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International Journal of Drug Policy

Elsevier BV

Preprints posted in the last 30 days, ranked by how well they match International Journal of Drug Policy's content profile, based on 11 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

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Polysubstance Injection and Smoking Trajectories of Unregulated Drug Use in the San Diego-Tijuana Border Region: A Latent Transition Analysis

Eger, W. H.; Bazzi, A. R.; Crable, E. L.; Abramovitz, D.; Harvey-Vera, A.; Vera, C. F.; Rangel, M. G.; Friedman, J. R.; Pitpitan, E. V.; Patterson, T. L.; Strathdee, S. A.; Pines, H. A.

2026-05-29 addiction medicine 10.64898/2026.05.27.26354253 medRxiv
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Background and Aims: The North American overdose crisis is increasingly characterized by complex polysubstance use alongside a transition from injecting to smoking unregulated opioids. However, transitions involving multiple substances remain understudied. We characterized longitudinal transitions in the route of administration and frequency of heroin, fentanyl, and methamphetamine use and examined whether these transitions differed by multilevel factors hypothesized to influence patterns of polysubstance use and routes of administration over time. Design: People who inject drugs (PWID) enrolled in a cohort study completed baseline surveys (October 2020-2021) and three biannual follow-up visits (through April 2023). Setting: San Diego, California, and Tijuana, Baja California. Participants: Among 612 PWID, median age was 43 years; most were male (74%), Hispanic, Latino, or Mexican (72%), and San Diego residents (67%). Measurements: Based on past six-month substance use behaviors reported at each visit, we categorized participants according to six indicators over time: low- (< weekly) and high-frequency ([&ge;] weekly) smoking and injecting of heroin, fentanyl, and methamphetamine. We then used latent transition analysis (LTA) to identify distinct subgroups of participants with respect to these indicators at baseline and examine transitions between them over 18 months. We fit models with 2-5 subgroups, selecting the final model based on fit and interpretability and used multiple-groups LTA to examine differences in subgroup transitions by multilevel factors. Findings: We identified four subgroups: Subgroup 1 (Heroin-Methamphetamine Polyroute), characterized by high-frequency heroin and methamphetamine smoking and injection, included 22% of participants at baseline but 0% at 18 months. Subgroup 2 (Methamphetamine-dominant Smoking), characterized by high-frequency methamphetamine smoking, accounted for 14% of participants at baseline and 18 months. Subgroup 3 (Fentanyl-Methamphetamine Smoking), characterized by high-frequency fentanyl and methamphetamine smoking, included 4% of participants at baseline and 21% at 18 months. Subgroup 4 (Heroin-dominant Injecting), characterized by high-frequency heroin injection, included 61% of participants at baseline and 65% at 18 months. Participants in Subgroup 1 primarily transitioned to Subgroups 3 and 4 over time. Larger increases in Subgroup 3 prevalence occurred for participants who, at baseline, experienced homelessness, resided in San Diego (vs. Tijuana), received syringes from a syringe services program, and overdosed in the past six months. Conclusions: PWID in this region increasingly transitioned from high-frequency heroin and methamphetamine injection toward fentanyl and methamphetamine smoking, likely reflecting shifts in drug availability. Results highlight the need for multilevel interventions that address health harms resulting from polysubstance smoking alongside continued injection.

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Characteristics and Circumstances of US Overdose Deaths Identified as Heat-Related

Cano, M.; Mun, C. J.; Sweeney, K.; Daniulaityte, R.

2026-05-14 addiction medicine 10.64898/2026.05.11.26352941 medRxiv
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ObjectivesTo examine the extent to which heat-related causes of death are recorded in fatal drug overdoses, how these patterns vary across states and over time, and how overdose characteristics differ between deaths with, versus without, heat involvement recorded. MethodsDeath certificate data for all drug overdose deaths in US residents from 2001 to 2024 (from the National Center for Health Statistics) were analyzed to identify whether a heat-related cause of death was also listed on the death certificate. Joinpoint regression, descriptive statistics, and nonparametric tests were used to examine temporal trends and compare overdose deaths with versus without recorded heat involvement. ResultsIn 2001, fewer than 10 drug overdose deaths with recorded heat involvement were identified, but this number increased to 558 in 2024. From 2013 to 2024, mortality rates increased significantly, with an estimated annual percent change of 30.1 (95% Confidence Interval, 26.5-47.1). The highest mortality rates and numbers of deaths were observed in residents of Arizona and Nevada. American Indian/Alaska Native, Mexican-heritage, and foreign-born populations accounted for larger shares of overdose deaths with, compared to without, heat involvement recorded. A street or highway was more frequently identified as the place of injury in overdose deaths with (18.9%), versus without (2.2%) heat involvement reported. Psychostimulants such as methamphetamine were involved in 85.9% of overdose deaths with, compared to 28.9% without, recorded heat involvement. ConclusionsAlthough representing only a fraction of all overdose deaths, fatal overdoses involving heat exposure have increased markedly over time and disproportionately impact certain states and demographic groups.

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Opioid crisis in Germany? Insights from a cross-sectional nationwide survey within the German drug scene.

Roehrig, J.; Sutter, L.; Witsch, N.; Rademacher, L.; Cabanis, M.

