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The COVID-19 outbreak has forced countries to introduce severe restrictive measures to contain its spread. In particular, physical distancing and restriction of movement have important consequences on human behaviour and potentially also on illicit drug use and supply. These changes can be associated with additional risks for users due to reduced supplies, limited prevention and harm reduction activities. Furthermore, there have been limitations in the amount of data about drug use which can be collected due to restrictions. To goal of this study was to obtain information about potential changes in illicit drug use impacted by COVID-19 restrictions. Wastewater samples were collected in seven cities in the Netherlands, Belgium, Spain and Italy at the beginning of lockdowns (March-May 2020). Using previously established and validated methods, levels of amphetamine (AMP), methamphetamine (METH), MDMA, benzoylecgonine (BE, the main metabolite of cocaine) and 11-nor-9-carboxy-Δ 9 -tetrahydrocannabinol (THC-COOH, main metabolite of tetrahydrocannabinol (THC)) were measured and compared with findings from previous years. Important differences in levels of consumed drugs were observed across the considered countries. Whilst for some substances and locations, marked decreases in consumption could be observed (e.g., 50% decrease in MDMA levels compared to previous years). In some cases, similar or even higher levels compared to previous years could be found. Changes in weekly patterns were also observed, however these were not clearly defined for all locations and/or substances. Findings confirm that the current situation is highly heterogeneous and that it remains very difficult to explain and/or predict the effect that the present pandemic has on illicit drug use and availability. However, given the current difficulty in obtaining data due to restrictions, wastewater analysis can provide relevant information about the situation at the local level, which would be hard to obtain otherwise.

Substance use and suicide attempts are high-risk behaviors in adolescents, with serious impacts on health and well-being. Although multiple substance use among young people has become a common phenomenon, studies of its association with suicide attempts are scarce. The present study examines the association between multiple substance use and self-reported suicide attempts in a large multinational sample of adolescent students in Europe. Data on multiple substance use (tobacco, alcohol, tranquillizers/sedatives, cannabis, other illegal drugs) and self-reported suicide attempts were drawn from the 2007 European School Survey Project on Alcohol and Other Drugs (ESPAD). The ESPAD survey follows a standardized methodology in all participating countries. The present study is based on 45,086 16-year-old adolescents from 16 countries that had used the optional "psychosocial module" of the questionnaire, thereby including the question on suicide attempts. Logistic regression analyses were performed to examine the associations of any self-reported suicide attempt (dependent variable) with substance use controlling for country and gender. The strongest association with self-reported suicide attempts was for any lifetime tranquillizer or sedative use (odds ratio 3.34, 95 % confidence interval 3.00-3.71) followed by any lifetime use of illegal drugs other than cannabis (2.41, 2.14-2.70), 30-day regular tobacco use (2.02, 1.84-2.21), 30-day frequent alcohol use (1.47, 1.32-1.63) and any 30-day cannabis use (1.37, 1.18-1.58). The odds ratio of reporting a suicide attempt approximately doubled for every additional substance used. These findings on the association between multiple substance use, including legal drugs (tranquillizers or sedatives and tobacco), and the life-threatening behavior of suicide attempts provide important cues for shaping prevention policies.

AIM-Previous studies of the association between polydrug use and other risk behaviours have generally been limited to specific substances and a small number of behaviours. The aim of this study is to obtain better insight into polydrug use (comprising legal and illegal substances: tobacco, alcohol, tranquillisers/sedatives, cannabis, and other illegal drugs) and its association with cooccurring problem behaviours drawn from various broad domains (sexual, aggressive, delinquent, school achievement, relationships) among European adolescents. METHODS-Data were obtained from 101,401 16-year-old students from 35 European countries participating in the 2011 ESPAD survey. Associations between polydrug use and other problem behaviours were examined by multinomial and binary logistic regression analyses. RESULTS-Tranquillisers/sedatives appeared among the commonest combinations in the polydrug use pattern, especially for females. A strong trend was found between levels of involvement with polydrug use and other problem behaviours for both genders. The highest associations with polydrug use were for problems with the police, risky sexual behaviour and skipping school. Gender differences showed higher prevalences among boys than girls of problem behaviours of aggressive, antisocial type, while girls prevailed over boys in relationship problems. CONCLUSION-An incremental relationship exists between the level of involvement with polydrug use and the co-occurrence of problem behaviours. Preventative interventions should consider the misuse of tranquillisers/sedatives within the context of polydrug use by adolescents and expand their target groups towards multiple problem behaviours.

Inconsistencies in the assumptions linking punitive sanctions and use of cannabis and new psychoactive substances in EuropeChanging the severity of statutory penalties for cannabis use offences does not appear to have a consistent impact on cannabis use by young adults, and new policy responses to the proliferation of new psychoactive substances within European countries usually exclude any penalty for use.

Background: Cocaine-related health consequences are difficult to observe. Data on drug users in health-emergency settings may be a useful source of information on consequences that are not visible via other information sources. Methods: Thirty European countries submit an annual national report on the drug situation to the EMCDDA. All reports for the period 2007–2010 were analyzed, with particular attention given to auditing cocaine-related mentions. Analysis was also performed in order to identify sources and case definitions, assess coverage, audit cases and, where possible, to identify long-term trends. Results: Considerable heterogeneity existed between countries in their approach to recording drug-related emergencies, with only Spain and the Netherlands having established formal indicators. The highest annual numbers of cocaine-related episodes were reported by the UK (3,502), Spain (2,845) and the Netherlands (1,211). A considerable (2- to 3-fold) increase in the numbers of cocaine-related episodes has been reported since the end of the 1990s in these countries; these increases peaked in Spain and England around 2007/08. Conclusions: The analysis reported here suggests the need to develop more standardized approaches to monitoring drug-related emergencies. It points to the potential value of developing effective referral links between the emergency and specialized drug services working with cocaine users.

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In real optimization problems, usually the analytical expression of the objective function is not known, nor its derivatives, or they are complex. In these cases it becomes essential to use optimization methods where the calculation of the derivatives, or the verification of their existence, is not necessary: the Direct Search Methods or Derivative-free Methods are one solution.When the problem has constraints, penalty functions are often used. Unfortunately the choice of the penalty parameters is, frequently, very difficult, because most strategies for choosing it are heuristics strategies. As an alternative to penalty function appeared the filter methods. A filter algorithm introduces a function that aggregates the constrained violations and constructs a biobjective problem. In this problem the step is accepted if it either reduces the objective function or the constrained violation. This implies that the filter methods are less parameter dependent than a penalty function.In this work, we present a new direct search method, based on simplex methods, for general constrained optimization that combines the features of the simplex method and filter methods. This method does not compute or approximate any derivatives, penalty constants or Lagrange multipliers. The basic idea of simplex filter algorithm is to construct an initial simplex and use the simplex to drive the search. We illustrate the behavior of our algorithm through some examples. The proposed methods were implemented in Java.