Abuse of amphetamines and structural abnormalities in the brain

Bioinformatics-driven untargeted metabolomic profiling for clinical screening of methamphetamine abuse

PURPOSE

Amphetamine-type stimulants are very common, and their usage is becoming a very big social problem all over the world. Thousands of addicts encounter several health problems including mental, metabolic, behavioral and neurological disorders. In addition to these, there are several reports about the elevated risk of tendency on committing criminal cases by addicted persons. Hence, methamphetamine addiction is not only an individual health problem but also a social problem. In our study, we aimed to investigate the pathogenesis of chronic usage of methamphetamine via untargeted metabolomics approach.

METHODS

38 plasma samples were carefully collected and extracted for untargeted metabolomics assay. A liquid-liquid extraction was performed to get as much metabolite as possible from the samples. After the extraction procedure, samples were transferred into vials and they were evaluated via time of flight mass spectrometry instrument.

RESULTS

Significantly, altered metabolites were identified by the fold analysis and Welch's test between the groups. 42 different compounds were annotated regarding to data-dependent acquisition method. Pathway analysis were also performed to understand the hazardous effect of methamphetamine on human body.

CONCLUSION

It has been reported that drug exposure may affect several metabolic pathways for amino acids, fats, energy metabolism and vitamins. An alternative bioinformatic model was also developed and validated in order to predict the chronic methamphetamine drug users in any criminal cases. This generated model passes the ROC curve analysis and permutation test and classify the controls and drug users correctly by evaluating the metabolic alterations between the groups.

Crystal Clear: Metal-Organic Frameworks Pioneering the Path to Future Drug Detox

The growing number of acute drug abuse overdoses demands the development of innovative detoxification strategies for emergency purposes. In this study, an innovative approach for the application of porous Zr-based metal-organic frameworks for the treatment of acute overdoses of popular drugs of abuse including amphetamine, methamphetamine, cocaine, and MDMA is presented. A comprehensive approach determining the efficacy and the kinetics of drug removal, considering dosage, adsorption time, and adsorption mechanisms, was tested and corroborated with density functional theory (DFT) modeling. The experimental results showed high removal efficiency reaching up to 90% in the case of the application of the NU-1000 metal-organic framework. The difference Raman spectroscopy method presented in this study corroborated with DFT-based vibrational analysis allows the detection of drug adsorbed in the MOF framework even with as low a concentration as 5 mg/g. Additionally, the drug adsorption mechanisms were modeled with DFT, showing the π-π stacking in a vast majority of considered cases. The performance and influence on the living organisms were evaluated throughout the in vitro and in vivo experiments, indicating that Zr-based MOFs could serve as efficient, organic, safe drug adsorbents.

Structural brain changes associated with cocaine use and digital cognitive behavioral therapy in cocaine use disorder treatment

Background

Few studies have investigated changes in brain structure and function associated with recovery from cocaine use disorder (CUD), and fewer still have identified brain changes associated with specific CUD treatments, which could inform treatment development and optimization.

Methods

In this longitudinal study, T1-weighted magnetic resonance imaging scans were acquired from 41 methadone-maintained individuals with CUD (15 women) at the beginning of and after 12 weeks of outpatient treatment. As part of a larger randomized controlled trial, these participants were randomly assigned to receive (or not) computer-based training for cognitive behavioral therapy (CBT4CBT), and galantamine (or placebo).

Results

Irrespective of treatment condition, whole-brain voxel-based morphometry analyses revealed a significant decrease in right caudate body, bilateral cerebellum, and right middle temporal gyrus gray matter volume (GMV) at post-treatment relative to the start of treatment. Subsequent region of interest analyses found that greater reductions in right caudate and bilateral cerebellar GMV were associated with higher relative and absolute levels of cocaine use during treatment, respectively. Participants who completed more CBT4CBT modules had a greater reduction in right middle temporal gyrus GMV.

Conclusions

These results extend previous findings regarding changes in caudate and cerebellar GMV as a function of cocaine use and provide the first evidence of a change in brain structure as a function of engagement in digital CBT for addiction. These data suggest a novel potential mechanism underlying how CBT4CBT and CBT more broadly may exert therapeutic effects on substance-use-related behaviors through brain regions implicated in semantic knowledge.

Structural indices of brain aging in methamphetamine use disorder

BACKGROUND

Methamphetamine use is surging globally. It has been linked to premature stroke, Parkinsonism, and dementia, suggesting that it may accelerate brain aging.

METHODS

We performed a retrospective study to determine if structural indices of brain aging were more prevalent prior to old age (26 - 54 years) in individuals with Methamphetamine Use Disorder (MUD), who were in early abstinence (M ± SD = 22.1 ± 25.6 days) than in healthy control (HC) participants. We compared T1-weighted MRI brain scans in age- and sex-matched groups (n = 89/group) on three structural features of brain aging: the brain volume/cerebrospinal fluid (BV/CSF) index, volume of white matter hypointensities/lesions, and choroid plexus volume.

RESULTS

The MUD group had a lower mean BV/CSF index and larger volumes of white matter hypointensities and choroid plexus (p-values < 0.01). Regression analyses showed significant age-by-group effects, indicating different age trajectories of the BV/CSF index and choroid plexus volume, consistent with abnormal global brain atrophy and choroid plexus pathology in the MUD group. Significant age and group main effects reflected a larger volume of white matter hypointensities for older participants across groups and for the MUD group irrespective of age. None of the three measures of brain aging correlated significantly with recent use or duration of recent abstinence from methamphetamine.

CONCLUSIONS

Premature brain pathology, which may reflect cerebrovascular damage and dysfunction of the choroid plexus, occurs in people with MUD. Such pathology may affect cognition and thereby efficacy of behavioral treatments for MUD.

Prelimbic cortex dynorphin/κ opioid receptor system modulates methamphetamine-induced cognitive impairment

Chronic exposure to methamphetamine (METH) causes severe and persistent cognitive impairment. The present study aimed to investigate the role of dynorphin/κ opioid receptor (KOR) system in the development of METH-induced cognitive impairment. We found that mice showed significant cognitive impairment in the novel object recognition test (NOR) following daily injections of METH (10 mg/kg) for seven consecutive days. Systemic blockade of KOR prevented METH-induced cognitive impairment by pretreatment of the selective KOR antagonist norBNI (10 mg/kg, i.p.) or KOR deletion. Then, significant increased dynorphin and KOR mRNA were observed exclusively in prelimbic cortex (PL) other than infralimbic cortex. Finally, microinjection with norBNI into PL also improved cognitive memory in METH-treated mice using NOR and spontaneous alternation behaviour test. Our results demonstrated that dynorphin/KOR system activation in PL may be a possible mechanism for METH-induced cognitive impairment and shed light on KOR antagonists as a potential neuroprotective agent against the cognitive deficits induced by drug abuse.

Overview of Movement Disorders Secondary to Drugs

Drug-induced movement disorders affect a significant percentage of individuals, and they are commonly overlooked and underdiagnosed in clinical practice. Many comorbidities can affect these individuals, making the diagnosis even more challenging. Several variables, including genetics, environmental factors, and aging, can play a role in the pathophysiology of these conditions. The Diagnostic and Statistical Manual of Mental Disorders (DSM) and the International Statistical Classification of Diseases and Related Health Problems (ICD) are the most commonly used classification systems in categorizing drug-induced movement disorders. This literature review aims to describe the abnormal movements associated with some medications and illicit drugs. Myoclonus is probably the most poorly described movement disorder, in which most of the reports do not describe electrodiagnostic studies. Therefore, the information available is insufficient for the diagnosis of the neuroanatomical source of myoclonus. Drug-induced parkinsonism is rarely adequately evaluated but should be assessed with radiotracers when these techniques are available. Tardive dyskinesias and dyskinesias encompass various abnormal movements, including chorea, athetosis, and ballism. Some authors include a temporal relationship to define tardive syndromes for other movement disorders, such as dystonia, tremor, and ataxia. Antiseizure medications and antipsychotics are among the most thoroughly described drug classes associated with movement disorders.