2026-06-01 addiction medicine 10.64898/2026.05.28.26354329 medRxiv
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Background and Aims: Synthetic opioids cause tens of thousands of deaths each year in North America, and there are indications that synthetic opioids are also becoming increasingly prevalent in the European drug market. This study aimed to examine high-risk substance use in the German drug-using community with a particular focus on the synthetic opioids fentanyl and nitazenes and related awareness, concerns, overdose experiences, and harm-reduction behavior. Design: Cross-sectional, observational online survey. Setting: Open drug-use scenes, addiction clinics, and substitution practices at numerous geographic locations throughout Germany, August to September 2025. Participants: 235 individuals aged 14+ from the drug using community (mean age 43.4 years; 57.9% male), 79.6% recruited by peers in open drug-use scenes. Measurements: The primary outcome was substances used within the past 12 months. In addition, sources, forms, routes of administration, and perceived changes in availability and price of (synthetic) opioids were assessed as well as risk perceptions, fears, harm-reduction behavior, and overdose-related experiences. Findings: 227 respondents reported substance use with an average of 6.2 substances, and 73.1% (95% confidence interval [CI] = 67.0-78.5%) had used at least one opioid in the past year. Synthetic opioids were consumed in many parts of Germany and across all age and gender groups. Among participants who experienced a shortage of their primary opioid in the past year, 25% (95% CI = 15.8-37.2%) reported having used fentanyl instead. 56.5% (95% CI = 36.8-74.3%) of individuals using synthetic opioids reported having experienced an overdose in the past twelve months. Most of the respondents perceived synthetic opioids as posing a high risk, and a substantial proportion expressed fear that they could be mixed into their own substances. However, only 9.9% (95% CI = 6.6-14.7%) use drug checking, although the vast majority stated they would use it if it were available to them. Conclusions: Synthetic opioids, including fentanyl and nitazenes, have entered the German drug scene, with users reporting high rates of overdose and limited access to harm reduction measures. Germany may be in an early phase of a synthetic opioid transition, warranting urgent expansion of surveillance, naloxone distribution, and drug checking services.

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Sexually Transmitted and Bloodborne Infections, Methamphetamine Use, and COVID-19 Vaccination in Manitoba, Canada: A Retrospective Matched Cohort Analysis Using Population-Based Administrative Healthcare Data (2020-2022)

Shaw, S. Y. Y.; Mahar, A.; Bailey, K.; Payne, M.; Kindrachuk, J.; Kelly, C.; Friesen, K. J.; Bernstein, C. N.; Reimer, J.; Becker, M. L.; McClarty, L. M.; Stein, D.; Nickel, N. C.

2026-05-21 epidemiology 10.64898/2026.05.18.26353507 medRxiv
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Objectives: To examine COVID19 vaccine uptake among people diagnosed with sexually transmitted and bloodborne infections (STBBI) and reported methamphetamine users in Manitoba, Canada, during the acute phase of the COVID19 pandemic. Methods: We conducted a retrospective matched cohort study using linked population based administrative healthcare, laboratory, and vaccination databases in Manitoba. Individuals aged 16+ years with laboratory confirmed chlamydia/gonorrhea (CT/NG), syphilis, HIV, and/or documented methamphetamine use during the four years prior to March 1, 2020 were included in eight exposed cohorts. Each cohort was matched to unexposed comparators on age, sex, geographic region, and income quintile. The primary outcome was receipt of 2+ COVID19 vaccine doses between December 1, 2020 and March 31, 2022. Poisson regression models estimated adjusted rate ratios (aRRs) and 95% confidence intervals (95% CIs) for vaccine uptake. Results: Compared with matched comparators, most exposed cohorts were less likely to complete the COVID19 primary vaccine series. Individuals in the Syphilis Only (aRR: 0.87, 95% CI: 0.85 0.90), Syphilis Plus (aRR: 0.84, 95% CI: 0.81 0.86), CT/NG Only (aRR: 0.95, 95% CI: 0.94 0.96), CT/NG Plus (aRR: 0.82, 95% CI: 0.80 0.85), Methamphetamine Only (aRR: 0.78, 95% CI: 0.76 0.80), and Methamphetamine + STBBI cohorts (aRR: 0.74, 95% CI: 0.72 0.77) had significantly lower vaccine uptake. The HIV Only cohort did not differ significantly from matched comparators (aRR: 0.98, 95% CI: 0.95 1.01). Lower uptake was concentrated among individuals living in lower-income areas. Conclusions: People diagnosed with STBBI and methamphetamine users in Manitoba experienced significant inequities in COVID19 vaccine uptake, particularly those with STBBI coinfections and concurrent substance use. Integrated vaccination approaches linked with HIV, harm reduction, and addiction services may improve vaccine equity during future public health emergencies.

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Comfort with AI for HIV Prevention Among Cisgender Women in New York City

Reyes Nieva, H.; Flanagan, M.; Huang, S.; Theodore, D. A.; Nkodo, A. F.; Parkinson, M.; Hill, S.; McAndrew, M.; Benitez, J. A.; Peralta, H.; Amesty, S.; Zucker, J. E.; Sobieszczyk, M.; Castor, D.

2026-06-03 health informatics 10.64898/2026.06.02.26354471 medRxiv
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Background: Long-acting pre-exposure prophylaxis (PrEP) expands HIV prevention options for women. However, PrEP impact depends on addressing persistent gaps in awareness, access, and use. Artificial intelligence (AI) tools, including conversational agents, are being explored to advance PrEP uptake, but comfort with AI may influence their impact. Thus, we examined women's comfort with AI and its association with PrEP awareness. Methods: We analyzed self-reported data from women aged [&ge;]18 years in a cross-sectional survey conducted in New York City from August 2023 to August 2024. We performed descriptive analyses, applied latent class analysis to identify AI knowledge/comfort profiles, and estimated unadjusted and adjusted odds ratios to assess associations between profile membership and PrEP awareness. Results: Among 306 respondents without a diagnosis of HIV who completed AI-related survey items, the median age was 36. Most women identified as Hispanic/Latina (60%) or Non-Hispanic Black (18%), had not completed college (53%), and spoke only English or were bilingual (81%). Latent class analysis identified four AI knowledge/comfort profiles that differed by PrEP awareness, race/ethnicity, borough, prior drug use, and technology utilization. Women with varied AI knowledge, broad AI discomfort, and comfort with clinicians maintaining privacy had lower odds of PrEP awareness (OR: 0.35, 95% CI: 0.16-0.75), but this association did not persist after statistical adjustment. Conclusions: PrEP awareness and AI knowledge were limited, yet many women expressed openness to AI-enabled tools when privacy was assured. AI-enabled HIV prevention tools should prioritize trust, transparency, confidentiality, and the lived contexts of the women they intend to serve.

