Table 1.

Summary of study design and differences between cohorts.

Design element	Bipolar cohort	College student cohort
Sample size, n	30	50
Baseline assessments (day 0)	A phone interviewa to complete the YMRSb [34], the SIGH-Dc [35], and the SF-36d [36]	An online assessment to complete the PSS-10e [32], the PHQ-9f [33], the PROMIS-29g [37], the AAQ-2h [38], and the CompACTi [39]
In-app assessments (days 1-42)	Delivered through the app twice daily: the shortened YMRS, the shortened SIGH-D, and the ACTj Activity Surveyk	Delivered through the app twice daily: the PHQ-2l, the PSS-4m, and the ACT Activity Surveyk
Activity tracker assessments (days 1-42)	Sleep, heart rate, and steps tracked through the Fitbit Alta HR	None
Microintervention (days 1-42)	Randomized to receive or not receive ACT microinterventionk after in-app assessments	Randomized to receive or not receive ACT microinterventionk after in-app assessments
Exit assessments (day 42)	A phone interview to complete same assessments from baseline	An online assessment to complete same assessments from baseline, along with an app engagement surveyk
Follow-up assessments (months 3 and 6)	None	Online assessments to complete same assessments from baseline
Primary outcomes	Safety and feasibility of microintervention in terms of the following: adherence to in-app assessments (ie, feasibility); change in YMRS and SIGH-D scores from baseline to exit assessment (ie, safety)	Effectiveness, safety, and feasibility of microintervention in terms of the following: changes in responses to ACT Activity Survey as a function of whether the microintervention was delivered at a prior time point (ie, effectiveness); adherence to in-app assessments (ie, feasibility); change in proportion of individuals who meet criteria for minor or major depression on PHQ-9 from baseline to exit and from baseline to each follow-up assessment (ie, safety)
Secondary outcomes	Power for larger study based on changes in responses to ACT Activity Survey as a function of whether the microintervention was delivered at a prior time point (ie, effectiveness)	Effectiveness of microintervention in terms of changes in responses to PHQ-2 and PSS-4 scores as a function of whether the microintervention was delivered at a prior time point (ie, effectiveness)

^aParticipants are recruited from the Prechter Longitudinal Study of Bipolar Disorder and have already completed interviews to determine demographic information and health and mental illness history.

^bYMRS: Young Mania Rating Scale.

^cSIGH-D: Structured Interview Guide for the Hamilton Depression Rating Scale.

^dSF-36: 36-Item Short Form Survey.

^ePSS-10: Perceived Stress Scale 10.

^fPHQ-9: Patient Health Questionnaire 9.

^gPROMIS-29: Patient-Reported Outcomes Measurement Information System.

^hAAQ2: Acceptance and Action Questionnaire-II.

ⁱCompACT: Comprehensive Assessment of Acceptance and Commitment Therapy Processes.

^jACT: acceptance and commitment therapy.

^kDeveloped for these studies.

^lPHQ-2: Patient Health Questionnaire 2.

^mPSS-4: Perceived Stress Scale 4.