Overdose from Unintentional Fentanyl Use when Intending to Use a Non-opioid Substance: An Analysis of Medically Attended Opioid Overdose Events

Fentanyl-mixed and substituted heroin is well-documented, but less is known about unintentional fentanyl use among people using stimulants. To determine the prevalence of and racial and ethnic disparities in unintentional fentanyl use among people experiencing a medically attended opioid overdose, we reviewed 448 suspected non-fatal overdose cases attended by a community paramedic overdose response team in San Francisco from June to September 2022. We applied a case definition for opioid overdose to paramedic records and abstracted data on intended substance use prior to overdose. Among events meeting case criteria with data on intended substance use, intentional opioid use was reported by 57.3%, 98.0% of whom intended to use fentanyl. No intentional opioid use was reported by 42.7%, with most intending to use stimulants (72.6%), including methamphetamine and cocaine. No intentional opioid use was reported by 58.5% of Black, 52.4% of Latinx, and 28.8% of White individuals (p = 0.021), and by 57.6% of women and 39.5% of men (p = 0.061). These findings suggest that unintentional fentanyl use among people without opioid tolerance may cause a significant proportion of opioid overdoses in San Francisco. While intentional fentanyl use might be underreported, the magnitude of self-reported unintentional use merits further investigation to confirm this phenomenon, explore mechanisms of use and disparities by race and ethnicity, and deploy targeted overdose prevention interventions.

Data-driven intelligent modeling, optimization, and global sensitivity analysis of a xanthan gum biosynthesis process

In this study, the focus was to produce xanthan gum from pineapple waste using Xanthomonas campestris. Six machine learning models were employed to optimize fermentation time and key metabolic stimulants (KH2PO4 and NH4NO3). The production of xanthan gum was optimized using two evolutionary optimization algorithms, particle swarm optimization, and genetic algorithm while the importance of input features was ranked using global sensitivity analysis. KH2PO4 was the most important input and was found to be beneficial for xanthan gum production, while a limited amount of nitrogen was needed. The extreme learning machine model was the most adequate for modeling xanthan gum production, predicting a maximum xanthan yield of 10.34 g/l (an 11.9 % increase over the control) at a fermentation time of 3 days, KH2PO4 of 15 g/l, and NH4NO3 of 2 g/l. This study has provided important insights into the intelligent modeling of a biostimulated process for valorizing pineapple waste.

Attention-Deficit Hyperactivity Disorder Stimulant Therapy and Prescription Drug Misuse During Transition to Young Adulthood

OBJECTIVE

Limited prospective data exist about the impact of stimulant therapy for attention-deficit hyperactivity disorder (ADHD) during adolescence on the risk for later prescription drug misuse (PDM; i.e., of benzodiazepines, opioids, and stimulants).

METHODS

National longitudinal multicohort panels (baseline cohort years 2005-2017) of U.S. 12th grade students (N=11,066; ages 17 and 18 years) from the Monitoring the Future study were surveyed via self-administered questionnaires and followed up biennially during young adulthood (ages 19-24). A multivariable analysis was used to assess whether adolescents' lifetime history of stimulant therapy for ADHD was associated with subsequent PDM.

RESULTS

Overall, 9.9% of adolescents reported lifetime stimulant therapy for ADHD at ages 17 and 18. No significant differences were found in the adjusted odds of later incidence or prevalence of past-year PDM during young adulthood between adolescents with lifetime stimulant therapy and adolescents with no stimulant therapy. Over the 5-year follow-up, past-year PDM during young adulthood was most prevalent among adolescents who reported both stimulant therapy and prescription stimulant misuse (53.1%) and those who reported prescription stimulant misuse only (51.5%). Compared with adolescents in a control group without lifetime stimulant therapy or misuse, adolescents reporting prescription stimulant misuse had significantly higher adjusted odds of later incidence and prevalence of PDM during young adulthood.

CONCLUSIONS

Adolescents' stimulant therapy for ADHD was not significantly associated with increased risk for later PDM during young adulthood. In contrast, adolescents' misuse of prescription stimulants strongly predicted later PDM. Monitoring adolescents for prescription stimulant misuse may help identify and mitigate the risk for future PDM.

Blunted Neurobehavioral Loss Anticipation Predicts Relapse to Stimulant Drug Use

BACKGROUND

Patients with stimulant use disorder experience high rates of relapse. While neurobehavioral mechanisms involved in initiating drug use have been studied extensively, less research has focused on relapse.

METHODS

To assess motivational processes involved in relapse and diagnosis, we acquired functional magnetic resonance imaging responses to nondrug (monetary) gains and losses in detoxified patients with stimulant use disorder (n = 68) and community control participants (n = 42). In a prospective multimodal design, we combined imaging of brain function, brain structure, and behavior to longitudinally track subsequent risk for relapse.

RESULTS

At the 6-month follow-up assessment, 27 patients remained abstinent, but 33 had relapsed. Patients with blunted anterior insula (AIns) activity during loss anticipation were more likely to relapse, an association that remained robust after controlling for potential confounds (i.e., craving, negative mood, years of use, age, and gender). Lower AIns activity during loss anticipation was associated with lower self-reported negative arousal to loss cues and slower behavioral responses to avoid losses, which also independently predicted relapse. Furthermore, AIns activity during loss anticipation was associated with the structural coherence of a tract connecting the AIns and the nucleus accumbens, as was functional connectivity between the AIns and nucleus accumbens during loss processing. However, these neurobehavioral responses did not differ between patients and control participants.

CONCLUSIONS

Taken together, the results of the current study show that neurobehavioral markers predicted relapse above and beyond conventional self-report measures, with a cross-validated accuracy of 72.7%. These findings offer convergent multimodal evidence that implicates blunted avoidance motivation in relapse to stimulant use and may therefore guide interventions targeting individuals who are most vulnerable to relapse.

Lack of effect of methamphetamine on reward-related brain activity in healthy adults

INTRODUCTION

Stimulant drugs are thought to alter processing of rewarding stimuli. However, the mechanisms by which they do this are not fully understood.

METHOD

In this study we used EEG to assess effects of single doses of methamphetamine (MA) on neural responses during anticipation and receipt of reward in healthy volunteers. Healthy young men and women (N = 28) completed three sessions in which they received placebo, a low MA dose (10 mg) or a higher MA dose (20 mg) under double blind conditions. Subjective and cardiovascular measures were obtained, and EEG was used to assess brain activity during an electrophysiological version of the Monetary Incentive Delay (eMID) task.

RESULTS

EEG measures showed expected patterns during anticipation and receipt of reward, and MA produced its expected effects on mood and cardiovascular function. However, MA did not affect EEG responses during either anticipation or receipt of rewards.

CONCLUSIONS

These findings suggest that the effects of MA on EEG signals of reward processing are subtle, and not related to the drug's effects on subjective feelings of well-being. The findings contribute to our understanding of the neural effects of MA during behaviors related to reward.

Is age of onset and duration of stimulant therapy for ADHD associated with cocaine, methamphetamine, and prescription stimulant misuse?

BACKGROUND

To assess whether age of onset and duration of stimulant therapy for attention-deficit/hyperactivity disorder (ADHD) are associated with cocaine, methamphetamine, and prescription stimulant misuse during adolescence.

METHODS

Nationally representative samples of US 10th and 12th grade students (N = 150,395) from the Monitoring the Future study were surveyed via self-administered questionnaires from 16 annual surveys (2005-2020).

RESULTS

An estimated 8.2% of youth received stimulant therapy for ADHD during their lifetime (n = 10,937). More than one in 10 of all youth reported past-year prescription stimulant misuse (10.4%)-past-year cocaine (4.4%) and methamphetamine (2.0%) use were less prevalent. Youth who initiated early stimulant therapy for ADHD (≤9 years old) and for long duration (≥6 years) did not have significantly increased adjusted odds of cocaine or methamphetamine use relative to population controls (ie, non-ADHD and unmedicated ADHD youth). Youth who initiated late stimulant therapy for ADHD (≥10 years old) and for short duration (<1 year) had significantly higher odds of past-year cocaine or prescription stimulant misuse in adolescence than those initiating early stimulant therapy for ADHD (≤9 years old) and for long duration (≥6 years). Youth who initiated late stimulant therapy for ADHD (≥10 years) for short duration (<1 year) had significantly higher odds of past-year cocaine, methamphetamine, and prescription stimulant misuse versus population controls during adolescence. No differences in past-year cocaine, methamphetamine, and prescription stimulant misuse were found between individuals who only used non-stimulant therapy for ADHD relative to youth who initiated early stimulant therapy (≤9 years old) and for long duration (≥6 years).

CONCLUSIONS

An inverse relationship was found between years of stimulant therapy and illicit and prescription stimulant misuse. Adolescents with later initiation and/or shorter duration of stimulant treatment for ADHD should be monitored for potential illicit and prescription stimulant misuse.

The association between suspected long-COVID and stimulant prescribing in the United States

OBJECTIVES

This study sought to determine the association between suspected long-COVID and receipt of a stimulant prescription among persons diagnosed with COVID-19 and to describe clinical and demographic factors associated with receiving a stimulant prescription.