Amphetamine-Related Fatalities and Altered Brain Chemicals: A Preliminary Investigation Using the Comparative Toxicogenomic Database

Amphetamine is a psychostimulant drug with a high risk of toxicity and death when misused. Abuse of amphetamines is associated with an altered organic profile, which includes omega fatty acids. Low omega fatty acid levels are linked to mental disorders. Using the Comparative Toxicogenomic Database (CTD), we investigated the chemical profile of the brain in amphetamine-related fatalities and the possibility of neurotoxicity. We classified amphetamine cases as low (0-0.5 g/mL), medium (>0.5 to 1.5 g/mL), and high (>1.5 g/mL), based on amphetamine levels in brain samples. All three groups shared 1-octadecene, 1-tridecene, 2,4-di-tert-butylphenol, arachidonic acid (AA), docosahexaenoic acid (DHA), eicosane, and oleylamide. We identified chemical-disease associations using the CTD tools and predicted an association between DHA, AA and curated conditions like autistic disorder, disorders related to cocaine, Alzheimer's disease, and cognitive dysfunction. An amphetamine challenge may cause neurotoxicity in the human brain due to a decrease in omega-3 fatty acids and an increase in oxidative products. Therefore, in cases of amphetamine toxicity, a supplement therapy may be needed to prevent omega-3 fatty acid deficiency.

Neuropathologic Features in Chronic Methamphetamine Use

ABSTRACT

Methamphetamine is a psychostimulant that exerts its euphoric and stimulant effects by increasing cytosolic monoamine concentration at the nerve terminal. In addition to its known systemic cardiovascular effects, there is compelling evidence to suggest a direct neurotoxic effect of methamphetamine; however, the existing body of literature includes very few human tissue studies. This exploratory analysis used postmortem human brain specimens to examine histologic and immunohistochemical features associated with chronic methamphetamine use. This retrospective cohort study included 60 decedents who were autopsied at the University of Iowa Hospitals and Clinics between the years 2015 and 2021. Logistic regression models demonstrated no definite pathologic changes in the hippocampi of individuals with a history of chronic methamphetamine use. Decedents with a history of methamphetamine use had a marginally increased odds of basal ganglia arteriosclerosis, which did not reach statistical significance (odds ratio, 3.33; 95% confidence interval, 0.6-19.2; P = 0.17), which may be independent of the systemic hypertensive effects of methamphetamine. Future studies that include targeted examination of brain regions of interest, such as the basal ganglia and specifically the striatum, may prove revealing.

Effect of methamphetamine on ultraweak photon emission and level of reactive oxygen species in male rat brain

All living cells, including neurons, generate ultra-weak photon emission (UPE) during biological activity, and in particular, in the brain, it has been shown that UPE is correlated with neuronal activity and associated metabolic processes. Various intracellular factors, as well as external factors, can reduce or increase the intensity of UPE. In this study, we have used Methamphetamine (METH) as one potentially effective external factor, which is a substance that has the property of stimulating the central nervous system. METH can impair mitochondrial function by causing toxicity via various pathways, including an increase in the number of mitochondria, hyperthermia, the increased metabolic activity of the brain, and the production of glutamate and excess calcium. In addition to mitochondrial dysfunction, METH alters cellular homeostasis, leading to cell damage and the production of excess ROS. The aim of this study is to measure and compare the UPE intensity and reactive oxygen species (ROS) levels of the prefrontal, motor, and visual cortex before and after METH administration. Twenty male rats were randomly assigned to two groups, the control, and METH groups. In the control group, 2 h after injection of normal saline and without any intervention, and in the experimental group 2 h after IP injection of 20 mg/kg METH, sections were prepared from three areas: prefrontal, motor, and V1-V2 cortex, which were used to evaluate the emission of UPE using a photomultiplier tube (PMT) device and to evaluate the amount of ROS. The results showed that the amount of ROS and UPE in the experimental group in all three areas significantly increased compared to the control group. So, METH increases UPE and ROS in the prefrontal, motor, and visual regions, and there is a direct relationship between UPE intensity and ROS production. Therefore, UPE may be used as a dynamic reading tool to monitor oxidative metabolism in physiological processes related to ROS and METH research. Also, the results of this experiment may create a new avenue to test the hypothesis that the excess in UPE generation may lead to the phenomenon of phosphene and visual hallucinations.

Brain volume in chronic ketamine users - relationship to sub-threshold psychotic symptoms and relevance to schizophrenia

RATIONALE

Ketamine may model aspects of schizophrenia arising through NMDA receptor activity deficits. Although acute ketamine can induce effects resembling both positive and negative psychotic symptoms, chronic use may be a closer model of idiopathic psychosis.

OBJECTIVES

We tested the hypotheses that ketamine users had lower brain volumes, as measured using MRI, and greater sub-threshold psychotic symptoms relative to a poly-drug user control group.

METHODS

Ketamine users (n = 17) and poly-drug using controls (n = 19) were included in the study. All underwent volumetric MRI imaging and measurement of sub-threshold psychotic symptoms using the Comprehensive Assessment of At-Risk Mental State (CAARMS). Freesurfer was used to analyse differences in regional brain volume, cortical surface area and thickness between ketamine users and controls. The relationship between CAARMS ratings and brain volume was also investigated in ketamine users.

RESULTS

Ketamine users were found to have significantly lower grey matter volumes of the nucleus accumbens, caudate nucleus, cerebellum and total cortex (FDR p < 0.05; Cohen's d = 0.36-0.75). Within the cortex, ketamine users had significantly lower grey matter volumes within the frontal, temporal and parietal cortices (Cohen's d 0.7-1.31; FDR p < 0.05). They also had significantly higher sub-threshold psychotic symptoms (p < 0.05). Frequency of ketamine use showed an inverse correlation with cerebellar volume (p < 0.001), but there was no relationship between regional brain volumes and sub-threshold psychotic symptoms.

CONCLUSIONS

Chronic ketamine use may cause lower grey matter volumes as well as inducing sub-threshold psychotic symptoms, although these likely arise through distinct mechanisms.

Strukturelle Gehirnveränderungen und Läsionen durch den Konsum illegaler Drogen und Psychedelika

Drogen können sowohl die Funktion wie auch die Struktur des Gehirns verändern. Gelegentlicher oder regelmäßiger Drogenkonsum ist in der Bevölkerung weit verbreitet. Daher ist die Kenntnis möglicher Nebenwirkungen und charakteristischer Bildbefunde bei Untersuchungen des Gehirns für den klinischen Alltag wichtig. Dieser Artikel beschreibt die für die am weitesten verbreiteten Substanzen typischen Komplikationen und morphologisch-radiologischen Veränderungen. Zu den möglichen Pathomechnismen gehören neurotoxische Effekte, die zu Leukenzephalopathie oder Hirnatrophie führen können, und vaskuläre Komplikationen wie Vasokonstriktion, Vaskulitis oder Hypertonus, durch die es zu intrazerebralen Blutungen oder Infarkten kommen kann. Da die klinische Präsentation oft unspezifisch ist, und die betroffenen Patienten ihren Drogenkonsum häufig verschweigen, ist das Erkennen typischer Bildbefunde essentiell für eine zuverlässige Diagnosestellung und zielgerichtete Therapie.

