A nationally representative analysis of "twin epidemics": Rising rates of methamphetamine use among persons who use opioids

Addiction Consultation Services for Opioid Use Disorder Treatment Initiation and Engagement: A Randomized Clinical Trial

Importance

Medications for opioid use disorder (MOUD) are highly effective, but only 22% of individuals in the US with opioid use disorder receive them. Hospitalization potentially provides an opportunity to initiate MOUD and link patients to ongoing treatment.

Objective

To study the effectiveness of interprofessional hospital addiction consultation services in increasing MOUD treatment initiation and engagement.

Design, Setting, and Participants

This pragmatic stepped-wedge cluster randomized implementation and effectiveness (hybrid type 1) trial was conducted in 6 public hospitals in New York, New York, and included 2315 adults with hospitalizations identified in Medicaid claims data between October 2017 and January 2021. Data analysis was conducted in December 2023. Hospitals were randomized to an intervention start date, and outcomes were compared during treatment as usual (TAU) and intervention conditions. Bayesian analysis accounted for the clustering of patients within hospitals and open cohort nature of the study. The addiction consultation service intervention was compared with TAU using posterior probabilities of model parameters from hierarchical logistic regression models that were adjusted for age, sex, and study period. Eligible participants had an admission or discharge diagnosis of opioid use disorder or opioid poisoning/adverse effects, were hospitalized at least 1 night in a medical/surgical inpatient unit, and were not receiving MOUD before hospitalization.

Interventions

Hospitals implemented an addiction consultation service that provided inpatient specialty care for substance use disorders. Consultation teams comprised a medical clinician, social worker or addiction counselor, and peer counselor.

Main Outcomes and Measures

The dual primary outcomes were (1) MOUD treatment initiation during the first 14 days after hospital discharge and (2) MOUD engagement for the 30 days following initiation.

Results

Of 2315 adults, 628 (27.1%) were female, and the mean (SD) age was 47.0 (12.4) years. Initiation of MOUD was 11.0% in the Consult for Addiction Treatment and Care in Hospitals (CATCH) program vs 6.7% in TAU, engagement was 7.4% vs 5.3%, respectively, and continuation for 6 months was 3.2% vs 2.4%. Patients hospitalized during CATCH had 7.96 times higher odds of initiating MOUD (log-odds ratio, 2.07; 95% credible interval, 0.51-4.00) and 6.90 times higher odds of MOUD engagement (log-odds ratio, 1.93; 95% credible interval, 0.09-4.18).

Conclusions

This randomized clinical trial found that interprofessional addiction consultation services significantly increased postdischarge MOUD initiation and engagement among patients with opioid use disorder. However, the observed rates of MOUD initiation and engagement were still low; further efforts are still needed to improve hospital-based and community-based services for MOUD treatment.

Trial Registration

ClinicalTrials.gov Identifier: NCT03611335.

A multilevel analysis of changing telehealth availability in opioid use disorder treatment settings: Conditional effects of rurality, the number and types of medication for opioid use disorder available, and time, US, 2016-2023

PURPOSE

The opioid overdose crisis requires strengthening treatment systems with innovative technologies. How people use telehealth for opioid use disorder (OUD) is evolving and differs in rural versus urban areas, as telehealth is emerging as a local resource and complementary option to in-person treatment. We assessed changing trends in telehealth and medication for OUD (MOUD) and pinpoint locations of low telehealth and MOUD access.

METHODS

We used national data from the Mental health and Addiction Treatment Tracking Repository (2016-2023) to identify specialty outpatient SUD treatment facilities in the United States (N = 83,988). We modeled the availability of telehealth using multilevel multivariable logistic regression, adjusting for covariates. We included a 3-way interaction to test for conditional effects of rurality, the number of MOUD medication types dispensed, and year. We included two random effects to account for clustering within counties and states.

FINDINGS

We identified 495 facilities that offered both telehealth and all three MOUD medication types (methadone, buprenorphine, naltrexone) in 2023, clustered in the eastern United States. We identified a statistically significant 3-way interaction (p < 0.0001), indicating that telehealth in facilities that did not offer MOUD shifted from more telehealth in rural facilities in earlier years to more telehealth in urban facilities in later years.

CONCLUSIONS

Treatment facilities that offer both telehealth and all three MOUD medication types may improve access for hard-to-reach populations. We stress the importance of continued health system strengthening and technological resources in vulnerable rural communities, while acknowledging a changing landscape of increased OUD incidence and MOUD demand in urban communities.

Vesicular monoamine transporter-2 inhibitor JPC-141 prevents methamphetamine-induced dopamine toxicity and blocks methamphetamine self-administration in rats

Previous research has demonstrated therapeutic potential for VMAT2 inhibitors in rat models of methamphetamine use disorder. Here, we report on the neurochemical and behavioral effects of 1-(2-methoxyphenethyl)-4-phenethypiperazine (JPC-141), a novel analog of lobelane. JPC-141 potently inhibited (Ki = 52 nM) [3H]dopamine uptake by VMAT2 in striatal vesicles with 50 to 250-fold greater selectivity for VMAT2 over dopamine, norepinephrine and serotonin plasmalemma transporters. Also, JPC-141 was 57-fold more selective for inhibiting VMAT2 over [3H]dofetilide binding to hERG channels expressed by HEK293, suggesting relatively low potential for cardiotoxicity. When administered in vivo to rats, JPC-141 prevented the METH-induced reduction in striatal dopamine content when given either prior to or after a high dose of METH, suggesting a reduction in METH-induced dopaminergic neurotoxicity. In behavioral assays, JPC-141 decreased METH-stimulated locomotor activity in METH-sensitized rats at doses of JPC-141 which did not alter locomotor activity in the saline control group. Moreover, JPC-141 specifically decreased iv METH self-administration at doses that had no effect on food-maintained responding. These findings support the further development of VMAT2 inhibitors as pharmacotherapies for individuals with methamphetamine use disorder.

A brief measure of non-drug reinforcement: Association with treatment outcomes during initial substance use recovery

BACKGROUND

Translational research demonstrates that drug use is inversely associated with availability and engagement with meaningful non-drug reinforcers. Evaluation of non-drug reinforcement in treatment-receiving clinical populations is limited, likely owing to the time intensive nature of existing measures. This study explores the association of non-drug reinforcers with treatment outcomes using a novel, brief measure of past month non-drug reinforcement quantifying three elements: relative frequency, access, and enjoyability.

METHODS

Respondents enrolled in substance use treatment (residential, intensive outpatient, and medically managed withdrawal) in clinics across the United States (N = 5481) completed standardized assessments of non-drug reinforcement and treatment outcomes (i.e., return to use and life satisfaction) one-month after treatment discharge. Non-drug reinforcement measures (availability, engagement, enjoyability) were used as predictors of return to use and life satisfaction using generalized linear models.

RESULTS

Non-drug reinforcement indices were associated with return to use and life satisfaction in unadjusted models (e.g., 12.4 % versus 58.3 % return to use for those with the highest and lowest availability, respectively). Consistent results were observed in models adjusted for sociodemographic variables and risk factors (i.e., sleep disturbance, anhedonia, stress). Comparisons by drug class generally showed lower non-drug reinforcement among patients reporting heroin or methamphetamine as their primary drug.

CONCLUSIONS

Results highlight the importance of non-drug reinforcement during the first month following treatment. Rapid measurement of non-drug reinforcement in stepped care settings may illuminate critical deficits in early stages of behavior change, identify those at greatest risk for return to use, and provide targets for treatment to improve recovery trajectories.

Associations of hepatitis C virus (HCV) antibody positivity with opioid, stimulant, and polysubstance injection among people who inject drugs (PWID) in rural U.S. communities

BACKGROUND

People who inject drugs (PWID) in the rural U.S. often inject stimulants, alone or with opioids. The impact of these substance use patterns may influence HCV risk behaviors. This analysis examines the associations of HCV antibody positivity with injecting only opioids, only stimulants (methamphetamine/cocaine), and opioids and stimulants together among rural PWID.

METHODS

The Rural Opioid Initiative (ROI) consists of eight research sites that enrolled people who use drugs in rural communities in ten U.S. states from 2018 to 2020. This cross-sectional analysis included adult participants who resided in a study area and injected any drug in the past 30 days. The primary outcome was HCV antibody positivity. The exposure of interest was injection drug use classified as only opioids, only stimulants, separate injections of opioids and stimulants, and same-syringe injection of both in the past 30 days. We used multivariable log-binomial regression with generalized linear mixed models to generate prevalence ratios (P.R.) adjusted for demographics, injection history, health insurance, and substance use treatment.

RESULTS

Among 3,084 participants enrolled in the ROI, 1,982 met inclusion criteria. Most participants injected opioids and stimulants in the same syringe (34%) or separately (21%), followed by injecting only stimulants (26%), and injecting only opioids (19%). Half (51%) were HCV antibody positive. Compared to people who injected only stimulants, HCV antibody positivity was more prevalent among people who injected opioids alone (aPR=1.62, 95% CI:(1.29-2.03)), injected both opioids and stimulants separately (aPR=1.61, 95% CI:(1.32-1.95)), and in the same syringe (aPR=1.54, 95% CI:(1.28-1.85)).

CONCLUSION

HCV antibody positivity, indicating prior exposure, was highest among those who had recently injected opioids, alone or with stimulants. Additional nucleic acid testing is necessary to confirm active infection. More research is needed to determine the underlying causes of HCV antibody positivity by injection use.

