaine use (adjusted relative hazard [ARH] = 2.24 [95% CI: 1.20-4.20]) and recent drug dealing (ARH = 1.98 [95% CI: 1.05-3.71]). Those initiating methamphetamine were also more likely to report a recent nonfatal overdose (ARH = 3.63 [95% CI: 1.65-7.98]) and to be male (ARH = 2.12 [95% CI: 1.06-4.25]).

CONCLUSIONS

We identified high rates of crystal methamphetamine initiation among this population. Males those involved in the drug trade, and those who used crack cocaine were more likely to initiate crystal methamphetamine use. Evidence-based strategies to prevent and treat crystal methamphetamine use are urgently needed.

Stimulant use disorders: characteristics and comorbidity in an Australian population sample

OBJECTIVE

To describe the correlates of stimulant use disorders (abuse, dependence) in an Australian population sample, to compare the characteristics of stimulant users with and without stimulant use disorders and to describe the patterns of service use and help-seeking in people with stimulant use disorders.

METHODS

Data were drawn from the 2007 National Survey of Mental Health and Wellbeing, which sampled 8841 residents of private dwellings in Australia in 2007. Lifetime DSM-IV substance use and mental disorder diagnoses were obtained from interviews conducted by lay interviewers, using the Composite International Diagnostic Interview (CIDI). Socio-demographic, socio-economic and clinical correlates of stimulant use disorders were identified using binary logistic regression models. Stimulant users with and without stimulant use disorders were compared to non-stimulant users via multinomial logistic regression models.

RESULTS

Compared to Australians without stimulant use disorder, people with stimulant use disorders were younger, more likely to be male, of non-heterosexual orientation and born in Australia, but were not more socially disadvantaged. Lifetime comorbidity rates were high: 79% of persons with stimulant use disorders had a lifetime alcohol use disorder, 73% a lifetime cannabis use disorder, and more than one third a lifetime mood or anxiety disorder. Stimulant use disorders were associated with a family history of substance use, affective disorders and psychosis. One in five people with lifetime stimulant use disorders had been imprisoned, homeless or hospitalised for substance or mental health problems, and 13% reported at least one symptom of psychosis. Nearly half had sought help for substance or mental health problems, primarily from General Practitioners (GPs), psychologists or psychiatrists.

CONCLUSIONS

Stimulant use disorders in a representative population sample are associated with significant comorbidity and harm. Many persons with stimulant use disorders had sought care and found this helpful. There is scope for screening and intervention in this group.

Amphetamine use and its associated factors in body builders: a study from Tehran, Iran

INTRODUCTION

Epidemiological studies on all types of illicit drug use among athletes are essential for both the sport community and drug control achievements. Here, we investigated the prevalence and associated factors of amphetamine use in body builders in Tehran, Iran, 2007.

MATERIAL AND METHODS

This study is a secondary analysis of a substance use survey done in 103 randomly selected gymnasia in Tehran (capital city of Iran). The survey was conducted from November 2007 to January 2008 and included 843 randomly selected bodybuilders (aged 40 years or less). By interviews via questionnaires the following data were obtained: age, job, marital status, education level, housing status, average monthly family income, number of family members, gymnasium area (m(2)), number of trainers, number of gymnasium members, initiation time (months), weekly duration of the sporting activity (h), monthly cost of the sporting activity, purpose of participating in sporting activity, and history of anabolic steroid and amphetamine use.

RESULTS

One hundred twenty (13.3%) body builders reported a history of amphetamine use. According to the results of regression analysis, being married (risk ratio - RR = 0.540), and participating in body building to enhance self-esteem (RR = 0.423) or to enhance sport performance (RR = 0.545) had protective effects on amphetamine use. However, having university qualifications (RR = 1.843), using anabolic steroids (RR = 1.803) and participating in sport to maintain fitness (RR = 2.472) were linked to increased risk of amphetamine use.

CONCLUSIONS

Well-educated bodybuilders were more likely to use amphetamines, and why this is so needs to be discovered. If further studies show that they are not aware of the dangers associated with amphetamine use, providing them with information should be considered.

