To find great ideas on mental hygiene, consider to paths. One is writing an article from a pictographic you discover on Pinterest, and doing so in your own words. Or finding press releases from the national institute on mental health that target specific human problems common to employees, families, and coworker relationships.
We commonly address this topic in Frontline Employee Wellness Newsletter. You can see a few copies of it and get a few issues downloaded at the link shown on the page.