Methylamphetamine toxicity and its involvement in death: A retrospective observational study of deaths reported to the Victorian Coroner, Australia

A retrospective observational study of Victorian deaths involving MA between 2010 and 2019 was conducted to determine the prevalence and contribution of methylamphetamine (MA) toxicity to death in the absence of other factors. Demographics, autopsy findings, toxicology, and the cause of death were reviewed. Coronial cases were categorized into five groups: deaths due to MA toxicity in the absence of other factors (Group A1); deaths due to MA toxicity in the setting of other potentially contributing factors (Group A2); deaths due to MA toxicity in the setting of significant natural disease (Group B); deaths primarily due to multiple-drug toxicity (Group C); and deaths primarily due to natural causes (Group D). There were 506 deaths involving MA categorized into Group A1 (n = 1, 0.6%), Group A2 (n = 8, 1.6%), Group B (n = 28, 5.5%), Group C (n = 229, 45%), and Group D (n = 240, 47%). Significant natural disease was prevalent among deaths involving MA and mainly concerned forms of cardiovascular disease (n = 277, 55%). The MA concentration in the one death included in Group A1 was 2.1 mg/L. The median MA concentrations of Group A2 (1.6 mg/L) and Group B (0.5 mg/L) were significantly higher than Group C (0.2 mg/L) and Group D (0.2 mg/L). Additionally, many other toxicologically significant drugs were detected and mostly comprised of central nervous system depressants. Deaths due to MA toxicity in the absence of other factors were rare despite the greater availability of crystal MA in the Australian community. The study highlights the interpretative challenges of MA blood concentrations and the continuing harms of this drug in Australia.

The impact of methamphetamine use on medications for opioid use disorder (MOUD) treatment retention: a scoping review

BACKGROUND

An emerging public health threat of methamphetamine/opioid co-use is occurring in North America, including increases in overdoses related to concomitant methamphetamine/opioid use. This presents a potential risk to established treatments for opioid use disorder (i.e., medications for opioid use disorder [MOUD]). To date, few studies have examined the impact of methamphetamine use on MOUD-related outcomes, and no studies have synthesized data on MOUD retention.

METHODS

A scoping review was undertaken to examine the impact of methamphetamine use on MOUD retention. All original published research articles were searched in Embase, MEDLINE, PsychINFO, CINAHL, Scopus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and Cochrane Protocols, and Google scholar databases. Data were extracted into a standardized data extraction chart. Findings were presented narratively.

RESULTS

All eight included studies demonstrated an increased likelihood of treatment discontinuation or dropout among patients enrolled in MOUD who used methamphetamine. The frequency of methamphetamine use was also associated with MOUD dropout, in that those who used methamphetamine more often were more likely to discontinue MOUD. The definitions and measurements of MOUD retention varied considerably, as did the magnitude of effect size.

CONCLUSIONS

Results indicate that methamphetamine use has an undesirable impact on MOUD retention and results in an increased risk of treatment discontinuation or dropout. Strategies to identify concurrent methamphetamine use among individuals engaging in MOUD and educate them on the increased risk for dropout should be undertaken. Further research is needed to understand how MOUD retention among patients with concomitant opioid and methamphetamine use can be improved.

"No Good Choice": What are the Issues of Having no Harm Reduction Strategies in Hospitals?

Background

Despite an increase in methamphetamine use and subsequent hospitalizations, the majority of Canadian hospitals currently lack harm reduction strategies for substance use. This can mean that people with lived experience of methamphetamine use are faced with a number of difficult decisions to make when admitted to hospital. Caring for people with lived experience of methamphetamine use can also be problematic with zero tolerance policies requiring abstinence to be maintained. This analysis set out to understand potential health care issues due to a lack of harm reduction strategies from the prospective of people with lived experience of methamphetamine use as well as health care/service professionals.

Methods

Based on a larger study, this secondary analysis explored issues discussed by people with lived experience of methamphetamine use and health care/service professionals regarding the challenges of providing harm reduction approaches in the hospital setting. A total of 108 individuals with lived experience of methamphetamine use completed a qualitative component of a mixed-method interview. In addition, 31 health care/service professionals participated in virtual focus groups and one-to-one interviews. Responses were analyzed using an ethnographic thematic approach.

Results

People with lived experience of methamphetamine use reported 3 choices upon admission: leave or avoid the hospital, stay but experience unsupported withdrawal, or stay but hide their substance usage from health care professionals. Health care/service professionals described 2 options: uphold zero tolerance that can lead to stigma and a lack of knowledge regarding addiction, or accept harm reduction but be unable to implement such strategies. This could lead to health being compromised due to policy and practice that requires abstinence. Neither group of participants described a good choice for them.

Conclusion

Current policy and education related to substance use needs to be revised.

Pharmacology of R-(-)-Methamphetamine in Humans: A Systematic Review of the Literature

Methamphetamine exists as two stereoisomers: S-(+)-methamphetamine ((+)-MAMP) and R-(-)-methamphetamine ((-)-MAMP). The (+)-MAMP stereoisomer is a well-known central nervous system stimulant, available as a pharmaceutical and clandestine drug of abuse. However, the (-)-MAMP stereoisomer is less well understood despite commercial availability for over 30 years as an over-the-counter (OTC) nasal decongestant in the Vicks Vapor Inhaler (a product of Procter & Gamble). Recently, several generic versions have become available, decreasing the cost and increasing the availability of (-)-MAMP-containing nasal sprays to consumers. Despite widespread commercial availability and use in the United States, a paucity of literature exists on the pharmacology of (-)-MAMP in humans. This knowledge gap is problematic, given the difficulty in separating (-)-MAMP and (+)-MAMP isomers in laboratory assays for workplace drug testing, suspected impaired drivers, post-mortem investigations, and assessment of drug involvement in crimes. In response, this systematic review of the literature coalesces and summarizes available knowledge of (-)-MAMP pharmacology in humans. It was found that available knowledge relies heavily on urine drug and metabolite concentrations, systematic pharmacokinetics studies are lacking, and existing knowledge has been derived from a total of 99 unique participants. The impacts of highlighted gaps in the literature are discussed, focusing on forensic toxicology and law enforcement, and future research directions are suggested.

Differential Effects of Cocaine and Morphine on the Diurnal Regulation of the Mouse Nucleus Accumbens Proteome

Substance use disorders are associated with disruptions in sleep and circadian rhythms that persist during abstinence and may contribute to relapse risk. Repeated use of substances such as psychostimulants and opioids may lead to significant alterations in molecular rhythms in the nucleus accumbens (NAc), a brain region central to reward and motivation. Previous studies have identified rhythm alterations in the transcriptome of the NAc and other brain regions following the administration of psychostimulants or opioids. However, little is known about the impact of substance use on the diurnal rhythms of the proteome in the NAc. We used liquid chromatography coupled to tandem mass spectrometry-based quantitative proteomics, along with a data-independent acquisition analysis pipeline, to investigate the effects of cocaine or morphine administration on diurnal rhythms of proteome in the mouse NAc. Overall, our data reveal cocaine and morphine differentially alter diurnal rhythms of the proteome in the NAc, with largely independent differentially expressed proteins dependent on time-of-day. Pathways enriched from cocaine altered protein rhythms were primarily associated with glucocorticoid signaling and metabolism, whereas morphine was associated with neuroinflammation. Collectively, these findings are the first to characterize the diurnal regulation of the NAc proteome and demonstrate a novel relationship between the phase-dependent regulation of protein expression and the differential effects of cocaine and morphine on the NAc proteome. The proteomics data in this study are available via ProteomeXchange with identifier PXD042043.

Exploring Gender and Ethnoracial Differences and Trends in Methamphetamine Treatment

Introduction

Given the significant rise in methamphetamine use and related mortality in the United States, it is critical to explore differences in treatment trends with particular attention to women and ethnoracial groups in hard-hit areas like Los Angeles County.

Methods

We analyzed a large sample across 4 waves: 2011 (105 programs, 10 895 clients), 2013 (104 programs, 17 865 clients), 2015 (96 programs, 16 584 clients), and 2017 (82 programs, 15 388 clients). We completed a comparative analysis to identify differences across subgroups and a trend analysis of treatment episodes by gender and ethnoracial group to differentiate users of methamphetamine and users of other drugs.

Results

Treatment clients using methamphetamine increased over time for each gender and race. There were also significant differences across age groups. Women comprised a greater proportion of treatment episodes involving methamphetamine use (43.3%) compared to all other drugs combined (33.6%). Latinas represented 45.5% of methadone-related admissions. Compared with other drug users, methamphetamine users had a lower successful treatment completion rate and were served by programs with less financial and culturally responsive capacity.

Conclusions

Findings highlight a sharp increase in treatment admissions for methamphetamine users of all gender and ethnocultural groups. Women, especially Latinas, saw the most significant increases, with a widening gender gap over time. All subgroups of methamphetamine users had a lower treatment completion rate compared with users of other drugs, and critical differences existed in the programs where they received services.

'The High Five Club': Social Relations and Perspectives on HIV-Related Stigma During an HIV Outbreak in West Virginia

In the United States, HIV outbreaks are occurring in areas most affected by the opioid epidemic, including West Virginia (WV). Cultural Theory contends that multiple cultures co-exist within societies distinguished by their differing intensities of rules or norms of behavior ('grid') or degree of group allegiance/individual autonomy ('group'). Accordingly, we would expect that perceptions about HIV, including stigma, correspond with individuals' grid/group attributes. To explore this, we conducted qualitative interviews with people who inject drugs (PWID) recruited from a WV syringe service program. This paper focuses on our unexpected findings on stigma during a coinciding HIV outbreak. PWID living homeless identified as belonging to a 'street family'. Its members were mutually distrustful and constrained by poverty and drug dependence but despite their conflicts, reported openness between each other about HIV + status. Interviewees living with HIV perceived little enacted stigma from peers since the local outbreak. Contrasting stigmatizing attitudes were attributed to the town's mainstream society. The 'High Five' (Hi-V) Club, expressing defiance towards stigmatizing behavior outside the street family, epitomized the tensions between a desire for solidary and mutual support and a fatalistic tendency towards division and distrust. Fatalism may hinder cooperation, solidarity and HIV prevention but may explain perceived reductions in stigma.

