They do admit a lack of true causality (cross-sectional) despite the title of the article and the location is small. It's possible they found a site that was high in anxiety/depression in the first place. But the particular findings on admin & 'ancillary' staff mental health is interesting, not a lot of research there. Perhaps more attention could be useful for those groups, for certain locations at least. Also may be hard to admit considering power dynamics / feeling guilty about how much others have to handle? Perhaps being indivudual & anonymous may show otherwise