Methamphetamine Use: A Narrative Review of Adverse Effects and Related Toxicities

Methamphetamine has been labeled "America's most dangerous drug" and has received significant public health attention. Stimulant addiction and tolerance are heavily documented in the literature; increasingly larger doses maintain euphoria in short time periods to withstand stimulant tolerance. Stimulant deaths are high in the United States and abroad. Between 2013 and 2019, deaths related to methamphetamine use quadrupled from 3,616 to 16,127. Methamphetamine use increased four-fold from 2015 to 2016. Due to this increase in methamphetamine use and its associated medical complications, the mortality rate associated with methamphetamine use has doubled over the past ten years. Cardiopulmonary symptoms include chest pain, palpitations, and shortness of breath. Methamphetamine-related myocardial infarction can also occur. Central nervous system symptoms include agitation, anxiety, delusions, hallucinations, and seizures. Methamphetamine-induced psychosis may unmask underlying psychiatric disorders. It can also cause cerebral vasculitis, which elicits cortical blindness and ischemic strokes. Methamphetamine-induced neurotoxicity in serotonergic systems is more diffuse, involving the striatum, hippocampus, septum, amygdala, and hypothalamus leading to mood changes, psychosis, and memory impairment. This narrative review will aim to highlight the adverse effects as well as the toxicity that can occur with methamphetamine use.

Cortical thickness and related depressive symptoms in early abstinence from chronic methamphetamine use

Methamphetamine use is surging globally as a cause of morbidity and mortality. Treatment is typically sought in early abstinence, when craving and depressive symptoms are intense, contributing to relapse and poor outcomes. To advance an understanding of this problem and identify therapeutic targets, we conducted a retrospective analysis of brain structure in 89 adults with Methamphetamine Use Disorder who were in early abstinence and 89 healthy controls. Unlike most prior research, the participants did not significantly differ in age, sex and recent use of alcohol and tobacco (p-values ≥ 0.400). We analysed thickness across the entire cerebral cortex by fitting a general linear model to identify differences between groups. Follow-up regressions were performed to determine whether cortical thickness in regions showing group differences was related to craving, measured on a visual analogue scale, or to the Beck Depression Inventory score. Participants in early methamphetamine abstinence (M ± SD = 22.1 ± 25.6 days) exhibited thinner cortex in clusters within bilateral frontal, parietal, temporal, insular, and right cingulate cortices relative to controls (p-values < 0.001, corrected for multiple comparisons). Unlike craving (β = 0.007, p = 0.947), depressive symptoms were positively correlated with cortical thickness across clusters (β = 0.239, p = 0.030) and with thickness in the anterior cingulate cluster (β = 0.246, p = 0.027) in the methamphetamine-dependent group. Inasmuch as anterior cingulate pathology predicts response to antidepressants for Major Depressive Disorder, cingulate structure may also identify patients with Methamphetamine Use Disorder who can benefit from antidepressant medication.

A review of functional brain differences predicting relapse in substance use disorder: Actionable targets for new methods of noninvasive brain stimulation

Neuroimaging studies have identified a variety of brain regions whose activity predicts substance use (i.e., relapse) in patients with substance use disorder (SUD), suggesting that malfunctioning brain networks may exacerbate relapse. However, this knowledge has not yet led to a marked improvement in treatment outcomes. Noninvasive brain stimulation (NIBS) has shown some potential for treating SUDs, and a new generation of NIBS technologies offers the possibility of selectively altering activity in both superficial and deep brain structures implicated in SUDs. The goal of the current review was to identify deeper brain structures involved in relapse to SUD and give an account of innovative methods of NIBS that might be used to target them. Included studies measured fMRI in currently abstinent SUD patients and tracked treatment outcomes, and fMRI results were organized with the framework of the Addictions Neuroclinical Assessment (ANA). Four brain structures were consistently implicated: the anterior and posterior cingulate cortices, ventral striatum and insula. These four deeper brain structures may be appropriate future targets for the treatment of SUD using these innovative NIBS technologies.

Local efficiency analysis of restingstate functional brain network in methamphetamine users

This study set out to assess restingstate functional connectivity (rs-FN) and graph theorybased local efficiency within the left and right hemispheres of methamphetamine (MA) abusers. Functional brain networks of 19 MA abusers and 21 control participants were analyzed using restingstate fMRI. Graph edges in functional networks of the brain were defined and recurrence plot was used. We found that MA abuse may be accompanied by alterations of rs-FN within the defaultmode network (DMN), executive control network (ECN), and the salience network (SN) in both hemispheres of the brain. We also observed that such effects of MA may be correlated with duration of MA abuse and abstinence in many components of the DMN and SN. The results would seem to suggest that MAinduced alterations of local efficiency may, in part, account for maladaptive decision making, deficits in executive function and control over drug seeking/taking, and relapse.

Association between white matter microstructure and cognitive function in patients with methamphetamine use disorder

Methamphetamine use disorder (MUD) has been associated with broad neurocognitive impairments. While the cognitive impairments of MUD have been demonstrated, the neuropathological underpinnings remain inadequately understood. To date, the published human diffusion tensor imaging (DTI) studies involving the correlation between diffusion parameters and neurocognitive function in MUD are limited. Hence, the present study aimed to examine the association between cognitive performance and white matter microstructure in patients with MUD. Forty-five patients with MUD and 43 healthy controls (HCs) completed their demographic information collection, cognitive assessments, and DTI imaging. DTI images were preprocessed to extract fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of various fiber tracts. Univariate tests were used to examine group differences in cognitive assessments and DTI metrics. Linear regression was used to examine the relationship between these two metrics. The results revealed that patients with MUD had lower subset scores of the MATRICS Consensus Cognitive Battery (MCCB), which reflects five cognitive domains: processing speed, attention, verbal learning, visual learning, problem-solving. Patients with MUD also had significantly higher AD, MD, and RD values of the left superior longitudinal fasciculus than HCs. Furthermore, the RD value of the left superior longitudinal fasciculus was a significant predictor of processing speed and problem-solving ability, as shown by the digit-symbol coding test and NAB-Mazes scores, respectively. Findings extended our understanding of white matter microstructure that is related to neurocognitive deficits in MUD and provided potential targets for the prevention and treatment of this chronic disorder.

Characterization of basal ganglia volume changes in the context of HIV and polysubstance use

HIV and psychoactive substances can impact the integrity of the basal ganglia (BG), a neural substrate of cognition, motor control, and reward-seeking behaviors. This study assessed BG gray matter (GM) volume as a function of polysubstance (stimulant and opioid) use and HIV status. We hypothesized that comorbid polysubstance use and HIV seropositivity would alter BG GM volume differently than would polysubstance use or HIV status alone. We collected structural MRI scans, substance use history, and HIV diagnoses. Participants who had HIV (HIV +), a history of polysubstance dependence (POLY +), both, or neither completed assessments for cognition, motor function, and risk-taking behaviors (N = 93). All three clinical groups showed a left-lateralized pattern of GM reduction in the BG relative to controls. However, in the HIV + /POLY + group, stimulant use was associated with increased GM volume within the globus pallidus and putamen. This surpassed the effects from opioid use, as indicated by decreased GM volume throughout the BG in the HIV-/POLY + group. Motor learning was impaired in all three clinical groups, and in the HIV + /POLY + group, motor learning was associated with increased caudate and putamen GM volume. We also observed associations between BG GM volume and risk-taking behaviors in the HIV + /POLY- and HIV-/POLY + groups. The effects of substance use on the BG differed as a function of substance type used, HIV seropositivity, and BG subregion. Although BG volume decreased in association with HIV and opioid use, stimulants can, inversely, lead to BG volume increases within the context of HIV.

