Process evaluation of PsyCovidApp, a digital tool for mobile devices aimed at protecting the mental health of healthcare professionals during the COVID-19 pandemic: a mixed method study.

Introduction: PsyCovidApp, a digital intervention aimed at safeguarding the mental health of healthcare workers during the COVID-19 pandemic, demonstrated in a randomized clinical trial to yield significant improvements solely among healthcare workers undergoing psychotherapy or receiving psychotropic medication. Objectives: (1) To identify contextual factors and mechanisms of action that influenced the impact of PsyCovidApp during the aforementioned trial; (2) To pinpoint enhancements for optimizing its efficacy. Materials and methods: For the first objective, a process evaluation was conducted, amalgamating quantitative techniques (surveying 216 healthcare professionals who had utilized PsyCovidApp during the trial) and qualitative methods (in-depth interviews with 16 healthcare workers). The second objective involved a panel of seven experts, utilizing the RAND-UCLA methodology. Results: The quantitative study (response rate = 40%) revealed that 22% of respondents had not fully accessed the content of PsyCovidApp. The average usage time was 22.7 min/day, being higher (p < 0.05) among consumers of psychotropic medications. Contents related to relaxation and mindfulness were most highly rated. Acceptability and usefulness scores ranged between 7.3-7.5/10 points, with higher ratings (p < 0.05) among women and older healthcare workers. The qualitative study uncovered that the primary barriers to using PsyCovidApp were workload, lack of time, and exhaustion. Its primary mechanisms of action included emotion identification, mental health regulation (e.g., insomnia, intense emotions), and learning of techniques and skills. The expert panel reached a consensus on 29 proposals to optimize PsyCovidApp. Conclusion: The knowledge derived from this study could inform the design and implementation of future similar digital tools.

Exploring attributional and coping strategies in competitive injured athletes: a qualitative approach.

Introduction: This study explores the attributions and coping strategies of athletes who experienced psychological impact from sport injuries or illness from a qualitative methodology. Purpose: To understand athletes' unique perspectives on injury and recovery, framed in the Global Model of Sport Injuries, and contribute to the development of effective interventions and support programs for athletes. Methods: A qualitative research approach was employed, conducting semi-structured interviews with an ad hoc sample of 16 athletes, representing diverse backgrounds and competitive levels. Interviews were transcribed and analyzed using NVivo software, identifying themes and codes related to attributions and coping strategies. Results: Athletes attributed their sport injury mostly to bad luck, routine deviations, and negative mental states, while coping strategies used included cognitive restructuring, emotional calming, seeking social support, mental withdrawal, and behavioral risk. Factors such as training deviations, social support, psychological responses, and injury diagnosis seems to have influenced the coping strategies employed. Conclusions: Sport injuries and illnesses significantly impact athletes' careers and wellbeing. Support and effective communication from coaching staff and healthcare professionals were identified as crucial for athletes' wellbeing. These findings contribute to understanding the psychological processes and experiences involved in sport injury recovery and highlight key elements for prevention and intervention protocols. Future research should explore communication patterns in sports contexts and assess attributions and coping strategies at different stages of injury recovery.

Mindfulness skills and experiential avoidance as therapeutic mechanisms for treatment-resistant depression through mindfulness-based cognitive therapy and lifestyle modification.