High levels of interest in access to free safer smoking equipment to reduce injection frequency among people who inject drugs in Seattle, Washington

Background

Drug use route transition interventions promote safer consumption by facilitating a switch from injection to safer routes such as smoking or oral consumption.

Methods

We performed a descriptive analysis using data from questions about "free, clean equipment for smoking" heroin, methamphetamine and/or crack from the Seattle 2018 National HIV Behavioral Surveillance survey of people who inject drugs (N = 555). We estimated the proportion of respondents with access to free safer smoking equipment, and among these participants, the proportion who reported that this access reduced their injection frequency. Among respondents without access to free safer smoking equipment, we described the proportion who were interested in getting access, and whether they thought this access would reduce their injection frequency.

Results

Among participants who reported prior year heroin (n = 495), methamphetamine (n = 372), or crack (n = 88) injection, 11%, 11% and 12% reported access to free safer smoking equipment, respectively. Of those with access, the proportion that reported that access reduced their injection frequency ranged from 12% to 44%. Among participants without access, 28% who used heroin, 45% who used methamphetamine, and 49% who used crack were interested in access. Of interested participants, a majority reported that they thought this access would reduce their frequency of injection.

Conclusions

Access to free safer smoking equipment was limited. Many participants were interested in getting free safer smoking equipment and reported that this access may reduce their injection frequency. Safer smoking equipment is a harm reduction strategy that should be available to reduce risks from opioid and stimulant injection.

Antecedents of fatal overdose in an adult cohort identified through administrative record linkage in Indiana, 2015-2022

BACKGROUND

The United States continues to experience unprecedented rates of overdose mortality and need to identify effective policies or practices that can be implemented. This study aims to measure the prevalence, frequency, timing, and rate of touchpoints that occurred prior to a fatal overdose where communities might intervene.

METHODS

In collaboration with Indiana state government, we conducted record-linkage of statewide administrative datasets to vital records (January 1, 2015, through August 26, 2022) to identify touchpoints (jail booking, prison release, prescription medication dispensation, emergency department visits, and emergency medical services). We examined touchpoints within 12-months prior to a fatal overdose among an adult cohort and explored variation over time and by demographic characteristics.

RESULTS

Over the 92-month study period there were 13,882 overdose deaths (89.3% accidental poisonings, X40-X44) in our adult cohort that were record-linked to multiple administrative datasets and revealed nearly two-thirds (64.7%; n=8980) experienced an emergency department visit, the most prevalent touchpoint followed by prescription medication dispensation, emergency medical services responses, jail booking, and prison release. However, with approximately 1 out of every 100 returning citizens dying from drug overdose within 12-months of release, prison release had the highest touchpoint rate followed by emergency medical services responses, jail booking, emergency department visits, and prescription medication dispensation.

CONCLUSION

Record-linking administrative data from routine practice to vital records from overdose mortality is a viable means of identifying where resources should be situated to reduce fatal overdose, with potential to evaluate the effectiveness of overdose prevention efforts.

The impact of opioid-stimulant co-use on tonic and cue-induced craving

The twin opioid-stimulant epidemics have led to increased overdose deaths and present unique challenges for individuals entering treatment with opioid-stimulant polysubstance use. This study examined tonic and cue-induced craving as a primary outcome among persons in substance use treatment who reported primary substances of opioids, methamphetamine, or cocaine. The sample consisted of 1974 individuals in 55 residential substance-use treatment centers in the United States in 2021. Weekly surveys were delivered via a third-party outcomes tracking system, including measures of tonic and cue-induced craving. Initial comparisons on tonic and cue-induced craving were made among those who primarily used opioids, cocaine, or methamphetamine. Further, the effect of opioid/stimulant polysubstance use on tonic and cue-induced craving was evaluated using marginal effect regression models. Primary methamphetamine use was associated with decreased tonic craving compared to primary opioid use (β = -5.63, p < 0.001) and primary cocaine use was also associate with decreased tonic craving compared to primary opioid use (β = -6.14, p < 0.001). Primary cocaine use was also associated with lower cue-induced cravings compared to primary opioid use (β = -0.53, p = 0.037). Opioid-methamphetamine polysubstance use was associated with higher tonic craving (β = 3.81, p = <0.001) and higher cue-induced craving (β = 1.55, p = 0.001); however, this was not the case for opioid-cocaine polysubstance use. The results of this study indicate that individuals who primarily use opioids and have secondary methamphetamine use experience higher cue-induced and tonic-induced craving, suggesting that these individuals may benefit from additional interventions that target craving and mitigate relapse risk and other negative sequelae.

Kratom's Emergence and Persistence Within the US Polydrug Epidemic

Purpose of Review

Use of "kratom" products, derived from the bioactive botanical Mitragyna speciosa have increased amidst US polydrug use epidemics. Kratom alkaloids interact with opioid, serotonergic, adrenergic, and other receptors and regular users have described experiencing a wide range of effects. Some with polydrug use histories have reported using kratom as a substitute for other drugs or to nonmedically self-manage substance use disorder (SUD) symptoms. Data describing this remain scare and come from self-report. We review this literature describing kratom use as a drug substitute, or as a nonmedical "self-treatment" for attenuating dependence or SUD symptoms.

Recent Findings

Kratom products have been documented as being used as a licit and illicit opioid substitute. Use to reduce alcohol or stimulant consumption is less well documented. Although prior and current polydrug use appear common among a some kratom users, it is unclear if co-use is contemporaneous or concomitant. Temporal order of use initiation is typically undocumented. Use for energy and recreation are also increasingly reported.

Summary

Data on kratom consumption come primarily from self-report with significant limitations. Until controlled human laboratory studies have been conducted, we can presently only describe what is known about human kratom use based on self-report. Such data describe real-world kratom use, leaving unaddressed human abuse liability or therapeutic potential of kratom alkaloids. Clinicians should be mindful of use motivations among people with SUD histories, sensitively assessing use. The paucity of data highlights the urgent need to increase funding and research for understanding kratom's effects in humans.

Differential Effects of Cocaine and Morphine on the Diurnal Regulation of the Mouse Nucleus Accumbens Proteome

Substance use disorders (SUDs) are associated with disruptions in sleep and circadian rhythms that persist during abstinence and may contribute to relapse risk. Repeated use of substances such as psychostimulants and opioids may lead to significant alterations in molecular rhythms in the nucleus accumbens (NAc), a brain region central to reward and motivation. Previous studies have identified rhythm alterations in the transcriptome of the NAc and other brain regions following the administration of psychostimulants or opioids. However, little is known about the impact of substance use on the diurnal rhythms of the proteome in the NAc. We used liquid chromatography coupled to tandem mass spectrometry-based (LC-MS/MS) quantitative proteomics, along with a data-independent acquisition (DIA) analysis pipeline, to investigate the effects of cocaine or morphine administration on diurnal rhythms of proteome in the mouse NAc. Overall, our data reveals cocaine and morphine differentially alters diurnal rhythms of the proteome in the NAc, with largely independent differentially expressed proteins dependent on time-of-day. Pathways enriched from cocaine altered protein rhythms were primarily associated with glucocorticoid signaling and metabolism, whereas morphine was associated with neuroinflammation. Collectively, these findings are the first to characterize the diurnal regulation of the NAc proteome and demonstrate a novel relationship between phase-dependent regulation of protein expression and the differential effects of cocaine and morphine on the NAc proteome.

Estimating the impact of stimulant use on initiation of buprenorphine and extended-release naltrexone in two clinical trials and real-world populations

BACKGROUND

Co-use of stimulants and opioids is rapidly increasing. Randomized clinical trials (RCTs) have established the efficacy of medications for opioid use disorder (MOUD), but stimulant use may decrease the likelihood of initiating MOUD treatment. Furthermore, trial participants may not represent "real-world" populations who would benefit from treatment.

METHODS

We conducted a two-stage analysis. First, associations between stimulant use (time-varying urine drug screens for cocaine, methamphetamine, or amphetamines) and initiation of buprenorphine or extended-release naltrexone (XR-NTX) were estimated across two RCTs (CTN-0051 X:BOT and CTN-0067 CHOICES) using adjusted Cox regression models. Second, results were generalized to three target populations who would benefit from MOUD: Housed adults identifying the need for OUD treatment, as characterized by the National Survey on Drug Use and Health (NSDUH); adults entering OUD treatment, as characterized by Treatment Episodes Dataset (TEDS); and adults living in rural regions of the U.S. with high rates of injection drug use, as characterized by the Rural Opioids Initiative (ROI). Generalizability analyses adjusted for differences in demographic characteristics, substance use, housing status, and depression between RCT and target populations using inverse probability of selection weighting.