DFT-D4 Insight into the Inclusion of Amphetamine and Methamphetamine in Cucurbit[7]uril: Energetic, Structural and Biosensing Properties

The host-guest interactions of cucurbit[7]uril (CB[7]) as host and amphetamine (AMP), methamphetamine (MET) and their enantiomeric forms (S-form and R-form) as guests were computationally investigated using density functional theory calculations with the recent D4 atomic-charge dependent dispersion corrections. The analysis of energetic, structural and electronic properties with the aid of frontier molecular orbital analysis, charge decomposition analysis (CDA), extended charge decomposition analysis (ECDA) and independent gradient model (IGM) approach allowed to characterize the host-guest interactions in the studied systems. Energetic results indicate the formation of stable non-covalent complexes where R-AMP@CB[7] and S-AMP@CB[7] are more stable thermodynamically than R-MET@CB[7] and S-MET@CB[7] in gas phase while the reverse is true in water solvent. Based on structural analysis, a recognition mechanism is proposed, which suggests that the synergistic effect of van der Waals forces, ion-dipole interactions, intermolecular charge transfer interactions and intermolecular hydrogen bonding is responsible for the stabilization of the complexes. The geometries of the complexes obtained theoretically are in good agreement with the X-ray experimental structures and indicate that the phenyl ring of amphetamine and methamphetamine is deeply buried into the cavity of CB[7] through hydrophobic interactions while the ammonium group remains outside the cavity to establish hydrogen bonds with the portal oxygen atoms of CB[7].

Cardiac Complications of Common Drugs of Abuse: Pharmacology, Toxicology and Management

Cardiovascular complications from drugs of abuse are becoming more apparent due to increased usage worldwide. Substance abuse can cause both acute and chronic cardiovascular complications and is increasing in prevalence especially in young adults. These substances contribute to the development of acute coronary syndrome, type II myocardial injury, arrhythmias, cardiomyopathies and have numerous other cardiovascular complications. Although no screening guidelines exist, clinical awareness of these potential complications and their prevention, clinical presentation, diagnosis, and treatment are critically important. Management of cardiovascular disease should be coupled with appropriate social and mental health interventions to provide sustained clinical benefit. The higher the number of substances used recreationally, the greater the risk of premature heart disease. Epidemiological studies showed that 1 in 5 young adults misuse several substances and often start using at younger ages with a greater risk for adverse health outcomes over the long-term. The aim of this review is to highlight the basic epidemiology, cardiac complications, and disease-specific treatment options of commonly abused substances including methamphetamine, cocaine, alcohol, anabolic-androgenic steroids, cannabis, and tobacco.

Chemo-Profiling of Illicit Amphetamine Tablets Seized from Jazan, Saudi Arabia, Using Gas Chromatography-Mass Spectrometry and Chemometric Techniques

A number of illegal drug tablets with unknown constituents are supplied to countries around the world, most of which are habit forming. Amphetamine constitutes the majority of illegal tablets supplied to Saudi Arabia. In this study, we investigated illicit amphetamine tablets seized from Jazan region located in the southwest of Saudi Arabia to identify the insidious additives present in them and their health-related risks. Tablets were analyzed for the presence of amphetamine and other additives using gas chromatography-mass spectroscopy (GC-MS) technique. Amphetamine was detected in good to high area % values in all analyzed tablets in the range of 16.29–41.23%. Interestingly, a number of other additives were also detected with amphetamine in most of the tested samples including caffeine, lidocaine, diphenhydramine, and 8-chlorotheophylline in considerable area %. Caffeine may have been added to enhance the psychotic effect of amphetamine, whereas lidocaine was added to prevent the cardiovascular side effects of amphetamine. Diphenhydramine was probably added to prevent other undesirable side effects of amphetamine such as insomnia and tremors. Chemometric hierarchical cluster analysis was carried out to make samples clusters which have similar characteristics. It resulted into a dendrogram tree showing eight clusters signifying different sources of tablet samples. Owing to the toxic effects of amphetamine and other psychoactive constituents in the tested tablets, the illegal trafficking of these tablets should be prevented by all means and public awareness should be increased.

Neurotoxicity of methamphetamine: Main effects and mechanisms

Methamphetamine (METH) is an illicit psychostimulant that is abused throughout the world. METH addiction is also a major public health concern and the abuse of large doses of the drug is often associated with serious neuropsychiatric consequences that may include agitation, anxiety, hallucinations, paranoia, and psychosis. Some human methamphetamine users can also suffer from attention, memory, and executive deficits. METH-associated neurological and psychiatric complications might be related, in part, to METH-induced neurotoxic effects. Those include altered dopaminergic and serotonergic functions, neuronal apoptosis, astrocytosis, and microgliosis. Here we have endeavored to discuss some of the main effects of the drug and have presented the evidence supporting certain of the molecular and cellular bases of METH neurotoxicity. The accumulated evidence suggests the involvement of transcription factors, activation of dealth pathways that emanate from mitochondria and endoplasmic reticulum (ER), and a role for neuroinflammatory mechanisms. Understanding the molecular processes involved in METH induced neurotoxicity should help in developing better therapeutic approaches that might also serve to attenuate or block the biological consequences of use of large doses of the drug by some humans who meet criteria for METH use disorder.

A network of phosphatidylinositol (4,5)-bisphosphate (PIP2) binding sites on the dopamine transporter regulates amphetamine behavior in Drosophila Melanogaster

Reward modulates the saliency of a specific drug exposure and is essential for the transition to addiction. Numerous human PET-fMRI studies establish a link between midbrain dopamine (DA) release, DA transporter (DAT) availability, and reward responses. However, how and whether DAT function and regulation directly participate in reward processes remains elusive. Here, we developed a novel experimental paradigm in Drosophila melanogaster to study the mechanisms underlying the psychomotor and rewarding properties of amphetamine (AMPH). AMPH principally mediates its pharmacological and behavioral effects by increasing DA availability through the reversal of DAT function (DA efflux). We have previously shown that the phospholipid, phosphatidylinositol (4, 5)-bisphosphate (PIP₂), directly interacts with the DAT N-terminus to support DA efflux in response to AMPH. In this study, we demonstrate that the interaction of PIP₂ with the DAT N-terminus is critical for AMPH-induced DAT phosphorylation, a process required for DA efflux. We showed that PIP₂ also interacts with intracellular loop 4 at R443. Further, we identified that R443 electrostatically regulates DA efflux as part of a coordinated interaction with the phosphorylated N-terminus. In Drosophila, we determined that a neutralizing substitution at R443 inhibited the psychomotor actions of AMPH. We associated this inhibition with a decrease in AMPH-induced DA efflux in isolated fly brains. Notably, we showed that the electrostatic interactions of R443 specifically regulate the rewarding properties of AMPH without affecting AMPH aversion. We present the first evidence linking PIP₂, DAT, DA efflux, and phosphorylation processes with AMPH reward.

The Effect of Crystal Dependence on Brain Activity Related to the Perception of Pleasure Using fMRI

Background: Addiction is currently one of the problems of human society. Drug abuse is one of the most important issues in the field of addiction. Methamphetamine (crystal) is one of the drugs that has been abused in recent decades. Methods: In this case-control study, 10 individuals aged 20 to 40 years old with at least 2 years of experience of methamphetamine consumption without any history of drug use or other stimulants from clients and drug withdrawal centers in Tehran City, and 10 healthy volunteers were selected. Age, social status, and economic status of addicts were included in the fMRI apparatus, and 90 selected pleasurable, non-pleasurable, and neutral images (IAPS) were displayed by the projector through an event-related method. The playback time of each photo was 3 s, and after this process, the person outside the device, without the time limit selected the enjoyable and unpleasant images. Results: The results showed that there was no significant difference between the groups in terms of age, alcohol use, and smoking history (P < 0.05). There was no significant difference in terms of the age at first use between members of the methamphetamine-dependent group. Also, the methamphetamine-dependent group showed more brain activity in their pre-center and post-center gyrus than the normal (control) group. Conclusions: According to the results obtained in this study, in general, it can be concluded that there are some areas in the brain of addicts that are activated when watching pleasant photos, while these areas are not active in the brains of normal people.