Background/objective: The COVID-19 pandemic and consequent physical distancing has made it difficult to provide care for those with Treatment-Resistant Depression (TRD). As a secondary analysis of a clinical trial, the aim of this study was to explore potential mechanisms through which three online-delivered approaches, added to treatment as usual, improve depressive symptoms in TRD patients. Methods: The three approaches included (a) Minimal Lifestyle Intervention (MLI), (b) Mindfulness-Based Cognitive Therapy (MBCT), and (c) Lifestyle Modification Program (LMP). Sixty-six participants with TRD completed assessments pre-post intervention (mindfulness skills [FFMQ]; self-compassion [SCS]; and experiential avoidance [AAQ-II]) and pre-intervention to follow-up (depressive symptoms [BDI-II]). Data were analyzed using within-subjects regression models to test mediation. Results: Mindfulness skills mediated the effect of MBCT on depressive symptoms (ab = -4.69, 95% CI = -12.93 to-0.32), whereas the lack of experiential avoidance mediated the effect of LMP on depressive symptoms (ab = -3.22, 95% CI = -7.03 to-0.14). Conclusion: Strengthening mindfulness skills and decreasing experiential avoidance may promote recovery in patients with TRD, MBCT, and LMP have demonstrated that they may help increase mindfulness skills and decrease experiential avoidance, respectively. Future work will need to unpick the components of these interventions to help isolate active ingredients and increase optimization.

Associations Between Severity of Depression, Lifestyle Patterns, and Personal Factors Related to Health Behavior: Secondary Data Analysis From a Randomized Controlled Trial.

Background: Depression is a prevalent condition that has a significant impact on psychosocial functioning and quality of life. The onset and persistence of depression have been linked to a variety of biological and psychosocial variables. Many of these variables are associated with specific lifestyle characteristics, such as physical activity, diet, and sleep patterns. Some psychosocial determinants have an impact on people' health-related behavior change. These include personal factors such as sense of coherence, patient activation, health literacy, self-efficacy, and procrastination. This study aims to analyze the association between the severity of depression, lifestyle patterns, and personal factors related to health behavior. It also aims to analyze whether personal factors moderate the relationship between lifestyles and depression. Methods: This study is a secondary data analysis (SDA) of baseline data collected at the start of a randomized controlled trial (RCT). A sample of 226 patients with subclinical, mild, or moderate depression from primary healthcare centers in two sites in Spain (Zaragoza and Mallorca) was used, and descriptive, bivariate, multivariate, and moderation analyses were performed. Depression was the primary outcome, measured by Beck II Self-Applied Depression Inventory. Lifestyle variables such as physical exercise, adherence to Mediterranean diet and sleep quality, social support, and personal factors such as self-efficacy, patient activation in their own health, sense of coherence, health literacy, and procrastination were considered secondary outcomes. Results: Low sense of coherence (ß = -0.172; p < 0.001), poor sleep quality (ß = 0.179; p = 0.008), low patient activation (ß = -0.119; p = 0.019), and sedentarism (more minutes seated per day; ß = 0.003; p = 0.025) are predictors of having more depressive symptoms. Moderation analyses were not significant. Discussion: Lifestyle and personal factors are related to depressive symptomatology. Our findings reveal that sense of coherence, patient's activation level, sedentarism, and sleep quality are associated with depression. Further research is needed regarding adherence to Mediterranean diet, minutes walking per week and the interrelationship between lifestyles, personal factors, and depression.

Procedures for Comparison of Two Means in Independent Groups with R

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A Mobile Phone-Based Intervention to Reduce Mental Health Problems in Health Care Workers During the COVID-19 Pandemic (PsyCovidApp): Randomized Controlled Trial.

