Applying machine learning to international drug monitoring: classifying cannabis resin collected in Europe using cannabinoid concentrations.

In Europe, concentrations of ∆9-tetrahydrocannabinol (THC) in cannabis resin (also known as hash) have risen markedly in the past decade, potentially increasing risks of mental health disorders. Current approaches to international drug monitoring cannot distinguish between different types of cannabis resin which may have contrasting health effects due to THC and cannabidiol (CBD) content. Here, we compared concentrations of THC and CBD in different types of cannabis resin collected in Europe (either Moroccan-type, or Dutch-type). We then tested the ability of machine learning algorithms to classify the type of cannabis resin (either Moroccan-type, or Dutch-type) using routinely collected monitoring data on THC and CBD. Finally, we applied the optimal algorithm to new samples collected in countries where the type of cannabis resin was unknown, the UK and Denmark. Results showed that overall, Dutch-type samples had higher THC (Hedges' g = 2.39) and lower CBD (Hedges' g = 0.81) than Moroccan-type samples. A Support Vector Machine algorithm achieved classification accuracy exceeding 95%, with little variation in this estimate, good interpretability, and plausibility. It made contrasting predictions about the type of cannabis resin collected in the UK (94% Moroccan-type; 6% Dutch-type) and Denmark (36% Moroccan-type; 64% Dutch-type). In conclusion, we provide proof-of-concept evidence for the potential of machine learning to inform international drug monitoring. Our findings should not be interpreted as objective confirmatory evidence but suggest that Dutch-type cannabis resin has higher THC concentrations than Moroccan-type cannabis resin, which may contribute to variation in drug markets and health outcomes for people who use cannabis in Europe.

The International Cannabis Toolkit (iCannToolkit): a multidisciplinary expert consensus on minimum standards for measuring cannabis use.

BACKGROUND: The lack of an agreed international minimum approach to measuring cannabis use hinders the integration of multidisciplinary evidence on the psychosocial, neurocognitive, clinical and public health consequences of cannabis use. METHODS: A group of 25 international expert cannabis researchers convened to discuss a multidisciplinary framework for minimum standards to measure cannabis use globally in diverse settings. RESULTS: The expert-based consensus agreed upon a three-layered hierarchical framework. Each layer-universal measures, detailed self-report and biological measures-reflected different research priorities and minimum standards, costs and ease of implementation. Additional work is needed to develop valid and precise assessments. CONCLUSIONS: Consistent use of the proposed framework across research, public health, clinical practice and medical settings would facilitate harmonisation of international evidence on cannabis consumption, related harms and approaches to their mitigation.

Will the Current COVID-19 Pandemic Impact on Long-term Cannabis Buying Practices?

: The COVID-19 pandemic and the response to have resulted in an increase in sales activity levels on darknet markets during the first 3 months of 2020, mainly related to cannabis products. One key question is whether more people will become used to this form of purchasing their drugs and will they continue with it post COVID-19 lockdown. As one-to-one encrypted communication services or social media apps are increasingly being used, monitoring and interdiction will become much more challenging.

Increasing potency and price of cannabis in Europe, 2006-16.

AIMS: To quantify changes in (i) potency (concentration of Δ9 -tetrahydrocannabinol; %THC), (ii) price (euros/g of cannabis) and (iii) value (mg THC/euro) of cannabis resin and herbal cannabis in Europe. DESIGN: Repeated cross-sectional study. SETTING AND PARTICIPANTS: Data collected from 28 European Union (EU) member states, Norway and Turkey by the European Monitoring Centre for Drugs and Drug Addiction. MEASUREMENTS: Outcome variables were potency, price and value for cannabis resin and herbal cannabis in Europe, 2006-16. Inflation was estimated using the Harmonised Indices of Consumer Prices. Mixed-effects linear regression models were used to estimate linear and quadratic time trends, with a random intercept and slope fitted to account for variation across countries. FINDINGS: Resin potency increased from a mean [95% confidence interval (CI)] of 8.14% THC (6.89, 9.49) in 2006 to 17.22 (15.23, 19.25) in 2016. Resin price increased from 8.21 euros/g (7.54, 8.97) to 12.27 (10.62, 14.16). Resin increased in value, from 11.00 mg THC per euro (8.60, 13.62) to 16.39 (13.68, 19.05). Quadratic time trends for resin potency and value indicated minimal change from 2006 to 2011, followed by marked increases from 2011 to 2016. Herbal cannabis potency increased from 5.00% THC (3.91, 6.23) to 10.22 (9.01, 11.47). Herbal price increased from 7.36 euros/g (6.22, 8.53) to 12.22 (10.59, 14.03). The value of herbal cannabis did not change from 12.65 mg of THC per euro (10.18, 15.34) to 12.72 (10.73, 14.73). All price trends persisted after adjusting for inflation. CONCLUSIONS: European cannabis resin and herbal cannabis increased in potency and price from 2006 to 2016. Cannabis resin (but not herbal cannabis) increased in the quantity of Δ9 -tetrahydrocannabinol per euro spent. Marked increases in resin potency and value from 2011 to 2016 are consistent with the emergence of new resin production techniques in European and neighbouring drug markets.