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State Xylazine Scheduling and Changes in Xylazine and Medetomidine Reports in the U.S. Illicit Drug Supply: A Quasi-Experimental Study

Zhu, D. T.; Oh, S.

2026-05-15 health economics 10.64898/2026.05.12.26353052 medRxiv
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Background: Xylazine and medetomidine are veterinary sedatives increasingly detected as adulterants in the U.S. illicit drug supply. In response, several states have scheduled xylazine. Whether these policies are associated with subsequent changes in xylazine and medetomidine detections remains unclear. Methods: We conducted a state-level, semiannual, serial cross-sectional study using National Forensic Laboratory Information System (NFLIS) data from 1999 to 2025. The primary outcomes were xylazine and medetomidine reports per 100,000 NFLIS drug reports. We used staggered difference-in-differences event-study models to estimate changes in report rates after xylazine scheduling. Sensitivity analyses excluded Florida and expanded the treatment definition to include states that criminalized xylazine without formal scheduling. Falsification analyses examined steroid and antidepressant reports as negative-control outcomes. Results: NFLIS recorded 101,987 xylazine reports and 12,085 medetomidine reports. Xylazine scheduling was not associated with a significant change in xylazine report rates (ATT, 2,872.29 per 100,000; 95% CI, -2,024.63 to 7,769.21; p=.250). In contrast, xylazine scheduling was associated with a significant increase in medetomidine report rates (ATT, 1,536.51 per 100,000; 95% CI, 211.14 to 2,861.88; p=.023). Sensitivity analyses produced similar findings. Negative-control outcomes showed no significant changes. Conclusions: State xylazine scheduling was associated with increases in medetomidine reports but no significant change in xylazine reports. These findings suggest that scheduling may be followed by changes in adulterant composition rather than reductions in overall 2-adrenergic agonist involvement. Our study highlights the importance of monitoring the unintended effects of xylazine scheduling and supporting continued investment in public health surveillance, drug checking, and harm reduction services.

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Temporal Relationships between Smartphone Application Use and Online Substance Procurement in U.S. Youth

Gansner, M.; Adams, M.; Nikam, P.; Huntley, N.; Ramrajesh, S.; Marsch, L. A.; Levy, S.; Schuman-Olivier, Z.

2026-05-19 pediatrics 10.64898/2026.05.15.26353324 medRxiv
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Background: Despite the significant risks associated with online substance procurement (SP), few researchers have examined this practice in U.S. youth. The studies that do exist are cross-sectional and cannot temporally connect specific digital behaviors to online SP. This longitudinal cohort study examined youth SP and digital media habits to determine whether use of certain smartphone applications correlated with increased odds of online SP or being contacted online about procuring drugs or alcohol. Methods: A cohort of U.S. youth (aged 15-20) with a history of non-daily substance use in the 3 months prior to enrollment was recruited to use the digital phenotyping smartphone application EARS for 90 days. On a nightly basis, participants were asked to complete surveys about online experiences related to SP and instances of substance use. Smartphone-generated screen use data were also collected passively each day. Results: Out of 112 enrolled participants, 106 were able to be included in analyses. Over approximately 3 months, 28.3% of participants (n=30) reported a collective 91 instances where they used social media to acquire drugs or alcohol. Screen use data demonstrated temporal relationships between social media SP and applications previously connected to the social media drug-purchasing process (e.g., TikTok, encrypted apps), as well as other school-specific social media. Discussion: Our results provide critically needed research evidence to support a body of literature composed predominantly of anecdotal reports. Despite measures taken by social media companies to prevent use of their platforms for drug procurement, underage youth continue to engage in this practice.

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Impact of minimum wage increases on homicide mortality in the US

Fitch, K. V.; Santaularia Gomez, N. J.; Tanveer, M.; Holmes, G. M.; Moracco, K. E.; Fliss, M. D.; Fulcher, N.; Ranapurwala, S. I.

2026-05-24 health policy 10.64898/2026.05.21.26353800 medRxiv
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Introduction: Even though state minimum wage (MW) is a policy lever that affects income and poverty and can prevent of violence, no prior study has comprehensively evaluated its impact in the United States (US). In this study, we estimated the impact of at least a $1 USD increase in state MW above the federal MW on overall, firearm, and non-firearm homicide mortality and examined its impact on racialized inequities. Methods: We conducted a quasi-experimental study using controlled interrupted time series (CITS) and synthetic controlled interrupted time series (SCITS) approaches to examine immediate and sustained impact of state MW increases. We used state-month level homicide victimization mortality data from 2010-2019. Homicide victimization death was identified using International Classification of Disease codes, 10th revision. State MW data was obtained from the Bureau of Labor Statistics. Results: Demographic and social variables from intervention, never-exposed, and always-exposed states were similar to each other and representative of the total US population from all 50 states. The CITS results show that after MW increases in the intervention states, these states experienced a sustained decline of -0.22 (-0.37, -0.07) homicide victimizations/ 100,000 person-years/ year relative to the never-exposed states and -0.39 (-0.59, -0.18) relative to always-exposed states. This resulted in 5,657 fewer homicide victimization deaths in the intervention states over four years of post-MW increase period compared to the never-exposed states. SCITS results were similar to the CITS results, and the majority of sustained declines were observed in firearm-related deaths and among Black population. Conclusion: MW increase was associated with a reduction in homicide victimization rates, which were robust in multiple sensitivity analyses, more pronounced for firearm-related homicide deaths, and reduced homicide victimization inequities for Black Americans.