BACKGROUND: The global health emergency generated by the COVID-19 pandemic is posing an unprecedented challenge to health care workers, who are facing heavy workloads under psychologically difficult situations. Mental mobile Health (mHealth) interventions are now being widely deployed due to their attractive implementation features, despite the lack of evidence about their efficacy in this specific population and context. OBJECTIVE: The aim of this trial is to evaluate the effectiveness of a psychoeducational, mindfulness-based mHealth intervention to reduce mental health problems in health care workers during the COVID-19 pandemic. METHODS: We conducted a blinded, parallel-group, controlled trial in Spain. Health care workers providing face-to-face health care to patients with COVID-19 were randomly assigned (1:1) to receive the PsyCovidApp intervention (an app targeting emotional skills, healthy lifestyle behavior, burnout, and social support) or a control app (general recommendations about mental health care) for 2 weeks. The participants were blinded to their group allocation. Data were collected telephonically at baseline and after 2 weeks by trained health psychologists. The primary outcome was a composite of depression, anxiety, and stress (overall score on the Depression Anxiety Stress Scale-21 [DASS-21]). Secondary outcomes were insomnia (Insomnia Severity Index), burnout (Maslach Burnout Inventory Human Services Survey), posttraumatic stress (Davidson Trauma Scale), self-efficacy (General Self-Efficacy Scale), and DASS-21 individual scale scores. Differences between groups were analyzed using general linear modeling according to an intention-to-treat protocol. Additionally, we measured the usability of the PsyCovidApp (System Usability Scale). The outcome data collectors and trial statisticians were unaware of the treatment allocation. RESULTS: Between May 14 and July 25, 2020, 482 health care workers were recruited and randomly assigned to PsyCovidApp (n=248) or the control app (n=234). At 2 weeks, complete outcome data were available for 436/482 participants (90.5%). No significant differences were observed between the groups at 2 weeks in the primary outcome (standardized mean difference -0.04; 95% CI -0.11 to 0.04; P=.15) or in the other outcomes. In our prespecified subgroup analyses, we observed significant improvements among health care workers consuming psychotropic medications (n=79) in the primary outcome (-0.29; 95% CI -0.48 to -0.09; P=.004), and in posttraumatic stress, insomnia, anxiety, and stress. Similarly, among health care workers receiving psychotherapy (n=43), we observed improvements in the primary outcome (-0.25; 95% CI -0.49 to -0.02; P=.02), and in insomnia, anxiety, and stress. The mean usability score of PsyCovidApp was high (87.21/100, SD 12.65). After the trial, 208/221 participants in the intervention group (94.1%) asked to regain access to PsyCovidApp, indicating high acceptability. CONCLUSIONS: In health care workers assisting patients with COVID-19 in Spain, PsyCovidApp, compared with a control app, reduced mental health problems at 2 weeks only among health care workers receiving psychotherapy or psychotropic medications. TRIAL REGISTRATION: ClinicalTrials.gov NCT04393818; https://clinicaltrials.gov/ct2/show/NCT04393818.

Effect of a mobile-based intervention on mental health in frontline healthcare workers against COVID-19: Protocol for a randomized controlled trial.

AIM: To evaluate the impact of a psychoeducational, mobile health intervention based on cognitive behavioural therapy and mindfulness-based approaches on the mental health of healthcare workers at the frontline against COVID-19 in Spain. DESIGN: We will carry out a two-week, individually randomized, parallel group, controlled trial. Participants will be individually randomized to receive the PsyCovidApp intervention or control App intervention. METHODS: The PsyCovidApp intervention will include five modules: emotional skills, lifestyle behaviour, work stress and burnout, social support, and practical tools. Healthcare workers having attended patients with COVID-19 will be randomized to receive the PsyCovidApp intervention (intervention group) or a control App intervention (control group). A total of 440 healthcare workers will be necessary to assure statistical power. Measures will be collected telephonically by a team of psychologists at baseline and immediately after the 2 weeks intervention period. Measures will include stress, depression and anxiety (DASS-21 questionnaire-primary endpoint), insomnia (ISI), burnout (MBI-HSS), post-traumatic stress disorder (DTS), and self-efficacy (GSE). The study was funded in May 2020, and was ethically approved in June 2020. Trial participants, outcome assessors and data analysts will be blinded to group allocation. DISCUSSION: Despite the increasing use of mobile health interventions to deliver mental health care, this area of research is still on its infancy. This study will help increase the scientific evidence about the effectiveness of this type of intervention on this specific population and context. IMPACT: Despite the lack of solid evidence about their effectiveness, mobile-based health interventions are already being widely implemented because of their low cost and high scalability. The findings from this study will help health services and organizations to make informed decisions in relation to the development and implementation of this type of interventions, allowing them pondering not only their attractive implementability features, but also empirical data about its benefits. CLINICAL TRIAL REGISTRATION: NCT04393818 (ClinicalTrials.gov identifier). APPROVED FUNDING: May 2020.