RESULTS

Analyses included 673 clinical trial participants, 139 NSDUH respondents (weighted to represent 661,650 people), 71,751 TEDS treatment episodes, and 1,933 ROI participants. The majority were aged 30-49 years, male, and non-Hispanic White. In RCTs, stimulant use reduced the likelihood of MOUD initiation by 32% (adjusted HR [aHR] = 0.68, 95% CI 0.49-0.94, p = 0.019). Stimulant use associations were slightly attenuated and non-significant among housed adults needing treatment (25% reduction, aHR = 0.75, 0.48-1.18, p = 0.215) and adults entering OUD treatment (28% reduction, aHR = 0.72, 0.51-1.01, p = 0.061). The association was more pronounced, but still non-significant among rural people injecting drugs (39% reduction, aHR = 0.61, 0.35-1.06, p = 0.081). Stimulant use had a larger negative impact on XR-NTX initiation compared to buprenorphine, especially in the rural population (76% reduction, aHR = 0.24, 0.08-0.69, p = 0.008).

CONCLUSIONS

Stimulant use is a barrier to buprenorphine or XR-NTX initiation in clinical trials and real-world populations that would benefit from OUD treatment. Interventions to address stimulant use among patients with OUD are urgently needed, especially among rural people injecting drugs, who already suffer from limited access to MOUD.

Selecting the appropriate hurdles and endpoints for pentilludin, a novel antiaddiction pharmacotherapeutic targeting the receptor type protein tyrosine phosphatase D

Substance use disorders provide challenges for development of effective medications. Use of abused substances is likely initiated, sustained and "quit" by complex brain and pharmacological mechanisms that have both genetic and environmental determinants. Medical utilities of prescribed stimulants and opioids provide complex challenges for prevention: how can we minimize their contribution to substance use disorders while retaining medical benefits for pain, restless leg syndrome, attention deficit hyperactivity disorder, narcolepsy and other indications. Data required to support assessments of reduced abuse liability and resulting regulatory scheduling differs from information required to support licensing of novel prophylactic or therapeutic anti-addiction medications, adding further complexity and challenges. I describe some of these challenges in the context of our current efforts to develop pentilludin as a novel anti-addiction therapeutic for a target that is strongly supported by human and mouse genetic and pharmacologic studies, the receptor type protein tyrosine phosphatase D (PTPRD).

Potency-Enhancing Synthetics in the Drug Overdose Epidemic: Xylazine ("Tranq"), Fentanyl, Methamphetamine, and the Displacement of Heroin in Philadelphia and Tijuana

Multiple transformations-referred to as "waves" in a panoply of recent public health and law enforcement publications-have rendered North American drug markets increasingly toxic since the early 2010s. The introduction of exceptionally potent synthetic sedatives and stimulants is initiating a new generation of drug injectors into co-use of opioids and methamphetamine, catapulting rates of deadly overdoses and infectious diseases. Drawing on extensive participant-observation research in Philadelphia (2007-present) and Tijuana (2018-present), we document the experience of street-based drug users across these two North American cities to focus on regional shifts in narcotics supplies and endpoint user preferences. We link the dramatic proliferation of fentanyl, methamphetamine, xylazine, and Mexican white powder heroin to: 1) pre-existing drug supply networks on the western and eastern coasts of the North American subcontinent; 2) material characteristics of local heroin supplies in pre-fentanyl opiate markets (Mexican black tar vs. Colombian off-white powder heroin); and 3) racialized repression/incarceration of drug sellers and users on both sides of the Mexico-US border. The article combines economic and medical anthropology to develop an ethnographically-informed political economy approach to an urgent public health challenge among street-based drug users with the highest overdose mortality rates in the US Northeastern Rust Belt and the Northwestern Mexican borderland metroplex anchored by Tijuana. It foregrounds street users' experiences in real time amidst rapidly shifting narcotics supply chains, linking market-driven logics of profit-seeking to the war on drugs' prohibitionist policy context, highlighting increasing toxic impacts on vulnerable sectors across regions.

Rewarding recovery: the time is now for contingency management for opioid use disorder

Contingency management (i.e. rewarding people, often with money, for achieving their recovery goals) is backed by decades of empirical support yet remains highly underutilized. Rewards are rarely used in real-world clinical practice due to a number of concerns, including most notably, the apparent lack of innovation, as well as moral, philosophical, ethical, and economic concerns, and even federal rules meant to prevent illegal inducements in health care. Still, other opponents argue that some patients will try to "game" the system by simply doing whatever it takes to earn monetary rewards. This paper provides a succinct, up-to-date overview of the current evidence base for contingency management for opioid use disorder. Common barriers and solutions to implementation, as well as implications for future research and clinical practice are discussed. Although important, greater uptake of contingency management interventions is about more than legislation and regulations; it's about recognizing stigma, shaping attitudes, and increasing awareness. Provider involvement in advocacy efforts at all levels and collaboration involving academic-industry partnerships is necessary to advance the burgeoning digital health care space and improve outcomes for people with opioid use disorder. Key MessagesContingency management is highly effective but highly underutilized.Low uptake is largely attributed to a lack of innovation and moral, ethical, and economic concerns, among other barriers.Technology-enabled solutions and academic-industry partnerships are critical to advance opioid use disorder care.

Opioid agonist therapy engagement and crystal methamphetamine use: The impact of unregulated opioid use in Vancouver, Canada

BACKGROUND

Crystal methamphetamine use has substantially increased among people who use opioids in recent years, yet the impact of opioid agonist therapy (OAT) on crystal methamphetamine use remains poorly characterized. Therefore, we sought to examine the relationship between OAT engagement and crystal methamphetamine use and to assess if this relationship differs according to the ongoing use of unregulated opioids.

METHODS

Data was collected from two harmonized ongoing prospective cohorts of people who use drugs in Vancouver, Canada, between December 2005 and March 2020. We employed multivariable generalized estimating equations to study the relationship between OAT engagement and crystal meth use stratified by ongoing unregulated opioid use.

RESULTS

Of 1742 participants who reported frequent opioid use at baseline, the median age was 42 years, and 61.3% were male. Multivariable analyses showed that compared to those who had not received OAT for at least one year: in the absence of ongoing unregulated opioid use, individuals who recently discontinued (adjusted Odds Ratio [aOR] = 0.47, 95% CI = 0.27-0.79), newly initiated (aOR = 0.52, 95% CI = 0.31-0.89), or were retained on OAT (aOR = 0.48, 95% CI = 0.31-0.72) reported a lower frequency of crystal methamphetamine use; in the presence of ongoing unregulated opioid use, individuals who newly initiated OAT reported a greater crystal methamphetamine use frequency (aOR = 1.24, 95% CI = 1.02-1.51).

CONCLUSIONS

We demonstrated a differential relationship between OAT engagement and crystal methamphetamine use that was conditional on the ongoing use of unregulated opioids. Our findings highlight the complexity of OAT implementation and suggest that polysubstance use patterns should be an important consideration for care providers when devising comprehensive treatment strategies and prognosticating treatment effects.

Shifts in substance use patterns among a cohort of people who use opioids after delisting of OxyContin in BC, Canada: An interrupted time series study

BACKGROUND

OxyContin was delisted from Canadian provincial drug formularies in March 2012 and replaced with a reformulated tamper-resistant form of oxycodone (i.e., OxyNeo). We assessed if delisting of OxyContin was associated with changes in the use of unregulated opioids and other substances among people who use opioids (PWUO).

METHODS

Data were derived from two prospective cohort studies of people who use drugs in Vancouver, BC, Canada from 2006 to 2018. PWUO who had at least one follow-up visit before and after delisting of OxyContin were included. Outcomes of interest were self-reported regular (i.e., at least weekly) use of heroin, non-prescribed prescription opioids, cannabis, methamphetamine, crack cocaine, and powder cocaine during the previous six months. Using quasi-experimental interrupted time series, we fit generalized least squares models to assess participants' immediate and long-term substance use practices after the policy change.

RESULTS

We analyzed data from 1014 participants who contributed to 17457 visits during the study. Following the delisting of OxyContin, heroin use increased immediately by 5.17% (95% confidence intervals [CI]: 0.68 to 9.67) and over time by 0.47% (0.35 to 0.58) per month. Non-prescribed prescription opioid use increased immediately by 1.80% (0.10 to 3.50) and over time by 0.16% (0.12 to 0.19) per month. Cannabis use increased immediately by 4.37% (0.88 to 7.87) and over time by 0.11% (0.02 to 0.19) per month. Methamphetamine use did not increase immediately but increased over time by 0.10% (0.01 to 0.18) per month. Crack cocaine use decreased immediately by 6.13% (-10.94 to -1.69) but not significantly over time. Lastly, powder cocaine use did not increase immediately or over time.

CONCLUSIONS

Delisting of OxyContin in BC was not associated with a reduction in unregulated opioid use among PWUO. Our findings point to a shift in substance use patterns of PWUO post-intervention and further highlight the unintended consequences of supply-reduction interventions in addressing the opioid epidemic.

Associations of Lifetime Nonmedical Opioid, Methamphetamine, and Kratom Use within a Nationally Representative US Sample

Co-use of non-medical opioids (NMO) and methamphetamine is increasing. So too is the use of the psychoactive botanical "kratom," including among people with NMO and methamphetamine use histories. We assessed characteristics associated with respondent groups who reported lifetime methamphetamine and/or kratom use within a nationally representative US sample using 2019 National Survey on Drug Use and Health data from respondents reporting lifetime NMO use (diverted prescription opioids, heroin). Weighted prevalence estimates for demographic, mental health, and substance use outcomes were determined. Logistic regression examined associations between group membership and outcomes. Among this sample of respondents with lifetime NMO use, 67.6% (95% CI = 65.6-69.4%) reported only NMO use; 4.6% (3.9-5.4%) reported NMO+Kratom; 24.7% (22.7-26.7%) reported NMO+Methamphetamine; and 3.2% (2.5-3.9%) reported NMO+Methamphetamine+Kratom. Compared to those in the NMO-only group, the NMO+Kratom group was more likely to report past-year serious mental illness (SMI; OR = 2.27), suicidality (OR = 1.89), and past-month psychological distress (OR = 1.88). The NMO+Methamphetamine+Kratom group was more likely to report past-year SMI (OR = 2.65), past-month psychological distress (OR = 2.06), and unmet mental health needs (OR = 2.03); increased odds for drug injection, opioid withdrawal, and perceived treatment need also emerged. Risk factors were observed for all groups but were greatest among those reporting use of all three substances.