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Behavioral and Functional Neuroimaging Effects of Delivering a Course of Repetitive Transcranial Magnetic Stimulation to Personalized Targets Within the Ventrolateral Or Dorsolateral Prefrontal Cortex in Treatment-Seeking Participants with Cannabis Use Disorder

McCalley, D.; Wong, B.; Geoly, A.; Struckman, W.; Azeez, A.; Kaloiani, I.; Kim, B.; Ninomiya, S.; Ehrie, J.; Austelle, C. W.; Rolle, C. E.; Kim, J. P.; Froeliger, B.; McRae-Clark, A. L.; Sahlem, G.

2026-06-10 addiction medicine 10.64898/2026.06.08.26355193 medRxiv
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Background: Repetitive Transcranial Magnetic Stimulation (rTMS) is a promising treatment across addictive disorders including Cannabis Use Disorder (CUD). Stimulation of two rTMS-targets, the ventromedial prefrontal cortex (vmPFC) and the left dorsolateral prefrontal cortex (LDLPFC), limbic and executive control network hubs respectively, may yield differential effects. In this pilot trial, we explored the differential effects of 36-sessions of rTMS applied to either the vmPFC or LDLPFC. Methods: Treatment-seeking participants with moderate or severe CUD (n=20, 10F, age=33.3+9.8SD) were randomized to 36-sessions of open-label rTMS (two sessions-per-visit, two or three visits-per-week) to either the LDLPFC (3000-pulses; 10Hz) or vmPFC (900-pulses; 1Hz) using personalized functional Magnetic Resonance Imaging (fMRI) targets along with three-sessions of Motivational Enhancement Therapy. At baseline and following rTMS, the Time-Line Follow-Back was used to measure Days-per-week of cannabis use and the fMRI Regulation of Craving (ROC) task was used to measure network activation to cues associated with long-term negative ('Later') and short-term positive ('Now') consequences of cannabis use. Results: Eighty percent of participants completed study-rTMS. There was a significant decrease in days-per-week of cannabis use in both groups (vmPFC: d=7.9; DLPFC, d=3.1) between the four-weeks of baseline and seven-weeks of follow-up. LDPFC-rTMS reduced fMRI BOLD signal magnitude and increased LDLPFC functional connectivity in response to cues, while vmPFC-TMS reduced functional connectivity. Conclusions: Treatment-seeking participants with CUD reduced the number of days-per-week they used cannabis when receiving rTMS applied to either the LDPFC or vmPFC, while fMRI effects differed by treatment target. Future larger sham-controlled trials are needed for efficacy and biomarker determination.

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Adapting a Regulation of Craving Magnetic Resonance Imaging Task to Generate Functional Repetitive Transcranial Magnetic Stimulation Targets for the Ventromedial and Dorsolateral Prefrontal Cortex in Treatment-Seeking Participants with Cannabis Use Disorder

Geoly, A.; McCalley, D. M.; Struckmann, W.; Azeez, A.; Wong, B.; Kim, B.; Ninomiya, S.; Ahmed, S.; Kim, J. P.; McRae-Clark, A. L.; Froeliger, B.; Sahlem, G. L.

2026-06-06 addiction medicine 10.64898/2026.06.04.26353616 medRxiv
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Background: Repetitive Transcranial Magnetic Stimulation (rTMS) is a promising treatment across addictive disorders including Cannabis Use Disorder (CUD). Targeting incentive-salience circuitry via the ventromedial prefrontal cortex (vmPFC) and central-executive circuitry via the left dorsolateral prefrontal cortex (LDLPFC) are both promising treatment approaches; however, to date structural targets have predominated whereas functional targeting may allow for more precision. In this pilot trial we adapted a functional Magnetic Resonance Imaging (fMRI) Regulation of Craving (ROC) task to generate fMRI-based rTMS targets in the vmPFC and LDLPFC. Methods: We recruited treatment-seeking participants with moderate or severe CUD as a part of an open-label trial and administered an adapted ROC-task during fMRI following 24-hours of cannabis abstinence. We identified sub-portions of maximal activation of the LDLPFC when participants thought of long-term consequences of cannabis use (Later) and of the vmPFC when participants thought of short-term positive aspects of cannabis use (Now). We hypothesized that our task would generate acceptable rTMS targets in >66% of baseline fMRI scans. Results: A total of 20-participants enrolled in the trial (50%F, age=33.3+9.8) and completed the baseline fMRI. The adapted ROC-task elicited group level activation in the LDLPFC and precuneus in the Later>Now and in the bilateral vmPFC, ACC, and striatum in the Now>Later contrast. Acceptable functional targets resolved in both the vmPFC and LDLPFC in 19 of 20 participants (one participant did not tolerate MRI). Conclusions: The adapted ROC-task elicits activation in incentive salience and central executive circuitry and can feasibly generate rTMS targets when using a cluster selection algorithm.

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Stigmatizing Language Detection in Opioid Use Disorder Patient-Directed Discharge Clinical Documentation: A Privacy-Preserving Analysis Using a Locally Deployed Large Language Model

Izzo, J. A.; McIntyre, A. M.; Nguyen, J.; Bashaw, D.; Torrance, C. A.; Foster, J.

