Abstract
Andresen discussed vulnerability as an analytical category in childhood studies and reflected on how the concept could be linked to structural, systemic and individual factors. This article starts by asking what vulnerability is and by examining its relation to agency. It suggests conceptualising agency as a dynamic experience rather than as a static condition, based on the exploration of narrative interviews with adolescent drug users (aged 16–21) in treatment. These narratives retrospectively follow the trajectories of attention-deficit/hyperactivity diagnosis and subsequent drug treatment that later developed into habitual drug use in adolescence. Our data show how drug use can shape vulnerable conditions yet also create new connections with given environments, becoming a source of agency for child and adolescent drug users. Along with the empirical findings, we reflect on the analytical potentials of Actor-Network-Theory.
Introduction
This article is based on the observation that, in childhood studies, agency and vulnerability are often positioned as binary concepts (Andresen et al., 2015). To illustrate the tension between the two concepts, this article argues for a relational perspective on agency and vulnerability. While agency can be seen as the capacity and freedom to act as well as participate in decision-making, vulnerability entails dependence on others and bodily dispositions that are socially conditioned. These conditions can also be understood as ‘dispositional’ and ‘occurrent’ modes of vulnerability (Mackenzie et al., 2014: 8). Children and adolescents are particularly vulnerable due to their position in society and their dependence on caregivers. In this respect, ‘dominators may care deeply for those they dominate; they may believe that domination is necessary for the eventual happiness and perhaps even the survival of the dominated’ (Ruddick, 1995: 213). This hierarchical relationship is evident in medical and drug interventions into children’s lives; parents make choices about children’s treatment, operating in a framework within which schools and teachers expect students to conform with the rules and expectations of educational institutions. We argue that attention-deficit/hyperactivity disorder (ADHD) diagnosis in children and subsequent drug treatment is a useful example. The article uses qualitative data that come from an Actor-Network-Theory (ANT)-based dissertation project.
While ADHD in children and adolescents remains a highly polarised topic on an interdisciplinary level, research should draw more attention to the vulnerability of children with this diagnosis and their agentic role as consumers of ADHD drugs. This article is based on adolescents’ retrospective narratives of their childhood experiences and provides insights into how experiences of vulnerability were shaped and developed as a result of diagnosis and drug use. In this respect, the question of how the prescription of ADHD drugs goes against the welfare-state notion of child well-being and minimisation of risk (Andresen, 2014) presents the challenge of dualistic schemes. We also ask whether the use of drugs leads to increased levels of autonomy and agency or, on the contrary, to children’s dependency and decreased ability to express agency through decision-making. It is not the purpose of this article to claim that early prescription of ADHD drugs inevitably leads to later non-medical 1 drug use, nor do we wish to demonise drugs or drug users. The aim is to trace vulnerability within the context of ADHD drug treatment transitioning into active pursuit of drug careers in adolescence, as part of children’s development and socialisation that can also be understood as their agentic position. The article suggests that ADHD acts as a phenomenon that illustrates tensions between children’s agency and vulnerability. This has a special relevance to educational settings placing pressure on both children and their parents, affecting student–teacher relations as well as parent–teacher communication. Within this context, the medical perspective on childhood enters the pedagogical setting.
ADHD, drug use, and their importance in childhood and adolescence
An 1844 children’s story titled ‘Fidgety Phil’ ( ‘Zappelphilipp’) by Heinrich Hoffman is the most prominent allegory used for discussions of hyperactive children in German literature (Lange et al., 2010). It starts with a stanza where Philip is challenged to perform according to his father’s wishes: Let me see if Philip can Be a little gentleman; Let me see if he is able To sit still for once at table.