Substance use disorders and social determinants of health from electronic medical records obtained during Kentucky's "triple wave"

Social determinants of health (SDOH) play a critical role in the risk of harmful drug use. Examining SDOH as a means of differentiating populations with multiple co-occurring substance use disorders (SUDs) is particularly salient in the era of prevalent opioid and stimulant use known as the "Third Wave". This study uses electronic medical records (EMRs) from a safety net hospital system from 14,032 patients in Kentucky from 2017 to 2019 in order to 1) define three types of SUD cohorts with shared/unique risk factors, 2) identify patients with unstable housing using novel methods for EMRs and 3) link patients to their residential neighborhood to obtain quantitative perspective on social vulnerability. We identified patients in three cohorts with statistically significant unique risk factors that included race, biological sex, insurance type, smoking status, and urban/rural residential location. Adjusting for these variables, we found a statistically significant, increasing risk gradient for patients experiencing unstable housing by cohort type: opioid-only (n = 7385, reference), stimulant-only (n = 4794, odds ratio (aOR) 1.86 95 % confidence interval (CI): 1.66-2.09), and co-diagnosed (n = 1853, aOR = 2.75, 95 % CI: 2.39 to 3.16). At the neighborhood-level, we used 8 different measures of social vulnerability and found that, for the most part, increasing proportions of patients with stimulant use living in a census tract was associated with more social vulnerability. Our study identifies potentially modifiable factors that can be tailored by substance type and demonstrates robust use of EMRs to meet national goals of enhancing research on social determinants of health.

Knowledge, attitudes, and behaviors related to the fentanyl-adulterated drug supply among people who use drugs in Oregon

INTRODUCTION

Nonpharmaceutical fentanyl has reconfigured the U.S. illicit drug market, contributing to a drastic increase in overdose drug deaths. While illicit fentanyl has subsumed the drug supply in the Northeast and Midwest, it has more recently reached the West. For this study, we explored knowledge, attitudes, and behaviors among people who use drugs in Oregon in the context of the emergence of fentanyl in the drug supply.

METHODS

We conducted in-depth interviews by phone with 34 people who use drugs in Oregon from May to June 2021. We used thematic analysis to analyze transcripts and construct themes.

RESULTS

People who use drugs knew about fentanyl, expressed doubt that fentanyl could be found in methamphetamine; believed those who were younger or less experienced were at higher risk for harm; and received information about fentanyl from drug dealers, syringe service programs, or peers (other people who use drugs). Preference for fentanyl's presence in drugs like heroin or methamphetamine was mixed. Some felt that their preference was irrelevant since fentanyl was unavoidable. Participants reported engaging in harm reduction practices, including communicating about fentanyl with dealers and peers, testing for fentanyl, using smaller quantities of drugs, switching from injecting to smoking, and using naloxone.

CONCLUSION

People who use drugs are responding to the rise of fentanyl on the West Coast and are concerned about the increasing uncertainty and hazards of the drug supply. They are willing and motivated to adopt harm reduction behaviors. Harm reduction promotion from syringe service programs and public health agencies is essential to reduce injury and death from nonpharmaceutical fentanyl.

Amphetamine-related care in the USA, 2003-2014: cross-sectional analyses examining inpatient trends and factors associated with hospitalisation outcomes

OBJECTIVES

Although amphetamine use is a growing health problem in the USA, there are limited data on amphetamine-related hospitalisations. The primary objective of our study was to examine trends in amphetamine-related hospitalisations in the USA between 2003 and 2014, including by age and sex. Our secondary objectives were to examine whether demographic, clinical and care setting characteristics were associated with select outcomes of amphetamine-related hospitalisations, including in-hospital mortality, prolonged length of stay and leaving against medical advice.

DESIGN, SETTING AND PARTICIPANTS

Using the 2003-2014 National Inpatient Sample, we estimated the rate of amphetamine-related hospitalisations for each year in the USA among individuals 18+ years of age, stratified by age and sex. Subgroup analyses examined hospitalisations due to amphetamine causes. Unconditional logistic regression modelling was used to estimate the adjusted odds of admission outcomes for sociodemographic, clinical and hospital indicators.

PRIMARY AND SECONDARY OUTCOMES

Our primary outcome was amphetamine-related hospitalisations between 2003 and 2014; secondary outcomes included in-hospital mortality, prolonged length of stay and leaving against medical advice.

RESULTS

Amphetamine-related hospitalisation rates increased from 27 to 69 per 100 000 population between 2003 and 2014. Annual rates were consistently greater among younger (18-44 years) individuals and men. Regional differences were observed, with admission to Western hospitals being associated with increased mortality (adjusted OR, AOR 5.07, 95% CI 1.22 to 21.04) and shorter (0-2 days) lengths of stay (AOR 0.70, 95% CI 0.58 to 0.83) compared with Northeast admissions. Males (AOR 1.26, 95% CI 1.15 to 1.38; compared with females) and self-pay (AOR 2.30, 95% CI 1.90 to 2.79; compared with private insurance) were associated with leaving against medical advice.

CONCLUSIONS

Increasing rates of amphetamine-related hospitalisation risk being overshadowed by other public health crises. Regional amphetamine interventions may offer the greatest population health benefits. Future studies should examine long-term outcomes among patients hospitalised for amphetamine-related causes.

Biochemical Neuroadaptations in the Rat Striatal Dopaminergic System after Prolonged Exposure to Methamphetamine Self-Administration

Perturbations in striatal dopamine (DA) homeostasis might underlie the behavioral and pathobiological consequences of METH use disorder in humans. To identify potential consequences of long-term METH exposure, we modeled the adverse consequence DSM criterion of substance use disorders by giving footshocks to rats that had escalated their intake of METH during a drug self-administration procedure. Next, DA D1 receptor antagonist, SCH23390 was injected. Thereafter, rats were euthanized to measure several indices of the striatal dopaminergic system. Footshocks split the METH rats into two phenotypes: (i) shock-sensitive that decreased their METH-intake and (ii) shock-resistant that continued their METH intake. SCH23390 caused substantial dose-dependent reduction of METH taking in both groups. Stopping SCH23390 caused re-emergence of compulsive METH taking in shock-resistant rats. Compulsive METH takers also exhibited greater incubation of METH seeking than non-compulsive rats during withdrawal from METH SA. Analyses of DA metabolism revealed non-significant decreases (about 35%) in DA levels in resistant and sensitive rats. However, striatal contents of the deaminated metabolites, DOPAL and DOPAC, were significantly increased in sensitive rats. VMAT2 and DAT protein levels were decreased in both phenotypes. Moreover, protein expression levels of the D1-like DA receptor, D5R, and D2-like DA receptors, D3R and D4R, were significantly decreased in the compulsive METH takers. Our results parallel findings in post-mortem striatal tissues of human METH users who develop Parkinsonism after long-term METH intake and support the use of this model to investigate potential therapeutic interventions for METH use disorder.

Practical Technology for Expanding and Improving Substance Use Disorder Treatment: Telehealth, Remote Monitoring, and Digital Health Interventions

The US opioid crisis and the COVID-19 pandemic have sparked innovation in substance use disorder (SUD) treatment such that telehealth, remote monitoring, and digital health interventions are increasingly feasible and effective. These technologies can increase SUD treatment access and acceptability, even for nontreatment seeking, remote, and underserved populations, and can be used to reduce health disparities. Overall, digital tools will likely overcome many barriers to delivery of evidence-based behavioral treatments such as cognitive behavioral therapy and contingency management, that, along with appropriate medications, constitute the foundation of treatment of SUDs.

Prevalence and correlates of incarceration following emergency medical services response to overdose

BACKGROUND

To describe the prevalence of incarceration among survivors of non-fatal overdose addressed through an emergency medical services (EMS) response, and compare incarceration by whether the emergency was for opioid-involved or stimulant-involved overdose.

METHODS

Administrative records on 192,113 EMS incidents and 70,409 jail booking events occurring between January 1, 2019 and December 31, 2020 in Indianapolis, Indiana were record-linked at the event level. Incarceration taking place within 6-hours of an EMS incident was associated with that incident. Logistic regression was used to calculate adjusted odds ratios (AOR) of incarceration after an overdose.

RESULTS

Among all EMS incidents, 2.6% were followed by incarceration. For overdose EMS incidents, the prevalence of incarceration was 10.0%. Overdose incidents had higher odds than non-overdose incidents of leading to a charge of felony, booked on a warrant, and transferred to another law enforcement agency upon release. Prevalence of incarceration following a stimulant-involved overdose was 21.3%, compared to 9.3% for opioid-involved overdose survivors. Compared to persons from other EMS incidents, overdose survivors had greater odds of incarceration (AOR=3.48, 95% confidence interval (CI)= 3.22, 3.75, p < .001), with opioid-involved overdoses (AOR=3.03, 95% CI=2.76, 3.33, p < .001) and stimulant-involved overdoses (AOR=6.70, 95% CI=5.26, 8.55, p < .001) leading to higher odds of incarceration.

