  There has been a significant expansion in the use of online social networks
(OSNs) to support people experiencing mental health issues. This paper studies
the role of Instagram influencers who specialize in coaching people with mental
health issues. Using a dataset of 97k posts, we characterize such users'
linguistic and behavioural features. We explore how these observations impact
audience engagement (as measured by likes). We show that the support provided
by these accounts varies based on their self-declared professional identities.
For instance, Instagram accounts that declare themselves as Authors offer less
support than accounts that label themselves as Coach. We show that increasing
information support in general communication positively affects user
engagement. However, the effect of vocabulary on engagement is not consistent
across the Instagram account types. Our findings shed light on this
understudied topic and guide how mental health practitioners can improve
outreach.