ERPS AS AN INDEX OF IMPAIRED WORKING MEMORY IN AN ISCHEMIC BRAIN STROKE APHASIC PATIENT AWAKENED FROM A LONG-TERM COMA FOLLOWING AN AMPHETAMINE OVERDOSE

Nowadays, amphetamines constitute the prescription drugs most commonly abused by adolescents and young adults (Berman, O’Neill, Fears et al. 2008). The prevalence of problematic (mainly illegal) use of amphetamines as a stimulant by college students, and here especially before serious examinations, has also been rising. This fact represents a serious public health concern. The patient, aged 19, was awakened from from a long-term coma that had lasted 21 days following an amphetamine overdose and manifested tetraparesis, cortical blindness and deficits in cognitive and emotional processes. After a year of rehabilitation the majority of symptoms had disappeared, but cortical blindness andworking memory deficits remained. In addition, frontal lobe syndrome symptoms appeared. After two years of therapy as a result of immense tiredness caused by all an night wedding reception she started to manifest Charles-Bonnet syndrome. She experienced strange visual sensations such as visual hallucinations and saw various non-existing shapes (coloured blots, patterns and fireworks of vivid colours). She also saw objects (often terrifying) as well as animals (mainly African) and people with deformed faces and long teeth, and persons in African dress with feathers and coral beads in their hair. Her real identity was not remembered by the patient for longer than 2 hours and even then she insisted on being referred to as Shakira. She was given a qEEG examination (in open and closed eyes conditions) and ERPs with the use of auditory stimuli at the period when the hallucinations (to a small degree) still occurred. Studies conducted into the functional neuroimaging of the brain work in milliseconds in the examined patient can explain her symptoms. A comparison of the subject’s ERPs with the grand average of ERPs in healthy controls shows that the N170 and N 250 components are impaired in the subject: the occipital-temporal area of the subject brain shows a strong positivity instead of negativities. This positivity might reflect an enhanced reactivity of neurons in the corresponding area induced by the removal of lateral inhibition from the neurons as a result of local damage. ------------------------------------------------------------------------------------------------------------------------------------

Psychoactive Drugs-From Chemical Structure to Oxidative Stress Related to Dopaminergic Neurotransmission. A Review

Nowadays, more and more young people want to experience illegal, psychoactive substances, without knowing the risks of exposure. Besides affecting social life, psychoactive substances also have an important effect on consumer health. We summarized and analyzed the published literature data with reference to the mechanism of free radical generation and the link between chemical structure and oxidative stress related to dopaminergic neurotransmission. This review presents data on the physicochemical properties, on the ability to cross the blood brain barrier, the chemical structure activity relationship (SAR), and possible mechanisms by which neuronal injuries occur due to oxidative stress as a result of drug abuse such as "bath salts", amphetamines, or cocaine. The mechanisms of action of ingested compounds or their metabolites involve intermediate steps in which free radicals are generated. The brain is strongly affected by the consumption of such substances, facilitating the induction of neurodegenerative diseases. It can be concluded that neurotoxicity is associated with drug abuse. Dependence and oxidative stress are linked to inhibition of neurogenesis and the onset of neuronal death. Understanding the pathological mechanisms following oxidative attack can be a starting point in the development of new therapeutic targets.

A prospective longitudinal study shows putamen volume is associated with moderate amphetamine use and resultant cognitive impairments

Background

Amphetamine-type stimulants (ATS) have become a critical public health issue. Animal models have indicated a clear neurotoxic potential of ATSs. In humans, chronic use has been associated with cognitive deficits and structural brain abnormalities. However, cross-sectional retrospective designs in chronic users cannot truly determine the causal direction of the effects.

Objective

To prospectively determine effects of occasional ATS use on cognitive functioning and brain structure.

Methods

In a prospective longitudinal study design, cognitive functioning and brain structure were assessed at baseline and at 12-month follow-up in occasional ATS users (cumulative lifetime use <10 units at baseline).

Results

Examination of change scores between the initial examination and follow-up revealed declined verbal memory performance and putamen volume in users with high relative to low interim ATS exposure. In the entire sample, interim ATS use, memory decline, and putamen volume reductions were strongly associated.

Conclusions

The present findings support the hypothesis that ATS use is associated with deficient dorsal striatal morphology that might reflect alterations in dopaminergic pathways. More importantly, these findings strongly suggest that even occasional, low-dose ATS use disrupts striatal integrity and cognitive functioning.

Amphetamine Modulation of Long-Term Object Recognition Memory in Rats: Influence of Stress

Amphetamine is a potent psychostimulant that increases brain monoamine levels. Extensive evidence demonstrated that norepinephrine is crucially involved in the regulation of memory consolidation for stressful experiences. Here, we investigated amphetamine effects on the consolidation of long-term recognition memory in rats exposed to different intensities of forced swim stress immediately after training. Furthermore, we evaluated whether such effects are dependent on the activation of the peripheral adrenergic system. To this aim, male adult Sprague Dawley rats were subjected to an object recognition task and intraperitoneally administered soon after training with amphetamine (0.5 or 1 mg/kg), or its corresponding vehicle. Rats were thereafter exposed to a mild (1 min, 25 ± 1°C) or strong (5 min, 19 ± 1°C) forced swim stress procedure. Recognition memory retention was assessed 24-h after training. Our findings showed that amphetamine enhances the consolidation of memory in rats subjected to mild stress condition, while it impairs long-term memory performance in rats exposed to strong stress. These dichotomic effects is dependent on stress-induced activation of the peripheral adrenergic response.

Peripheral Inflammatory Biomarkers of Methamphetamine Withdrawal Patients Based on the Neuro-Inflammation Hypothesis: The Possible Improvement Effect of Exercise

Methamphetamine (MA) induced addiction and neuroinflammation has been implicated. Based on the neuroinflammation hypothesis, this study aims to investigate how exercise influences the craving of patients in MA withdrawal, and explore the mechanism of peripheral inflammation. A total of 90 patients in MA withdrawal were recruited. No difference was noted in the number of years of drug use and the frequency of drug use among patients, and the withdrawal time was within 2 months. The subjects were grouped based on the degree of craving induced by the cues: non-craving control group (NCC group), craving control group (CC group), and craving exercise group (CE group). The CE group was subjected to aerobic combined resistance training. Then, the ELISA method was used to detect plasma IL-6, TNF-α, and IL-1β concentrations; Visual Analog Scale (VAS) measurement of cue-induced cravings under Virtual Reality (VR) exposure (VR-VAS) and the Desires for Drug Questionnaire (DDQ) were used to assess cravings. Consequently, plasma IL-6, TNF-α, IL-1β, levels, and the VR-VAS and DDQ scores of MA withdrawal patients were significantly reduced after exercise. This study confirmed that 8 weeks of incremental load aerobic combined with resistance training reduces peripheral inflammation and significantly reduces the level of craving for MA.

Comparisons of Voxel-Based Morphometric Brain Volumes of Individuals with Methamphetamine-Induced Psychotic Disorder and Schizophrenia Spectrum Disorder and Healthy Controls

BACKGROUND

Several psychological and neurological pathways are described to explain the emergence and maintenance of psychiatric disorders, and changes in brain volumes and brain activity are observed as correlates of psychiatric disorders. In the present study, we investigated if and to what extent specific voxel-based morphometric brain volume differences could be observed among individuals with methamphetamine-induced psychosis (MAIP) and schizophrenia spectrum disorder (SSD) compared to healthy controls.

METHODS

A total of 69 individuals took part in the present study. Of those, 26 were diagnosed with MAIP, 23 with SSD, and 20 were healthy controls. After a thorough psychiatric assessment, participants underwent brain volume measurement.