Effectiveness and cost-effectiveness of a lifestyle modification programme in the prevention and treatment of subclinical, mild and moderate depression in primary care: a randomised clinical trial protocol.

INTRODUCTION: Major depression is a highly prevalent pathology that is currently the second most common cause of disease-induced disability in our society. The onset and continuation of depression may be related to a wide variety of biological and psychosocial factors, many of which are linked to different lifestyle aspects. Therefore, health systems must design and implement health promotion and lifestyle modification programmes (LMPs), taking into account personal factors and facilitators. The main objective of this protocol is to analyse the clinical effectiveness, cost-effectiveness and cost utility of an LMP and an LMP with information and communication technologies (ICTs) as adjunctive treatment for depression in primary care patients. The secondary objectives are to analyse the clinical effectiveness in the subgroup that presents comorbidity and to analyse the correlation between personal factors on health behaviour and lifestyle patterns. METHODS AND ANALYSIS: A randomised, multicenter pragmatic clinical trial with three parallel groups consisting of primary healthcare patients suffering from subclinical, mild or moderate depression. The following interventions will be used: (1) Usual antidepressant treatment with psychological advice and/or psychotropic drugs prescribed by the general practitioner (treatment as usual (TAU)). (2) TAU+LMP. A programme to be imparted in six weekly 90-minute group sessions, intended to improve the following aspects: behavioural activation+daily physical activity+adherence to the Mediterranean diet pattern+sleep hygiene+careful exposure to sunlight. (3) TAU+LMP+ICTs: healthy lifestyle recommendations (TAU+LMP)+monitoring using ICTs (a wearable smartwatch). The primary outcome will be the depressive symptomatology and the secondary outcomes will be the quality of life, the use of health and social resources, personal factors on health behaviour, social support, lifestyle patterns and chronic comorbid pathology. Data will be collected before and after the intervention, with 6-month and 12-month follow-ups. ETHICS AND DISSEMINATION: This study has been approved by the Clinical Research Ethics Committee of Aragón (approval number: C.P.-C.I. PI18/286) and the Research Ethics Committee of the Balearic Islands (IB3950/19 PI). Data distribution will be anonymous. Results will be disseminated via conferences and papers published in peer-reviewed, open-access journals. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT03951350).

Dejar de fumar, terapia cognitivo-conductual y perfiles diferenciales con árboles de decisión / Quitting smoking, cognitive behavioral therapy and differential profiles with decision tres

Este estudio evalúa si el sexo, la dependencia a la nicotina y variables emocionales (ansiedad, depresión e ira) permiten describir un perfil de paciente que pueda beneficiarse de una terapia cognitivo-conductual para abandonar la adicción al tabaco. Se analizaron los resultados de una muestra de 120 fumadores adultos que voluntariamente recibieron TCC. Se valoró la adherencia de los pacientes y el éxito del programa a través de árboles de decisión. Los resultados indicaron que la adherencia al tratamiento ya implica alta probabilidad de éxito (86.4%), aumentando hasta el 95.6% cuando los participantes presentaban altos niveles de ira externa. Además, la adherencia al tratamiento fue completa (100%) cuando la ansiedad en contexto de evaluación, la ansiedad fisiológica y la motivación fueron altas. La obtención de este tipo de perfiles diferenciales permite determinar qué personas son más indicadas para cada tratamiento, lo que incrementaría la eficacia de los mismos

The aim of this study is to analyse if gender, nicotine dependence, and emotional variables (anxiety, depression, and anger) help to describe a patient profile that could benefit from a cognitive behavioral therapy (CBT) to quit tobacco addiction. The sample consisted of 120 adult smokers who voluntarily received the CBT. Decision trees were used to assess patients' treatment adherence and program success. Data showed that just programme adherence implied a high success probability (86.4%), increasing to 95.6% when participants showed a high anger response. Besides, treatment adherence was 100% when anxiety in an evaluative context, physiologic anxiety, and motivation were high. Finding these differential profiles would help to determine the patient profile that would benefit most from treatment, and would increase their effectiveness

Effectiveness of a Community-Based Intervention to Increase Supermarket Vendors' Compliance with Age Restrictions for Alcohol Sales in Spain: A Pilot Study.