In the story, Philip pulls the tablecloth and falls down in a pile of dishes, leaving ‘Papa’ and ‘Mama’ sad and frustrated. The depiction of disobedience and hyperactivity in this stanza resonates with the overall view of ADHD as a childhood pathology. The modern definition of ADHD is very similar to that suggested by Kramer and Pollnow (1932), the two German physicians who first viewed hyperkinetic activity – excessive motor activity and inattention – as a disorder. Among the initial studies on ADHD, Conrad’s (1975) work on hyperactive children was the first sociological study to address this medicalisation of deviance, namely, hyperactivity. The overwhelming majority of ADHD studies view the diagnosis as primarily indicating a lack of individual capacities, cognitive functions and complex brain development, resulting in behavioural characteristics that require medical intervention. Some recent reports show continuous increases in the number of ADHD diagnoses and also the amount of prescribed methylphenidate (Ritalin) for children in Germany (Conrad and Bergey, 2014). However, an overview of existing research points to a lack of ADHD research and follow-up longitudinal studies in Germany, especially among diagnosed youth transitioning into adulthood (Bachmann et al., 2017). Although the German Society for Child and Adolescent Psychiatry and Psychotherapy advises multi-dimensional intervention for ADHD treatment (Döpfner et al., 2000), medicalisation of children exhibiting hyperactivity is evident in statistical reports showing dramatic increases in the number of children diagnosed with ADHD, rising from 5000 in 1995 to 380,000 in 2008 and reaching 600,000 in 2012 (Deutsche Gesellschaft für Soziale Psychiatrie, 2013). Medical treatment of ADHD becomes hazardous when psychological aspects of children’s lives as well as their potential for habitual drug use are not evaluated before prescribing the medications or when comorbidities are not taken into account (Klein et al., 2015; Steinhausen, 2006). This is especially significant in light of the ethical debates surrounding the validity of ADHD on a global scale (Singh et al., 2013). Thus, questions of biased evaluations and medical interventions have yet to be addressed alongside a variety of interrelated social and material forces.
Interdisciplinary studies of early onset of drug use have shown that it is associated with precarious living conditions (O’Donnell et al., 1995), peer victimisation (Sullivan et al., 2006), neuro-physiological and cultural factors (Room, 2005; Steinberg, 2005), lower socio-economic status (SES) and abusive family relationships (Steinglass, 1981; Vakalahi, 2002), academic underachievement (Fothergill and Ensminger, 2006; Galambos and Silbereisen, 1987) and poor mental health (De Micheli et al., 2016; Newcomb and Bentler, 1988). In most studies, children’s vulnerability to drug use has been presented as a-priori, while gender, age, SES are posited as social explanations for this predisposition. These approaches usually discuss vulnerability in two ways: as a given pre-condition for drug use, and as an effect of drug use itself. This linear understanding of the cause-and-effect nexus could be re-addressed to consider children’s vulnerability in relation to agency.
The article’s aim is thus to conceptualise vulnerability as a dynamic condition and link it to agency without taking a dichotomising approach. Such an analysis requires a careful consideration of not only structural and systemic dimensions but also material relations, those that emerge through intertwined participation of both human and non-human actors. Drugs as active agents (although not in exactly the same manner as human agency, as will be discussed later) can reveal vulnerability as a complex experience rather than a result of a linear cause-and-effect relations. We will discuss how drugs can be understood as a source of both agency and vulnerability. In what follows, the article proposes ANT as a valuable framework for childhood studies, especially in relation to children’s agency (see also Prout, 2005, 2011). The sections on methods and findings will provide information on the empirical data and its systematic analysis in relation to structural, systemic, individual and material relations that shape experiences of vulnerability. The findings consider the role of drugs for children with ADHD diagnosis and follow their transition to drug careers in adolescence.
The potential of ANT for childhood studies
The empirical philosopher Latour, who is credited with creating and developing ANT, has challenged agency as a result of anthropocentric knowledge production. His invitation is to attribute agency to both human and non-human actors (e.g. Latour, 2005), thereby shifting focus from social explanations to material relations. If traditionally agency is ascribed to human actors and intentionality, then in ANT, this school of thinking is challenged by asking ‘what is action and how does it relate to other entities?’ instead of the usual ‘who acts?’ (Gomart and Hennion, 1999: 221). It seeks to describe the composition of heterogeneous elements in networks that produce emerging action from an indeterminate source, thereby shifting the focus from human actors ‘doing something’ to consider also mediators that provide actors with their sources of action (Gomart and Hennion, 1999: 225). This discussion emerges in light of new materialist ontologies that call for adding more sources of actantialities (Latour, 1999a: 18) onto already entrenched structural, systemic and social interpretations. This means that actants – a term used to emphasise the action rather than the actor – can also be understood as non-human entities relating to others and forming final agency together (Latour, 2014). The aim here is thus to discuss the possibilities of reconceptualising agency in a way that would encompass all sources that mediate actions and, therefore, vulnerability. We suggest that vulnerability is shaped, sustained and transformed through the continuous motion of constituting entities and actor–networks. ANT can potentially enunciate the ‘sometimes competing and sometimes conflicting orderings’ of childhood (Prout, 2011: 9). This is also evident when considering agency and vulnerability in a dynamic relation. Thus, vulnerability must be redefined as contexts change. This leads to the argument that continued non-medical use of ADHD drugs into adolescence has been reinforced by a range of human and non-human actors that have sustained vulnerability. These include doctors, institutional support of prescription drugs for school children, teachers, parental permission, drug effects, familial intra-relationships, social and physical environments, availability of means and social networks for acquiring drugs, as well as bodily capacities and corporeal agency in relation to various drug effects.
