Showing papers by "Tilburg University published in 2016"

Older Adults' Reasons for Using Technology while Aging in Place

Abstract: Background: Most older adults prefer to age in place, and supporting older adults to remain in their own homes and communities is also favored by policy makers. Technology can play a role in staying independent, active and healthy. However, the use of technology varies considerably among older adults. Previous research indicates that current models of technology acceptance are missing essential predictors specific to community-dwelling older adults. Furthermore, in situ research within the specific context of aging in place is scarce, while this type of research is needed to better understand how and why community-dwelling older adults are using technology. Objective: To explore which factors influence the level of use of various types of technology by older adults who are aging in place and to describe these factors in a comprehensive model. Methods: A qualitative explorative field study was set up, involving home visits to 53 community-dwelling older adults, aged 68-95, living in the Netherlands. Purposive sampling was used to include participants with different health statuses, living arrangements, and levels of technology experience. During each home visit: (1) background information on the participants' chronic conditions, major life events, frailty, cognitive functioning, subjective health, ownership and use of technology was gathered, and (2) a semistructured interview was conducted regarding reasons for the level of use of technology. The study was designed to include various types of technology that could support activities of daily living, personal health or safety, mobility, communication, physical activity, personal development, and leisure activities. Thematic analysis was employed to analyze interview transcripts. Results: The level of technology use in the context of aging in place is influenced by six major themes: challenges in the domain of independent living; behavioral options; personal thoughts on technology use; influence of the social network; influence of organizations, and the role of the physical environment. Conclusion: Older adults' perceptions and use of technology are embedded in their personal, social, and physical context. Awareness of these psychological and contextual factors is needed in order to facilitate aging in place through the use of technology. A conceptual model covering these factors is presented.

Thinking about U: Theorizing and testing U- and inverted U-shaped relationships in strategy research

Abstract: U- and inverted U-shaped relationships are increasingly explored in strategy research, with 11 percent of all articles published in Strategic Management Journal (SMJ) in 2008–2012 investigating such quadratic relationships. Moreover, a movement towards introducing moderation to quadratic relationships has emerged. By reviewing 110 articles published in SMJ from 1980 to 2012, we identify several critical issues in theorizing and testing of these relationships for which current practice falls short. These include insufficient causal argumentation, incorrect testing, mixing up two different types of moderation, and not realizing that the curve can flip completely. For these and other issues, a guideline is provided which, when followed, may bring clarity to theoretical motivation and rigor to empirical testing.

Robustness of Stepwise Latent Class Modeling With Continuous Distal Outcomes

Abstract: Recently, several bias-adjusted stepwise approaches to latent class modeling with continuous distal outcomes have been proposed in the literature and implemented in generally available software for latent class analysis. In this article, we investigate the robustness of these methods to violations of underlying model assumptions by means of a simulation study. Although each of the 4 investigated methods yields unbiased estimates of the class-specific means of distal outcomes when the underlying assumptions hold, 3 of the methods could fail to different degrees when assumptions are violated. Based on our study, we provide recommendations on which method to use under what circumstances. The differences between the various stepwise latent class approaches are illustrated by means of a real data application on outcomes related to recidivism for clusters of juvenile offenders.

On the Foundations of Corporate Social Responsibility

Abstract: A firm’s corporate social responsibility (CSR) practice and its country’s legal origin are strongly correlated. This relation is valid for various CSR ratings coming from several large datasets that comprise more than 23,000 large companies from 114 countries. We find that CSR is more strongly and consistently related to legal origins than to “doing good by doing well”-factors, and most firm and country characteristics such as ownership concentration, political institutions, and degree of globalization. In particular, companies from common law countries have lower level of CSR than companies from civil law countries, and Scandinavian civil law firms assume highest level of CSR. This link between legal origins and CSR seems to be explained by differences in ex post shareholder litigation risk as well as in stakeholder regulations and state involvement in the economy. Evidence from quasi-natural experiments such as scandals and natural disasters suggest that civil law firms are more responsive to CSR shocks than common law firms, and such responsiveness is not likely driven by declining market shares following the shock.