In Spain the legal age to buy alcohol is 18 years. However, official surveys show that minors perceive alcohol availability to be easy. This paper describes the impacts of a community-based intervention to increase vendors' compliance with age limits regarding alcohol sales in supermarkets. The aim of this study was to explore the association between implementation of a multicomponent intervention to reduce adolescents' alcohol use and sale of alcohol to minors in the city of Palma (Spain). Twenty trained adolescents (14-17 years old) conducted 138 alcohol test purchases in nine supermarket chains in August 2018 (baseline; n = 73) prior to the intervention, and again in January 2020 (follow-up; n = 65). Analysis was conducted according to three levels of intervention implemented across the supermarkets: (i) personnel from the supermarkets' Human Resources or Corporate Social Responsibility teams received alcohol service training as trainers (i.e., community mobilization); (ii) managers and vendors training by the capacitated trainers; and (iii) no training of managers or vendors (i.e., control group). In the supermarkets that completed the Training of Trainers and the vendors' training program, average sales decreased significantly from 76.9% in 2018 to 45.5% in 2020, asking for the age of the shopper significantly increased from 3.8% to 45.4%, and asking for proof of age significantly increased from 15.4% to 72.7%. Additionally, a statistically significant increase was observed in the visibility of prohibition to sell alcohol to minors' signs, from 61.5% to 100%. No statistically significant differences were found for the Training of Trainers intervention alone nor in the control group. In conclusion, community mobilization combined with staff training is associated with significant increases in supermarket vendors' compliance with alcohol legislation in Spain.

Community Intervention Self-Efficacy Scale for Parent Leaders (CONNECTED): Parents' Empowerment to Prevent Adolescent Alcohol Use.

Empowering parents by actively engaging them in environmental prevention strategies is a promising approach that only a few programs use. Evidence suggests that when families and the wider community are engaged, alcohol prevention is more efficient. However, due to the novelty of this approach, no specific assessment tools for measuring this type of engagement are available. The objective of this study is to design a parental empowerment measurement tool to evaluate parents' self-efficacy when engaging in environmental and community actions and to analyze its psychometric properties. A total of 132 parents active in in-school parent associations from Spain (n = 77; 58.4%) and Portugal (n = 55; 41.7%) completed a pencil and paper battery of four questionnaires, including the developed scale COmmuNity iNtervention SElf-Efficacy SCale for ParenT LEaDers (CONNECTED). The scale showed a good reliability and good test-retest stability in a three-month period. The convergent validity with other well-established instruments that assess similar constructs was significant. A preliminary confirmatory factor analysis (CFA) showed an acceptable fit. Environmental prevention supported by families is a promising preventive strategy because the participation and involvement of families is an effective way to address some risks in adolescence; however, new assessment tools are needed in this field. The developed scale could be a first step to identify the areas of need in a community and to monitor the progress and evaluate the outcomes of the preventive interventions implemented.

Doing a systematic review in health sciences / La revisión sistemática en las ciencias de la salud

This paper aims to provide a practical, summarized, and clear guide of steps to carry out a systematic review and is aimed at researchers in the field of Health Sciences. The review process runs from the initial questioning to the final report, providing useful information on tools available at each stage. Systematic review and meta-analysis are currently the evidence synthesis tools of the highest level of scientific quality. They are in themselves a secondary research methodology, whose objective is to locate, evaluate, and synthesize the best evidence by selecting original papers or quality primary publications. The procedure to achieve the objective is presented as a sequential and systematized process, in stages, following the transparency principle, so as to ensure its replicability