RESULTS

Compared to healthy controls, participants with MAIP had smaller volumes for left caudate and left and right parahippocampal gyrus. Compared to healthy controls, participants with SSD had smaller volumes for the gray and white matter, left amygdala, left hippocampus, left parahippocampal gyrus, left putamen, and the total volume. Compared to individuals with MAIP, individuals with SSD had a lower white matter brain volume.

CONCLUSIONS

The pattern of results suggests that individuals with MAIP and SSD showed specific and regional brain atrophies on the left hemisphere, always compared to healthy controls. Given the cross-sectional design, it remains undisclosed if specific and regional brain atrophies were the cause or the consequence of the psychiatric issues.

Hippocampal Shape Maturation in Childhood and Adolescence

The hippocampus is a subcortical structure critical for learning and memory, and a thorough understanding of its neurodevelopment is important for studying these processes in health and disease. However, few studies have quantified the typical developmental trajectory of the structure in childhood and adolescence. This study examined the cross-sectional age-related changes and sex differences in hippocampal shape in a multisite, multistudy cohort of 1676 typically developing children (age 1-22 years) using a novel intrinsic brain mapping method based on Laplace-Beltrami embedding of surfaces. Significant age-related expansion was observed bilaterally and nonlinear growth was observed primarily in the right head and tail of the hippocampus. Sex differences were also observed bilaterally along the lateral and medial aspects of the surface, with females exhibiting relatively larger surface expansion than males. Additionally, the superior posterior lateral surface of the left hippocampus exhibited an age-sex interaction with females expanding faster than males. Shape analysis provides enhanced sensitivity to regional changes in hippocampal morphology over traditional volumetric approaches and allows for the localization of developmental effects. Our results further support evidence that hippocampal structures follow distinct maturational trajectories that may coincide with the development of learning and memory skills during critical periods of development.

COMT val158met genotype alters the effects of methamphetamine dependence on dopamine and dopamine-related executive function: preliminary findings

The Met-allele of the COMT Val158Met polymorphism slows metabolism and increases bioavailability of dopamine (DA) in the prefrontal cortex compared to the Val-allele. Healthy Met-carriers outperform Val-carriers on executive function (EF) tests, yet this 'advantage' disappears in methamphetamine (METH) dependence. Met-carriers may be disproportionately vulnerable to METH-related perturbations of DA, yet it is unknown whether COMT modulates METH effects on CSF DA biomarkers. Participants were 75 METH+ and 47 METH- men who underwent neurocognitive testing, COMT genotyping, and lumbar puncture. CSF was assayed for DA and its metabolite, homovanillic acid (HVA). Separate linear models regressed DA, HVA, and HVA/DA ratios on COMT, METH and their interaction. Pearson correlations examined associations between DA and EF. Significant interactions indicated that METH+ had lower DA and higher HVA/DA ratios among Met/Met, but not Val/Met-or Val/Val. Met/Met-exhibited the highest DA levels among METH-, whereas DA levels were comparable between Met/Met-and Val-carriers among METH+. Higher DA correlated with better EF in METH- Met/Met, but did not predict EF in the entire sample. DA was expectedly higher in METH- Met/Met, yet a discordant genotype-phenotype profile emerged in METH+ Met/Met, consistent with the notion that slow DA clearance exacerbates METH-associated DA dysregulation.

The effect of low dose amphetamine in rotenone-induced toxicity in a mice model of Parkinson's disease

OBJECTIVES

The effects of low dose amphetamine on oxidative stress and rotenone-induced neurotoxicity and liver injury were examined in vivo in a mice model of Parkinson's disease.

MATERIALS AND METHODS

Male mice were treated with rotenone (1.5 mg/kg, every other day for two weeks, subcutaneously). Mice received either the vehicle or amphetamine intraperitoneally at doses of 0.5, 1.0, or 2.0 mg/kg. Oxidative stress was assessed by measurement of the lipid peroxidation product malondialdehyde (MDA), nitric oxide (NO), total anti-oxidant capacity (TAC), and paraoxonase-1 (PON-1) activity in the brain and liver. In addition, brain concentrations of nuclear factor kappa B (NF-κB) and tyrosine hydroxylase were determined and histopathology and Bax/Bcl-2 immunohistochemistry were performed.

RESULTS

The levels of lipid peroxidation and NO were increased and TAC and PON-1 were decreased significantly compared with vehicle-injected control mice. There were also significantly increased NF-κB and decreased tyrosine hydroxylase in the brain following rotenone administration. These changes were significantly attenuated by amphetamine. Rotenone caused neurodegenerative changes in the substantia nigra, cerebral cortex, and hippocampus. The liver showed degenerative changes in hepatocytes and infiltration of Kupffer cells. Bax/Bcl2 ratio was significantly increased in brain and liver tissues. Amphetamine prevented these histopathological changes and the increase in apoptosis evoked by rotenone.

CONCLUSION

These results suggest that low dose amphetamine exerts anti-oxidant and anti-apoptotic effects, protects against rotenone-induced neurodegeneration, and could prevent neuronal cell degeneration in Parkinson's disease.

Higher impulsivity and lower grey matter volume in the bilateral prefrontal cortex in long-term abstinent individuals with severe methamphetamine use disorder

BACKGROUND

Previous studies have shown that grey matter volume (GMV) might be lower in individuals with methamphetamine use disorder and that dynamic alterations in selected brain regions might appear in individuals after short-term abstinence. However, the GMV of brains in these individuals after long-term abstinence is poorly understood. Moreover, individuals with severe methamphetamine use disorder have been considered to have high levels of impulsivity, but the biological mechanism is still unclear.

METHODS

In this study, the impulsivity of all participants was assessed using the Barratt Impulsiveness Scale (BIS-11). Using voxel-based morphometry (VBM) in conjunction with statistical parametric mapping on structural magnetic resonance images, the GMVs of the whole brain were compared among 32 drug-naïve healthy controls (HC) and 40 individuals with severe methamphetamine use disorder who had been abstinent for at least 20 months (SMUD-A).

RESULTS

We observed significantly higher BIS-11 impulsivity scores and lower GMV in the bilateral superior frontal cortex of SMUD-A individuals than in those of control subjects. The impulsivity score was negatively correlated with GMV in the right superior frontal cortex.

CONCLUSIONS

These findings offer novel evidence with respect to the impulsivity trait and brain GMV feature in long-term abstinent individuals with severe methamphetamine use disorder. Moreover, our findings suggest that lower GMV in the right superior frontal cortex might reflect a trait marker of higher impulsivity in this population.

Analysis of amphetamine and methamphetamine contents in seized tablets from Jazan, Saudi Arabia by liquid chromatography-mass spectroscopy (LC-MS/MS) and chemometric techniques

A number of illegal amphetamine tablets were seized from three different cities of Jazan province of southern Saudi Arabia and were analyzed for amphetamine and methamphetamine contents using LC-MS/MS technique. Analyses were performed using a previously reported method taking 0.1 M ammonium formate buffer (85%) and 15% acetonitrile with 0.1% formic acid as mobile phase with a total runtime of 12 min. This method was successfully applied for the routine analysis of amphetamine and methamphetamine in the seized tablets using amphetamine-D5 and methamphetamine-D5 as internal standards. Hierarchical cluster analysis was performed to establish the similarity between samples. The retention times (RT) for internal standard, amphetamine and methamphetamine were observed to be within 6.0–7.1 min. Ten tablet samples from each city were subjected to analysis and the amount of amphetamine in all the samples were found to be in the range of 9.07–14.77 mg, whereas, the amount of methamphetamine ranged from 0.12 to 0.24 mg in each tablet. Hierarchical cluster analysis showed presence of five clusters of samples indicating different characteristics and possible sources of amphetamine tablets. The largest cluster consisted of 15 samples which are expected to be of the same origin. Both amphetamine and methamphetamine are considered to be illegal products and their illegal trade and use is banned in many countries including Saudi Arabia. Therefore, there is an urgent need of strict regulations worldwide to check the illicit trafficking of these psychoactive substances and should be considered on priority.