METHODS

US patients 18 and older who had a COVID-19 diagnosis or a positive COVID-19 PCR test from April 1st, 2020 through December 21st, 2022 recorded in a national electronic health record data set obtained from TriNetX were assessed. Comparison subjects were propensity score matched on baseline covariates to those with a symptom of or diagnosis of long-COVID. A Cox Proportional Hazards models was used to estimate the influence of long-COVID on stimulant prescription receipt.

RESULTS

Those with long-COVID (n = 65,329) were twice as likely to be prescribed a stimulant as persons with only acute COVID-19 (n = 189,438, HR=2.162; 1.929-2.423). Among persons with long-COVID, persons with new onset ADHD (HR=7.196; 5.749- 9.007), opioid-related disorders (HR=2.140; 1.264-3.621) and mood disorders (HR=1.649; 1.336-2.035) were more likely to be prescribed a stimulant.

CONCLUSION

Further research describing the risks associated with increased stimulant use among persons with long-COVID is warranted.

Translating the nuanced risk for substance use among adolescents treated for attention-deficit/hyperactivity disorder (ADHD) into clinical practice: a commentary on McCabe et al. (2023)

In their recent examination of the Monitoring the Future (MTF) data, McCabe et al. (Journal of Child Psychology and Psychiatry, 2023) address the complex, longstanding, and clinically valuable questions of whether and how stimulant medication treatment for adolescents with ADHD relates to their risk for substance use. Here, we expand on the authors' interpretations of their nuanced findings of increased risk for illicit stimulant use and non-prescribed stimulant medication use for youth with later age of medication treatment initiation and shorter treatment duration. We particularly focus on highlighting tangible clinical implications, and we recommend ways future research can build on the authors' findings to further clarify this important issue.

Nucleus accumbens shell neurons' early sensitivity to cocaine is associated with future increases in drug intake

The striatum, both dorsal and ventral, is strongly implicated in substance use disorder. Chronic consumption of abused substances, such as cocaine, can cause an oversaturation of mesostriatal dopamine, which results in alterations in the firing of striatal neurons. While most preclinical studies of drug self-administration (S-A) are focused on these alterations, individual differences in a subject's early responses to drugs can also account for substantial differences in addiction susceptibility. In this study, we modeled longitudinal pharmacokinetics using data from a previous longitudinal study (Coffey et al., 2015) and aimed to determine if firing in specific dorsal and ventral striatal subregions was subject to changes across chronic cocaine S-A, and if individual animal differences in striatal firing in response to early drug exposure correlated with increases in drug intake. We observed that the firing patterns of nucleus accumbens (NAc) core and shell neurons exhibited increasing sensitivity to cocaine over the first 6 S-A sessions and maintained a strong negative correlation between drug intake and neuronal firing rates across chronic S-A. Moreover, we observed that the early sensitivity of NAc shell neurons to cocaine correlated with future increases in drug intake. Specifically, rats whose NAc shell neurons were most inhibited by increasing levels of cocaine upon first exposure exhibited the strongest increases in cocaine intake over time. If this difference can be linked to a genetic difference, or druggable targets, it may be possible to screen for similar addiction susceptibility in humans or develop novel preemptive pharmacotherapies.

Hormonal involvement in boosting the vegetative vigour underlying caffeine-related improvements in lentil production

Previous studies have shown that caffeine (1,3,7-trimethylxanthine) has some potential for its use as a biostimulant ingredient for boosting lentil production at suboptimal temperatures. However, some limitations to its use include its potential side effects as an emerging contaminant and the current lack of knowledge of its mechanism of action. Here, we aimed to study the mechanisms underlying improved lentil production upon caffeine application. Greenhouse-grown plants treated with caffeine (at 10-5 M, 10-4 M, and 10-3 M) were compared to an untreated, control treatment, and both reproductive and vegetative vigour were evaluated in parallel with endogenous foliar concentrations of phytohormones, including both stress and growth-related hormones. Results showed an enhanced lentil production at the highest caffeine concentration (10-3 M) which might be attributed, at least in part, to a greater vegetative vigour. The hormonal profiling revealed a dual effect. Firstly, there was a specific increase in jasmonoyl-isoleucine (JA-Ile) in the short term, which may provide a priming effect. Secondly, abscisic acid (ABA) content kept at low levels and the active cytokinin (CK) isopentenyl adenine (2-iP) increased and persisted at high levels throughout the reproductive stage. Cytokinin-mediated effects on growth, and more specifically the high CK/ABA ratios in leaves, appeared to mediate caffeine-related effects in boosting vegetative vigour. In conclusion, caffeine emerges as a compelling alkaloid for integration into biostimulant formulations due to its favorable effect in boosting lentil production through an improvement of vegetative vigour. These outcomes appear to be modulated by phytohormones, most notably jasmonates, priming plants for improved performance under suboptimal temperatures, and cytokinins, alongside ABA and its associated ratios, collectively enhancing plant growth and reproductive vigour in challenging conditions.

Stimulant prodrugs: A pharmacological and clinical assessment of their role in treating ADHD and binge-eating disorder

In this review, we critically evaluate the contribution of prodrugs to treating two related psychiatric disorders, attention-deficit hyperactivity disorder (ADHD) and binge-eating disorder (BED). ADHD is characterized by inattentiveness, distractibility, impulsiveness, and hyperactivity. BED is also an impulse-control disorder which leads to frequent, compulsive episodes of excessive eating (binges). Lisdexamfetamine (LDX; prodrug of d-amphetamine) is approved to treat both ADHD and BED. Serdexmethylphenidate (SDX; prodrug of d-threo-methylphenidate) is not clinically approved as monotherapy but, in a fixed-dose combination with immediate release d-threo-methylphenidate (Azstarys™), SDX is approved for managing ADHD in children/adolescents. The pharmacological actions of a stimulant mediate both its efficacy and side-effects. Therefore, daily management of ADHD or BED to maintain optimum efficacy and tolerability places highly restrictive requirements on the pharmacokinetic/pharmacodynamic (PK/PD) characteristics of stimulant medications, especially prodrugs. Prodrugs must have good bioavailability and rapid metabolism to provide therapeutic efficacy soon after morning dosing combined with providing stimulant coverage throughout the day/evening. A wide selection of dosages and linear PK for the prodrug and its active metabolite are essential requirements for treatment of these conditions. The proposed neurobiological causes of ADHD and BED are described. The chemical, pharmacological and PK/PD properties responsible for the therapeutic actions of the prodrugs, LDX and SDX, are compared and contrasted. Finally, we critically assess their contribution as ADHD and BED medications, including advantages over their respective active metabolites, d-amphetamine and d-threo-methylphenidate, and also their potential for misuse and abuse.

Methamphetamine alters nucleus accumbens neural activation to monetary loss in healthy young adults

RATIONALE

Stimulant drugs like methamphetamine (MA) activate brain reward circuitry, which is linked to the development of problematic drug use. It is not clear how drugs like MA alter neural response to a non-drug reward.

OBJECTIVES

We examined how acute MA impacts neural response to receipt of a monetary reward relative to a loss in healthy adults. We hypothesized that MA (vs. placebo) would increase mesolimbic neural activation to reward, relative to loss.

METHODS

In a within-subject, randomized, cross-over, double-blind, placebo-controlled design, 41 healthy adults completed the Doors monetary reward task during fMRI after ingestion of placebo or 20 mg MA. We examined drug effects on neural response to reward receipt (Win vs. Loss) using a priori anatomical striatal regions of interest (nucleus accumbens (NAcc), caudate, putamen).

RESULTS

MA decreased NAcc BOLD activation to reward vs loss compared to placebo (p=.007) without altering caudate or putamen BOLD activation. Similar effects for reward vs. loss were obtained using whole brain analysis. Additional exploratory ROI analysis comparing reward and loss activation relative to a neutral "fixation" period indicated that MA increased NAcc BOLD activation during loss trials, without decreasing activation during win trials.

CONCLUSIONS

This preliminary evidence suggests that MA increases NAcc neural response to the receipt of monetary loss. Additional studies are needed to replicate our findings and clarify the mechanisms contributing to altered mesolimbic neural response to reward and loss receipt during stimulant intoxication.

l-Arginine/nitric oxide pathway and oxidative stress in adults with ADHD: Effects of methylphenidate treatment

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) is a mental disorder that was once thought to occur only in children. Meanwhile, it is known that adults can also be affected. The first-line drug in children and adults to treat symptoms of inattention, impulsivity, lack of self-regulation, and hyperactivity is methylphenidate (MPH). Known adverse effects of MPH include cardiovascular problems, such as elevated blood pressure and heart rate. Therefore, biomarkers to monitor potential cardiovascular side effects of MPH are needed. The l-Arginine/Nitric oxide (Arg/NO) pathway is involved in noradrenaline and dopamine release as well as in normal cardiovascular functioning and is therefore a prime candidate for the search of biomarkers. The aim of the present study was to investigate the Arg/NO pathway as well as oxidative stress in adult ADHD patients in plasma and urine and the potential influence of MPH medication.