CONCLUSION

Incarceration in county jail followed one in ten overdose-involved EMS responses. As illicit drug consumption increasingly involves stimulants, the frequency of incarceration following these events is likely to increase. Policy changes and interventions are needed to reduce incarceration after overdose emergencies.

Demographic and geographic shifts in the preferred route of methamphetamine administration among treatment cases in the US, 2010-2019

BACKGROUND

Methamphetamine use disorder has increased rapidly in the past decade. Injecting is also increasing and has multifaceted implications for disease severity, overall health, and treatment outcomes, but less is known about where or among whom injecting has shifted the most. This national study assessed temporal changes in the preferred route of methamphetamine administration by race/ethnicity and within urban/rural geographies.

METHODS

We used the Treatment Episode Dataset-Discharges (2010-2019) to identify outpatient treatment cases who reported methamphetamine as their primary drug of choice at admission (N = 531,799; 2010 n = 33,744; 2019 n = 81,885). We created a combined variable indicating race/ethnicity and the rural/urban location of treatment, and used logistic regression to model the predicted probability of cases reporting injection, smoking, or snorting as their preferred route of administration. We included an interaction term to determine differences over time (race/ethnicity/rurality*year).

RESULTS

Across all years, smoking methamphetamine was the most common route of administration (66%), followed by injection (24%) and snorting (10%). Over time and among most sub-groups, the rates of injection increased while the rates of smoking decreased. Compared to 2010, the odds of injecting methamphetamine in 2019 were highest among Black cases in urban areas (aOR = 2.30, 95% CI = 1.76-3.00, p < 0.0001).

CONCLUSION

Increasing methamphetamine injection was most pronounced among Black treatment cases in more urban areas, which is in contrast to the longstanding narrative that methamphetamine is a White and rural drug. Methamphetamine prevention, treatment, and harm reduction should target populations with high injection prevalence and growing incidence.

Dual public health crises: the overlap of drug overdose and firearm injury in Indianapolis, Indiana, 2018-2020

Background

Drug overdose and firearm injury are two of the United States (US) most unrelenting public health crises, both of which have been compounded by the COVID-19 pandemic. Programs and policies typically focus on each epidemic, alone, which may produce less efficient interventions if overlap does exist. The objective is to examine whether drug overdose correlates with and is associated with firearm injury at the census tract level while controlling for neighborhood characteristics.

Methods

An ecological study of census tracts in Indianapolis, Indiana from 2018 to 2020. Population rates per 100,000 and census tracts with the highest overlap of overdose and firearm injury were identified based on spatial clusters. Bivariate association between census tract characteristic and drug overdose and firearm violence rate within spatial clusters. Zero-inflated negative binominal regression was used to estimate if the drug overdose activity is associated with higher future firearm injury.

Results

In high overdose—high firearm injury census tracts, rates of firearm injury and drug overdose are two times higher compared to city wide rates. Indicators of structural disadvantage and structural racism are higher in high overdose—high firearm injury census tracts compared to city-wide averages. Drug overdoses are associated with higher rates of firearm injury in the following year (IRR: 1.004, 95% CI 1.001, 1.007, p < 0.05), adjusting for census tract characteristics and spatial dependence.

Conclusions

Drug overdose and firearm injury co-spatially concentrate within census tracts. Moreover, drug overdoses are associated with future firearm injury. Interventions to reduce firearm injuries and drug overdoses should be a co-response in high drug overdose—high firearm injury communities.

Young adult opioid misuse indicates a general tendency toward substance use and is strongly predicted by general substance use risk

OBJECTIVE

To examine whether young adult opioid misuse reflects a general tendency toward substance use and is influenced by general substance use risk or whether it is a different phenomenon from other drug use.

METHODS

At ages 23 (2016) and 26 (2019), a panel of young adults (n = 3794 to 3833) in the United States self-reported their past-month substance use (opioid misuse, heavy drinking, cigarettes, cannabis) and substance-specific risk factors (perceptions of harm; approval of use; and use of each substance by friends and romantic partners). Structural equation models examined non-opioid and opioid-specific associations between latent risk and substance use factors.

RESULTS

Opioid misuse and opioid-specific risk factors shared significant variance with latent substance use and latent substance use risk, respectively, which were strongly associated. A statistically significant residual correlation between opioid-specific risk and opioid misuse remained.

CONCLUSION

Young adult opioid misuse reflects a general tendency toward substance use and is strongly predicted by risk for substance use. Opioid-specific risk factors play only a small independent role. Existing evidence-based substance use interventions may be effective in preventing opioid misuse among young adults.

Signals of increasing co-use of stimulants and opioids from online drug forum data

Background

Despite recent rises in fatal overdoses involving multiple substances, there is a paucity of knowledge about stimulant co-use patterns among people who use opioids (PWUO) or people being treated with medications for opioid use disorder (PTMOUD). A better understanding of the timing and patterns in stimulant co-use among PWUO based on mentions of these substances on social media can help inform prevention programs, policy, and future research directions. This study examines stimulant co-mention trends among PWUO/PTMOUD on social media over multiple years.

Methods

We collected publicly available data from 14 forums on Reddit (subreddits) that focused on prescription and illicit opioids, and medications for opioid use disorder (MOUD). Collected data ranged from 2011 to 2020, and we also collected timelines comprising past posts from a sample of Reddit users (Redditors) on these forums. We applied natural language processing to generate lexical variants of all included prescription and illicit opioids and stimulants and detect mentions of them on the chosen subreddits. Finally, we analyzed and described trends and patterns in co-mentions.

Results

Posts collected for 13,812 Redditors showed that 12,306 (89.1%) mentioned at least 1 opioid, opioid-related medication, or stimulant. Analyses revealed that the number and proportion of Redditors mentioning both opioids and/or opioid-related medications and stimulants steadily increased over time. Relative rates of co-mentions by the same Redditor of heroin and methamphetamine, the substances most commonly co-mentioned, decreased in recent years, while co-mentions of both fentanyl and MOUD with methamphetamine increased.

Conclusion

Our analyses reflect increasing mentions of stimulants, particularly methamphetamine, among PWUO/PTMOUD, which closely resembles the growth in overdose deaths involving both opioids and stimulants. These findings are consistent with recent reports suggesting increasing stimulant use among people receiving treatment for opioid use disorder. These data offer insights on emerging trends in the overdose epidemic and underscore the importance of scaling efforts to address co-occurring opioid and stimulant use including harm reduction and comprehensive healthcare access spanning mental-health services and substance use disorder treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12954-022-00628-2.

Interactions between opioids and stimulants: Behavioral pharmacology of abuse-related effects

Opioid abuse continues to be a significant public health challenge, with rates of opioid-related overdose deaths increasing continuously over the last two decades. There also has been a sharp increase in overdose deaths involving stimulant drugs, primarily cocaine and methamphetamine. Recent estimates indicate a high prevalence of co-use of opioids and stimulants, which is a particularly complex problem. Behavioral pharmacology research over the last few decades has characterized interactions between opioids and stimulants as well as evaluated potential treatments. This chapter describes interactions between opioids and stimulants, with a focus on pre-clinical studies of abuse-related behavioral effects using self-administration, reinstatement, drug discrimination, place conditioning, and intracranial self-stimulation paradigms in laboratory animals. In general, the literature provides substantial evidence of mutual enhancement between opioids and stimulants for abuse-related effects, although such results are not ubiquitous. Enhanced abuse-related effects could manifest in many ways including engaging in drug seeking and taking behaviors with greater persistence, effort, and motivation and/or increased likelihood of relapse. Moreover, studies on opioid/stimulant combinations set the stage for evaluating potential treatments for polysubstance use. Behavioral pharmacology research has proven invaluable for elucidating these relationships using rigorous experimental designs and quantitative analyses of pharmacological and behavioral data.

Motivations for concurrent use of uppers and downers among people who access harm reduction services in British Columbia, Canada: findings from the 2019 Harm Reduction Client Survey

INTRODUCTION

An increase in crystal methamphetamine (methamphetamine) use during the overdose epidemic is being observed in British Columbia (BC), Canada, and across North America. Concurrent use (ie, using uppers and downers one after the other or together) can increase the risk of fatal and non-fatal opioid overdose.

OBJECTIVES

We investigated motivations for concurrent use of uppers and downers, specifically how (eg, in what order) and why people use concurrently, to identify potential interventions to prevent overdose and other harms.

SETTING AND PARTICIPANTS

The 2019 Harm Reduction Client Survey was administered across 22 harm reduction supply distribution sites in BC (n=621). This thematic analysis examined 307 responses by people who affirmed concurrent use to classify order and reasons for using uppers and downers concurrently.

RESULTS

Of the 307 people who responded 'yes' to concurrent use, 179 (58.3%) used downers then uppers, 76 (24.8%) used uppers then downers and 184 (59.9%) mixed uppers and downers together. Four main reasons for concurrent use emerged: self-medication, availability and preference, drug effects/properties, and financial and life situation. People who mixed drugs together predominantly wanted to achieve desired drug effects/properties, such as a specific high or balancing stimulating and sedating effects.

CONCLUSIONS

The ongoing rise in overdoses in BC is multifactorial, and the recent parallel increases in methamphetamine use and concurrent use with opioids may contribute. Qualitative interviews may further elucidate reasons for concurrent use. Addressing reasons for concurrent use identified in this study through harm reduction strategies and education may affect the rates of overdose morbidity and mortality.