Acknowledging the agency of drugs as actors that shape the experiences of use is an important step towards decentralising human agency. In this way, one can recognise most of the participating forces throughout the child’s development into adolescence without holding the child in a binary condition of either vulnerability or agency. Some critics of ANT believe that decentralising agency in humans flattens the power imbalances and hierarchies in society (Bloor, 1999; Collins and Yearley, 1992), which in this case is not a desirable outcome when discussing childhood vulnerability. On the contrary, ANT potentially offers a perspective where contexts can be perceived as fluid and dynamic rather than fixed by macro-structures. Whereas macro-structural perspectives reinforce the vulnerability of children as a pre-determined condition, ANT examines the immediate contexts and thereby acknowledges the materiality in children’s daily lives. To avoid the subject/object dyad that would place emphasis either on a child or on a drug, we see agency as a set of events and actors that both mediate the action and exist in a network. It is thus a result of heterogeneous relations, irreducible to a single act or an entity (Latour, 2014), that is, agency is an emergent capacity. The analysis of empirical data shows how agency and vulnerability co-constitute each other and are not mutually exclusive concepts. We seek to evaluate the potential of ANT to reveal the complex relations between agency and vulnerability in this example.
Retrospective narratives of adolescent drug users: methodology of the study
This article analyses partial empirical data from an independent doctoral project of the first author examining recovery experiences of adolescents in Azerbaijan and Germany. The overall project comprises 20 narrative interviews with youths who had consumed alcohol and other drugs such as cannabis and synthetic cannabinoids, amphetamines, MDMA (also known as Ecstasy) and ADHD drugs (Ritalin, Medikinet, etc.), among others. All participants had been admitted to forced treatment via court order and were enrolled either in organisations commissioned to provide residential treatment or at therapeutic youth centres for those who had completed inpatient detoxification. At the time of the interviews, which were conducted between June 2015 and February 2017, most research participants were either abstinent, having ceased consumption (e.g. living at home while attending special therapeutic schools) or under supervised treatment. Because the interviews were conducted specifically to elicit narratives on recovery and drug careers, childhood experiences preceding drug use were included as background information.
While early onset of illicit and polydrug use was found among all participants, only five (all male) related their drug career to initial ADHD diagnosis and subsequent Ritalin prescription in mid-childhood, indicating earlier introduction to drug use in comparison with the other 15 cases. These five cases serve as an illustration of how agency and vulnerability interact as children make the transition from prescribed drug taking towards non-medical use of drugs – and provide the basis for the article. The interviews were conducted in two German cities with adolescents aged 16–21 and took place in therapeutic schools or residential communities during the 8-month-long fieldwork undertaken by the researcher. Participants were asked to read and sign informed consent forms and were informed on the purpose and duration of the interviews. Confidentiality and anonymity were explained orally, and verbal consent was recorded at the beginning of the interviews. The transcribed interviews were anonymised, and all names used in the analysis are pseudonyms. The participants were given the researcher’s contact details for any follow-up questions or to withdraw participation even after the data collection was completed. The interviews were conducted as part of a fieldwork that allowed participants to communicate their post-interview thoughts and feelings afterwards. Meanwhile, additional professional support for participants was available through the institution.
A flat and descriptive analysis technique in line with ANT was used to follow the overall storyline. This method, as opposed to traditional biographical analysis methods, does not treat the transcripts hierarchically in thematic or categorical ways, but rather allows the visibility of all actants and mediators that participate in the formation of an experience, while simultaneously helping to avoid dualistic schemes such as agency/vulnerability or subject/object (Törrönen and Tigerstedt, 2018).