The acute effects of 3,4-methylenedioxymethamphetamine and d-methamphetamine on human cognitive functioning

RATIONALE

This study investigated the acute (3-h) and 24-h post-dose cognitive effects of oral 3,4-methylenedioxymethamphetamine (MDMA), d-methamphetamine, and placebo in a within-subject double-blind laboratory-based study in order to compare the effect of these two commonly used illicit drugs on a large number of recreational drug users.

METHODS

Sixty-one abstinent recreational users of illicit drugs comprised the participant sample, with 33 females and 28 males, mean age 25.45 years. The three testing sessions involved oral consumption of 100 mg MDMA, 0.42 mg/kg d-methamphetamine, or a matching placebo. The drug administration was counter-balanced, double-blind, and medically supervised. Cognitive performance was assessed during drug peak (3 h) and at 24 h post-dosing time-points. Blood samples were also taken to quantify the levels of drug present at the cognitive testing time-points.

RESULTS

Blood concentrations of both methamphetamine and MDMA at drug peak samples were consistent with levels observed in previous studies. The major findings concern poorer performance in the MDMA condition at peak concentration for the trail-making measures and an index of working memory (trend level), and more accurate performance on a choice reaction task within the methamphetamine condition. Most of the differences in performance between the MDMA, methamphetamine, and placebo treatments diminished by the 24-h testing time-point, although some performance improvements subsisted for choice reaction time for the methamphetamine condition.

CONCLUSIONS

Further research into the acute effects of amphetamine preparations is necessary to further quantify the acute disruption of aspects of human functioning crucial to complex activities such as attention, selective memory, and psychomotor performance.

The effect of d-methamphetamine on simulated driving performance

OBJECTIVES

Methamphetamine is considered to be one of the most popularly abused drugs by drivers; however, its exact effect on driving and driving behaviour has yet to be thoroughly investigated. This being despite methamphetamine's increased prevalence in injured and deceased drivers.

METHODS

Twenty healthy recreational illicit stimulant users (10 male and 10 female), aged between 21 and 32 years (mean = 25.4 years, SD = 3.3 years) attended two testing sessions involving oral consumption of 0.42 mg/kg d-methamphetamine or a matching placebo. The drug administration was counter-balanced, double-blind, and medically supervised. At each session driving, performance was assessed 2.5 h post drug administration.

RESULTS

d-methamphetamine (0.42 mg/kg) did not significantly impair overall simulated driving performance 2.5 h post drug administration. At the individual driving variable level, participants in the d-methamphetamine condition were observed to be driving slower when an emergency situation occurred (T = 44, p < 0.05), but interestingly, participants in both conditions recorded average speeds in excess of the speed limit (100 km/h) when the emergency situations occurred. The d-methamphetamine condition did also produce four times more infringements where participants did not stop at red traffic light in comparison to the placebo, but this effect was only evident at a trend level (T = 7, p = 0.11).

CONCLUSIONS

The findings presented herein suggest that d-methamphetamine administered at the levels supplied did not impair driving performance in a manner consistent with epidemiological evidence. Further research is certainly required to elucidate the effects of various doses of methamphetamine, alone and in combination with other legal and illicit substances.

Socio-economic determinants of drugged driving--a register-based study

AIMS

To examine the associations between socio-economic characteristics and driving under the influence of drugs (DUID), and to elaborate determinants of drugged driving.

DESIGN

A register-based case-control study.

SETTING

Finland.

PARTICIPANTS

Cases (n = 5859) apprehended by the police and suspected of DUID during 1993-2006 and controls (n = 74 809) drawn from the general Finnish population.

MEASUREMENTS

The effects of parents' and own education, urbanization of municipality, socio-economic position (SEP), main activity, income, marital status and living arrangements on DUID were estimated using logistic regression analysis. The analyses were conducted separately for men and women, age groups of under 45 years and aged 45 or over, and for substance groups of benzodiazepines only, benzodiazepines with alcohol, amphetamines and cannabinoids.

FINDINGS

Low education, unemployment, disability pension, being divorced and living alone were the strongest individual predictors of DUID in all substance groups. Illicit drug users were more disadvantaged compared to those in the benzodiazepines groups. Contrary to other substance and age groups, higher educational level and higher SEP were associated with DUID among benzodiazepine users aged 45 or over.

CONCLUSIONS

A disadvantaged social background is a significant predictor of driving while under the influence of drugs for all substance use groups in Finland. The gradient is greater for amphetamines and cannabinoids than benzodiazepines.