Este trabajo pretende proporcionar una guía práctica, resumida y clara de los pasos para llevar a cabo una revisión sistemática y está dirigido a los investigadores del ámbito de las ciencias de la salud. El proceso de revisión se desarrolla desde el planteamiento inicial de la pregunta hasta la elaboración del informe final, proporcionando información útil sobre herramientas disponibles en cada etapa. La revisión sistemática y el metaanálisis son actualmente las herramientas de síntesis de evidencia de más alto nivel de calidad científica. Constituyen en sí mismas una metodología de investigación secundaria, cuyo objetivo es localizar, valorar y sintetizar la mejor evidencia seleccionando los trabajos originales o publicaciones primarias de calidad. El procedimiento para alcanzar el objetivo se plantea como un proceso secuencial y sistematizado, por etapas, siguiendo el principio de transparencia, de modo que se asegure su replicabilidad

Adolescents' Alcohol Use in Botellon and Attitudes towards Alcohol Use and Prevention Policies.

Alcohol is a common drug misused by young people worldwide. Previous studies have found that attitudes towards heavy consumption are stronger predictors than general norms concerning alcohol. This study aims to explore adolescents' alcohol use and drunkenness, to understand adolescents' attitudes towards alcohol use, drunkenness and prevention approaches, and to explore associations between attitudes and personal alcohol use and demographics. Methods: Cross-sectional face-to-face survey of 410 adolescents (61.2% women) who were socializing at night in the streets of Palma (Spain). Breath Alcohol Concentration (BrAC), self-reported measures of alcohol use and social variables were assessed. Results: 70.7% of respondents had a BrAC score higher than 0. The full sample reported having a mean of 3.9 drunk episodes in the last month, and a mean of 7.34 in Alcohol Use Disorders Identification Test (AUDIT). A total of 30.7% were under the minimum age limit for alcohol drinking in Spain and males showed higher BrAC than females. Bivariate analyses identified some differences in attitudes across participant demographics and personal alcohol use. In conclusion, we found high levels of alcohol use and drunkenness amongst adolescents, and adolescents' attitudes towards drunkenness and prevention approaches were associated with their alcohol consumption as well as with age.

Breath Alcohol Concentration and Perception of Drunkenness: A Comparison between Adolescents and Young Adults Drinking Alcohol in Public Settings.

Alcohol use is a persisting social and health problem in Spain that often takes place within the recreational context. This study aims to analyze objective and self-reported measures of alcohol use and to assess the potential role of social factors on alcohol intake in open-air public settings. A total of 1475 participants (47.4% women), including 27.8% adolescents organized into 355 natural groups of friends, were interviewed while they were socializing at night in the streets of Palma (Spain). Breath alcohol concentration (BrAC), self-reported measures of alcohol use, and social variables were assessed. Men showed statistically higher scores in BrAC than women. However, adolescents' Alcohol Use Disorders Identification Test (AUDIT) scores were not statistically different by gender. Correlation between objective and self-reported measures was low. Interestingly, BrAC of drinkers was lower when some friends in the group were sober. Moreover, especially in young adults, variables related to the social environment were statistically significant factors to predict BrAC. In conclusion, we found a high prevalence of alcohol intake in young people in open-air public settings, low relationship of objective and self-reported measures, and social factors linked to alcohol use, although differences by age and gender must be considered.

Data mining techniques for drug use research.

Drug use motives are relevant to understand substance use amongst students. Data mining techniques present some advantages that can help to improve our understanding of drug use issue. The aim of this paper is to explore, through data mining techniques, the reasons why students use drugs. A random cluster sampling of schools was conducted in the island of Mallorca. Participants were 9300 students (52.9% girls) aged between 14 and 18 years old (M = 15.59, SD = 1.17). They answered an anonymous questionnaire about the frequency and type of drug used, as well as the motives. Five classifiers techniques are compared; all of them have much better performance (% of correct classifications) than the simplest classifier (more repeated category: drug use/never drug use) in all the compared drugs (alcohol, tobacco, cannabis, cocaine). Nevertheless, alcohol and tobacco have the lower percentage of correct classifications concerning the drug use motives, whereas these use motives have better classification performance when predicts cannabis and cocaine use. When we analyse the specific motives that better predicts the category classification (drug use/never drug use), the following reasons are highlighted in all of them: "pleasant activity" (most frequent among drug users), and "friends consume" and "addiction" (both of them most frequent among never drug users). These results relate to the social dimension of drug use and agree with the statement that environmental context influences adolescent's involvement in risk behaviours. Implications of these results are discussed.