Drug-related homicide in Europe-First review of data and sources.

BACKGROUND: Drugs can act as facilitators for all types of violence, including drug-related homicide (DRH). Addressing this phenomenon is not only of importance given the severity of a homicide event and its high costs on society, but also because DRH has the potential to act as a valuable indicator or proxy of wider drug-related violent crime. However, there appears to be an important gap in terms of available European data on DRH. This study aimed to identify relevant European data sources on DRH, to assess the role of drugs in national homicide data, and to assess these sources and data in terms of monitoring potential. METHODS: A critical review was conducted of existing national and international homicide data sources. A three-step approach was adopted, including systematic searches for data sources and literature, snowballing methods, and contacting professionals. RESULTS: Data on DRH is systematically prepared in the Czech Republic, Denmark, Finland, Germany, Italy, the Netherlands, Norway, Slovakia, Sweden, and the United Kingdom (England, Wales, and Scotland). Available data suggests both between- and within country variability in relation to the role of drugs in homicide events. Based on these findings, four key obstacles can be identified in terms of the current ability to monitor DRH: missing data, fragmented data, comparability issues and data quality reservations. CONCLUSION: To overcome these obstacles, there is a need for an international monitoring system that incorporates DRH. Ideally, the system should employ a single shared definition, standardised terminology, one coordinating body, and the use of multiple data sources. There are several approaches towards such a system, notably expanding the European Homicide Monitor (EHM) framework. Options should be explored to incorporate DRH into this existing and growing monitoring system.

Drug supply indicators: Pitfalls and possibilities for improvements to assist comparative analysis.

Interventions to tackle the supply of drugs are seen as standard components of illicit drug policies. Therefore drug market-related administrative data, such as seizures, price, purity and drug-related offending, are used in most countries for policy monitoring and assessment of the drug situation. International agencies, such as the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) and the UN Office of Drugs and Crime, also monitor and report on the drug situation cross-nationally and therefore seek to collect and make available key data in a uniform manner from the countries they cover. However, these data are not primarily collected for this purpose, which makes interpretation and comparative analysis difficult. Examples of limitations of these data sources include: the extent to which they reflect operational priorities rather than market changes; question marks over the robustness of and consistency in data collection methods, and issues around the timeliness of data availability. Such problems are compounded by cultural, social and contextual differences between countries. Making sense of such data is therefore challenging and extreme care needs to be taken using it. Nevertheless, these data provide an important window on a hidden area, so improving the quality of the data collected and expanding its scope should be a priority for those seeking to understand or monitor drug markets and supply reduction. In addition to highlighting some of the potential pitfalls in using supply indicators for comparative analysis, this paper presents a selection of options for improvements based on the current EMCDDA programme of work to improve their supply-related monitoring and analysis. The conceptual framework developed to steer this work may have wider application. Adopting this approach has the potential to provide a richer picture of drug markets, at both national and international levels, and make it easier to compare data between countries.

Drug affordability-potential tool for comparing illicit drug markets.