METHODS

In plasma and urine samples of 29 adults with ADHD (39.2 ± 10.9 years) and 32 healthy adults serving as controls (CO) (38.0 ± 11.6 years) the major NO metabolites nitrite and nitrate, Arg, the NO synthesis inhibitor asymmetric dimethylarginine (ADMA) and its major urinary metabolite dimethylamine (DMA) as well as malondialdehyde (MDA) were measured by gas chromatography-mass spectrometry.

RESULTS

Of the 29 patients with ADHD 14 were currently without MPH treatment (-MPH) and 15 were treated with MPH (+MPH). Plasma nitrate concentrations were significantly higher in patients not treated with MPH vs. CO (-MPH 60.3 μM [46.2-76.0] vs. CO 44.4 μM [35.0-52.7]; p = 0.002), while plasma nitrite tended to be higher in -MPH patients (2.77 μM [2.26-3.27]) vs. CO (2.13 μM [1.50-2.93]; p = 0.053). Additionally, plasma creatinine concentrations were significantly different, with -MPH showing significantly higher concentrations than the other two groups (-MPH 141 μM [128-159]; +MPH 96.2 μM [70.2-140]; Co 75.9 μM [62.0-94.7]; p < 0.001). Urinary creatinine excretion tended to be lowest in -MPH group vs. +MPH and CO (-MPH 11.4 ± 8.88 mM; +MPH 20.7 ± 9.82 mM; 16.6 ± 7.82 mM; p = 0.076). None of the other metabolites, including MDA, a marker of oxidative stress, showed a difference between the groups.

CONCLUSION

Adult patients with ADHD, who are not treated with MPH (-MPH), showed varied Arg/NO pathway, but Arg bioavailability seemed to be consistent over the groups. Our findings imply that urinary reabsorption may be increase and/or excretion of nitrite and nitrate may be decreased in ADHD, resulting in an increase in the plasma concentration of nitrite. MPH seems to partially reverse these effects by not yet known mechanisms, and does not affect oxidative stress.

Drugs involved in Kentucky drug poisoning deaths and relation with antecedent controlled substance prescription dispensing

BACKGROUND

The shift from prescription to illicit drugs involved in drug poisoning deaths raises questions about the current utility of prescription drug monitoring program (PDMP) data to inform drug poisoning (overdose) prevention efforts. In this study, we describe relations between specific drugs involved in Kentucky drug poisoning deaths and antecedent controlled substance (CS) dispensing.

METHODS

The study used linked death certificates and PDMP data for 2,248 Kentucky resident drug poisoning deaths in 2021. Death certificate literal text analysis identified drugs mentioned with involvement (DMI) in drug poisoning deaths. We characterized the concordance between each DMI and the CS dispensing history for this drug at varying timepoints since 2008.

RESULTS

Overall, 25.5% of all decedents had dispensed CS in the month before fatal drug poisoning. Over 80% of decedents were dispensed opioid(s) since 2008; the percentage was similar regardless of opioid involvement in the poisoning death. One-third of decedents had dispensed buprenorphine for treatment of opioid use disorder since 2008, but only 6.1% had dispensed buprenorphine in the month preceding death. Fentanyl/fentanyl analogs were DMI in 1,568 (69.8%) deaths, yet only 3% had received a fentanyl prescription since 2008. The highest concordance in the month preceding death was observed for clonazepam (43.6%).

CONCLUSION

Overall, concordance between CS dispensing history and the drugs involved in poisoning deaths was low, suggesting a need to reevaluate the complex relationships between prescription medication exposure and overdose death and to expand harm reduction interventions both within and outside the healthcare system to reduce drug poisoning mortality.

Effect of 3 and 6 mg/kg of caffeine on fat oxidation during exercise in healthy active females

The aim of this study was to investigate the effect of 3 and 6 mg of caffeine per kg of body mass (mg/kg) on whole-body substrate oxidation during an incremental cycling exercise test in healthy active women. Using a double-blind placebo-controlled counterbalanced experimental design, 14 subjects performed three identical exercise trials after the ingestion of 3 or 6 mg/kg of caffeine or placebo. The exercise trials consisted of an incremental test on a cycle ergometer with 3-min stages at workloads from 30 to 70% of maximal oxygen uptake (VO2max). Substrate oxidation rates were measured by indirect calorimetry. During exercise, there was a significant effect of substance (F = 5.221; p = 0.016) on fat oxidation rate. In comparison to the placebo, 3 mg/kg of caffeine increased fat oxidation rates at 30 to 60% of VO2max (all p < 0.050) and 6 mg/kg at 30 to 50% of VO2max (all p < 0.050). There was also a significant effect of substance (F = 5.221; p = 0.016) on carbohydrate oxidation rate (F = 9.632; p < 0.001). In comparison to placebo, both caffeine doses decreased carbohydrate oxidation rates at 40 to 60% VO2max (all p < 0.050). The maximal rate of fat oxidation with placebo was 0.24 ± 0.03 g/min, which increased with 3 mg/kg to 0.29 ± 0.04 g/min (p = 0.032) and to 0.29 ± 0.03 with 6 mg/kg of caffeine (p = 0.042). Acute intake of caffeine improves the utilization of fat as a fuel during submaximal aerobic exercise in healthy active women with an effect of similar magnitude after the intake of 3 and 6 mg of caffeine per kg of body mass. Thus, the use of 3 mg/kg of caffeine would be more recommended than 6 mg/kg for women seeking increased fat utilization during submaximal exercise.

Secondary outcomes and qualitative findings of an open-label feasibility trial of lisdexamfetamine dimesylate for adults with bulimia nervosa

BACKGROUND

There is emerging evidence that stimulants warrant further investigation as a treatment for bulimia nervosa (BN) including a recent open-label feasibility trial examining the use of lisdexamfetamine dimestylate (LDX) for BN. The current report presents the secondary outcomes and qualitative interview results from that feasibility trial. These outcomes explore several purported mechanisms that may explain how stimulants affect symptoms of BN: appetite, impulsivity, obsessive and compulsive symptoms, eating disorder psychopathology/impairment and reward-based decision-making.

METHODS

Twenty-three participants with BN received LDX for eight weeks. Questionnaires assessing appetite, impulsivity, obsessive and compulsive symptoms, eating disorder psychopathology and impairment were administered at baseline and post-treatment. Participants also completed a two-step reinforcement learning task to assess their decision-making. Semi-structured interviews took place at baseline, week 5, and follow-up.

RESULTS

Reductions in hunger, food-related impulsivity, obsessive and compulsive features, eating disorder psychopathology and impairment were found. However, reward learning, as far as it is assessed by the task, did not seem to contribute to the effect of LDX on BN symptoms. Qualitative analysis suggested four themes: (1) reprieve from the eating disorder, (2) improvement in function and quality of life, (3) renewed hope for recovery, and (4) ability to normalize eating.

CONCLUSIONS

This report suggests several potential mechanisms by which LDX may reduce symptoms of binging and purging in those with BN. Importantly, due to the open-label design, we are unable to attribute findings to the medication. Instead, our results should be interpreted as hypothesis generating to inform future studies such as adequately powered randomized controlled trials. Trial registration NCT03397446.

Type of medication therapy for ADHD and stimulant misuse during adolescence: a cross-sectional multi-cohort national study

Background

Attention-deficit/hyperactivity disorder (ADHD) is associated with higher substance use rates. Stimulant and non-stimulant pharmacotherapy improve adolescent ADHD, but their associations with prescription stimulant misuse (PSM), cocaine, and methamphetamine use are unclear. Using 2005-2020 US Monitoring the Future data, we investigated relationships between ADHD pharmacotherapy history and PSM, cocaine, or methamphetamine use.

Methods

Secondary students (13-19 years) provided data on pharmacotherapy history (N = 199,560; 86.3% of total sample) between January 1, 2005 and May 31, 2020 in a cross-sectional multi-cohort study; weights assured a nationally representative sample. Participants were grouped by ADHD pharmacotherapy history: none (88.7%; principally non-ADHD controls); stimulant-only (5.8%); non-stimulant-only (3.3%); both stimulant and non-stimulant (2.1%). Outcomes were past-year PSM, cocaine, and methamphetamine use. Logistic regressions examined relationships between pharmacotherapy history and outcomes, controlling for sociodemographics, recent substance use, and stimulant treatment cessation.

Findings

Past-year outcome rates were lowest in adolescents with no pharmacotherapy history: 4.7% for PSM [8310/174,561], 1.6% for cocaine [2858/174,688], and 0.7% for methamphetamine [1036/148,378]. A history of both stimulant and non-stimulant treatment was associated with the highest rates: 22.3% for PSM [940/4098], 10.4% for cocaine [450/4110], and 7.8% for methamphetamine [275/3427]. Adolescents who received monotherapy (stimulant- or non-stimulant-only) had intermediate rates, with no differences between monotherapy groups.

Interpretation

While elevated PSM and illicit stimulant use rates are likely influenced by ADHD, our findings suggested adolescents with a history of both stimulant and non-stimulant pharmacotherapy are at highest risk for these stimulant outcomes. Adolescents receiving ADHD pharmacotherapy should be monitored for PSM and illicit stimulant use.

Funding

National Institute on Drug Abuse/National Institutes of Health (USA) and Food and Drug Administration (USA).