Predictors of young adults' amphetamine use and disorders: a prospective study

INTRODUCTION AND AIMS

Understanding the risk factors that predict amphetamine use and development of amphetamine abuse or dependence (disorder) may help guide preventive interventions. This study aimed to investigate the correlates and predictors of young adults' amphetamine use and use disorders.

DESIGN AND METHODS

Prospective cohort, population-based study which started in Brisbane, South East Queensland (Australia) in 1981. The study participants were a cohort of 2042 young adults, followed up from birth to young adulthood. At the 21-year follow-up, amphetamine use was assessed via a self-report questionnaire, and amphetamine use disorder (AUD) was assessed using the Composite International Diagnostic Interview (CIDI-Auto). Potential predictors (15 risk factors) were assessed between baseline (antenatal visit) and the 21-year follow-up. These included participant's gender, mother's age and education, maternal marital status and quality of marital relationship, maternal tobacco and alcohol consumption, mother-child communication, child mental health and problem behaviours, child smoking and alcohol consumption and child school performance.

RESULTS

Young adult amphetamine users were more likely to have concurrent symptoms of mental illness and problem behaviours and to use or abuse cigarettes, cannabis, or other illicit drugs. In multivariate analyses, young adults' amphetamine use and disorder were disproportionately more common among males and those who have prospectively reported aggression/delinquency or smoking at 14 years, or who have experienced childhood sexual abuse.

CONCLUSIONS

Our findings suggest that problem behaviours, smoking and childhood sexual abuse are predictors of initiation to use of amphetamines and development of amphetamine abuse and dependence.

[Initiation of ecstasy use in Québec senior high school adolescents: distal and proximal predictors]

OBJECTIVE

To identify distal and proximal predictors of ecstasy use initiation during adolescence.

METHOD

The sample included 2162 adolescents from Québec disadvantaged community high schools, with an annual follow-up for 5 years. Path analysis was used to predict ecstasy use initiation in secondary 5 (aged 16 to 17 years) from predictors in secondary 1 and 2 (aged 12 to 14 years) and in secondary 4 (aged 15 to 16 years).

RESULTS

Secondary 5 adolescents initiating ecstasy use showed a higher risk on multiple factors, compared with nonusers. Initiation was mainly predicted by proximal risk factors related to individual use as well as peer use and deviance. Nevertheless, many proximal factors developed consistently with their corresponding distal factor (indirect link). Marijuana use was the strongest predictor of ecstasy use initiation. All things being equal, relative risk was 2.04 times higher in adolescents having used marijuana in the past year (secondary 4).

CONCLUSIONS

Ecstasy use initiation in secondary 5 seems to be globally related to an externalized, rather than internalized, profile. This ecstasy use was strongly associated with other substance use and likely shares many risk factors with other substance use, specifically marijuana use.

Health outcomes associated with methamphetamine use among young people: a systematic review

OBJECTIVES

Methamphetamine (MA) use among young people is of significant social, economic and public health concern to affected communities and policy makers. While responses have focused upon various perceived severe harms of MA use, effective public health interventions require a strong scientific evidence base.

METHODS

We conducted a systematic review to identify scientific studies investigating health outcomes associated with MA use among young people aged 10-24 years. The International Classification of Diseases (ICD-10) was used to categorize outcomes and determine the level of evidence for each series of harms.

RESULTS

We identified 47 eligible studies for review. Consistent associations were observed between MA use and several mental health outcomes, including depression, suicidal ideation and psychosis. Suicide and overdose appear to be significant sources of morbidity and mortality among young MA users. Evidence for a strong association between MA use and increased risk of human immunodeficiency virus (HIV) and other sexually transmitted infections is equivocal. Finally, we identified only weak evidence of an association between MA use and dental diseases among young people.

CONCLUSIONS

Available evidence indicates a consistent relationship between MA use and mental health outcomes (e.g. depression, psychosis) and an increased risk of mortality due to suicide and overdose. We found insufficient evidence of an association between MA use and other previously cited harms, including infectious diseases and dental outcomes. As such, future research of higher methodological quality is required to further investigate possible associations. Current interventions should focus attention upon MA-related health outcomes for which sound scientific evidence is available.