The empirical studies in this thesis have contributed several novel findings to the field of MHISG research using methods and analyses not previously applied to this topic.
Firstly, a power law (Zipfian distribution) had not previously been fitted to or reported to describe the distribution of participation in an MHISG (Chapter 3 [6]). However, the findings are consistent with those previously reported for a range of other digital and non-digital phenomena [6], providing further evidence of the ubiquitous nature of the Zipfian distribution.
Secondly, user characteristics data collected during registration has not previously been reported in a study of an ISG for depression and related mental disorders to reduce the selection biases observed in survey data studies (Chapter 4 [2]), although such data has been reported in studies of problem drinking and smoking IGSs [7, 8]. Accordingly, the validity of the resulting findings is likely to be greater than those from previous studies of the MHISGs for
conditions such as depression. Certainly, the findings from the current study indicate that respondents in some surveys are not representative of all registrants. For example, a recent study employing a cross-sectional survey [9] of respondents to an advertisement posted on 40 different MHISGs yielded a sample in which the average self-reported participant membership duration was four years. This figure is very high in comparison to BlueBoard, in which only 3.7% of members were active for more than a year, and 49.0% were active for less than a day [2], which together with the known distribution of activity on ISGs in general suggests that the survey sample was biased towards the very highest-engaged users across those MHISGs. This points to the need for a more careful consideration of research design in future studies of the characteristics of ISG users.
Thirdly, the analysis of user sub-group modularity in Chapter 5 [5] and the topic modelling technique implemented in Chapter 6 [4] each employed methods that were novel in the field of MHISGs and provided a new perspective on large-scale patterns of participation that have not previously been reported in the literature and which may otherwise not be visible to community managers.
Fourthly, no study had previously systematically investigated the way in which users first present to an MHISG, nor taken an inductive approach to content analysis to determine if there are systematic differences between differentially engaged users (Chapter 7 [3]). The study was the first to demonstrate differences in awareness characteristics between the high- and low-engaged MHISG users.
Overall, the mixed-methods approach employed across the thesis has enabled the
triangulation of findings, particularly regarding potential differences in conceptions of recovery among differentially engaged users.
Since the publication of the three articles in Chapters 3, 4 and 5, subsequently published research has yielded results that are consistent with their findings; that is, the distribution of engagement is repeatedly and optimally described by a power law [10], user characteristics (demographics and indicated symptoms) are not strongly predictive of engagement [11], and the modularity in community structure is broadly cohesive and united across different topical threads by highly-engaged central users, [12]. The latter was observed, however, in an ISG that was dedicated to a single condition, problem drinking, a condition for which, in contrast to the Chapter 5 study, modularity cannot be differentiated by different condition-specific interests.
The empirical studies in Chapters 6 and 7 have not yet been investigated or replicated in another MHISG. A key finding of each of these studies was the differing conceptions of recovery that were apparent in the content of the posts of higher- and lower-engaged users. While the distinction between medical and consumer models of recovery may be particularly relevant to mental health, it is also consistent with a broader trend in online health
communities in which higher-engaged users tend to engage more in emotional support and companionship than lower-engaged users who tend to focus more on informational support [13-15]. Indeed, this distinction may be consistent with an observation regarding
prototypicality in online communities generally. A recent study using natural language
processing techniques to analyse the nature of three different online communities found that the prototypicality of a user, as measured by the nature of their language use, was predictive of leadership status as judged by peers [16]. The notion that leaders in an MHISG are those who are most prototypical of the group is consistent with well-established social psychological theories of group membership [17].This may be exemplified anecdotally by a report from a recent study in which participants who self-identified as having depression and/or anxiety were directed to participate in a long-established MHISG (Psych Central). One participant who encountered difficulties in engaging in the intervention reported: ‘It seemed that the majority of the regular posters on Psych Central went way beyond a tad anxious or a bit blue. A lot of the members had severe mental illnesses or told stories about going through horrendously traumatic experiences. I felt a little over my head in the community.’ [18].
Although it is not the subject of research in the current thesis, it is conceivable that the clinical outcomes of MHISG users with different participation styles differ. It is also possible that the current findings shed some light on the inconsistencies in findings in the current literature. As noted in Chapter 1, Griffiths et al [19] reported that a depression ISG intervention purpose- developed for the research study resulted in a significantly greater reduction in depression than an attention control condition. By contrast, Dean et al [18] found no difference in depression outcomes for participants referred to a pre-existing MHISG compared to participants encouraged to engage in an expressive writing exercise, and that the observed changes in outcomes were similar to those recorded in no-treatment control groups of other studies that employed computer-based treatment programs. In the past, Barak et al [20] has asserted that research on purpose-built ISGs lack ecological validity as they lack the
therapeutic components that occur in ‘real’ ISGs. In this context, the differing findings from the two studies might appear somewhat paradoxical. However, in the absence of a pre-established culture and leadership, it is possible that the purpose-constructed MHISGs provided
participants who might otherwise have failed to engage or identify with a pre-existing MHISG, a greater opportunity to engage in mutual help [19, 21, 22]. Previously, studies have shown that there is an association between higher levels of activity in an MHISG and better outcomes in terms of self-reported emotional distress in the content of posts [23] and depressive
symptoms as measured by a cross-sectional survey [24] and longitudinal surveys [25].
However, none of these studies employed a randomised controlled trial design. Thus, it is not clear if this is a causal relationship, nor, if it is causal, whether higher posting frequency is beneficial in of itself, or whether it is simply a proxy measure of different types of peer support that differ in their benefits. Further research could test these hypotheses.
Certainly, it is clear that there is a dearth of knowledge regarding the experience of low- engaged active help seekers of whom the majority of users in ‘real-world’ MHISGs are
comprised. It is possible that MHISGs do not reduce symptoms for the majority of low-engaged users. However, Barak et al. have asserted that there may be other more pertinent potential benefits of MHISGs [20]. It has been suggested that in ‘real life’ the impetus for seeking help from an MHISG comprises a combination of symptoms, social isolation, stigma, convenience and reluctance to seek professional help, and that the benefit of engagement is not symptom reduction per se, but rather the resulting consumer activation, challenge to self-stigma and help seeking from a professional [26, 27]. There is evidence based on self-reported data that for a substantial minority of users (36%), the MHISG has been a catalyst for formal help- seeking, and that active users are more likely to have sought formal support than passive users [9], albeit that the latter may reflect pre-existing characteristics that prompted active
participation in the MHISG. Further research is required to investigate the factors associated with professional help seeking in association in MHISG use, particularly among low-engaged users.