The effect of caffeine on subsequent sleep: A systematic review and meta-analysis

The consumption of caffeine in response to insufficient sleep may impair the onset and maintenance of subsequent sleep. This systematic review and meta-analysis investigated the effect of caffeine on the characteristics of night-time sleep, with the intent to identify the time after which caffeine should not be consumed prior to bedtime. A systematic search of the literature was undertaken with 24 studies included in the analysis. Caffeine consumption reduced total sleep time by 45 min and sleep efficiency by 7%, with an increase in sleep onset latency of 9 min and wake after sleep onset of 12 min. Duration (+6.1 min) and proportion (+1.7%) of light sleep (N1) increased with caffeine intake and the duration (-11.4 min) and proportion (-1.4%) of deep sleep (N3 and N4) decreased with caffeine intake. To avoid reductions in total sleep time, coffee (107 mg per 250 mL) should be consumed at least 8.8 h prior to bedtime and a standard serve of pre-workout supplement (217.5 mg) should be consumed at least 13.2 h prior to bedtime. The results of the present study provide evidence-based guidance for the appropriate consumption of caffeine to mitigate the deleterious effects on sleep.

Effect of caffeine intake on fat oxidation rate during exercise: is there a dose-response effect?

PURPOSE

The effect of caffeine to enhance fat utilisation as fuel for submaximal aerobic exercise is well established. However, it is unknown whether this effect is dose dependent. The aim of this study was to investigate the effect of 3 and 6 mg of caffeine per kg of body mass (mg/kg) on whole-body substrate oxidation during an incremental cycling exercise test.

METHODS

In a double-blind, randomised, and counterbalanced experiment, 18 recreationally active males (maximal oxygen uptake [VO_2max] = 56.7 ± 8.2 mL/kg/min) performed three experimental trials after ingesting either 3 mg/kg of caffeine, 6 mg/kg of caffeine or a placebo (cellulose). The trials consisted of an incremental exercise test on a cycle ergometer with 3-min stages at workloads from 30 to 80% of VO_2max. Energy expenditure, fat oxidation rate, and carbohydrate oxidation rate were continuously measured by indirect calorimetry.

RESULTS

During exercise, there was significant effect of substance (F = 7.969; P = 0.004) on fat oxidation rate. In comparison to the placebo, the rate of fat oxidation was higher with 3 mg/kg of caffeine at 30, 40, 50 and 70% of VO_2max [all P < 0.050, effect sizes (ES) from 0.38 to 0.50] and with 6 mg/kg of caffeine at 30, 40, 50, 60 and 70% of VO_2max (all P < 0.050, ES from 0.28 to 0.76). Both 3 mg/kg (0.40 ± 0.21 g/min, P = 0.021, ES = 0.57) and 6 mg/kg of caffeine (0.40 ± 0.17 g/min P = 0.001, ES = 0.60) increased the maximal rate of fat oxidation during exercise over the placebo (0.31 ± 0.15 g/min). None of the caffeine doses produced any significant effect on energy expenditure or heart rate during exercise, while both caffeine doses reduced perceived fatigue at 80% of VO_2max (all P < 0.050, ES from 0.71 to 1.48).

CONCLUSION

The effect of caffeine to enhance fat oxidation during submaximal aerobic exercise is of similar magnitude with 3 and 6 mg of caffeine per kg of body mass. Thus, a dose of 3 mg of caffeine per kg of body mass would be sufficient to enhance fat utilisation as fuel during submaximal exercise.

Influence of fecal microbial transplant (FMT) between male and female rats on methamphetamine-induced hyperthermia

OBJECTIVE

To investigate the effect of bidirectional fecal microbial transplant (FMT) between male and female rats on methamphetamine (MA)-induced hyperthermia.

METHODS

FMT was performed between male and female rats prior to MA (10 mg/kg, sc) treatment. Core body temperature, plasma drug and norepinephrine (NE) levels were measured and compared between treatment groups. 16S rRNA gene sequencing of bacterial communities between male and female rats was performed.

RESULTS

MA treatment resulted in significantly higher core body temperatures in male groups (control and FMT-treated) compared to MA-treated female groups (control and FMT-treated). Plasma concentrations of MA and amphetamine were higher in females than males. Whereas, plasma norepinephrine (NE) levels were not different between male and female rats 90 minutes after MA treatment. At the phyla level, the microbiome of male and female control rats were dominated by Firmicutes and Bacteroidetes. Males had a higher relative abundance of Firmicutes and lower relative abundances of Bacteroidetes than females. The FMT procedure changed the recipient group towards their donor with males getting closer to their donors than females. In the control groups following MA treatment, Firmicutes increased and Bacteroides decreased in females and males. Conversely, in the FMT treatment groups following MA treatment, Firmicutes decreased while Bacteroidetes increased in females and males.

CONCLUSIONS

Although definite differences in the structure and diversity of the gut microbiome were observed using 16S rRNA gene sequencing of bacterial communities between male and female rats, these differences do not seem to contribute to the sex-based differences in MA-induced hyperthermia.

Reciprocal effects of single or repeated exposure to methylphenidate or sex in adult male rats

RATIONALE

Exposure to rewards can alter behavioral reactivity to them. For example, stimulants sensitize locomotor activation, whereas sexual experience sensitizes copulatory behaviors. Moreover, rewards can cross-sensitize one another. Although stimulants are known to cross-sensitize locomotor effects, the evidence for cross-sensitization between stimulants and sex is less clear.

OBJECTIVES

This study determined the effects of single and repeated pre-exposure to methylphenidate (MPH) or sex on one another in adult male rats.

METHODS

Cross-sensitization between MPH (5 mg/kg) and sex (30 min with sexually experienced female) was examined. Adult male rats were pre-exposed to 0, 1, or 10 trials of either sex or MPH before being exposed to the other reward. Locomotor chambers were used in MPH trials. Bilevel chambers were used in sexual trials, and sexual behaviors were video scored.

RESULTS

The amount of prior sexual experience differentially influenced the ceiling of MPH-dependent sensitization; in the last drug trial, locomotion was highest in males given 1 previous sexual trial compared with 0 or 10. Compared with MPH-naive males, pre-exposure to MPH (1 and 10 trials) reduced the number of ejaculations without impacting sexual performance (intromission/mount latency and frequency).

CONCLUSIONS

These findings indicate that the degree of pre-exposure to a reward can differentially affect reactivity to novel rewards. The results showed that previous findings of cross-sensitization between amphetamine and sex do not extend to MPH. However, exposure to MPH prior to sexual experience can increase the amount of sexual stimulation needed to achieve ejaculation.

Lisdexamfetamine for the treatment of acute methamphetamine withdrawal: A pilot feasibility and safety trial

BACKGROUND

There is no effective treatment for methamphetamine withdrawal. This study aimed to determine the feasibility and safety of a tapering dose of lisdexamfetamine for the treatment of acute methamphetamine (MA) withdrawal.

METHODS

Open-label, single-arm pilot study, in an inpatient drug and alcohol withdrawal unit assessing a tapering dose of oral lisdexamfetamine dimesylate commencing at 250 mg once daily, reducing by 50 mg per day to 50 mg on Day 5. Measures were assessed daily (days 0-7) with 21-day telephone follow-up. Feasibility was measured by the time taken to enrol the sample. Safety was the number of adverse events (AEs) by system organ class. Retention was the proportion to complete treatment. Other measures included the Treatment Satisfaction Questionnaire for Medication (TSQM), the Amphetamine Withdrawal Questionnaire and craving (Visual Analogue Scale).

RESULTS

Ten adults seeking inpatient treatment for MA withdrawal (9 male, median age 37.1 years [IQR 31.7-41.9]), diagnosed with MA use disorder were recruited. The trial was open for 126 days; enroling one participant every 12.6 days. Eight of ten participants completed treatment (Day 5). Two participants left treatment early. There were no treatment-related serious adverse events (SAEs). Forty-seven AEs were recorded, 17 (36%) of which were potentially causally related, all graded as mild severity. Acceptability of the study drug by TSQM was rated at 100% at treatment completion. Withdrawal severity and craving reduced through the admission.

CONCLUSION

A tapering dose regimen of lisdexamfetamine was safe and feasible for the treatment of acute methamphetamine withdrawal in an inpatient setting.

Phenolic Compounds Present in Yerba Mate Potentially Increase Human Health: A Critical Review

Yerba Mate (YM) is a food product derived from Ilex paraguariensis whose constituents obtained from its extract, mainly the phenolic fraction, have been linked to numerous health benefits, such as cardiovascular protection, weight reduction, glucose control, and gene modulation. However, evidences linking phenolic compounds (PC) intake and human health are still limited and often contentious. Several researches have shown that key PC elements are poorly absorbed in humans and exist predominantly as conjugates, which may not be bioactive but may play a crucial role when interacting with the gut microbiota (GM). As the intestine is the largest microorganism-populated organ in the human body, GM has been regarded as a "microbial organ", acting as a second genome for modulating the host's health phenotype. For this reason, the study of intestinal microbiota has received considerable attention in recent years. Its impact on the development of nutrition-related diseases must motivate broader researches on the interaction between YM's PC and GM regarding the production of metabolites that may influence human health. This review aimed to gather and assess the available information about how PC from YM may impact host metabolism and the immune system and GM.