Degrees of Freedom in Planning, Running, Analyzing, and Reporting Psychological Studies: A Checklist to Avoid p-Hacking

Abstract: The designing, collecting, analyzing, and reporting of psychological studies entail many choices that are often arbitrary. The opportunistic use of these so-called researcher degrees of freedom aimed at obtaining statistically significant results is problematic because it enhances the chances of false positive results and may inflate effect size estimates. In this review article, we present an extensive list of 34 degrees of freedom that researchers have in formulating hypotheses, and in designing, running, analyzing, and reporting of psychological research. The list can be used in research methods education, and as a checklist to assess the quality of preregistrations and to determine the potential for bias due to (arbitrary) choices in unregistered studies.

Age and Gender Differences in Self-Esteem—A Cross-Cultural Window

Abstract: Research and theorizing on gender and age differences in self-esteem have played a prominent role in psychology over the past 20 years. However, virtually all empirical research has been undertaken in the United States or other Western industrialized countries, providing a narrow empirical base from which to draw conclusions and develop theory. To broaden the empirical base, the present research uses a large Internet sample (N = 985,937) to provide the first large-scale systematic cross-cultural examination of gender and age differences in self-esteem. Across 48 nations, and consistent with previous research, we found age-related increases in self-esteem from late adolescence to middle adulthood and significant gender gaps, with males consistently reporting higher self-esteem than females. Despite these broad cross-cultural similarities, the cultures differed significantly in the magnitude of gender, age, and Gender × Age effects on self-esteem. These differences were associated with cultural differences in socioeconomic, sociodemographic, gender-equality, and cultural value indicators. Discussion focuses on the theoretical implications of cross-cultural research on self-esteem. (PsycINFO Database Record

Mixture Models: Latent Profile and Latent Class Analysis

Abstract: Latent class analysis (LCA) and latent profile analysis (LPA) are techniques that aim to recover hidden groups from observed data. They are similar to clustering techniques but more flexible because they are based on an explicit model of the data, and allow you to account for the fact that the recovered groups are uncertain. LCA and LPA are useful when you want to reduce a large number of continuous (LPA) or categorical (LCA) variables to a few subgroups. They can also help experimenters in situations where the treatment effect is different for different people, but we do not know which people. This chapter explains how LPA and LCA work, what assumptions are behind the techniques, and how you can use R to apply them.

The prevalence of statistical reporting errors in psychology (1985-2013).

Abstract: This study documents reporting errors in a sample of over 250,000 p-values reported in eight major psychology journals from 1985 until 2013, using the new R package “statcheck.” statcheck retrieved null-hypothesis significance testing (NHST) results from over half of the articles from this period. In line with earlier research, we found that half of all published psychology papers that use NHST contained at least one p-value that was inconsistent with its test statistic and degrees of freedom. One in eight papers contained a grossly inconsistent p-value that may have affected the statistical conclusion. In contrast to earlier findings, we found that the average prevalence of inconsistent p-values has been stable over the years or has declined. The prevalence of gross inconsistencies was higher in p-values reported as significant than in p-values reported as nonsignificant. This could indicate a systematic bias in favor of significant results. Possible solutions for the high prevalence of reporting inconsistencies could be to encourage sharing data, to let co-authors check results in a so-called “co-pilot model,” and to use statcheck to flag possible inconsistencies in one’s own manuscript or during the review process.

Six principles of effectice global talent management

Abstract: To determine how leading companies in North America, Europe, and Asia develop and sustain strong talent pipelines, this research investigates talent management processes and practices in a sample of 37 multinational corporations, selected on the basis of their international scope, reputation, and long-term performance. In-depth case studies and a Web-based survey of human resources professionals identify various effective practices that can help companies attract, select, develop, and retain talent. However, the results suggest that competitive advantage comes not primarily from designing and implementing best practices but rather from the proper internal alignment of various elements of a company's talent management system, as well as their embeddedness in the value system of the firm, their links to business strategy, and their global coordination.

Accumulative job demands and support for strength use: Fine-tuning the job demands-resources model using conservation of resources theory.