Patient characteristics and treatment utilization in fatal stimulant-involved overdoses in the United States Veterans Health Administration

BACKGROUND AND AIMS

This study aimed to (1) describe trends in stimulant-alone and stimulant and other substance use overdose deaths from 2012 to 2018 and (2) measure patient and service use characteristics across stimulant-related overdose death profiles.

DESIGN

Retrospective cohort study of patients who died from stimulant-involved overdose between annual years 2012 and 2018.

SETTING

United States Veterans Health Administration (VHA). A total of 3631 patients died from stimulant-involved overdose, as identified through the National Death Index.

MEASUREMENTS

Stimulant-involved overdose deaths were categorized by stimulant type (cocaine or methamphetamine/other) and other substance co-involvement. Cause of death data were linked to patient characteristics, including demographic and treatment use preceding overdose from VHA administrative data. We examined trends over time and compared treatment use factors between the following mutually exclusive overdose profiles: cocaine alone, methamphetamine alone, cocaine + opioid, methamphetamine + opioid, any stimulant + other substance and cocaine + methamphetamine.

FINDINGS

The rate of overdose death was 3.06 times higher in 2018 than 2012, with increases across all toxicology profiles. Compared with cocaine-involved overdoses, methamphetamine-involved overdoses were less likely in people who were older [adjusted odds ratio (aOR) = 0.22, 95% confidence interval (CI) = 0.06-0.87 aged 65+ versus 18-29] and more likely among those who lived in rural areas (aOR = 2.73, 95% CI = 1.43-5.23). People who died from stimulant + opioid overdoses had lower odds of a stimulant use disorder diagnosis compared with stimulant alone deaths (cocaine: aOR = 0.55, 95% CI = 0.41-0.75, methamphetamine: aOR = 0.44, 95% CI = 0.29-0.68).

CONCLUSIONS

The rate of deaths among US Veterans from stimulant-related overdose was three times higher in 2018 than 2012. Key differences in characteristics of patients across overdose toxicology profiles, such as geographic location and health-care use, point to distinct treatment needs based on stimulant use type.

Opioid Use Disorder Diagnosis and Management

Opioid Use Disorder Diagnosis and ManagementThe last 20 years have seen a staggering increase in opioid-related morbidity and mortality. Although the consequences of untreated OUDs are significant, OUD is a treatable illness. This article reviews the epidemiology of OUD and its complications, screening, diagnosis, treatment, and harm reduction interventions.

Patterns and motivations of polysubstance use: a rapid review of the qualitative evidence

INTRODUCTION

Polysubstance use-the use of substances at the same time or close in time-is a common practice among people who use drugs. The recent rise in mortality and overdose associated with polysubstance use makes understanding current motivations underlying this pattern critical. The objective of this review was to synthesize current knowledge of the reasons for combining substances in a single defined episode of drug use.

METHODS

We conducted a rapid review of the literature to identify empirical studies describing patterns and/or motivations for polysubstance use. Included studies were published between 2010 and 2021 and identified using MEDLINE, Embase, PsycINFO and Google Scholar.

RESULTS

We included 13 qualitative or mixed-method studies in our analysis. Substances were combined sequentially to alleviate withdrawal symptoms or prolong a state of euphoria ("high"). Simultaneous use was motivated by an intention to counteract or balance the effect(s) of a substance with those of another, enhance a high or reduce overall use, and to mimic the effect of another unavailable or more expensive substance. Self-medication for a pre-existing condition was also the intention behind sequential or simultaneous use.

CONCLUSION

Polysubstance use is often motivated by a desire to improve the experience based on expected effects of combinations. A better understanding of the reasons underlying substance combination are needed to mitigate the impact of the current overdose crisis.

Methamphetamine use in the United States: epidemiological update and implications for prevention, treatment, and harm reduction

Recent attention has focused on the growing role of psychostimulants, such as methamphetamine in overdose deaths. Methamphetamine is an addictive and potent stimulant, and its use is associated with a range of physical and mental health harms, overdose, and mortality. Adding to the complexity of this resurgent methamphetamine threat is the reality that the increases in methamphetamine availability and harms are occurring in the midst of and intertwined with the ongoing opioid overdose crisis. Opioid involvement in psychostimulant-involved overdose deaths increased from 34.5% of overdose deaths in 2010 to 53.5% in 2019-an increase of more than 50%. This latest evolution of the nation's overdose epidemic poses novel challenges for prevention, treatment, and harm reduction. This narrative review synthesizes what is known about changing patterns of methamphetamine use with and without opioids in the United States, other characteristics associated with methamphetamine use, the contributions of the changing illicit drug supply to use patterns and overdose risk, motivations for couse of methamphetamine and opioids, and awareness of exposure to opioids via the illicit methamphetamine supply. Finally, the review summarizes illustrative community and health system strategies and research opportunities to advance prevention, treatment, and harm reduction policies, programs, and practices.

U.S. older adults' heroin and psychostimulant use treatment admissions, 2012-2019: Sociodemographic and clinical characteristics

BACKGROUND

Increases in U.S. older adults' nonprescription opioid and psychostimulant use call for examining their treatment admissions for these substances.

METHODS

Using admissions age 55 + involving heroin (N = 299,073) from the 2012-2019 Treatment Episode Data Set-Admissions, we examined trends and sociodemographic and clinical characteristics of three groups: (1) heroin-only admissions (i.e., not involving cocaine or methamphetamine), (2) heroin-cocaine admissions, and (3) heroin-methamphetamine admissions. Bivariable and multivariable logistic regression analyses were conducted to examine the research questions.

RESULTS

Between 2012 and 2019, the numbers of both heroin-only and heroin-cocaine admissions increased 2.3-fold and heroin-methamphetamine admissions increased seven-fold. First time heroin-methamphetamine admissions increased 18-fold. Heroin-methamphetamine admissions were concentrated in the Western region and heroin-cocaine admissions in the Northeastern region. Multivariable analyses showed a nearly 6 times higher relative risk ratio (RRR; 95% CI=5.24-6.74) for heroin-methamphetamine vs. heroin-only admissions in 2019 compared to 2012. Being non-Hispanic Black, compared to non-Hispanic White, was associated with a RRR of 2.4 (95% CI=2.34-2.46) for heroin-cocaine admissions and a RRR of 0.14 (95% CI=0.12-0.15) for heroin-methamphetamine admissions. Late-onset heroin use, experience of homelessness and other psychiatric problems, and past 30-day arrest episodes were associated with a higher likelihood of heroin-cocaine and heroin-methamphetamine admissions, while injection drug use (IDU) was associated with a higher likelihood of heroin-methamphetamine admissions only.

CONCLUSIONS

Healthcare providers should assess and monitor psychostimulant, methamphetamine in particular, use among older adults. Those who use heroin and psychostimulants should receive substance use treatment and help to secure stable housing and meet other living needs.

Correlates of methamphetamine use severity among patients receiving methadone maintenance treatment for opioid use disorder in Vietnam

OBJECTIVES

To assess the severity of methamphetamine use among methadone maintenance treatment (MMT) patients in Vietnam with opioid use disorder and concurrent methamphetamine use, and to identify risk factors associated with higher severity of methamphetamine use.

METHODS

We used survey data and medical record abstractions from 428 people with opioid use disorder who also use methamphetamine while partaking in methadone treatment in five clinics in Hanoi, Vietnam. We used multinomial logistic regression to assess other risk factors and problems associated with high methamphetamine use severity.

RESULTS

Those who reported injecting heroin in the past 3 months (AOR = 4.05, 95% CI [1.30, 12.55], p = 0.02), having a longer history of lifetime heroin use (AOR = 1.13, 95% CI [1.03, 1.24], p < 0.01), and having higher cravings (AOR = 1.97, 95% CI [1.31, 2.98], p < 0.01) and fatigue (AOR = 1.25, 95% CI [0.96, 1.61], p = 0.09) related to methamphetamine withdrawal had greater odds of high methamphetamine use severity. One of five clinics had a significantly higher percentage of methamphetamine use severity than others.

CONCLUSION

Successful MMT in patients with opioid use disorder in Vietnam may additionally require methamphetamine-focused screening and intervention.

Increasing preference for fentanyl among a cohort of people who use opioids in Vancouver, Canada, 2017-2018

Background: Despite increasing prevalence of illicit fentanyl use in the US and Canada, preference for fentanyl over other illicit opioids has not been fully characterized. Therefore, we sought to describe changes in illicit opioid preferences over time among people who inject drugs (PWID). Methods: Data were obtained from two prospective cohort studies between 2017 and 2018. Trends in opioid preference over time were examined using bivariable generalized estimating equation (GEE) analysis. Multivariable models were used to identify factors associated with fentanyl preference. Results: Among 732 eligible participants, including 425 (58%) males, the prevalence of preference for fentanyl increased from 4.4% in 2017 to 6.6% in 2018 (Odds Ratio [OR] = 1.27, 95% Confidence Interval [CI]: 1.05-1.52). In a multivariable analysis, younger age (Adjusted Odds Ratio [AOR] = 0.94, 95% CI: 0.92-0.96) and daily crystal methamphetamine injection (AOR = 1.68, 95% CI: 1.01-2.78) were independently associated with preference for fentanyl. The most common reasons for preferring fentanyl included "better high than other opioids" (45%), and "lasts longer than heroin" (27%). Conclusions: The current study has demonstrated that preference for fentanyl has been increasing over time among our sample of PWID who use opioids. Further work is needed to clarify risk factors surrounding transitions to illicit fentanyl.