Findings
To begin with, it is necessary to contextualise vulnerability. In this article, we acknowledge that vulnerability in childhood is shaped by a range of heterogeneous actors and that the progression from ADHD to non-medical drug use is a shared experience among all five participants. The data are used to describe specific contexts and relations through which vulnerability emerges. We do not wish to interpret the ways children perceive vulnerability, but rather seek to establish the relations that produce a vulnerable condition. As in the narratives, agency is debated indirectly and retrospectively when research participants emphasised the action they could have taken, had they had the opportunity to interfere with the prescription of drugs early in their childhood.
The analysis begins by depicting how structural, systematic and individual dimensions of vulnerability need to be considered together with material relations. First, we seek to establish whether institutional facilitation of ADHD diagnosis and subsequent drug treatment creates vulnerability on a structural level. The health care system facilitates the diagnosis of ADHD and drug treatment, followed by a network of teachers, doctors and parents enabling its implementation on behalf of the child. Second, the systemic level of vulnerability is enacted through the behavioural norms in accordance with school rules. The data show that the children were prescribed ADHD drugs after teachers had complained to parent(s) or to school social workers about the child’s non-conforming behaviour. Furthermore, teachers’ complaints are the main reasons recalled by adolescents that led to diagnosis and subsequent prescription. In these cases, manifestation of the diagnosis is bound primarily to the school setting, with parents and social workers, as well as prescribing doctors, mediating the enactment of the ADHD diagnosis. Third is the individual level, which can be analysed through ways the children’s role becomes evident in these stories when they start engaging with the effects of the drug. Finally, attending to material aspects and immediate contexts help to recognise the heterogeneity of children’s experiences by pointing out the role of drugs, their effects and the relations arising through drug use.
Latour (1999b) argues that ‘causality follows the events and does not precede them’ (p. 152), suggesting that effects need to be rescued from the a-priori assumptions of the cause and explored first. In her important contribution to the use of ANT in social drug research, Gomart (2002) investigated different treatment results of methadone-maintenance programmes in the United States and France. Gomart’s analysis found that duration, expectations and additional support systems change the ‘effects’ of what is essentially the same methadone. Following Gomart’s ideas, we look at different ‘effects’ of Ritalin through the ways children use it. The effects of Ritalin are limited not only to medical and euphoric effects as the analysis will show. Participants also reported being mis-prescribed Ritalin, which produced unexpected and unintended effects. Maier and Schaub (2015) found that people who do not suffer from ADHD display higher impulsivity when taking such prescription drugs. For some children, ADHD drugs were not appropriate prescriptions and resulted in effects opposite to those considered desirable. Some of the children were able to identify such effects and stopped taking Ritalin but, mostly, a transition to non-medical use occurred when Ritalin did not work as intended.
Given that all study participants eventually progressed on to illicit drug use, the vulnerabilities associated in this subsequent phase are multi-dimensional, including street violence, exposure to police, illicit ways of financing drug careers, homelessness, physical injuries, social isolation, quitting school and deteriorating relationships at home and with friends. A set of questions thus arises: What is the child’s role in their own vulnerability? Does the child’s agency cause vulnerability but also diminish it? The article argues that vulnerability is a dynamic experience, with agency mediating it. The experience of vulnerability consists of actor–networks of heterogeneous entities (human and non-human) that continuously change their positions depending on the relations they exist in. Hence, the analysis focuses on how two phases of vulnerability are informed by the motion of these actor–networks: the transition from prescribed drug taking towards non-medical use of ADHD drugs and the mediating role of drugs in these transitions.
Transitions
Among their manifold effects, drugs require active participation to sustain the use and needs of the user in the long term. Children who have progressed onto non-medical use of prescription drugs usually conceal this habit from their caregivers and teachers at school. Further drug use involves greater participation and decision-making on the part of the child. Such agency requires specific actions, such as ensuring adequate supply, a safe space to enjoy use and a preferred social environment. The new activities and associations made possible by ADHD drug use can have both enabling and restricting effects on the lives of children and adolescents. These changes engender a different experience of vulnerability, where the previous actors – teachers, doctors, parents, ADHD drugs – do not occupy the same territory and roles. In other words, their actantiality is affected by newer actors entering the context and affecting the ways in which entities relate to each other. That said, a condition which previously constituted vulnerability can become liberating and vice versa. The quote below describes such a transition as 18-year-old Peter reflects on his childhood: With me it was more like it helped me at school, for example, to understand the lessons. When I took these tablets, I used to lead the entire class alone, I was just completely acing it. But, on the other hand, I also couldn’t talk to my friends anymore, I just sat there all the time and sweated, and I couldn’t eat anything, which is normal with amphetamines. Yeah, I kinda became completely introverted.