Cardiovascular Considerations for Stimulant Class Medications

The cardiovascular (CV) impact of stimulants has been examined for decades, with investigations ranging from small sample targeted studies of heart rate (HR) and blood pressure (BP), to large scale epidemiologic investigations. The preponderance of evidence is reassuring, albeit generally based on healthy samples using variable methodology, excluding those at theoretic high risk (eg, comorbid cardiac illness). Screening for theoretically vulnerable patients are recommended, as well as monitoring for CV symptoms and BP/HR, with shared inquiry/further evaluation if concerned. Future investigations to support the identification of risk are needed, while attention to stimulant-associated CV risk is an opportunity for clinicians to engage in general CV risk identification and intervention.

Attention deficit/hyperactivity disorder in adults: A case study

Attention-Deficit/Hyperactivity Disorder (ADHD) is often misdiagnosed or mistreated in adults because it is often thought of as a childhood problem. If a child is diagnosed and treated for the disorder, it often persists into adulthood. In adult ADHD, the symptoms may be comorbid or mimic other conditions making diagnosis and treatment difficult. Adults with ADHD require an in-depth assessment for proper diagnosis and treatment. The presentation and treatment of adults with ADHD can be complex and often requires interdisciplinary care. Mental health and non-mental health providers often overlook the disorder or feel uncomfortable treating adults with ADHD. The purpose of this manuscript is to discuss the diagnosis and management of adults with ADHD.

Stimulant-related incident surveillance using emergency medical service records in Massachusetts, 2013-2020

BACKGROUND

As stimulant use increases across the United States, emergency medical services (EMS) are crucial touchpoints in the health care system. To better measure the prevalence of stimulant use, misuse, and EMS incidents related to stimulant intoxication, definitions for stimulant-related incidents (SRIs) are needed.

METHODS

We used the Massachusetts Ambulance Trip Record Information System (MATRIS) from 2013 to 2020 to develop definitions of stimulant-related incidents. EMS runs reported to MATRIS were categorized based on stimulant-related words and symptoms. The three tiers were "any stimulant use" (class 1), "problematic stimulant use" (class 2), and "acute stimulant-related incidents" (class 3). A group of four reviewers studied over 650 cases in eight rounds to refine the search terms, achieving definitions with a correct characterization of over 80% of cases that the code selected.

RESULTS

SRI definitions were applied against all EMS runs within Massachusetts between 2013 and 2020 (n = 6,584,836 runs). Of these, 43,538 (0.7%) met the class 1 definition, 38,669 (0.6%) met the class 2 definition, and 19,157 (0.3%) met the class 3 definition. Incidents at all tiers of severity increased over time and were more likely to occur among younger adults and males. Race and ethnicity data indicated that Hispanic/Latinx and Black non-Hispanic/non-Latinx residents formed a disproportionately large percentage of SRIs relative to their total percentage of EMS runs.

CONCLUSIONS

The prevalence of all three tiers of SRIs are increasing in Massachusetts, and this protocol provides a source of administrative data on stimulant use that complements sources such as hospital, treatment-based, and/or prescribing records.

Finding the "Sweet Spot": Sharing the decision-making in ADHD treatment selection

BACKGROUND

Stimulants are often prescribed as first-line therapy for attention-deficit/hyperactivity disorder. Currently, there are many therapeutic options available for clinicians and families to consider when making the decision to use a medication. In practice, selection of a stimulant medication for ADHD is highly personalized and can be narrowed down to two major factors: finding the optimal duration of the medication effect, and then estimating a starting dose and subsequently "fine-tuning" the medication to the optimal dosage of the medication. With the possibility of titrating to an optimal stimulant dosage within one prescription of a liquid stimulant, prescribers can recruit the parent/caregiver to actively participate in managing the transition to medication, allowing for greater ownership and a sense of shared control over the process.

CASE PRESENTATION

The short case series offers a communication method by which clinicians can apply the principles of shared decision-making in helping the parent or caregiver of a newly diagnosed patient with ADHD make informed decisions about medication selection, and to obtain a greater sense of comfort with the new medication regimen.

CONCLUSIONS

Much has been published on the importance of clinicians and their patients fostering an environment of clear and unrestricted information-sharing. This short case series illustrates the effectiveness of this approach. Once parents are comfortable with the decision to start drug treatment for ADHD, it is incumbent upon the healthcare provider to ensure that an open channel of communication is maintained, and that parent/caregivers are encouraged to raise concerns as soon as possible.

Identifying individual and environmental predictors of opioid and psychostimulant use among adolescents and young adults following outpatient treatment

BACKGROUND

The United States (US) continues to grapple with a drug overdose crisis. While opioids remain the main driver of overdose deaths, deaths involving psychostimulants such as methamphetamine are increasing with and without opioid involvement. Recent treatment admission data reflect overdose fatality trends suggesting greater psychostimulant use, both alone and in combination with opioids. Adolescents and young adults are particularly vulnerable with generational trends showing that these populations have particularly high relapse rates following treatment.

METHODS

We assessed demographic, psychosocial, psychological comorbidity, and environmental factors (percent below the poverty line, percent unemployed, neighborhood homicide rate, population density) that confer risk for opioid and/or psychostimulant use following substance use disorder treatment using two complementary machine learning approaches-random forest and least absolute shrinkage and selection operator (LASSO) modelling-with latency to opioid and/or psychostimulant as the outcome variable.

RESULTS

Individual level predictors varied by substance use disorder severity, with age, tobacco use, criminal justice involvement, race/ethnicity, and mental health diagnoses emerging at top predictors. Environmental variabels including US region, neighborhood poverty, population, and homicide rate around patients' treatment facility emerged as either protective or risk factors for latency to opioid and/or psychostimulant use.

CONCLUSIONS

Environmental variables emerged as one of the top predictors of latency to use across all levels of substance use disorder severity. Results highlight the need for tailored treatments based on severity, and implicate environmental variables as important factors influencing treatment outcomes.

Crystal methamphetamine use subgroups and associated addiction care access and overdose risk in a Canadian urban setting

OBJECTIVES

Methamphetamine use is rising globally and we have limited treatments for this. Subgroups within the diverse methamphetamine-using population may have distinct treatment needs. Among a community-recruited sample of people who use crystal methamphetamine, we aimed to identify subgroups and characterize their overdose risk and access to addiction care.

METHODS

Data from prospective cohorts of people who use drugs in Vancouver, Canada from 2014 to 2018 were used to conduct a repeated measures latent class analysis among participants who used crystal methamphetamine. Multivariable generalized estimating equations models were fit to determine the associated factors.

RESULTS

Among 824 eligible participants, a five-class model was identified as the best fit: (1) primary stimulant use (15.7%); (2) women engaged in sex work and opioid use (21.4%); (3) street income generation and opioid use (31.6%); (4) opioid agonist therapy (OAT) patients (22.3%); and (5) men who have sex with men (9.0%). In multivariable analyses, compared to the primary stimulant use group, non-fatal overdose was positively associated with street income generation (adjusted odds ratio [AOR] = 1.49, 95% confidence interval [95% CI]=1.30-1.71), sex work (AOR = 1.38, 95% CI=1.20-1.59) and OAT (AOR = 1.22, 95% CI=1.06-1.41) subgroups; engagement in non-OAT addiction care was negatively associated with street income generation (AOR = 0.81, 95% CI=0.68-0.97) and sex work (AOR = 0.78, 95% CI=0.63-0.98) subgroups.

DISCUSSION

Socioeconomically marginalized subgroups with opioid and crystal methamphetamine co-use were at highest risk of non-fatal overdose and had poorer access to addiction care, highlighting the need for tailored interventions.

MDMA and memory, addiction, and depression: dose-effect analysis

RATIONALE

±3,4-Methylenedioxymethamphetamine (MDMA) is a recreational drug that shows substantial promise as a psychotherapeutic agent. Still, there is some concern regarding its behavioral toxicity, and its dose-effect relationship is poorly understood. We previously explored the role of dose in the cognitive effects of MDMA in a systematic review of existing literature and found no evidence in animals that MDMA impairs memory at low doses (< 3 mg/kg) but mixed results at high doses (≥ 3 mg/kg). Since this review comprised mostly of single-dose studies and an assortment of methodologies, an empirical dose-ranging study on this topic is warranted.

OBJECTIVES

The current study aims to evaluate the conclusion from our systematic review that 3 mg/kg may be the threshold for MDMA-induced amnesia, and to further understand the dose-effect relationship of MDMA on behavioral assays of memory, addiction, and depression.

METHODS

We systematically examined the effects of 0.01 to 10 mg/kg MDMA on Pavlovian fear conditioning; behavioral sensitization, conditioned place preference, and conditioned responding; and the Porsolt forced swim test in mice.

RESULTS

High doses of MDMA (≥ 3 mg/kg) produced amnesia of fear conditioning memory, some evidence of an addictive potential, and antidepressant effects, while low doses of MDMA (≤ 1 mg/kg) had no effect on these behaviors.