2026-06-01 health informatics 10.64898/2026.05.29.26354402 medRxiv
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Objective: Stigmatizing language in the electronic health record (EHR) has been associated with adverse patient experience in substance use disorder care, including opioid use disorder (OUD). This study evaluated a privacy-preserving, locally-deployed large language model as a method to detect stigmatizing language documentation in OUD patients with patient-directed discharge (PDD). Methods: A retrospective cohort study of 477 inpatient admissions from the MIMIC-IV database with a diagnosis of opioid use disorder were classified using a locally deployed Gemma-4-31b-it-bf16 model and predefined 140 term lexicon to identify stigmatizing language in clinical documentation. Results: Analysis of clinical documentation showed stigmatizing language was present in 84.1% (190/226) in the PDD cohort vs 62.2% (156/251) in the non-PDD cohort, with an unadjusted odds ratio of 3.21 (95% CI 2.07-4.98; p < 0.0001). After adjustment for age, sex, insurance status, marital status, and race, PDD discharge remained an independent predictor of stigmatizing documentation (aOR 2.24, 95% CI 1.40-3.59; p < 0.0001). Further analysis of stigma intensity showed higher stigmatizing markers in the PDD cohort vs the non-PDD cohort (2.85 {+/-} 2.39 vs 2.02 {+/-} 2.44; p < 0.0001). Discussion and Conclusion: Stigmatizing language is detected with increased frequency and prevalence in clinical documentation of OUD patients that initiate PDD compared to those that adhere to standard discharge processes. A locally deployed large language model (LLM) offers a scalable, privacy-preserving method to audit clinical documentation for stigmatizing language.

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Developing a Unified Criminal Justice Pathway into Drug and Alcohol Treatment from Police Custody: A Public Health Service Evaluation and Pathway-Design Project in Blackpool, United Kingdom

Badmos, A. O.; AbdulKareem, A. O.; Mills, J.; Gawne, A.; Idris, T.

2026-06-10 health systems and quality improvement 10.64898/2026.06.07.26355095 medRxiv
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Introduction: Blackpool, England's most deprived local authority, has the highest drug-related death rate in the country. People in police custody with problem substance use are a key Core20PLUS5 inclusion-health group, yet referral from the police into structured drug and alcohol treatment is fragmented and relies heavily on self-report. We evaluated the current police-to-treatment route in Blackpool and designed an evidence-informed unified pathway. Materials and Methods: A mixed-methods service evaluation and pathway-design project was conducted during a six-month General Practice / Public Health rotation. Routinely collected referral data from Horizon (the local specialist drug and alcohol service) covering the 47-month period from December 2019 to October 2023 were analysed. Findings were triangulated with national policy, the Project ADDER and Liaison and Diversion evaluations, and the international evidence on police-led pre-arrest diversion. Results: Of 5,900 total referrals into Horizon over 47 months, only 269 (4.56%) originated from the police. Police referrals accounted for fewer than 5% of monthly referrals in 30 of 47 months, for 5 to 9.9% in 16 months, and for >/= 10% in only one month (10.8%, December 2022). Blackpool recorded 76 drug-misuse deaths in 2019-21 (19.4 per 100,000, approximately four times the England rate). A six-step unified pathway is proposed: Initiate Referral (opt-out, from ADDER Police and Liaison and Diversion); Initial Assessment; Tailored Treatment Plan; Continuous Support; Collaboration and Monitoring; and Evaluation and Adjustment. Conclusions: Police contact is markedly under-used as a gateway to treatment despite Blackpool having the highest drug-related mortality in England. An opt-out, multi-agency pathway anchored in Core20PLUS5 has the potential to narrow the treatment gap, reduce re-offending, and address the structural health inequalities that drive premature mortality.

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Protocol for: Lockable Smartphone Pouches in UK Secondary Schools. A Cohort Study

John, J.; Khambhayta, A.; Lange, M.; Maher, F.; Localleti, C.; Kalk, N.; Carter, B.

2026-05-21 health policy 10.64898/2026.05.15.26353291 medRxiv
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Background Smartphone ownership among UK adolescents is near universal. Teachers report phones increasingly being involved in classroom disruption, and misuse during school hours is among the more common serious behavioural issues in secondary schools. Evidence on whether restrictive policies improve behaviour, attainment, or wellbeing remains limited. Objectives The primary objective is to assess the impact of a lockable smartphone pouch on educational attainment and behaviour. Secondary objectives are to assess impacts on general functioning, psychological wellbeing, and school level indicators such as exclusions, and to examine whether effects differ for pupils who may be most at risk. Methods We will conduct a mixed methods cohort study in secondary schools across Northern Ireland and England during the 2025 to 2026 academic year. The quantitative component uses a serial cross sectional design. Students will complete an online questionnaire at 0, 4 weeks, and 8 weeks, covering homework completion, classroom disruption, participation in PE and extracurricular activities, peer interaction during break, and patterns of smartphone use. Measures include the Strengths and Difficulties Questionnaire (SDQ), the Revised Child Anxiety and Depression Scale (RCADS), the short form of the Smartphone Addiction Scale (SAS SV), and the Bergen Social Media Addiction Scale (BSMAS). Each participating school will also supply half termly aggregate data on exclusions, detentions, CAMHS referrals, counsellor visits, and parent visits between September 2023 and May 2026. Assuming 90% power, a two-sided type 1 error of 0.05, an intracluster correlation of 0.02, and 25% loss to follow up, we aim to recruit a minimum of 3,200 students from six or more schools to detect a small effect (Cohen's d = 0.2) on SDQ hyperactivity score. Continuous outcomes will be analysed with linear regression and binary outcomes with logistic regression. Prespecified subgroup analyses cover SEN or neurodivergent status, area level deprivation, and which phone policy is in place at each school. Qualitative analyses comprise focus groups with students and staff at each participating school and semi-structured interviews with school leads. Transcripts will be coded both inductively and deductively and analysed thematically with Braun and Clarke's six phase approach. Ethics and Dissemination The study has been approved by the King's College London Research Ethics Committee. A Data Protection Impact Assessment has been agreed with the Northern Ireland Department of Education. Findings will be published in peer reviewed journals and shared with participating schools, parents, and policy makers to inform smartphone policy in schools.