Abstract: Absenteeism associated with accumulated job demands is a ubiquitous problem We build on prior research on the benefits of counteracting job demands with resources by focusing on a still untapped resource for buffering job demands-that of strengths use We test the idea that employees who are actively encouraged to utilize their personal strengths on the job are better positioned to cope with job demands Based on conservation of resources (COR) theory, we hypothesized that job demands can accumulate and together have an exacerbating effect on company registered absenteeism In addition, using job demands-resources theory, we hypothesized that perceived organizational support for strengths use can buffer the impact of separate and combined job demands (workload and emotional demands) on absenteeism Our sample consisted of 832 employees from 96 departments (response rate = 403%) of a Dutch mental health care organization Results of multilevel analyses indicated that high levels of workload strengthen the positive relationship between emotional demands and absenteeism and that support for strength use interacted with workload and emotional job demands in the predicted way Moreover, workload, emotional job demands, and strengths use interacted to predict absenteeism Strengths use support reduced the level of absenteeism of employees who experienced both high workload and high emotional demands We conclude that providing strengths use support to employees offers organizations a tool to reduce absenteeism, even when it is difficult to redesign job demands

The academic, economic and societal impacts of Open Access: an evidence-based review

Abstract: Ongoing debates surrounding Open Access to the scholarly literature are multifaceted and complicated by disparate and often polarised viewpoints from engaged stakeholders. At the current stage, Open Access has become such a global issue that it is critical for all involved in scholarly publishing, including policymakers, publishers, research funders, governments, learned societies, librarians, and academic communities, to be well-informed on the history, benefits, and pitfalls of Open Access. In spite of this, there is a general lack of consensus regarding the potential pros and cons of Open Access at multiple levels. This review aims to be a resource for current knowledge on the impacts of Open Access by synthesizing important research in three major areas: academic, economic and societal. While there is clearly much scope for additional research, several key trends are identified, including a broad citation advantage for researchers who publish openly, as well as additional benefits to the non-academic dissemination of their work. The economic impact of Open Access is less well-understood, although it is clear that access to the research literature is key for innovative enterprises, and a range of governmental and non-governmental services. Furthermore, Open Access has the potential to save both publishers and research funders considerable amounts of financial resources, and can provide some economic benefits to traditionally subscription-based journals. The societal impact of Open Access is strong, in particular for advancing citizen science initiatives, and leveling the playing field for researchers in developing countries. Open Access supersedes all potential alternative modes of access to the scholarly literature through enabling unrestricted re-use, and long-term stability independent of financial constraints of traditional publishers that impede knowledge sharing. However, Open Access has the potential to become unsustainable for research communities if high-cost options are allowed to continue to prevail in a widely unregulated scholarly publishing market. Open Access remains only one of the multiple challenges that the scholarly publishing system is currently facing. Yet, it provides one foundation for increasing engagement with researchers regarding ethical standards of publishing and the broader implications of 'Open Research'.

Brand Buzz in the Echoverse

Abstract: Social media sites have created a reverberating “echoverse” for brand communication, forming complex feedback loops (“echoes”) between the “universe” of corporate communications, news media, and user-generated social media. To understand these feedback loops, the authors process longitudinal, unstructured data using computational linguistics techniques and analyze them using econometric methods. By assembling one of the most comprehensive data sets in the brand communications literature with corporate communications, news stories, social media, and business outcomes, the authors document the echoverse (i.e., feedback loops between all of these sources). Furthermore, the echoverse has changed as online word of mouth has become prevalent. Over time, online word of mouth has fallen into a negativity spiral, with negative messages leading to greater volume, and firms are adjusting their communications strategies in response. The nature of brand communications has been transformed by online technology ...

Poverty and Aspirations Failure

Abstract: We develop a theoretical framework to study the psychology of poverty and ‘aspirations failure’, defined as the failure to aspire to one's own potential. In our framework, rich and the poor persons share the same preferences and same behavioural bias in setting aspirations. We show that poverty can exacerbate the effects of this behavioural bias leading to aspirations failure and hence, a behavioural poverty trap. Aspirations failure is a consequence of poverty, rather than a cause. We specify the conditions under which raising aspirations alone is sufficient to help escape from a poverty trap, even without relaxing material constraints.