CONCLUSIONS

The present dose-ranging study provides further evidence that 3 mg/kg is the threshold for MDMA-induced amnesia. These findings, in addition to our systematic review, demonstrate that careful selection of MDMA dose is critical. High doses (≥ 3 mg/kg) should likely be avoided due to evidence that they can produce amnesia and addiction. Conversely, there is little evidence to suggest that low doses, which are usually administered in clinical studies (approximately 1-2 mg/kg), will lead to these same adverse effects. Ultra-low doses (< 1 mg/kg) are likely even safer and should be investigated for therapeutic effects in future studies.

Current Pharmacological Treatments for ADHD

Attention-Deficit Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental condition associated with impaired function and increased risk of poor outcomes in children, young people and adults with the condition. Currently approved pharmacological treatments for ADHD include a range of stimulant (methylphenidate, amphetamine) and nonstimulant (atomoxetine, guanfacine, clonidine) medications. All have been shown to be effective in treating the symptoms of ADHD and improving other functional outcomes including quality of life, academic performance, rates of accidents and injuries, and do not appear to be associated with significant adverse outcomes or side effects. In this chapter, we review medications for ADHD by summarising the mechanisms of action of each of the two main classes of compounds (stimulants and nonstimulants), the formulations of the most commonly prescribed medications within each class, their efficacy in treating ADHD symptoms and other outcomes, and other factors that influence treatment decisions including side effects and tolerability, comorbidities and medical history. We conclude with a summary of the treatment decisions made by clinicians and suggest some next steps for research. Further research is needed to understand the mechanisms of action of these medications and how exactly they improve symptoms, and to examine their effects on commonly occurring comorbidities.

Illicit Drug Use in Older Adults: An Invisible Epidemic?

Illicit drug use/misuse among older adults is understudied, although current trends point to older adults being the fastest-growing segment in the United States and other developed countries. There is a need for further insight into drug use patterns in older adults, who face their own set of socioeconomic, medical, and psychiatric problems. We reviewed the literature for data related to use/misuse of heroin and stimulants (cocaine, amphetamines, and methamphetamines) among people over the age of 40 years. We focused on prevalence rates of use/misuse of these substances, comorbidities, diagnostic challenges, screening tools, and treatment recommendations specific to the geriatric population.

Methylphenidate augmentation of escitalopram to enhance adherence to antidepressant treatment: a pilot randomized controlled trial

BACKGROUND

Adherence to treatment, i.e. the extent to which a patient's therapeutic engagement coincides with the prescribed treatment, is among the most important problems in mental health care. The current study investigated the influence of pairing an acute positive reinforcing dopaminergic/noradrenergic effect (methylphenidate, MPH) with a standard antidepressant on the rates of adherence to medication treatment. The primary objective of this study was to determine whether MPH + escitalopram resulted in higher rates of medication adherence relative to placebo + escitalopram.

METHODS

Twenty participants with moderate to severe depression were 1-1 randomized to either (1) 5 mg MPH + 10 mg escitalopram or (2) placebo + 10 mg escitalopram with the possibility for a dose increase at 4 weeks. A Bayesian analysis was conducted to evaluate the outcomes.

RESULTS

First, neither percent Pill count nor Medication Electronic Monitoring System adherence showed that MPH was superior to placebo. In fact, placebo showed slightly higher adherence rates on the primary (7.82% better than MPH) and secondary (7.07% better than MPH) outcomes. There was a less than 25% chance of MPH augmentation showing at least as good or better adherence than placebo. Second, both groups showed a significant effect of treatment on the QIDS-SR with a median effect of an 8.6-point score reduction. Third, neither subjective measures of adherence attitudes nor socio-demographic covariates had a significant influence on the primary or secondary outcome variables.

CONCLUSIONS

These data do not support the use of MPH to increase adherence to antidepressant medication in individuals with moderate to severe depression. CLINICALTRIALS.

GOV IDENTIFIER

NCT03388164 , registered on 01/02/2018.

Development and validation of the Stimulant Refusal Self-Efficacy Questionnaire (SRSEQ) in stimulant users in treatment

BACKGROUND

Self-efficacy is a core component of Social Cognitive Theory. Refusal self-efficacy is an individual's belief in their ability to refuse a substance in specific high-risk situations. Change in refusal self-efficacy is predictive of positive treatment outcomes. Measurement of refusal self-efficacy is critical as it directs coping skills development techniques though existing behavioural treatments. There is no validated measure of stimulant refusal self-efficacy. This study developed and validated the Stimulant Refusal Self-Efficacy Questionnaire (SRSEQ) to measure confidence in the ability to refuse stimulants in specific high-risk situations.

METHOD

Two hundred and seven stimulant-using patients referred for assessment completed the SRSEQ and measures including stimulant dependence severity (Severity of Dependence Scale-Stimulant, SDS-S). Confirmatory Factor Analysis (CFA) using structural equation modelling (SEM) was conducted to test the theoretically-driven three-factor structure of the SRSEQ. Criterion validity was tested with severity of stimulant dependence.

RESULTS

The CFA supported the three-factor structure. Emotional Relief (β = -0.27, p = .008), Opportunistic (β = -0.24, p = .013) and Social Facilitation (β = -0.32, p < .001) refusal self-efficacy were uniquely associated with stimulant dependence severity, explaining 55.1% variance.

CONCLUSIONS

The SRSEQ is psychometrically sound and may be clinically useful to assist with assessment and treatment planning for stimulant use disorder.

Non-fatal stimulant overdose among homeless and unstably housed women in San Francisco, California

BACKGROUND

US rates of overdose deaths involving stimulants (e.g., cocaine or methamphetamine) have increased, but little is known about non-fatal stimulant overdoses, particularly among vulnerable populations. We characterized rates of non-fatal stimulant overdose identified outside of health care settings among women at high risk.

METHODS

Homeless and unstably housed women in San Francisco, California using stimulants were administered questionnaires on drug use and outcomes (stimulant overdose, health care utilization) monthly for six months. Based on pilot interviews, stimulant overdose during follow-up was defined as acute toxicity from stimulant use ("over-amping") resulting in "feeling sick, really scared, or like one's life may be in danger". Poisson regression estimated unadjusted incidence rate ratio (IRR) comparing participant characteristics.

RESULTS

We included 160 women (41% Black, 26% White, 15% Latina, median age 54 years) using crack cocaine (81%), methamphetamine (48%), and powdered cocaine (36%). Participants reported 67 non-fatal stimulant overdoses over 685 person-months of observation, a rate of 117.4 per 100 person-years (95% CI 85.8-160.5). Rates were higher among participants who were Latina vs. White (IRR 4.18 [1.60-10.94]), used methamphetamine (IRR 1.80 [0.96-3.38]), or used any stimulant daily/almost daily (IRR 2.63 [1.41-4.91]). Among women reporting stimulant overdose, 4% received emergency and 3% inpatient care for overdose of any drug.

CONCLUSIONS

Women in this setting, particularly those who used stimulants frequently or used methamphetamine, experienced high non-fatal stimulant overdose and rarely received health care for these events. Efforts should be made to increase awareness and reduce harms of stimulant toxicity in vulnerable populations.

Acute drug effects differentially predict desire to take dextroamphetamine again for work and recreation

RATIONALE

Misuse of dextroamphetamine occurs in work and recreational contexts. While acute drug effects broadly predict abuse liability, few studies have considered the relationship between acute effects and context.

OBJECTIVES

This study examined how individual differences in acute effects of dextroamphetamine relate to desire to take dextroamphetamine again in different contexts.

METHODS

This secondary analysis used data from healthy adults with no history of moderate-to-severe substance use disorder, who received oral doses of placebo and dextroamphetamine (10 and 20 mg) over 3 sessions under double-blind, randomized conditions. Subjects rated subjective effects and completed reward-related behavioral tasks. Subjects rated their desire to take dextroamphetamine again in hypothetical work and recreational contexts. Multilevel models examined within-subjects change scores (10 mg-placebo; 20 mg-placebo) to determine how subjective effects and behavioral outcomes predicted desire to take dextroamphetamine again for work versus recreation.

RESULTS

Subjects reported more desire to take 20 mg dextroamphetamine again for work than for recreation. At 20 mg, there was an interaction between context and liking/wanting, such that liking/wanting predicted desire to use dextroamphetamine for work only. There was also an interaction at 20 mg between context and psychomotor speed, such that psychomotor speed predicted interest in using dextroamphetamine for recreation only.

CONCLUSIONS

We found that positive subjective effects predicted desire to use dextroamphetamine again for work, while increased motor effects predicted desire to use dextroamphetamine recreationally. Hedonic effects may be perceived as advantageous when working, while increased physical energy may be preferred during recreation, suggesting that context of intended use is important when examining abuse liability.