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Global Burden Of Problematic Internet Use: An Umbrella Review and Metanalysis

Schwarze-Taufiq, T.; Weber, S.; Larrain, B.; Gatica-Bahamonde, G.; Corazza, O.; Neicun, J.; Stein, D. J.; Ioannidis, K.; Demetrovics, Z.; Chamberlain, S. R.; Carmi, L.; Zohar, J.; Rumpf, H.-J.; Hall, N.; Menchon, J. M.; Sales, C.; Montag, C.; Lindenberg, K.; Susi, M.; Huizink, A.; Potenza, M. N.; Pallanti, S.; Morgan, N.; Moreno, C.; Purper-Ouakil, D.; Brand, M.; Yucel, M.; Czako, A.; Walitza, S.; Burkauskas, J.; Felvinczi, K.; Smith, M.; Wellsted, D.; Jones, J.; Dias, T. S.; Foster, S.; Mohler-Kuo, M.; Neumann, I.; Fongaro, E.; Fally, S.; Oliveira, H.; Abregu-Crespo, R.; Sepulveda-Palomo, M.;

2026-05-25 addiction medicine 10.64898/2026.05.23.26353953 medRxiv
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Importance: Problematic use of the internet (PUI) behaviors, including problematic gaming, social media use, smartphone use, and general internet use, have been increasingly studied worldwide. So far, it is unclear what the global prevalence of PUI is. Objective: To critically appraise existing systematic reviews and meta-analyses on the prevalence of PUI behaviors and generate aggregated global prevalence estimates across different manifestations and definitions. Data Sources: MEDLINE (Ovid), Embase (Ovid), Scopus, Web of Science, CINAHL, and the Cochrane Review Library were searched for relevant articles from database inception to the most recent available search prior to manuscript preparation. Searches targeted systematic reviews and meta-analyses reporting prevalence for PUI-related behaviors. Study Selection: Systematic reviews and meta-analyses of observational studies reporting prevalence estimates for problematic gaming, problematic internet use, problematic smartphone use, problematic social media use, or sexting were included. Scoping reviews were retained for descriptive synthesis only. Data Extraction and Synthesis: An umbrella review methodology was used. Data extraction and methodological appraisal were conducted using AMSTAR-2 to assess the quality of included systematic reviews up to February 2026. Primary studies included in each review were extracted and pooled using random-effects meta-analysis. Analyses were conducted to estimate pooled prevalence with 95% confidence intervals (CIs) and heterogeneity across non-overlapping primary studies. Small-study effects were examined. Main Outcomes and Measures: Global pooled prevalence estimates for PUI behaviors, including problematic gaming, problematic internet use, problematic smartphone use, problematic social media use, and sexting. Results: Eleven reviews, including 10 systematic reviews and 1 scoping review, met inclusion criteria, representing data from 3,145,428 individuals, of whom 3,030,023 were included in pooled prevalence analyses. Across regions, pooled prevalence estimates were 6% (95% CI, 5%-7%) for problematic gaming, 16% (95% CI, 15%-17%) for problematic internet use, 32% (95% CI, 28%-35%) for problematic smartphone use, and 23% (95% CI, 19%-28%) for problematic social media use. Substantial heterogeneity (I2 > 99%) was observed across primary studies, reflecting variation in study methodologies, sampled populations, and definitions of PUI behaviors. Conclusions and Relevance: PUI behaviors appear to affect a substantial proportion of the global population. However, methodological concerns were common, with 9 of 10 systematic reviews rated as having low or critically low confidence according to AMSTAR-2. Evidence remains concentrated in East Asia and Europe, and many reviews combine heterogeneous populations and sampling strategies. Additional high-quality epidemiological research, including studies in underrepresented regions, is needed to refine prevalence estimates, clarify risk factors, and support the development of standardized criteria for PUI behaviors.

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Joint Effects of Real-World Cue Exposure and Affective States on Momentary Alcohol Craving in Adults with Alcohol Use Disorder

Aggarwal, A.; Monti, P. M.; Promrat, K.; Magill, M.; Mellinger, J. L.; Treloar Padovano, H.

2026-05-21 public and global health 10.64898/2026.05.18.26353518 medRxiv
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Background: Alcohol use disorder (AUD) is marked by high relapse rates often driven by craving, yet less is known about whether in vivo, social, and place-based alcohol cues are differentially associated with craving across affective states. This study examined independent and affect-contingent associations of these cues with momentary craving in adults with AUD enrolled in an alcohol intervention study. Methods: Thirty-three adults with AUD completed up to four daily ecological momentary assessments (EMA) for 28 days. EMA prompts assessed craving, in vivo alcohol exposure, being around usual drinking partners, being in usual drinking places, and high-arousal positive affect (PA) and negative affect (NA). Multilevel mixed-effects models adjusted for demographics, intervention phase (1 = post, 0 = pre), AUD severity, and temporal and contextual covariates. Results: EMA compliance was high (median per-participant = 86.6%). Within-person elevations in in vivo alcohol exposure and being around usual drinking partners were independently associated with greater momentary craving, whereas being in usual drinking places was not. In vivo alcohol exposure was more strongly associated with craving during higher-than-usual PA ({beta} = 0.08, p = .032), whereas being in usual drinking places was more strongly associated with craving during higher-than-usual NA ({beta} = 0.06, p = .036), adjusting for intervention phase, which was associated with lower craving. Conclusions: Findings support the need for personalized just-in-time adaptive interventions tailored to high-risk, momentary cue-affect contexts in AUD, beyond low-frequency clinician-delivered feedback that may reduce average craving but not fully address real-time risk. ClinicalTrials.gov registration: NCT05135767.