Polysubstance Overdose Deaths in the Fentanyl Era: A Latent Class Analysis

OBJECTIVES

To elucidate the main latent classes of substances detected among overdose decedents, and latent class associations with age, sex, race, and jurisdiction of death in Maryland.

METHODS

We used toxicology data from the Office of the Chief Medical Examiner of Maryland for all decedents. We analyzed all cases of drug overdose deaths that occurred from 2016 to 2018 (N = 6566) using latent class analysis and regression.

RESULTS

Drug overdose deaths were concentrated in 2 of 24 counties in Maryland (Baltimore City and County). Fentanyl was involved in 71% of all drug overdose deaths, and the majority (76%) of these deaths included multiple substances. Three latent classes emerged: (1) fentanyl/heroin/cocaine (64%); (2) fentanyl/alcohol (18%); and (3) prescription drugs including opioids, benzodiazepines and antidepressants (18.0%). The fentanyl/heroin/cocaine class members were significantly younger (<30 years), female and White compared to the fentanyl/alcohol class, but more male and non-White than the prescription drugs class (all P < 0.05). Deaths in Baltimore City/County were more likely than in other locations to involve fentanyl/alcohol (P < 0.05).

CONCLUSIONS

The majority of fentanyl-involved overdose deaths in Maryland involved multiple substances, and several demographic and geographic differences in these patterns emerged. Geographically-targeted interventions that are tailored to reduce the harms associated with polysubstance use (including cocaine, alcohol, and prescription drugs) for different demographic groups are warranted.

Dopamine Supersensitivity: A Novel Hypothesis of Opioid-Induced Neurobiological Mechanisms Underlying Opioid-Stimulant Co-use and Opioid Relapse

Emergent harms presented by the co-use of opioids and methamphetamine highlight the broader public health challenge of preventing and treating opioid and stimulant co-use. Development of effective therapeutics requires an understanding of the physiological mechanisms that may be driving co-use patterns, specifically the underlying neurobiology of co-use and how they may facilitate (or be leveraged to prevent) continued use patterns. This narrative review summarizes largely preclinical data that demonstrate clinically-meaningful relationships between the dopamine and opioid systems with direct implications for opioid and stimulant co-use. Synthesized conclusions of this body of research include evidence that changes in the dopamine system occur only once physical dependence to opioids develops, that the chronicity of opioid exposure is associated with the severity of changes, and that withdrawal leaves the organism in a state of substantive dopamine deficit that persists long after the somatic or observed signs of opioid withdrawal appear to have resolved. Evidence also suggests that dopamine supersensitivity develops soon after opioid abstinence and results in increased response to dopamine agonists that increases in magnitude as the abstinence period continues and is evident several weeks into protracted withdrawal. Mechanistically, this supersensitivity appears to be mediated by changes in the sensitivity, not quantity, of dopamine D2 receptors. Here we propose a neural circuit mechanism unique to withdrawal from opioid use with implications for increased stimulant sensitivity in previously stimulant-naïve or inexperienced populations. These hypothesized effects collectively delineate a mechanism by which stimulants would be uniquely reinforcing to persons with opioid physical dependence, would contribute to the acute opioid withdrawal syndrome, and could manifest subjectively as craving and/or motivation to use that could prompt opioid relapse during acute and protracted withdrawal. Preclinical research is needed to directly test these hypothesized mechanisms. Human laboratory and clinical trial research is needed to explore these clinical predictions and to advance the goal of developing treatments for opioid-stimulant co-use and/or opioid relapse prevention and withdrawal remediation.

Co-exposure of cannabinoids with amphetamines and biological, behavioural and health outcomes: a scoping review of animal and human studies

RATIONALE

The growing prevalence of psychostimulant (including amphetamine) use and associated health harms, with limited treatment options, present a global challenge. There is an increasing availability and medical applications of cannabinoids, and growing interest in their therapeutic potential for addictive disorders.

OBJECTIVES

The objective of this study is to review available data regarding cannabis/cannabinoid co-use or exposure on amphetamine-related outcomes.

METHODS

Towards the present scoping review, we systematically searched four databases (Medline, Web-of-Science, CINAHL Plus and PsycInfo) using cannabis/cannabinoid and amphetamine text-terms identifying peer-reviewed, English-language studies published in 2000-2020 involving multiple methods approaches among both human and animal study samples, assessing the association of co-use/administration of cannabis/cannabinoids products with non-medical amphetamines on biological, behavioural or health outcomes.

RESULTS

Twenty-five articles were included. Pre-clinical studies (n = 15) found mostly protective effects of single or repeated cannabinoids administration on rodents in amphetamine addiction models, amphetamine-induced models of human mental disorders (e.g. schizophrenia) and amphetamine-induced neurotoxicity. Human studies (n = 10) were more heterogeneously designed (e.g. cross-sectional, case-control, longitudinal) and assessed natural ongoing cannabis and methamphetamine use or dependence, showing mostly enhanced harms in a diversity of outcomes (e.g. mental health, methamphetamine use, cognition).

CONCLUSIONS

While human studies suggest cannabis use as an adverse risk factor among non-medical amphetamine users, pre-clinical studies suggest therapeutic potential of cannabinoids, especially cannabidiol, to alleviate amphetamine addiction and harms, including treatment outcomes. Given increasing psychostimulant harms but lack of care options, rigorous, high-quality design studies should aim to translate and investigate pre-clinical study results for potential therapeutic benefits of cannabinoids for amphetamine use/abuse in human subjects.

Understanding Stimulant Use and Use Disorders in a New Era

Extending from the triple wave epidemic of opioid-related overdose deaths, a fourth wave of high mortality involving methamphetamine and cocaine use has been gathering force. This article provides a review of the published literature on stimulants including epidemiology, pharmacology, neurobiology, medical and psychiatric consequences, withdrawal management, and medical and behavioral treatments.

Methamphetamine Use, Methamphetamine Use Disorder, and Associated Overdose Deaths Among US Adults

IMPORTANCE

Mortality associated with methamphetamine use has increased markedly in the US. Understanding patterns of methamphetamine use may help inform related prevention and treatment.

OBJECTIVE

To assess the national trends in and correlates of past-year methamphetamine use, methamphetamine use disorder (MUD), injection, frequent use, and associated overdose mortality from 2015 to 2019.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study analyzed methamphetamine use, MUD, injection, and frequent use data from participants in the 2015 to 2019 National Surveys on Drug Use and Health (NSDUH). Mortality data were obtained from the 2015 to 2019 National Vital Statistics System Multiple Cause of Death files.

EXPOSURES

Methamphetamine use.

MAIN OUTCOMES AND MEASURES

Methamphetamine use, MUD, injection, frequent use, and overdose deaths.

RESULTS

Of 195 711 NSDUH respondents aged 18 to 64 years, 104 408 were women (weighted percentage, 50.9%), 35 686 were Hispanic individuals (weighted percentage, 18.0%), 25 389 were non-Hispanic Black (hereafter, Black) individuals (weighted percentage, 12.6%), and 114 248 were non-Hispanic White (hereafter, White) individuals (weighted percentage, 60.6%). From 2015 to 2019, overdose deaths involving psychostimulants other than cocaine (largely methamphetamine) increased 180% (from 5526 to 15 489; P for trend <.001); methamphetamine use increased 43% (from 1.4 million [95% CI, 1.2-1.6 million] to 2.0 million [95% CI, 1.7-2.3 million]; P for trend = .002); frequent methamphetamine use increased 66% (from 615 000 [95% CI, 512 000-717 000] to 1 021 000 [95% CI, 860 000-1 183 000]; P for trend = .002); methamphetamine and cocaine use increased 60% (from 402 000 [95% CI, 306 000-499 000] to 645 000 [95% CI, 477 000-813 000]; P for trend = .001); and MUD without injection increased 105% (from 397 000 [95% CI, 299 000-496 000] to 815 000 [95% CI, 598 000-1 033 000]; P for trend = .006). The prevalence of MUD or injection surpassed the prevalence of methamphetamine use without MUD or injection in each year from 2017 to 2019 (60% to 67% vs 37% to 40%; P for trend ≤.001). Adults with MUD or using injection were more likely to use methamphetamine frequently (52.68%-53.84% vs 32.59%; adjusted risk ratio, 1.62-1.65; 95% CI, 1.35-1.94). From 2015 to 2019, the adjusted prevalence of MUD without injection more than tripled among heterosexual women (from 0.24% to 0.74%; P < .001) and lesbian or bisexual women (from 0.21% to 0.71%; P < .001) and more than doubled among heterosexual men (from 0.29% to 0.79%; P < .001) and homosexual or bisexual men (from 0.29% to 0.80%; P = .007). It increased over 10-fold among Black individuals (from 0.06% to 0.64%; P < .001), nearly tripled among White individuals (from 0.28% to 0.78%; P < .001), and more than doubled among Hispanic individuals (from 0.39% to 0.82%; P < .001). Risk factors for methamphetamine use, MUD, injection, and frequent use included lower educational attainment, lower annual household income, lack of insurance, housing instability, criminal justice involvement, comorbidities (eg, HIV/AIDS, hepatitis B or C virus, depression), suicidal ideation, and polysubstance use.

CONCLUSIONS AND RELEVANCE

This cross-sectional study found consistent upward trends in overdose mortality, greater risk patterns of methamphetamine use, and populations at higher risk for MUD diversifying rapidly, particularly those with socioeconomic risk factors and comorbidities. Evidence-based prevention and treatment interventions are needed to address surges in methamphetamine use and MUD.