Stimulation of Bacillus sp. by lipopeptide biosurfactant for the degradation of aromatic amine 4-Chloroaniline

This study aims to reveal that the biosurfactant act as a stimulant in aromatic amine 4-Chloroaniline (4-CA) degradation. Isolated degrading strain Bacillus sp. was used for the production of biosurfactant with help of substrate such as engine oil. The surfactant production by the strain was studied by using various screening methods and the results showed best emulsification activity (75%), surface tension reduction activity (28.6 mNm^-1) and oil spreading activity (5.9 cm). The obtained surfactant was characterized using Fourier transform infrared spectroscopy (FT-IR), Gas chromatography-Mass Spectrometry (GC-MS), Matrix-Assisted Laser Desorption/ Ionization Time of Flight (MALDI-TOF) which confirmed that the nature of surfactant is lipopeptide. The maximum removal of 4-CA was achieved in different environmental conditions at concentration 100 mg L^-1, neutral pH and temperature 30 °C. In the degradation studies, the 4-CA was removed upto 76% by Bacillus sp but in the presence of lipopeptide surfactant, the Bacillus sp removed 4-CA upto 100%. The degraded metabolites were further characterized using High-Pressure Liquid Chromatography (HPLC) and GC-MS. This research indicated that strain Bacillus sp along with the lipopeptide biosurfactant possesses higher potential in the bioremediation of 4-CA compound from the environment.

The continued rise of methamphetamine use among people who use heroin in the United States

BACKGROUND

Methamphetamine use is a growing public health concern in the United States. Prior analyses with nationally representative data from 2015 to 2017 suggested that increases in methamphetamine use appeared largely selective to people using heroin. This analysis updated prior estimates to determine if trends are selectively persistent and how they compare to historical trends. We also evaluate sociodemographic risk factors associated with methamphetamine use among people using heroin.

METHODS

Data from the 2015-2019 National Surveys on Drug Use and Health (NSDUH) were analyzed. Data from the 2006-2014 NSDUH were summarized for historical trends. Past month and past year methamphetamine use prevalence was determined within populations using heroin as well as those using other drugs (e.g., cocaine, cannabis). Multivariable logistic models accounting for complex survey design evaluated predictors of methamphetamine use among people using heroin.

RESULTS

From 2015 to 2019, past month methamphetamine use increased from 9.0% to 44.0% within the population of people reporting past month heroin use. Similarly, past year methamphetamine use increased from 22.5% to 46.7% among those reporting past year heroin use. Risk factors for methamphetamine use among people using heroin included rurality, past year injection drug use, and serious mental illness.

CONCLUSIONS

A rapid, selective, and sustained increase in methamphetamine use is evident among people using heroin. These findings combined with similar findings in treatment admission and overdose data emphasize the need for increased attention to a specific type of high-risk use pattern in the United States, an issue that appears increasingly unlikely to naturally resolve.

Effect of caffeine on alcohol drinking in mice

Mixing alcohol (ethanol) with caffeinated beverages continues to be a common and risky practice. Energy drinks are one type of caffeinated beverage that may be especially problematic when used as mixers, due to their relatively high caffeine content in combination with their highly sweetened flavor profile. The present study used a mouse model of limited-access drinking and lickometer circuitry to examine the effects of an energy drink anid its caffeine content on ethanol consumption. Predictably, the highly sweetened energy drink significantly increased ethanol intake compared to a plain ethanol solution (6.34 ± 0.2 vs. 5.01 ± 0.3 g/kg; Cohen's d = 1.79). Interestingly, adulterating a plain ethanol solution with the same concentration of caffeine (without sweetener) found in the energy drink also increased ethanol intake (5.47 ± 0.3 vs. 4.11 ± 0.3 g/kg; Cohen's d = 1.4). A lower concentration of caffeine was without effect on ethanol drinking. Interestingly, plain caffeine solutions at both tested concentrations provoked high numbers of bottle contacts, indicating that the mice found the solution palatable. These findings suggest that altering the bitterness profile of an ethanol solution with the addition of caffeine can increase intake in a similar manner as sweetening the solution. Further, the findings underscore the importance of taste in motivating ethanol consumption and the potential role that caffeine can have in this process.

Gut and brain profiles that resemble pre-motor and early-stage Parkinson's disease in methamphetamine self-administering rats

INTRODUCTION

Methamphetamine is a potent psychomotor stimulant, and methamphetamine abusers are up to three times more likely to develop Parkinson's disease (PD) later in life. Prodromal PD may involve gut inflammation and the accumulation of toxic proteins that are transported from the enteric nervous system to the central nervous system to mediate, in part, the degeneration of dopaminergic projections. We hypothesized that self-administration of methamphetamine in rats produces a gut and brain profile that mirrors pre-motor and early-stage PD.

METHODS

Rats self-administered methamphetamine in daily 3 h sessions for two weeks. Motor function was assessed before self-administration, during self-administration and throughout the 56 days of forced abstinence. Assays for pathogenic markers (tyrosine hydroxylase, glial fibrillary acidic protein (GFAP), α-synuclein) were conducted on brain and gut tissue collected at one or 56 days after cessation of methamphetamine self-administration.

RESULTS

Motor deficits emerged by day 14 of forced abstinence and progressively worsened up to 56 days of forced abstinence. In the pre-motor stage, we observed increased immunoreactivity for GFAP and α-synuclein within the ganglia of the myenteric plexus in the distal colon. Increased α-synuclein was also observed in the substantia nigra pars compacta. At 56 days, GFAP and α-synuclein normalized in the gut, but the accumulation of nigral α-synuclein persisted, and the dorsolateral striatum exhibited a significant loss of tyrosine hydroxylase.

CONCLUSION

The pre-motor profile is consistent with gut inflammation and gut/brain α-synuclein accumulation associated with prodromal PD and the eventual development of the neurological disease.

Community overdose surveillance: Comparing substances collected from the death scene investigation to toxicology results

BACKGROUND

Recent overdose trends are characterized by increased toxicological detection of stimulants with opioids, yet it is unclear whether these substances are mixed prior to consumption or purposefully used simultaneously.

METHODS

Postmortem toxicology data were collected in Marion County, Indiana, from 45 fatal overdose cases involving heroin, fentanyl, methamphetamine, or cocaine. Substances found by death scene investigators at the scene of the fatal overdose (57 samples) were tested using high-pressure liquid chromatography mass-spectrometry (LC-MS) technology. We compared toxicology and LC-MS results to understand whether substances contributing to overdose were found in combination or separately at the scene of the overdose.

RESULTS

Comparing toxicology reports with LC-MS results from substances found at the scene of overdose deaths involving opioids and stimulants reveal that deaths are largely the result of the co-use of opioids and stimulants, rather than use of stimulants combined with opioids.

CONCLUSIONS

Collecting and testing physical samples from fatal overdose scenes and comparing these to post-mortem toxicology results is a new way to examine polydrug use patterns. This community overdose surveillance method can be used to improve overdose prevention and response efforts.

Is expected substance type associated with timing of drug checking service utilization?: A cross-sectional study

BACKGROUND

Drug checking is a harm reduction intervention aiming to reduce substance use-related risks by improving drug user knowledge of the composition of unregulated drugs. With increasing fears of fentanyl adulteration in unregulated drugs, this study sought to examine whether the expected type of drug checked (stimulant vs. opioid) was associated with timing of drug checking service utilization (pre-consumption vs. post-consumption).

METHODS

Data were derived from drug checking sites in British Columbia between October 31, 2017 and December 31, 2019. Pearson's Chi-square test was used to examine the relationship between expected sample type (stimulant vs. opioid) and timing of service utilization. Odds ratios (OR) were calculated to assess the strength of this relationship. The Mantel-Haenszel (MH) test was used to adjust for service location.

RESULTS

A total of 3561 unique stimulant and opioid samples were eligible for inclusion, including 691 (19.40%) stimulant samples; and 2222 (62.40%) samples that were tested pre-consumption. Results indicated a positive association between testing stimulant samples and testing pre-consumption (OR = 1.45; 95% CI 1.21-1.73). Regions outside of the epicenter of the province's drug scene showed a stronger association with testing pre-consumption (ORMH = 2.33; 95% CI 1.51-3.56) than inside the epicenter (ORMH = 1.33; 95% CI 1.09-1.63).

CONCLUSION

Stimulant samples were more likely to be checked pre-consumption as compared with opioid samples, and stimulant samples were more likely to be tested pre-consumption in regions outside the epicenter of the province's drug scene. This pattern may reflect a concern for fentanyl-adulterated stimulant drugs.

Effects of acute ingestion of caffeinated chewing gum on performance in elite judo athletes

Purpose

Previous investigations have found positive effects of acute ingestion of capsules containing 4-to-9 mg of caffeine per kg of body mass on several aspects of judo performance. However, no previous investigation has tested the effectiveness of caffeinated chewing gum as the form of caffeine administration for judoists. The main goal of this study was to assess the effect of acute ingestion of a caffeinated chewing gum on the results of the special judo fitness test (SJFT).

Methods

Nine male elite judo athletes of the Polish national team (23.7 ± 4.4 years, body mass: 73.5 ± 7.4 kg) participated in a randomized, crossover, placebo-controlled and double-blind experiment. Participants were moderate caffeine consumers (3.1 mg/kg/day). Each athlete performed three identical experimental sessions after: (a) ingestion of two non-caffeinated chewing gums (P + P); (b) a caffeinated chewing gum and a placebo chewing gum (C + P; ~2.7 mg/kg); (c) two caffeinated chewing gums (C + C; ~5.4 mg/kg). Each gum was ingested 15 min before performing two Special Judo Fitness Test (SJFT) which were separated by 4 min of combat activity.