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Before Birth, Beyond Childhood: Understanding the Influence of Prenatal Substance Exposure on Psychiatric Diagnoses

Houghton, A.; Caola, L.; Dastin-Van Rijn, E.; Anderson, S.; Kummerfeld, E.; Sullivan, C.; Simpson, S.; Kalkar, A.; Banerjee, R.; Fiecas, M.; Randolph, A.

2026-05-29 pediatrics 10.64898/2026.05.27.26354275 medRxiv
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Background: Prenatal substance exposure (PSE) occurs when an individual is exposed to substances in utero. PSEs may have lasting effects on mental health. We tested whether PSEs show threshold, cumulative, or individual substance associations with childhood psychiatric diagnoses. Methods: Clinical variables (demographics, ICD-9/10 diagnoses, PSE history) were extracted from electronic health records from the University of Minnesota Adoption Medicine Clinic. PSEs were identified from caregiver and child-protective-services narratives and/or toxicology (cord tissue/blood, meconium). For each ICD-9/10 diagnostic category, we fit logistic regression models comparing (1) exposure thresholds (0, 1, 2, 3, 4+ exposures), (2) a cumulative exposure count, and (3) individual substances to estimate marginal odds ratios (ORs) with 95% Confidence Intervals (CIs). Results: Psychiatric diagnoses increased with the number of PSEs. Relative to no exposure, odds of an Anxiety Disorder rose from OR 1.47 (95% CI 1.16-1.87) with one exposure to OR 2.03 (1.64-2.52) with >=4 exposures. Higher cumulative exposure scores were associated with Anxiety Disorders (OR 1.28, 1.18-1.38), Behavioral and Emotional Disorders (OR 1.42, 1.31-1.54), Substance Use Disorders (OR 1.52, 1.29-1.79), and Mood Disorders (OR 1.16, 1.04-1.30). Alcohol, tobacco, and marijuana exposures were associated with increased odds of at least one psychiatric diagnosis, and each substance showed at least one significant diagnostic cluster when modeled independently. Conclusion: Increasing numbers of PSEs were associated with higher odds of psychiatric diagnoses, with patterns varying by substance and outcome. These findings motivate research on exposure timing and combinations to support earlier identification and intervention for at-risk children.

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High-resolution Orbitofrontal Cortex Morphometry and Cannabis Use Disorder Severity in High-risk Emerging Adults: A Preliminary Study

Hargreaves, T. L.; McIntyre-Wood, C.; Elsayed, M.; Vandehei, E.; Belisario, K. L.; Lee, L.; Blakely, A.; Halladay, J. L.; Amlung, M.; Sweet, L. H.; MacKillop, J.

2026-05-27 addiction medicine 10.64898/2026.05.26.26354113 medRxiv
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Background: Cannabis use is highly prevalent among emerging adults (18-25 years), a developmental period marked by ongoing neurodevelopment and heightened risk for cannabis use disorder (CUD). Structural alterations in the orbitofrontal cortex (OFC) and medial prefrontal/anterior cingulate cortex (mPFC/ACC) have been linked to cannabis use, though findings remain inconsistent in directionality. To address this, we examined cortical thickness and surface area of the OFC and mPFC/ACC subregions using the high-resolution Glasser atlas, allowing for more granular characterization of associations with CUD severity. Method: One hundred eleven emerging adults (41% male, aged=20.6{+/-}1.1 years) reporting significant alcohol and/or cannabis use completed clinical assessments and structural MRI. The OFC and mPFC/ACC were segmented into seven and six subregions per hemisphere, respectively. Multiple linear regressions tested associations between cortical thickness or surface area and DSM-5 CUD symptom count, controlling for alcohol use and intracranial volume. Subregions surviving false discovery rate correction were examined in relation to depression, trauma-related symptoms, impulsivity, and cannabis use motives. Results: Greater CUD severity was associated with lower cortical surface area and greater cortical thickness in OFC and mPFC/ACC subregions. Lower OFC surface area was correlated with coping- and enhancement-related cannabis use motives. Lower mPFC/ACC surface area and greater thickness were associated with more severe depression, trauma-related symptoms, and impulsivity. Conclusion: In high-risk emerging adults, greater CUD symptom burden is associated with lower surface area and greater thickness in OFC and mPFC/ACC subregions. Using the high-resolution Glasser atlas, these findings provide a more precise characterization of structural correlates of CUD and highlight potential neurobiological markers linked to affective and motivational processes underlying cannabis use.

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Identifying Clinical Diagnostic Trajectories Associated With Suicide Death Using Temporal Sequence Mining of Linked Claims and Mortality Data

Belouali, A.; Kitchen, C.; Haroz, E.; Lehmann, H.; Nestadt, P. S.; Wilcox, H. C.; Kharrazi, H.