BACKGROUND: The importance of illicit drug price data and making appropriate adjustments for purity has been repeatedly highlighted for understanding illicit drug markets. The European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) has been collecting retail price data for a number of drug types alongside drug-specific purity information for over 15 years. While these data are useful for a number of monitoring and analytical purposes, they are not without their limitations and there are circumstances where additional adjustment needs to be considered. This paper reviews some conceptual issues and measurement challenges relevant to the interpretation of price data. It also highlights the issues with between-country comparisons of drug prices and introduces the concept of affordability of drugs, going beyond purity-adjustment to account for varying national economies. METHODS: Based on a 2015 European data set of price and purity data across the heroin and cocaine retail markets, the paper demonstrates a new model for drug market comparative analysis; calculation of drug affordability is achieved by applying to purity-adjusted prices 2015 Price Level Indices (PLI, Eurostat). RESULTS: Available data allowed retail heroin and cocaine market comparison for 27 European countries. The lowest and highest unadjusted prices per gram were observed for heroin: in Estonia, Belgium, Greece and Bulgaria (lowest) and Finland, Ireland, Sweden and Latvia (highest); for cocaine: the Netherlands, Belgium and the United Kingdom (lowest) and Turkey, Finland, Estonia and Romania (highest). The affordability per gram of heroin and cocaine when taking into account adjustment for both purity and economy demonstrates different patterns. CONCLUSION: It is argued that purity-adjusted price alone provides an incomplete comparison of retail price across countries. The proposed new method takes account of the differing economic conditions within European countries, thus providing a more sophisticated tool for cross-national comparisons of retail drug markets in Europe. Future work will need to examine other potential uses of the drug affordability tool. LIMITATIONS: The limitations of this measure reflect primarily the limitations of the constituent data; in addition to issues inherent in collecting accurate data on illicit markets, analysis that relies on data collected from multiple countries is susceptible to discrepancies in data collection practices from country to country.

Development and validation of a Brief Assessment of Recovery Capital (BARC-10) for alcohol and drug use disorder.

BACKGROUND: It has been long established that achieving recovery from an alcohol or other drug use disorder is associated with increased biobehavioral stress. To enhance the chances of recovery, a variety of psychological, physical, social, and environmental resources, known as "recovery capital", are deemed important as they can help mitigate this high stress burden. A 50-item measure of recovery capital was developed (Assessment of Recovery Capital [ARC]), with 10 subscales; however, a briefer version could enhance further deployment in research and busy clinical/recovery support service settings. To help increase utility of the measure, the goal of the current study was to create a shorter version using Item Response Theory models. METHOD: Items were pooled from the original treatment samples from Scotland and Australia (N=450) for scale reduction. A reduced version was tested in an independent sample (N=123), and a Receiver Operating Characteristic Curve was constructed to determine optimal cut-off for sustained remission (>12months abstinence). RESULTS: An abbreviated 10-item measure of recovery capital captured item representation from all 10 original subscales, was invariant across participant's locality and gender, had high internal consistency (α=.90), concurrent validity with the original measure (rpb=.90), and predictive validity with sustained remission using a cut-off score of 47. CONCLUSION: The brief assessment of recovery capital 10-item version (BARC-10) concisely measures a single unified dimension of recovery capital that may have utility for researchers, clinicians, and recovery support services.

Heroin on trial: systematic review and meta-analysis of randomised trials of diamorphine-prescribing as treatment for refractory heroin addiction†.

BACKGROUND: Supervised injectable heroin (SIH) treatment has emerged over the past 15 years as an intensive treatment for entrenched heroin users who have not responded to standard treatments such as oral methadone maintenance treatment (MMT) or residential rehabilitation. AIMS: To synthesise published findings for treatment with SIH for refractory heroin-dependence through systematic review and meta-analysis, and to examine the political and scientific response to these findings. METHOD: Randomised controlled trials (RCTs) of SIH treatment were identified through database searching, and random effects pooled efficacy was estimated for SIH treatment. Methodological quality was assessed according to criteria set out by the Cochrane Collaboration. RESULTS: Six RCTs met the inclusion criteria for analysis. Across the trials, SIH treatment improved treatment outcome, i.e. greater reduction in the use of illicit 'street' heroin in patients receiving SIH treatment compared with control groups (most often receiving MMT). CONCLUSIONS: SIH is found to be an effective way of treating heroin dependence refractory to standard treatment. SIH may be less safe than MMT and therefore requires more clinical attention to manage greater safety issues. This intensive intervention is for a patient population previously considered unresponsive to treatment. Inclusion of this low-volume, high-intensity treatment can now improve the impact of comprehensive healthcare provision.