This shows how agency led to conformity with certain social norms and engendered newer vulnerabilities. Ritalin’s effect accentuated Peter’s intellectual capabilities, allowing him to ‘ace it’ within the context of school rules and expected student behaviour. The drug treatment, however, also added to Peter’s social isolation, depriving him of the usual, pleasant activities of eating or spending time with friends. Later, Peter started using the ADHD drugs to reverse these effects as he battled mental health complications. He skilfully navigated through his preferences and the possible effects of various drugs, translating his needs, experiences and knowledge into a recreational activity. Speaking of the effects of ADHD drugs, Peter added: I cannot say that I’m using it [Ritalin] as a stimulant, of course I’m abusing it too, but I just do not have a craving, like addiction. So, I’ve never said I need it right now, um, like I need to be on it. I just always want to feel bright and have that warm feeling in me, that … that displaces everything else.
Agency, thus, becomes an inherent part of the vulnerable condition. But starting to use (other) drugs and for different purposes, in part, transforms vulnerability into a more controlled condition. Therefore, vulnerability and agency remain in continuous relation, because by continuing to consume drugs (in addition to ADHD drugs), children experience other difficulties such as dropping out of school, worsened relationships at home, and physical and mental health deterioration. Drugs help to displace the previous structure of actor–networks that were present at the emergence of ADHD; at the same time, with them the child becomes agentic by exhibiting drug use preferences or partaking in the social habits that include using drugs.
The drugs shape children’s experiences by allowing them to experience feelings outside of their usual bodily capacities that can eventually lead to loss of control and agency on a certain level. The children have progressed onto more dedicated and habitual drug use partially because of discovering intoxication at very early ages: At the age of 11, I noticed that this is intoxicating. That feeling of euphoria, I mean. Ritalin is a drug! It really is. […] Its effects remind you a lot of Ecstasy or Speed. It is a drug, Ritalin. Only no one knows that. (Carsten, aged 17)
The participant describes the ways early exposure to Ritalin brought him to a world of other drugs through the discovery of intoxication and euphoric feelings. This creates a specific context where vulnerability is presented through the unintentional discovery of pleasure. Once the child realised the pleasurable potential of the drug, agency is enacted via further drug use by choice. This is not to imply that all ADHD drugs lead to further drug use. However, it does demonstrate that for some children and adolescents, the medications play a prominent role in realising the pleasurable or helpful effects of drugs in their lives. The euphoric feelings induced by drug use may have a variety of functions, helping children to manage other aspects of their lives such as difficult familial interrelationships, poverty, social anxiety or mental health issues, and academic underachievement. In a way, the children need to exert agency to aid their social, material and sometimes also bodily requirements. This agency – partially emergent from the inter-relation of a body and the drug – can also involve behaviours which simultaneously enact vulnerability. In this sense, early awakening to the world of intoxication is not something related to children’s individual capacities alone, but also to how the context is created through the participation of a variety of heterogeneous actors. Through this dynamism, the newly discovered intoxicating potential of Ritalin changes too, as it entails new associations. One could argue that there is no simple cause-and-effect relation, but an experience of vulnerability intertwined with agency in which both co-exist simultaneously. Involving drugs in one’s life, in consideration of the above, often changes the conditions that could otherwise be viewed as vulnerability and inactivity. Ritalin and other ADHD medications mark the emergence of vulnerability and its transition into agency as the children who have been introduced to the medication by systemic forces learn to utilise it in their favour.
Drugs as mediators of agency
In line with the previous argument that agency is an emergent capacity, we seek to stress the role of a drug as an actant that provides children the source for their agency. In this sense, Sayes (2014) invites us to think of the agency of non-human bodies (e.g. drugs) as mediators, while Bloor (1999) suggests that even though objects cannot possess the same level of agency as humans, they may nonetheless display a rather limited ‘causal agency’ (p. 91). In contrast to the overwhelming representation of drugs as evil and users as victims of their power, Gomart and Hennion (1999) analyse relations between the user and drug effects as ‘dis-possession’ (p. 221) of self. In their analysis, they highlight what other critical drug scholars also call ‘controlled loss of control’ (Measham, 2004: 343), arguing that drugs act as a means of allowing oneself to dis-possess full control over the body and actions, in order to enable certain bodily and psychological effects not otherwise experienced.
