Depression is one of the most prevalent mental disorders to afflict adults. It seriously impacts role functioning and often takes a recurrent or chronic course. Because most adults who suffer from depression never receive treatment, there is a critical need to develop interventions that can be easily implemented and widely disseminated. Interventions that reduce the performance-impairing symptoms of subclinical depression and prevent the onset of major depression can improve employee well-being, while reducing healthcare costs and improving productivity. This project produced a mobile-web program to activate cognitive behavioral skills in workers with subthreshold depression, reduce depression symptoms, improve functioning in the workplace, and potentially reduce the risk for escalation to full-syndrome depression.

The responsive mobile-web MoodHacker app was designed to: (a) educate users about depression; (b) educate users about the logistics and benefits of mood and activity monitoring; (c) promote daily mood and activity monitoring; (d) help users increase their positive activity engagement; (e) help users decrease negative thinking and increase positive thinking; and (f) promote daily practice of the skills taught.

Program content was adapted from the Coping with Depression group therapy course [18], enhanced with mindfulness-based [22] and other evidence-based positive psychology strategies [23-25]. Content for the application was refined based on input from experts in the field who had extensive experience working with adult employees at risk for depression. Additional program modifications were made based on data from individual interviews and iterative user testing with the population of interest during the formative and production phases of the project.

The MoodHacker user experience is structured around twelve learning objectives delivered through daily emails, in-app messaging, and in the "Articles & Videos" library. Daily emails (Figure 1) are sent to engage users in program content, provide sequenced guidance through the learning objectives in the articles and whiteboard-style videos, give tips for getting the most out of MoodHacker, and prompt the user to track their mood and activities daily. Users are encouraged to view the articles and videos as ordered, but viewing is not restricted, and users can view content according to their interest. The emails, articles and videos promote practice of the featured cognitive and behavioral skills outside the app experience.

Inclusion Criteria:

• 18 years or older
• mild-to-moderate depressive symptoms as measured by the PHQ-9 (score of 10-19)
• not currently suicidal or meeting criteria for bipolar or schizo-affective disorder
• employed at least part-time
• English speaking
• access to a high-speed internet connection

Exclusion Criteria:

• younger than 18 years old
• severe depressive symptoms as measured by the PHQ-9 (score of 20+)
• currently suicidal or meeting criteria for bipolar or schizo-affective disorder
• employed less than part-time or unemployed
• not English speaking
• no access to a high-speed internet connection