Drug use, health and social outcomes of hard-to-treat heroin addicts receiving supervised injectable opiate treatment: secondary outcomes from the Randomized Injectable Opioid Treatment Trial (RIOTT).

AIMS: The Randomized Injectable Opioid Treatment Trial (RIOTT) compared supervised injectable heroin (SIH) and supervised injectable methadone (SIM) with optimized oral methadone (OOM) (ISRCTN0133807). Heroin addicts (previously unresponsive to treatment) made significant reductions in street heroin use at 6 months when treated with SIH. We now examine secondary outcomes. DESIGN: Multi-site randomized controlled trial (RCT) comparing SIH versus OOM and SIM versus OOM. SETTING: Three supervised injectable opiate clinics in England. PARTICIPANTS: Chronic refractory heroin addicts continuing to inject street heroin virtually daily despite oral substitution treatment (n = 127), randomized to either SIH(n = 43), SIM(n = 42) or OOM(n = 42). All received high levels of medical and psychosocial support. SECONDARY OUTCOMES: wider drug use, crime, health and social functioning at 6 months. FINDINGS: At 6 months, no significant differences were found between treatment groups in wider drug use (crack/cocaine, benzodiazepines, alcohol), physical and mental health (SF-36) or social functioning. Within each treatment group, significant reductions were observed in crime [SIH = odds ratio (OR) 0.05; P < 0.001; SIM = OR 0.11; P = 0.002; OOM = OR 0.11; P = 0.003] and money spent per week on illicit drugs (SIH = mean change £-289.43; P < 0.001; SIM = mean change £-183.41; P < 0.001; OOM = mean change £-162.80; P < 0.001), with SIH significantly more likely to have reduced money spent on illicit drugs versus OOM (mean difference £-92.04; P < 0.001). Significant improvements were seen in physical health for SIH and SIM (SIH = mean change 3.97; P = 0.008; SIM = mean change 4.73; P = 0.002) and mental health for OOM (mean change 6.04; P = 0.013). CONCLUSIONS: Supervised injectable heroin treatment and supervised injectable methadone treatment showed no clearly identified benefit over optimized oral methadone in terms of wider drug use, crime, physical and mental health within a 6-month period, despite reducing street heroin use to a greater extent. However, all interventions were associated with improvements in these outcomes.

Factors associated with uptake, adherence, and efficacy of hepatitis C treatment in people who inject drugs: a literature review.

INTRODUCTION AND METHODS: Hepatitis C virus (HCV) infections are highly prevalent amongst people who inject drugs (PWID). Despite well documented evidence of its effectiveness, suggested cost-effectiveness, and potential to reduce HCV prevalence rates, the uptake of antiviral HCV treatment by PWID is low. This nonsystematic literature review describes factors associated with the uptake, adherence, and efficacy of HCV treatment among PWID and discusses strategies to increase their uptake of treatment. RESULTS: Low HCV treatment uptake among PWID is associated with a number of patient-related and provider-related barriers. Beliefs and fears about low efficacy and adverse effects on the patient's part are common. A substantial number of factors are associated with the chaotic lifestyle and altered social functioning of PWID, which are often associated with decompensation or relapsing into drug addiction. This may lead to perceived low adherence with treatment and low efficacy on the provider's part too, where lack of support, inadequate management of addiction, and other drug-related problems and poor treatment of side effects have been described. Practical issues such as the accessibility of treatment and finances also play a role. Strategies to improve the HCV treatment rate among PWID involve pretreatment management and assessment, a multidisciplinary approach, management of side effects, and enhanced education and counseling. CONCLUSION: Specific factors are associated with poorer treatment outcomes in PWID on the side of both the patient and the treatment system. However, given that PWID can achieve treatment adherence and sustained virologic response rates comparable with those in nondrug users, drug use per se should not be considered a criterion for exclusion from treatment. Further development of measures leading to higher uptake of treatment and adherence in PWID and appropriate adaptation of HCV treatment guidelines represent important tools in this regard.

Treatment expectations and satisfaction of treatment-refractory opioid-dependent patients in RIOTT, the Randomised Injectable Opiate Treatment Trial, the UK's first supervised injectable maintenance clinics.

