A structured review of reasons for ecstasy use and related behaviours: pointers for future research

Although evidence that ecstasy use may be damaging to health accumulates [1, 2], its prevalence persists [3, 4]. Theory-based behavioural interventions have successfully generated behaviour change in other areas [5, 6], and may likewise have beneficial effects when applied to ecstasy use. However, development of an effective intervention requires knowledge about which modifiable determinants need to be targeted [7]. A recent meta-analysis of quantitative studies on ecstasy use and related behaviours, which aimed to provide this knowledge, concluded that much research is still necessary [8]. Specifically, of all behaviours relevant to ecstasy use (e.g. trying out ecstasy, applying harm reduction strategies, ceasing ecstasy use) only the broad behavioural category of 'using ecstasy' had been addressed by the included studies. Because meta-analyses aim to quantitatively integrate the literature, they generally exclude studies that do not report certain statistics. For example, the meta-analysis about ecstasy use included only studies that "assess quantitatively the relationship between determinants and behaviour or intention" [[8], p. 110]. These restrictive inclusion criteria led to the exclusion of all qualitative and exploratory studies into the reasons for ecstasy use, while paradoxically, it is exactly this exploratory methodology that renders these studies particularly valuable in setting the research agenda. The current review sets out to inform future research into ecstasy use and related behaviours by summarising this qualitative and exploratory quantitative literature.

Although the aforementioned meta-analysis did result in a list of determinants that seem relevant for ecstasy use (i.e. attitude, subjective norm, perceived behavioural control, moral norm, anticipated regret and habit), consideration of the most salient underlying beliefs indicated that some of these determinants of ecstasy use may prove exceptionally hard to modify [8]. For example, although ecstasy users had a higher descriptive norm than non-users (i.e. users perceived there to be more ecstasy use at dance events), this difference appeared to reflect an under-estimation of actual ecstasy use prevalence on the part of non-users. In this case, therefore, correcting this erroneous belief would lead to more ecstasy use, and an intervention aiming to decrease descriptive norms among ecstasy users would have to present incorrect information about the prevalence of ecstasy use (i.e. portray ecstasy use prevalence as lower than it is). The difficulties of intervening on the reported determinants seem to be underlined by a recent evaluation of an intervention among ecstasy users, where the authors concluded that a brief motivational intervention was no more efficient than the information-only control condition [though use decreased in both conditions, which most control participants attributed to the self-assessment at baseline; [9]]. In addition, none of the reviewed studies specifically addressed the initiation or cessation of ecstasy use or the application of harm reduction strategies. All studies addressed the broad behavioural category of 'using ecstasy' [e.g. by comparing users with non-users, or examining the intention to 'use ecstasy'; [8]], which may be problematic because determinants of related but different behaviours such as these are assumed to differ [7, 10]. Finally, it seemed that the summarized research had not addressed a number of potentially relevant determinants [8].

Thus, so far, only one of several relevant behaviours has been reviewed; the identified determinants appear hard to modify; and relevant determinants may have been omitted. The current paper investigates whether studies into other ecstasy use-related behaviours or addressing other determinants do exist, but were excluded by the rigid exclusion criteria of the meta-analysis drawing these conclusions. Specifically, the current paper reports a structured review of all qualitative studies and exploratory studies, which did not report an association with intention or behaviour but did report reasons for performing (or not performing) an ecstasy use-related behaviour (e.g. trying out ecstasy, ceasing ecstasy use, getting ecstasy tested, or drinking water during use). The aim of this overview is to guide further quantitative research into ecstasy use, eventually enabling development of effective evidence-based interventions.

Relevant literature was identified through the databases PsycINFO and MedLine. These were accessed through the Ovid SilverPlatter WebSpirs interface (version 5.12). At the 21^st of August 2008, the query "(("ecstasy" OR "mdma" OR "xtc" OR "methyldioxymethamphetamine" OR "party drug" OR "party drugs" OR "club drug" OR "club drugs" OR "dance drug" OR "dance drugs") IN TI, AB) AND (LA = "English")" was entered, which searched for all English records that contain ecstasy (or a synonym) in their title or abstract. This query yielded 4574 hits (1232 from PsycINFO and 2021 from MedLine). The phrase "NOT ("mouse" OR "mice" OR "rat" OR "rats")" was added, which eliminated 1321 hits. The remaining 3253 entries were downloaded and imported into a reference management program [11], which automatically identified and deleted 741 duplicates (defined as entries with the same title and year of publication). The titles and abstracts of the 2512 remaining records were manually inspected for relevance, and all publications reporting reasons for an ecstasy use-related behaviour were acquired. The acquired publications were examined in more detail, and if upon closer inspection a paper turned out to not report any reasons for ecstasy use or a related behaviour, it was excluded accordingly. In total, 2490 publications were excluded.