Quality of life after hip fracture in the elderly: A systematic literature review

Abstract: BACKGROUND: With an increasing ageing population, hip fractures have become a major public health issue in the elderly. It is important to examine the health status (HS) and health-related quality of life (HRQOL) of the elderly faced with the epidemic of hip fractures. OBJECTIVE: To provide an overview of reported HS and HRQOL in elderly patients with a hip fracture. DESIGN: A systematic literature search was performed in Embase, Medline, Web of Science, Scopus, CINAHL, Cochrane, PsycINFO, Pubmed, and Google Scholar in July 2014. Studies which reported the HS or HRQOL based on standardised questionnaires in patients older than 65 years with a hip fracture were considered eligible for inclusion. RESULTS: After inspecting the 2725 potentially eligible studies, 49 fulfilled the inclusion criteria. All included studies were randomised controlled trials or prospective cohort studies. The methodological quality of the studies was moderate. Patients' functioning on the physical, social, and emotional domains were affected after a hip fracture. The HS and HRQOL of the majority of patients recovered in the first 6 months after fracture. However, their HS did not return to prefracture level. Mental state, prefracture functioning on physical and psychosocial domains, comorbidity, female gender, nutritional status, postoperative pain, length of hospital stay, and complications were factors associated with HS or HRQOL. Treatment with total hip arthroplasty or hemi-arthroplasty provided better HS than treatment with internal fixation with displaced femoral neck fractures. Supportive psychotherapy in "low-functioning" patients, (home) rehabilitation programmes and nutritional supplementation appeared to have beneficial effects on HS. CONCLUSIONS: Optimizing nutrition intake, (home) rehabilitation programmes, and the possibility for psychological counselling in patients with difficulties in the psychosocial dimensions would be recommended after hip fracture surgery. Besides HS questionnaires like EQ-5D and SF-36, adequate measurements like the WHOQOL-Bref or ICECAP-O are warranted in future studies regarding hip fracture surgery and postoperative treatment options.Copyright © 2016 Elsevier Ltd. All rights reserved. Language: en

Predicting Heart Failure With Preserved and Reduced Ejection Fraction The International Collaboration on Heart Failure Subtypes

Abstract: Background— Heart failure (HF) is a prevalent and deadly disease, and preventive strategies focused on at-risk individuals are needed. Current HF prediction models have not examined HF subtypes. We sought to develop and validate risk prediction models for HF with preserved and reduced ejection fraction (HFpEF, HFrEF). Methods and Results— Of 28,820 participants from 4 community-based cohorts, 982 developed incident HFpEF and 909 HFrEF during a median follow-up of 12 years. Three cohorts were combined, and a 2:1 random split was used for derivation and internal validation, with the fourth cohort as external validation. Models accounted for multiple competing risks (death, other HF subtype, and unclassified HF). The HFpEF-specific model included age, sex, systolic blood pressure, body mass index, antihypertensive treatment, and previous myocardial infarction; it had good discrimination in derivation (c-statistic 0.80; 95% confidence interval [CI], 0.78–0.82) and validation samples (internal: 0.79; 95% CI, 0.77–0.82 and external: 0.76; 95% CI: 0.71–0.80). The HFrEF-specific model additionally included smoking, left ventricular hypertrophy, left bundle branch block, and diabetes mellitus; it had good discrimination in derivation (c-statistic 0.82; 95% CI, 0.80–0.84) and validation samples (internal: 0.80; 95% CI, 0.78–0.83 and external: 0.76; 95% CI, 0.71–0.80). Age was more strongly associated with HFpEF, and male sex, left ventricular hypertrophy, bundle branch block, previous myocardial infarction, and smoking with HFrEF ( P value for each comparison ≤0.02). Conclusions— We describe and validate risk prediction models for HF subtypes and show good discrimination in a large sample. Some risk factors differed between HFpEF and HFrEF, supporting the notion of pathogenetic differences among HF subtypes.

The Importance of Trust for Investment: Evidence from Venture Capital

Abstract: We examine the effect of trust on financial investment decisions in a micro-economic environment where trust is exogenous. Using hand-collected data on European venture capital, we show that the Eurobarometer measure of trust among nations significantly affects investment decisions. This holds even after controlling for investor and company fixed effects, geographic distance, information and transaction costs. We then consider the relationship between trust and performance, evaluating two competing hypotheses: one based on the notion that higher trust benefits investment performance, the other based on the notion that lack of trust constitutes a hurdle to investments. We find evidence of a negative relationship between trust and exit performance, especially for IPOs. We further show that more sophisticated investors are more likely to make low trust investments, and that by doing so they achieve superior performance. Based on this and some additional evidence we conclude that lack of trust is a hurdle to making venture capital investments, but that investors who overcome this hurdle tend to do well.