Striatal and white matter volumes in chronic ketamine users with or without recent regular stimulant use

BACKGROUND

Previous studies found enlarged striatum and white matter in those with stimulants use disorders. Whether primarily ketamine users (Primarily-K) and ketamine users who co-used stimulants and other substances (K+PolyS) have abnormal brain volumes is unknown. This study aims to evaluate possible brain structural abnormalities, cognitive function and depressive symptoms, between Primarily-K and K+PolyS users.

METHODS

Striatal and white matter volumes were automatically segmented in 39 Primarily-K users, 41 K+PolyS users and 46 non-drug users (ND). Cognitive performance in 7 neurocognitive domains and depressive symptoms were also evaluated.

RESULTS

Ketamine users had larger caudates than ND-controls (Right: 1-way-ANCOVA-p=0.035; K+PolyS vs. ND, p=0.030; Linear trend for K+PolyS>Primarily-K>ND, p=0.011; Left: 1-way-ANCOVA-p=0.047, Primarily-K vs. ND p=0.051) and larger total white matter (1-way ANCOVA-p=0.009, Poly+K vs. Primarily-K, p=0.05; Poly+K vs. ND p=0.011; Linear trend for K+PolyS>Primarily-K >ND, p=0.004). Across all ketamine users, they performed poorer on Arithmetic, learning and memory tasks, and were more depressed than Non-users (p<0.001 to p=0.001). Greater lifetime ketamine usage correlated with more depressive symptoms (r=0.27, p=0.008). Larger white matter correlated with better learning across all participants (r=0.21, p=0.019), while larger right caudate correlated with lower depression scores in ketamine users (r=-0.28, p=0.013).

CONCLUSION

Ketamine users had larger caudates and total white matter than ND-controls. The even larger white matter in K+PolyS users suggests additive effects from co-use of ketamine and stimulants. However, across the ketamine users, since greater volumes were associated with better learning and less depressive symptom, the enlarged caudates and white matter might represent a compensatory response.

Methamphetamine acutely alters frontostriatal resting state functional connectivity in healthy young adults

Chronic use of methamphetamine impairs frontostriatal structure and function, which may result in increased incentive-motivational responses to drug cues and decreased regulation of drug-seeking behavior. However, less is known regarding how the drug affects these circuits after acute administration. The current study examined the effects of a single dose of methamphetamine on resting state frontostriatal functional connectivity in healthy volunteers. Participants (n = 22, 12 female) completed two sessions in which they received methamphetamine (20 mg) and placebo before a resting state scan during functional magnetic resonance imaging. Participants also provided self-report measures of euphoria and stimulation at regular intervals. We conducted seed-based voxelwise functional connectivity analyses using three bilateral striatal seed regions: nucleus accumbens (NAcc), caudate, and putamen and compared connectivity following methamphetamine versus placebo administration. Additionally, we conducted correlational analyses to assess if drug-induced changes in functional connectivity were related to changes in subjective response. Methamphetamine increased NAcc functional connectivity with medial frontal regions (ie, orbitofrontal cortex, medial frontal gyrus, and superior frontal gyrus) and decreased NAcc functional connectivity with subgenual anterior cingulate cortex (ACC). Methamphetamine also increased functional connectivity between putamen and left inferior frontal gyrus (IFG), and individuals who displayed greater drug-induced increase in connectivity reported less euphoria and stimulation. These findings provide important information regarding the effects of methamphetamine on brain function in nonaddicted individuals. Further studies will reveal whether such effects contribute to the abuse potential of the drug and whether they are related to the frontostriatal impairments observed after chronic methamphetamine use.

Self-Reported Drug Use and Hearing Measures in Young Adults

Purpose The purpose of this study was to examine marijuana or other substance use on pure-tone thresholds and distortion product otoacoustic emissions (DPOAEs) in young adults. Method Young adults (n = 243; 182 women, 61 men; M _age = 20.9 years, SD = 2.7 years) participated in this study. Survey data included personal music system use, marijuana use, and misuse of prescription medications. Otoscopy, tympanometry, pure-tone audiometry, and DPOAEs were obtained. Pure tones from octave frequencies of 0.25 through 8 kHz were obtained, and DPOAEs were recorded between f₂ frequencies of 1 and 6 kHz using two continuously presented stimulus tones swept in frequency. Results Those who reported marijuana or stimulant use had similar pure-tone averages (0.5, 1, 2, and 4 kHz) compared to those who reported never using marijuana or stimulants. Women who reported marijuana use in the past 30 days > two times had statistically significant higher mean DPOAEs compared to women who reported ≤ two times or no marijuana use in the past 30 days. Men, however, who reported marijuana use in the past 30 days > two times had lower, but not statistically significant, mean DPOAEs compared to men who reported ≤ two times or no marijuana use in the past 30 days. Women who reported ever using stimulants had statistically significant higher mean DPOAEs compared to women who reported never using stimulants; for men, mean DPOAEs were similar between those who reported ever using stimulants and those who never used stimulants. Conclusions The results of this study demonstrate different and contradictory associations between marijuana use, stimulant use, and hearing outcomes as a function of sex. Future research is needed to explore these associations utilizing larger sample sizes while accounting for additional harmful exposures to other noise exposures.

Resting-state effective connectivity in the motive circuit of methamphetamine users: A case controlled fMRI study

Methamphetamine (MA) and other psychostimulants target the motive circuit of the brain, which is involved in reward, behavioral sensitization, and relapse to drug-seeking/taking behavior. In spite of this fact, the data regarding the effective connectivity (EC) in this circuit among MA users is scarce. The present study aimed to assess resting-state EC in the motive circuit of MA users during abstinence using the fMRI technique. Seventeen MA users after abstinence and 18 normal controls were examined using a 3 T Siemens fMRI scanner. After extracting time series of the motive circuit, EC differences in the motive circuit were analyzed using dynamic causal modeling (DCM). The findings revealed that abstinent MA users had an enhanced EC from the prefrontal cortex (PFC) to the ventral palladium (VP) (PFC→VP) and on the mediodorsal thalamus (MD) self-loop (MD→MD), but they showed a decreased connectivity on the VP self-loop (VP→VP) compared to healthy controls. The findings suggest that abstinent MA users may suffer from a limited pathology in connectivity within the motive circuit involved in reward, behavioral sensitization, and relapse. The enhanced PFC→VP seems to be a compensatory mechanism to control or regulate the subcortical regions involved in reward and behavioral sensitization. Furthermore, the enhanced connectivity on the MD self-loop and the decreased connectivity on the VP self-loop in abstinent MA users may, at least partially, affect the output of the limbic system, which can be seen in the behavioral sensitization and relapse processes. Nonetheless, further investigation in this area is strongly recommended to elucidate the exact mechanisms involved.

Disrupted resting-state brain functional network in methamphetamine abusers: A brain source space study by EEG

This study aimed to examine the effects of chronic methamphetamine use on the topological organization of whole-brain functional connectivity network (FCN) by reconstruction of neural-activity time series at resting-state. The EEG of 36 individuals with methamphetamine use disorder (IWMUD) and 24 normal controls (NCs) were recorded, pre-processed and source-reconstructed using standardized low-resolution tomography (sLORETA). The brain FCNs of participants were constructed and between-group differences in network topological properties were investigated using graph theoretical analysis. IWMUD showed decreased characteristic path length, increased clustering coefficient and small-world index at delta and gamma frequency bands compared to NCs. Moreover, abnormal changes in inter-regional connectivity and network hubs were observed in all the frequency bands. The results suggest that the IWMUD and NCs have distinct FCNs at all the frequency bands, particularly at the delta and gamma bands, in which deviated small-world brain topology was found in IWMUD.