Results

The total number of throws was not different between P + P, C + P, and C + C (59.66 ± 4.15, 62.22 ± 4.32, 60.22 ± 4.08 throws, respectively; p = 0.41). A two-way repeated measures ANOVA indicated no significant substance × time interaction effect as well as no main effect of caffeine for SJFT performance, SJFT index, blood lactate concentration, heart rate or rating of perceived exertion.

Conclusions

The results of the current study indicate that the use of caffeinated chewing gum in a dose up to 5.4 mg/kg of caffeine did not increase performance during repeated SJFTs.

Differences and similarities between emergency department syndromic surveillance and hospital discharge data for nonfatal drug overdose

PURPOSE

Emergency department syndromic surveillance and hospital discharge data have been used to detect and monitor nonfatal drug overdose, yet few studies have assessed the differences and similarities between these two data sources.

METHODS

The Centers for Disease Control and Prevention Drug Overdose Surveillance and Epidemiology system data from 14 states were used to compare these two sources at estimating monthly overdose burden and trends from January 2018 through December 2019 for nonfatal all drug, opioid-, heroin-, and stimulant-involved overdoses.

RESULTS

Compared to discharge data, syndromic data captured 13.3% more overall emergency department visits, 67.8% more all drug overdose visits, 15.6% more opioid-involved overdose visits, and 78.8% more stimulant-involved overdose visits. Discharge data captured 18.9% more heroin-involved overdoses. Significant trends were identified for all drug (Average Monthly Percentage Change [AMPC]=1.1, 95% CI=0.4,1.8) and stimulant-involved overdoses (AMPC=2.4, 95% CI=1.2,3.7) in syndromic data; opioid-involved overdoses increased in both discharge and syndromic data (AMPC_Discharge=0.9, 95% CI=0.2,1.7; AMPC_Syndromic=1.9, CI=1.1,2.8).

CONCLUSIONS

Results demonstrate that discharge data may be better for reporting counts, yet syndromic data are preferable to detect changes quickly and to alert practitioners and public health officials to local overdose clusters. These data sources do serve complementary purposes when examining overdose trends.

Molecular and clinical aspects of potential neurotoxicity induced by new psychoactive stimulants and psychedelics

New psychoactive stimulants and psychedelics continue to play an important role on the illicit new psychoactive substance (NPS) market. Designer stimulants and psychedelics both affect monoaminergic systems, although by different mechanisms. Stimulant NPS primarily interact with monoamine transporters, either as inhibitors or as substrates. Psychedelic NPS most potently interact with serotonergic receptors and mediate their mind-altering effects mainly through agonism at serotonin 5-hydroxytryptamine-2A (5-HT_2A) receptors. Rarely, designer stimulants and psychedelics are associated with potentially severe adverse effects. However, due to the high number of emerging NPS, it is not possible to investigate the toxicity of each individual substance in detail. The brain is an organ particularly sensitive to substance-induced toxicity due to its high metabolic activity. In fact, stimulant and psychedelic NPS have been linked to neurological and cognitive impairments. Furthermore, studies using in vitro cell models or rodents indicate a variety of mechanisms that could potentially lead to neurotoxic damage in NPS users. Cytotoxicity, mitochondrial dysfunction, and oxidative stress may potentially contribute to neurotoxicity of stimulant NPS in addition to altered neurochemistry. Serotonin 5-HT_2A receptor-mediated toxicity, oxidative stress, and activation of mitochondrial apoptosis pathways could contribute to neurotoxicity of some psychedelic NPS. However, it remains unclear how well the current preclinical data of NPS-induced neurotoxicity translate to humans.

Contributions of neuroimmune and gut-brain signaling to vulnerability of developing substance use disorders

Epidemiology and clinical research indicate that only a subset of people who are exposed to drugs of abuse will go on to develop a substance use disorder. Numerous factors impact individual susceptibility to developing a substance use disorder, including intrinsic biological factors, environmental factors, and interpersonal/social factors. Given the extensive morbidity and mortality that is wrought as a consequence of substance use disorders, a substantial body of research has focused on understanding the risk factors that mediate the shift from initial drug use to pathological drug use. Understanding these risk factors provides a clear path for the development of risk mitigation strategies to help reduce the burden of substance use disorders in the population. Here we will review the rapidly growing body of literature that examines the importance of interactions between the peripheral immune system, the gut microbiome, and the central nervous system (CNS) in mediating the transition to pathological drug use. While these systems had long been viewed as distinct, there is growing evidence that there is bidirectional communication between both the immune system and the gut microbiome that drive changes in neural and behavioral plasticity relevant to substance use disorders. Further, both of these systems are highly sensitive to environmental perturbations and are implicated in numerous neuropsychiatric conditions. While the field of study examining these interactions in substance use disorders is in its relative infancy, clarifying the relationship between gut-immune-brain signaling and substance use disorders has potential to improve our understanding of individual propensity to developing addiction and yield important insight into potential treatment options.

Lever-press duration as a measure of frustration in sucrose and drug reinforcement

RATIONALE

Currently there is little research into the role of frustration in substance use disorders despite research showing that frustration tolerance in humans is associated with a lower likelihood of developing substance use problems, better outcomes in recovery, and fewer relapses.

OBJECTIVE

In order to address this need, our studies use a rat model to focus on frustration-related behavior in natural reward and addiction-related behavioral procedures. Frustration is defined as when a subject is unable to achieve a reinforcer, receives less of a reinforcer than anticipated, or has to work harder to achieve a reinforcer.

RESULTS

In these studies, bar-press durations increase when rats are in a state of frustration during self-administration of sucrose, fentanyl, or cocaine.

CONCLUSIONS

These data also show that average bar-press durations do not correlate with the number of bar presses, meaning that press duration is an independent measurement that represents a behavioral construct distinct from craving, which is typically measured with number of bar presses. Essentially, these results support that bar press durations can be used as a real-time measure of frustration as a 4th major facet of addiction-related behavior, adding to craving, impulsivity, and habit.

High concentrations of illicit stimulants and cutting agents cause false positives on fentanyl test strips

Background

The opioid epidemic has caused an increase in overdose deaths which can be attributed to fentanyl combined with various illicit substances. Drug checking programs have been started by many harm reduction groups to provide tools for users to determine the composition of their street drugs. Immunoassay fentanyl test strips (FTS) allow users to test drugs for fentanyl by either filling a baggie or cooker with water to dissolve the sample and test. The antibody used in FTS is very selective for fentanyl at high dilutions, a characteristic of the traditional use of urine testing. These street sample preparation methods can lead to mg/mL concentrations of several potential interferents. We tested whether these concentrated samples could cause false positive results on a FTS.

Methods

20 ng/mL Rapid Response FTS were obtained from BTNX Inc. and tested against 4 different pharmaceuticals (diphenhydramine, alprazolam, gabapentin, and naloxone buprenorphine) and 3 illicit stimulants [cocaine HCl, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA)] in concentrations from 20 to 0.2 mg/mL. The FTS testing pad is divided into 2 sections: the control area and the test area. Control and test area signal intensities were quantified by ImageJ from photographs of the test strips and compared to a threshold set by fentanyl at the FTS limit of detection.

Results

False positive results indicating the presence of fentanyl were obtained from samples of methamphetamine, MDMA, and diphenhydramine at concentrations at or above 1 mg/mL. Diphenhydramine is a common cutting agent in heroin. The street sample preparation protocols for FTS use suggested by many online resources would produce such concentrations of these materials. Street samples need to be diluted more significantly to avoid interference from potential cutting agents and stimulants.

Conclusions

Fentanyl test strips are commercially available, successful at detecting fentanyl to the specified limit of detection and can be a valuable tool for harm reduction efforts. Users should be aware that when drugs and adulterants are in high concentrations, FTS can give a false positive result.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12954-021-00478-4.

Tobacco smoke exposure enhances reward sensitivity in male and female rats

RATIONALE

Systemic administration of the tobacco smoke constituent nicotine stimulates brain reward function in rats. However, it is unknown if the inhalation of tobacco smoke affects brain reward function.

OBJECTIVES

These experiments investigated if exposure to smoke from high-nicotine SPECTRUM research cigarettes increases reward function and affects the rewarding effects of nicotine in adult male and female Wistar rats.

METHODS

Reward function after smoke or nicotine exposure was investigated using the intracranial self-stimulation (ICSS) procedure. A decrease in reward thresholds reflects an increase in reward function. In the first experiment, the rats were exposed to tobacco smoke for 40 min/day for 9 days, and the rewarding effects of nicotine (0.03-0.6 mg/kg) were investigated 3 weeks later. In the second experiment, the dose effects of tobacco smoke exposure (40-min sessions, 1-4 cigarettes burnt simultaneously) on reward function were investigated.

RESULTS

Tobacco smoke exposure did not affect the nicotine-induced decrease in reward thresholds or response latencies in male and female rats. Smoke exposure lowered the brain reward thresholds to a similar degree in males and females and caused a greater decrease in latencies in females. There was a positive relationship between plasma nicotine and cotinine levels and the nicotine content of the SPECTRUM research cigarettes. Similar smoke exposure conditions led to higher plasma nicotine and cotinine levels in female than male rats.

CONCLUSION

These findings indicate that tobacco smoke exposure enhances brain reward function but does not potentiate the rewarding effects of nicotine in male and female rats.