Latour (1996) makes the distinction by writing that ‘an actor in ANT is a semiotic definition – an actant – […] is something that acts or to which activity is granted by others’ (p. 373; emphases added). In this sense, the prescription drug Ritalin is viewed as a mediator that enables actions, and not a full actor on its own (Gomart, 2002). Thus, drugs are the mediators that provide the agency with its source. It is through the drugs that children can experience greater vulnerability and it is the drugs too that mediate children’s agency. The underlying idea here is that children do not have as much of an agentic role to play in the first context in which drugs are prescribed to them via a collaboration of adults (teacher, social worker, doctor, parents) compared to later stages of their drug careers, when adolescents have a more engaged role in their own drug use. This happens when prescription drug use transitions into non-medical use, requiring a user to actively seek the certain feeling, the drug, its supply, and social company.
Latour writes that ‘the whole is always smaller than its parts’ (Latour et al., 2012: 591). On one hand, one can trace the explanations adolescents give themselves without involving structural, systemic or institutional actors, but rather reflecting on how a child reacts on the level of personal, psychological and bodily capacities, thereby defining their agency (human) and that of drugs (non-human) in their lives. On the other hand, we can see that children’s well-being is defined by those who decide what is in the best interests of the child, that is, the macro-structural actors discussed above. This next case helps to clarify these ideas.
At the age of 9, Sergei was prescribed his first Ritalin, which he quickly discovered did not work as intended, making him even more active and ‘annoying’ to everyone. He then, in agreement with his mother, stopped taking the drug, evaluating it as harmful: I have been prescribed Ritalin before, because, they used to say I had ADHD, but I don’t have ADHD, actually, and it didn’t work like it should somehow work, when you have ADHD, but it worked just like amphetamines. I was like really, really active and used to, I […] I used to annoy everyone in the morning in the train. I was somewhere between 9 and 11 years old and it was like […] a child on drugs, basically. (Sergei, aged 21)
The quote above exemplifies ADHD drugs being prescribed to the ‘wrong’ children. Having experienced the unintended effects of it himself, Sergei sees his later drug career as a result of this mistreatment. When received by ADHD patients, the properties of the drug exert effects that children cannot control. If children’s vulnerability results from the lack of participation in the initial stages of ADHD diagnosis and treatment, later they become more agentic by changing the meaning of ADHD drugs for themselves. This suggests that children, and later adolescents, establish new connections and relate to other entities in different ways as they start and continue non-medical drug use.
Discussion
The study presented two main results that focused on the transition from ADHD drug treatment to non-medical drug use and highlighted the mediating role of drugs in children’s capacity to act. ADHD diagnoses and subsequent drug treatment were understood as a phenomenon defined as an entanglement of human and non-human bodies (Barad, 2007). Based on a relational approach, we have shown how the relations between agency and vulnerability in childhood can be considered within specific contexts, without attending to binary definitions of the two concepts. ANT assists with this, demonstrating its usefulness to childhood studies.
We have specifically focused on avoiding antithetic relations between vulnerability and agency, by casting them as dynamic experiences. Through analysing non-medical drug use as a response of adolescents to ADHD drug treatment in childhood, the article has traced agency and vulnerability as context-specific experiences rather than given conditions. While institutions, doctors and parents decided to treat children’s ADHD diagnoses with medications, later the children and adolescents took an agentic stance by transforming their experiences with the drugs. Focusing instead on the relations and immediate contexts of how children interacted with both prescription and other drugs complements the macro-structural thinking. This brings us to the conclusion that all actors, human or non-human, individual or collective, need to be duly recognised regardless of their ontological status. The potential of ANT offered a heterogeneous and dynamic understanding, rather than the stable and given understandings of agency and vulnerability.
Footnotes
Acknowledgements
The authors would like to thank Gill Main and the anonymous reviewers for their helpful comments.
Funding
The authors received no financial support for the research, authorship and/or publication of this article.