A comparison of regional brain volumes and white matter connectivity in subjects with stimulant induced psychosis versus schizophrenia

RATIONALE

Schizophrenia and stimulant-induced psychosis (SIP) represent two different forms of psychotic disorder, with different etiologies. While many of the symptoms of psychosis are common to both disorders, there have been few direct comparisons between these conditions, especially when controlling for stimulant use in individuals with schizophrenia.

OBJECTIVES

We directly compared both psychotic disorders with a comprehensive battery of clinical, neurocognitive and neuroanatomical measures. This included one group with SIP (and concurrent stimulant dependence) and two groups with schizophrenia (either with or without concurrent stimulant dependence).

METHODS

Ninety-six participants were recruited from a marginalized urban population, which included 39 with SIP (and concurrent stimulant dependence), 18 with schizophrenia (without stimulant dependence), and 39 with schizophrenia (with concurrent stimulant dependence). All subjects had extensive clinical and neurocognitive evaluations, complemented with structural MRI including diffusion tensor imaging (DTI) sequences to determine regional brain volumes and white matter connectivity.

RESULTS

Both positive and negative symptoms were greater in the SZ-dependent group than the other two. Neurocognitive function was broadly similar. The structural brain imaging revealed lateralized changes to the left parietal/temporal lobe, in which regional volumes were smaller in the SZ-dependent than the SZ-non-dependent group. DTI analysis indicated extensive decreases in fractional anisotropy, with parallel increases in radial diffusivity, in the SIP group compared to the SZ-dependent group.

CONCLUSIONS

These findings reveal both similarities and differences between SIP and schizophrenia. Furthermore, schizophrenia with concurrent stimulant dependence may be associated with a different clinical and neuroanatomical profile as compared to schizophrenia alone.

Angiotensin II modulates amphetamine-induced glial and brain vascular responses, and attention deficit via angiotensin type 1 receptor: Evidence from brain regional sensitivity to amphetamine

Amphetamine-induced neuroadaptations involve vascular damage, neuroinflammation, a hypo-functioning prefrontal cortex (PFC), and cognitive alterations. Brain angiotensin II, through angiotensin type 1 receptor (AT₁ -R), mediates oxidative/inflammatory responses, promoting endothelial dysfunction, neuronal oxidative damage and glial reactivity. The present work aims to unmask the role of AT₁ -R in the development of amphetamine-induced changes over glial and vascular components within PFC and hippocampus. Attention deficit was evaluated as a behavioral neuroadaptation induced by amphetamine. Brain microvessels were isolated to further evaluate vascular alterations after amphetamine exposure. Male Wistar rats were administered with AT₁ -R antagonist, candesartan, followed by repeated amphetamine. After one week drug-off period, animals received a saline or amphetamine challenge and were evaluated in behavioral tests. Afterward, their brains were processed for cresyl violet staining, CD11b (microglia marker), GFAP (astrocyte marker) or von Willebrand factor (vascular marker) immunohistochemistry, and oxidative/cellular stress determinations in brain microvessels. Statistical analysis was performed by using factorial ANOVA followed by Bonferroni or Tukey tests. Repeated amphetamine administration increased astroglial and microglial markers immunoreactivity, increased apoptotic cells, and promoted vascular network rearrangement at the PFC concomitantly with an attention deficit. Although the amphetamine challenge improved the attentional performance, it triggers detrimental effects probably because of the exacerbated malondialdehyde levels and increased heat shock protein 70 expression in microvessels. All observed amphetamine-induced alterations were prevented by the AT₁ -R blockade. Our results support the AT₁ -R involvement in the development of oxidative/inflammatory conditions triggered by amphetamine exposure, affecting cortical areas and increasing vascular susceptibility to future challenges.

Post-retrieval Extinction Prevents Reconsolidation of Methamphetamine Memory Traces and Subsequent Reinstatement of Methamphetamine Seeking

Methamphetamine abuse has become a serious public health problem. However, effective treatment for methamphetamine addiction remains elusive, especially considering its high rate of relapse after treatment. A conditioned stimulus (CS) memory retrieval–extinction procedure has been demonstrated to decrease reinstatement of cocaine, heroin, and alcohol seeking in rats, and to reduce cue-induced cravings in heroin and nicotine addicts. The goal of the present study is to explore the effect of the CS memory retrieval–extinction procedure on methamphetamine seeking in rats and the underlying mechanisms. We found that daily retrieval of methamphetamine-associated memories 1 h before extinction sessions decreased subsequent drug priming-induced reinstatement, spontaneous recovery, and renewal of methamphetamine seeking. We also found that retrieval of methamphetamine-associated memories induced neuronal activation in the basolateral amygdala (BLA), while presenting extinction within the time window of reconsolidation abolished the neuronal activation in BLA. These results indicate that the CS memory retrieval–extinction procedure could prevent reconsolidation of methamphetamine memory traces in BLA and subsequent methamphetamine craving and relapse.

Stroboscopic light effects during electronic dance music festivals and photosensitive epilepsy: a cohort study and case report

OBJECTIVES

Electronic dance music (EDM) concerts are becoming increasingly popular. Strong stroboscopic light effects are commonly part of these shows, and may provoke seizures in individuals with photosensitive epilepsy. This study aims to examine the risk of epileptic seizures during EDM concerts.

SETTING

28 EDM concerts taking place in The Netherlands.

PARTICIPANTS

We describe a young man who experienced a seizure during an EDM concert, and who later showed a positive electroencephalographic provocation test during exposure to video footage of the same concert. Subsequently, we performed a cohort study of 400 343 visitors to EDM concerts, divided in those exposed (concert occurring in darkness) versus unexposed (concert in daylight) to stroboscopic light effects.

RESULTS

In total, 400 343 EDM concert visitors were included: 241 543 (representing 2 222 196 person hours) in the exposed group and 158 800 (representing 2 334 360 person hours) in the control group. The incidence density ratio of epileptic seizures in exposed versus unexposed individuals was 3.5 (95% CI: 1.7 to 7.8; p<0.0005). Less than one-third of cases occurred during use of ecstasy or similar stimulant drugs.

CONCLUSION

Stroboscopic light effects during EDM concerts occurring in darkness probably more than triple the risk of epileptic seizures. Concert organisers and audience should warn against the risk of seizures and promote precautionary measures in susceptible individuals.

Parkinson's Disease and the Environment

Parkinson's disease (PD) is a heterogeneous neurodegenerative disorder that affects an estimated 10 million sufferers worldwide. The two forms of PD include familial and sporadic, and while the etiology of PD is still largely unknown, the condition is likely to be multifactorial with genetic and environmental factors contributing to disease genesis. Diagnosis of the condition is attained through the observation of cardinal clinical manifestations including resting tremor, muscle rigidity, slowness or loss of movement, and postural instability. Unfortunately, by the time these features become apparent extensive neurological damage has already occurred. A cure for PD has not been identified and the current therapy options are pharmaceutical- and/or surgical-based interventions to treat condition symptoms. There is no specific test for PD and most diagnoses are confirmed by a combination of clinical symptoms and positive responses to dopaminergic drug therapies. The prevalence and incidence of PD vary worldwide influenced by several factors such as age, gender, ethnicity, genetic susceptibilities, and environmental exposures. Here, we will present environmental factors implicated in sporadic PD onset. By understanding the mechanisms in which environmental factors interact with, and affect the brain we can stride toward finding the underlying cause(s) of PD.