INTRODUCTION AND AIMS: The study investigates patients' pre-treatment expectations of, and post-treatment satisfaction with, supervised injectable opiate treatment delivered within UK's first such clinics within the Randomised Injectable Opiate Treatment Trial (RIOTT) (ISRCTN0133807). DESIGN AND METHODS: Data were collected from 127 chronic heroin addicts recruited to RIOTT and randomised to receive supervised injectable (heroin or methadone) treatment or optimised oral maintenance treatment at supervised injectable maintenance clinics in London, Darlington and Brighton. RESULTS: Of 127 RIOTT patients, 113 (89%) provided responses to structured enquiry about treatment expectations, and 94 (74%) subsequent responses about treatment satisfaction (at six months). Patients were hoping that injectable heroin treatment would: reduce substance misuse (81%); help achieve normality, routine and structure (16%); and increase education and work prospects (15%). At six months, an area of treatment satisfaction most commonly reported by all three trial groups was reduced substance misuse (supervised injectable heroin 59%, supervised injectable methadone 56%, optimised oral methadone 54%). Most found supervision acceptable, but some desired modifications were also identified. DISCUSSION AND CONCLUSIONS: Patients previously considered non-responsive to treatment appear to have similar treatment expectations and aspirations as other drug users in treatment. Supervised injectable opioid treatment patients consistently reported treatment satisfaction but also that more could be done to optimise aspects of current arrangement. This raised the challenging issue of the extent to which opinions of patients need to be taken into consideration in shaping future treatment provision. Future research may need to examine the extent of expectations 'fit' and the relationship between treatment sought and received.

Cost-effectiveness of injectable opioid treatment v. oral methadone for chronic heroin addiction.

BACKGROUND: Despite evidence of the effectiveness of injectable opioid treatment compared with oral methadone for chronic heroin addiction, the additional cost of injectable treatment is considerable, and cost-effectiveness uncertain. AIMS: To compare the cost-effectiveness of supervised injectable heroin and injectable methadone with optimised oral methadone for chronic refractory heroin addiction. METHOD: Multisite, open-label, randomised controlled trial. Outcomes were assessed in terms of quality-adjusted life-years (QALYs). Economic perspective included health, social services and criminal justice resources. RESULTS: Intervention costs over 26 weeks were significantly higher for injectable heroin (mean £8995 v. £4674 injectable methadone and £2596 oral methadone; P<0.0001). Costs overall were highest for oral methadone (mean £15 805 v. £13 410 injectable methadone and £10 945 injectable heroin; P = n.s.) due to higher costs of criminal activity. In cost-effectiveness analysis, oral methadone was dominated by injectable heroin and injectable methadone (more expensive and less effective). At willingness to pay of £30 000 per QALY, there is a higher probability of injectable methadone being more cost-effective (80%) than injectable heroin. CONCLUSIONS: Injectable opioid treatments are more cost-effective than optimised oral methadone for chronic refractory heroin addiction. The choice between supervised injectable heroin and injectable methadone is less clear. There is currently evidence to suggest superior effectiveness of injectable heroin but at a cost that policy makers may find unacceptable. Future research should consider the use of decision analytic techniques to model expected costs and benefits of the treatments over the longer term.

The Assessment of Recovery Capital: properties and psychometrics of a measure of addiction recovery strengths.

INTRODUCTION AND AIMS: Sociological work on social capital and its impact on health behaviours have been translated into the addiction field in the form of 'recovery capital' as the construct for assessing individual progress on a recovery journey. Yet there has been little attempt to quantify recovery capital. The aim of the project was to create a scale that assessed addiction recovery capital. DESIGN AND METHODS: Initial focus group work identified and tested candidate items and domains followed by data collection from multiple sources to enable psychometric assessment of a scale measuring recovery capital. RESULTS: The scale shows moderate test-retest reliability at 1 week and acceptable concurrent validity. Principal component analysis determined single factor structure. DISCUSSION AND CONCLUSIONS: The Assessment of Recovery Capital (ARC) is a brief and easy to administer measurement of recovery capital that has acceptable psychometric properties and may be a useful complement to deficit-based assessment and outcome monitoring instruments for substance dependent individuals in and out of treatment.