Critical Data Studies: A Dialog on Data and Space

Abstract: Questions of data and algorithmic analysis saturated the conference at which Dalton and Thatcher first called for a Critical Data Studies (Dalton and Thatcher, 2014a). Soon thereafter, Taylor published a response to their original call (Dalton and Thatcher, 2014b) that focused on the spatial nature of data and the need to critically contextualize it (Taylor, 2015a). This was one of multiple beginnings of Critical Data Studies, as it will always be three words cobbled together imperfectly signifying diverse sets of work around data’s recursive relationship to society (c.f. Graham 2014; Kitchin 2014, and elsewhere). We highlight that moment not to claim the concept, but to contextualize the focus of this co-interview. When Taylor published their response to Dalton and Thatcher, she focused on the specifically spatial nature of much data, not only in the content of said data, but also in the need to contextualize from where it originates and is put to use. Data varies across space in a variety of ways: from those included or excluded to those who access said data for analysis, manipulation and (re)presentation.Critical Data Studies calls attention to subject formation within these data regimes, for a critical examination of where the interpellation of the individual emerges in algorithmic culture (Striphas, 2015) and, through that, where the cracks and seams, the spaces for resistance and alternatives, might be found. When you append “critical” to a field of study, you run the risk of both offending other researchers, who rightly point out that all research is broadly critical and of bifurcating those who use critical theory from those who engage in rigorous empirical research. Kate Crawford recently observed that the meaning of Critical Data Studies is as political as the data it engages (Crawford, 2015). To extend that, it must remain contestable in order to contest the creation, commodification, analysis, and application of data. Ultimately, Critical Data Studies must make space for the recursive dialogue between the deeply theoretical and the robustly empiric and, in so doing, avoid the hubris of pseudopositivism and technological determinism, in favor of the nuanced and contingent.This is a dialogue between Dalton, Thatcher, and Taylor on the spatial nature of data with respect to Critical Data Studies. It highlights the historical variability of the processes of data production and accumulation and how this, in turn, has resulted in the uneven development of data. We ask both what is missing and what must be brought to the analysis of data in order to respond to the existence of particular dataspheres governed by the kinds of technology available in different locations. In form, Dalton and Thatcher ask the first question and Taylor responds before asking the second, alternating from there. As such, this dialog has many entry and exit points and is not meant as a definitive statement of what Critical Data Studies is or who can speak for it. Rather, we choose to live in the unresolved tensions between researcher and subject, technology and society, space and time (Haraway, 1991), and we encourage our readers to do the same.

Sustainable employability--definition, conceptualization, and implications: A perspective based on the capability approach.

Abstract: Objectives The aim of this paper is to propose a new model of sustainable employability based on the capability approach, encompassing the complexity of contemporary work, and placing particular emphasis on work-related values. Methods Having evaluated existing conceptual models of work, health, and employability, we concluded that prevailing models lack an emphasis on important work-related values. Amartya Sen’s capability approach (CA) provides a framework that incorporates a focus on values and reflects the complexity of sustainable employability. Results We developed a model of sustainable employability based on the CA. This model can be used as starting point for developing an assessment tool to investigate sustainable employability. Conclusions A fundamental premise of the CA is that work should create value for the organization as well as for the worker. This approach challenges researchers, policy-makers, and practitioners to investigate what people find important and valuable – what they would like to achieve in a given (work) context – and moreover to ascertain whether people are able and enabled to do so. According to this approach, it is not only the individual who is responsible for achieving this; the work context is also important. Rather than merely describing relationships between variables, as existing descriptive models often do, the CA depicts a valuable goal: a set of capabilities that constitute valuable work. Moreover, the CA fits well with recent conceptions of health and modern insights into work, in which the individual works towards his or her own goals that s/he has to achieve within the broader goals of the organization.

Bank size, capital, and systemic risk: Some international evidence

Abstract: This paper studies the significant variation in the cross-section of standalone and systemic risk of large banks during the recent financial crisis to identify bank specific factors that determine risk. We find that systemic risk grows with bank size and is inversely related to bank capital, and this effect exists above and beyond the effect of bank size and capital on standalone bank risk. Our results contribute to the ongoing debate on the merits of imposing systemic risk-based capital requirements on banks.