Cuando falle la media, utilice un M-estimador / When the mean fails, use an M-estimator

En el campo de las adicciones en muchas ocasiones se tiene que trabajar con variables cuantitativas, siendo la media aritmética el índice de localización utilizado mayoritariamente. No obstante, el uso de este índice debería limitarse a aquellas situaciones en las que las distribuciones de las variables sean simétricas. El objetivo de este trabajo es ejemplificar la importancia de recurrir a estadísticos descriptivos adecuados para resumir variables cuantitativas, mediante el estudio de la cantidad de consumo de sustancias adictivas en la adolescencia. La muestra está formada por 9300 estudiantes con edades entre los 14 y los 18 años (47.1% chicos y 52.9% chicas) que contestaron de forma anónima un cuestionario sobre consumo de sustancias. Se describe la cantidad de consumo semanal de diferentes sustancias mediante índices de localización clásicos y pertenecientes al Análisis Exploratorio de Datos (EDA). Se puede observar cómo los resultados varían notablemente en función del estadístico elegido, siendo el M-estimador de Huber un índice con valores más "reales". La media aritmética no es un buen índice para acercarnos debidamente a la realidad del consumo de drogas cuando las distribuciones son asimétricas, siendo necesario utilizar índices resistentes, tal como, entre otros, el M-estimador de Huber (AU)

In the field of addictions on many occasions one has to work with quantitative variables, and the arithmetic mean is the most used location index. Nevertheless, the use of this index should be limited to those situations in which the distributions of the variables are symmetrical. The aim of this work is to exemplify the importance of recurring to adequate descriptive statistics in order to summarize quantitative variables, through the study of the quantity of consumption of addictive substances in adolescence. The sample is made up of 9300 students between 14 and 18 years (47.1% boys and 52.9% girls) who anonymously answered a questionnaire on consumption of substances. The quantity of weekly consumption of different substances is described using classical location indexes belonging to Exploratory Data Analysis (EDA). It can be seen how the results vary noticeably according to the statistics selected, with the Huber M-estimator as the index giving more "real" values. The arithmetic mean is not a good index in order to duly approach the reality of drug consumption when the distributions are asymmetrical, in which cases it becomes necessary to use resistant indexes such as, among others, Huber’s M-estimator (AU)

Quantification of the influence of friends and antisocial behaviour in adolescent consumption of cannabis using the ZINB model and data mining.

Cannabis is the most consumed illegal drug in Europe and its repercussions are more important when taken up at an early age. The aim of this study is to analyse and quantify the predictive value of different personal, family and environmental variables on the consumption of cannabis in adolescence. The sample is made up of 9284 adolescents (47.1% boys and 52.9% girls) with an average age of 15.59 years (SE=1.17). The ZINB model highlights, as factors that increase the number of joints consumed per week, consumption by the peer group, nights out during the week, gender, the production of forbidden behaviour and the use of other substances, whereas the risk factors for the consumption of cannabis are consumption by friends, ease of access, production of forbidden behaviour and the use of other substances. Association rules highlight the relationship between cannabis consumption, ease of access, production of forbidden behaviour and tobacco consumption. Finally, decision trees enable us to predict cannabis consumption as well as the number of joints an adolescent will consume per week based on the production of forbidden behaviour, consumption of other substances and number of friends who consume cannabis. The results of this work have practical implications concerning the prevention of cannabis consumption in an adolescent population.