Most excluded records described biological studies [e.g. [12, 13]], followed by a large number of publications describing prevalence of drug use, sometimes combined with demographic variables [e.g. [14, 15]]. A number of studies also investigated consequences, perceived effects, or risks of ecstasy use [e.g. [16, 17]]. Unless these were reported in response to a question about reasons, or considered as reasons by the author of the original paper, these were not considered as reasons in the current paper either. Also, studies not reporting original empirical data were excluded [e.g., discussions or reviews, see for example [18, 19]]. Finally, studies that did not investigate the target population (i.e. young recreational ecstasy users in western society) were excluded [e.g. [20, 21]], as it has been shown that factors influencing behaviour can differ between populations [22‐24].

The papers included in this review contain valuable information. Compared to the synthesis of quantitative literature [8], the studies included here have indeed addressed more behaviours and more potential determinants. Though a minority of reasons reported here has already been quantitatively studied, those quantitative studies have only examined their relevance for the behaviour 'using ecstasy', and the results show that reasons for different behaviours (e.g. 'using ecstasy' and starting or ceasing ecstasy use) differ. This means that an intervention targeting the important determinants for 'using ecstasy' may be unable to effectively influence other behaviours (such as starting or ceasing ecstasy use). This also means that development of evidence-based interventions addressing these other behaviours first requires studies that map the determinant configurations for those specific behaviours.

Unfortunately, this review cannot inform intervention development, because this review only provides an overview of how frequently a reason was reported, and comparison of the frequency with which reasons were reported with the effect sizes found in the meta-analysis for the behaviour 'using ecstasy' showed that frequently reported reasons can correspond to beliefs that were not associated to frequency of use (i.e. beliefs held equally strongly by users and abstainers or by heavy users and light users). For example, in this review, using to 'enhance energy and dancing' was mentioned as a reason for using ecstasy by between 39% and 91%, yet in the meta-analysis [8], the belief that ecstasy helps to stay awake was associated to ecstasy use with a trivial effect size (i.e. Cohen's d < .2 [49]). A second limitation of this review is the fact that with two exceptions [26, 39] all included studies have been performed in the US, the UK and Australia. It remains to be seen whether these conclusions apply to other countries such as the Netherlands. Third, following from the qualitative methodology, no conclusions can be drawn except that reasons for related but different behaviours differ; nothing can be said about the degree to which they differ. This conclusion does, however, imply that determinant configurations (i.e. relative relevance of each of the determinants of a behaviour) of related but different behaviours differ as well.

Thus, there is a need to find out whether and to what degree determinant configurations for ecstasy use-related behaviours differ, ideally by comparing one or more behaviours (e.g. trying out ecstasy, using ecstasy and ceasing use) in one study. If these determinant structures do indeed differ, interventions should target different determinants depending on the specific behaviour that is targeted. In addition, future studies should measure the beliefs underlying the reasons for each behaviour. Ideally, for each behaviour, beliefs potentially underlying all reasons that have been studied (i.e. that have been marked in Table 4) are quantitatively examined. That way, over time, a clear picture will emerge as to the relative relevance of each of these reasons.

Just after the current review was completed, two new manuscripts were published that also addressed reasons to refrain from trying out ecstasy [50, 51]. Vervaeke, Benschop and Korf conducted a factor analysis and found support for three factors: fear of the effects, rationality, and lack of opportunity [50]. Rosenberg, Baylen, Murray, Phillips, Tisak, Versland and Pristas used a different method and distinguished eight factors: harm to thinking, school, work, or athletic performance; ecstasy use is contrary to values/self-image; fear of failing a drug-test; fear of effects on body; difficulty with acquiring ecstasy; fear of dangerous outcomes; no enjoyment expected from ecstasy; and fear of loss of control. Most reasons underlying these factors reflect reasons from the earlier studies that were included in this review, but additional reasons to refrain from starting ecstasy use are also reported: uncertainty about pill contents, medical reasons, no access to ecstasy, already using another substance, and not using on principle [in [50]], and against religion, fear of damage to reputation, want to be a role model, don't know where to get it, and fear of losing control [in [51]]. Especially interesting are the different factor structures revealed by these two studies. This may be attributed to their different methodologies of constructing the factors, or to the different locales (Dutch versus American).

The results of this review provide a clear agenda for the research needed to develop evidence-based interventions addressing ecstasy use. Worth noting in this respect is that many studies reported overlapping reasons, both within and between studies. For example, it is unclear whether, and if so, to what degree, the reasons "help enjoy the company of friends", "enhance socialising", and "being together with other people" reflect similar determinants. Ideally, a number of largely orthogonal beliefs can be identified [by studies such as [50] and [51]], the relevance of each of which can then be established for each behaviour. As multiple theoretical frameworks seem to apply to ecstasy use [8], it seems advisable for future studies to include variables specified by different theories so that it can be determined whether and how the relevant beliefs underlie these variables.

Finally, the combination of this study and the meta-analysis [8] has important implications. First, by virtue of their strict quantitative approach, meta-analyses provide only a very narrow view into the literature, excluding many studies that may provide valuable pointers for future research. By considering these excluded studies, qualitative reviews remain very valuable tools in synthesising the state of the literature. Second, conclusions from such qualitative reviews need to be quantitatively verified. As was also the case in the current review, results from qualitative research may not be corroborated by quantitative data. Thus, a balanced synthesis of the state of the art requires both meta-analytical and qualitative reviews.