Genome-wide DNA methylation levels and altered cortisol stress reactivity following childhood trauma in humans

Abstract: DNA methylation likely plays a role in the regulation of human stress reactivity. Here we show that in a genome-wide analysis of blood DNA methylation in 85 healthy individuals, a locus in the Kit ligand gene (KITLG; cg27512205) showed the strongest association with cortisol stress reactivity (P=5.8 × 10(-6)). Replication was obtained in two independent samples using either blood (N=45, P=0.001) or buccal cells (N=255, P=0.004). KITLG methylation strongly mediates the relationship between childhood trauma and cortisol stress reactivity in the discovery sample (32% mediation). Its genomic location, a CpG island shore within an H3K27ac enhancer mark, and the correlation between methylation in the blood and prefrontal cortex provide further evidence that KITLG methylation is functionally relevant for the programming of stress reactivity in the human brain. Our results extend preclinical evidence for epigenetic regulation of stress reactivity to humans and provide leads to enhance our understanding of the neurobiological pathways underlying stress vulnerability.

Demands or resources? The relationship between HR practices, employee engagement and emotional exhaustion within a hybrid model of employment relations

Abstract: This article explores the ways in which employees may experience and respond to tensions inherent in the mix of potentially confl icting human resource (HR) practices that compose hybrid models of employment relations. By drawing on the job demands–resources (JD-R) literature and viewing HR practices as “demands” and “resources,” we explore the impact of performance manage-ment and employee voice practices on employee well-being, as exemplifi ed by engagement and emotional exhaustion, in a large public-sector organization in Ireland. Our fi ndings suggest that employee voice mechanisms may act as a resource in both enhancing engagement and in counterbalancing the demands presented by a performance management system, thus reducing the deleteri-ous effects of emotional exhaustion. Our study extends understanding of hybrid models of human resource management (HRM) and of the ways in which employ-ees manage the contradictory signals that such models may send in terms of performance expectations.

Citizen Science for public health

Abstract: Community engagement in public health policy is easier said than done. One reason is that public health policy is produced in a complex process resulting in policies that may appear not to link up to citizen perspectives. We therefore address the central question as to whether citizen engagement in knowledge production could enable inclusive health policy making. Building on non-health work fields, we describe different types of citizen engagement in scientific research, or 'Citizen Science'. We describe the challenges that Citizen Science poses for public health, and how these could be addressed. Despite these challenges, we expect that Citizen Science or similar approaches such as participatory action research and 'popular epidemiology' may yield better knowledge, empowered communities, and improved community health. We provide a draft framework to enable evaluation of Citizen Science in practice, consisting of a descriptive typology of different kinds of Citizen Science and a causal framework that shows how Citizen Science in public health might benefit both the knowledge produced as well as the 'Citizen Scientists' as active participants.

Genome-wide association study of lifetime cannabis use based on a large meta-analytic sample of 32 330 subjects from the International Cannabis Consortium

Abstract: Cannabis is the most widely produced and consumed illicit psychoactive substance worldwide. Occasional cannabis use can progress to frequent use, abuse and dependence with all known adverse physical, psychological and social consequences. Individual differences in cannabis initiation are heritable (40-48%). The International Cannabis Consortium was established with the aim to identify genetic risk variants of cannabis use. We conducted a meta-analysis of genome-wide association data of 13 cohorts (N=32 330) and four replication samples (N=5627). In addition, we performed a gene-based test of association, estimated single-nucleotide polymorphism (SNP)-based heritability and explored the genetic correlation between lifetime cannabis use and cigarette use using LD score regression. No individual SNPs reached genome-wide significance. Nonetheless, gene-based tests identified four genes significantly associated with lifetime cannabis use: NCAM1, CADM2, SCOC and KCNT2. Previous studies reported associations of NCAM1 with cigarette smoking and other substance use, and those of CADM2 with body mass index, processing speed and autism disorders, which are phenotypes previously reported to be associated with cannabis use. Furthermore, we showed that, combined across the genome, all common SNPs explained 13-20% (P<0.001) of the liability of lifetime cannabis use. Finally, there was a strong genetic correlation (rg=0.83; P=1.85 × 10(-8)) between lifetime cannabis use and lifetime cigarette smoking implying that the SNP effect sizes of the two traits are highly correlated. This is the largest meta-analysis of cannabis GWA studies to date, revealing important new insights into the genetic pathways of lifetime cannabis use. Future functional studies should explore the impact of the identified genes on the biological mechanisms of cannabis use.