2026-06-10 health informatics 10.64898/2026.06.08.26355231 medRxiv
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Background: Most approaches to suicide risk assessment consider clinical conditions as independent risk factors, potentially overlooking prognostic information in the order in which conditions accumulate. We applied temporal sequence mining to linked claims and mortality data to identify ordered clinical diagnostic trajectories associated with suicide death. Results: The cohort included 3 647 059 insured Maryland residents aged 10 years or older with available claims records in the Maryland Suicide Data Warehouse from January 1, 2016, to December 31, 2020, among whom 768 suicide deaths were ascertained through medical examiner linkage. Sequential pattern mining of ICD-10-CM diagnoses grouped into Clinical Classifications Software Refined categories identified 89 221 candidate sequences, of which 1 816 remained significantly associated with suicide death in time-varying Cox models. Adjusted hazard ratios (AHRs) ranged from 2.4 to 134.1. Two-thirds of significant trajectories ended in physical conditions, and approximately half crossed from psychiatric to physical endpoints. Among suicide decedents, 62% were exposed to at least 1 significant sequence (median, 16 per case); median sequence duration was 18.7 months, and median time from completion to death was 13.1 months. In landmark analyses, among patients with depression who later developed suicidal ideation (n = 26 356), the path through anxiety, then anemia, was associated with higher risk (AHR, 4.6; 95% CI, 2.2-9.5), whereas the anxiety-only path was not (AHR, 1.3; 95% CI, 0.8-2.1). Among patients with anxiety who later developed hypertension (n = 149 215), the path through history of self-harm was associated with higher risk (AHR, 32.0; 95% CI, 16.6-61.6). Associations were generally consistent across sex and age. Conclusions: Temporal ordering of clinical conditions may carry prognostic information for suicide death. Clinical trajectories incorporating physical illness within psychiatric sequences identified higher-risk groups. These findings suggest that opportunities for risk detection may extend beyond psychiatric settings and that suicide risk signals may be fragmented across care settings and not apparent within isolated encounters.

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Comparing cannabinoid extracts for treating cancer-related symptoms: a randomized placebo-controlled, triple-blind aggregate n-of-1 clinical trial

Hawley, P. H.; Wade, K.; Daeninck, P.; Fitzgibbon, E.; Kerba, M.; Goldie, C.; Kopoplovic, I.

2026-06-02 palliative medicine 10.64898/2026.05.31.26354558 medRxiv
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Context Despite widespread use of medical cannabinoids for cancer-related symptom management, systematic reviews consistently call for more clinical trial evidence. Objectives This study aimed to determine and explore responses to medical cannabis extracts for cancer-related symptoms using patient-centred methodology. Methods An aggregate N-of-1 study of clinically stable but symptomatic outpatients from 8 Canadian cancer centres, comparing three blinded sublingual extracts (THC; CBD; 1:1) with placebo, self-titrated within a prescribed schedule for four consecutive days each in randomized sequence for up to three cycles (total 16-48 days). The primary outcome was the frequency of at least a 1.4-point (20%) improvement in a 7-point Patient Global Impression of Change (PGIC) for at least one extract over placebo. Results The primary outcome was achieved in 50/89 (56%) participants (p<0.001), with no significant preference of one extract over another on average, but a clear preference between extracts for most individuals. Changes in a modified Edmonton Symptom Assessment score and participant preference (n=91) confirmed these findings. Improved sleep, tiredness and anxiety contributed most to the overall improvement regardless of primary symptom. There were no demographic predictors of response. Mild adverse effects were common with all extracts including placebo but resolved rapidly on dose reduction/cessation. Moderate/severe adverse effects were rare but associated with THC. Conclusions Medical cannabis extracts can be meaningfully beneficial for cancer-related symptoms in approximately 50% of patients, particularly for sleep and related symptoms. A starting dose of 2.5mg of THC/CBD three times a day was well-tolerated. Personalization of treatment is required to optimize response.

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Longitudinal Evaluation of Harlem United Multiservice Model on Clinical, Behavioral, and Social Outcomes Among Clients Living with HIV

Monk, B. S.; Strauss, D.

2026-06-01 public and global health 10.64898/2026.05.23.26353941 medRxiv
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Background/Objectives People living with HIV face overlapping hardship through medical, behavioral, and social needs that require an integrated and coordinated approach. Harlem United multiservice model provides healthcare, food assistance, housing support, harm reduction services, behavioral health counseling, case management, and much more to support their clients. This study is an examination on how the participation in the Harlem United multiservice model is associated with changes over time in client health, behavioral health, and social outcomes. Methods This study performed a longitudinal program evaluation examining Harlem United clients enrolled between January 2020 and January 2025 who remained engaged in services for a minimum of one year. Client outcomes were assessed across three time points: Baseline, Year 1, and Year 2. The sample included 154 clients at baseline (N=154) with a total of 428 observations (N=428). Quantitative measures that were assessed included program involvement, housing stability, PHQ4 scores, food insecurity, medication adherence, and viral suppression. Data was analyzed using IBM SPSS Statistics through descriptive statistics, frequency tables, and generalized estimating equation models (GEE) to account for repeated observation over time. Results Medication adherence and viral suppression remained consistently high across all time points in the longitudinal study suggesting that most clients were virally suppressed or undetectable at baseline. Housing stability was statistically significant Wald X2 (2) = 156.073, p < 0.001 with improvements noted in Year 1 and Year 2 compared to baseline. Program level was significantly associated with PHQ4 scores, Wald X2 (1) = 7.902, p = 0.005. Food insecurity was also associated with PHQ4 scores, Wald X2 (1) = 5.462, p = 0.019. Findings suggest that clients with higher PHQ4 scores were involved in more programs compared to clients only enrolled in 1-2 programs. Additionally, clients with higher PHQ4 scores were more food insecure highlighting the relationship between social needs and mental health. Conclusion: Findings suggest that the Harlem United multiservice model played a supportive role in the maintenance of health and social outcomes through medication adherence and viral suppression. Although, significant improvement was not reflected across several outcomes, the association between PHQ4 scores, food insecurity, and an increase in program involvement suggest that the multiservice is reaching more clients with complex behavioral and social needs. Continued integration of these services is important for sustaining client stability while addressing social determinants of health.