Evaluating the Efficacy of a 91-day Self-talk Mental Health Self-care Journal

Assessed using the Self-Talk Scale. The scale consists of 16 items rated on a five-point frequency scale (1 = never, 5 = very often) using the common stem "I talk to myself when…"

It has a four factor-structure comprised of self-assessment, self-reinforcement, self-criticism and self-management.

Total scores range from 16-80. Individual subscales scores range from 16-20. The higher the score the greater frequency of one's self-talk.

Assessed using the Rosenberg Self-Esteem Scale, a 10-item measure of global self-esteem or self-worth.

Uses a 4-point likert scale ranging from 1 (strongly agree) to 4 (strongly disagree)

Possible scores range from 10-40, higher scores indicate higher levels of self-esteem

Aspects of self-consciousness, including private self-consciousness, internal state awareness, self-reflection, public self-consciousness, and social anxiety, will be assessed using the Fenigstein Self-Consciousness Scale.

The scale consists of 23 items, rated using a 5-point likert scale ranging from 0 (extremely uncharacteristic) to 4 (extremely characteristic), with higher scores denoting higher levels of self-consciousness.

The frequency of automatic negative self-statements will be assessed using the Automatic Thoughts Questionnaire, whose 30-items assess the frequency of negative self-statements associated with depression.

Uses a 5-point likert scale comprised of the following: 1 = not at all, 2 = sometimes, 3 = moderately often, 4 = often , and 5 = all of the time. Possible scores range from 30-150, with higher scores indicating greater rates of negative self-statements.

Adherence to the journal for the intervention group will be assessed using three items:

• "Currently, what is the last day of the journal [the participant] completed?": possible score range 0-91, 0 indicates no days have been completed
• "[Has the participant] skipped or not completed any days prior to the latest day [the participant] completed?": No or yes - indicate which days
• "Approximately how many minutes [did the participant] spend completing a day, within the journal?": self-reported number of daily minutes

Intervention group participants' experience using the journal will be assessed through a qualitative exit interview

Age, preferred gender, socio-economic status, ethnicity, educational attainment, and employment status will be collected

Depression and anxiety will be assessed using the Hospital Anxiety and Depression Scale.

Possible scores for each subscale range from 0-21. A score of 0-7 = "normal", 8-10 = "Borderline abnormal (borderline case)" and 11-21 = "Abnormal (case)."

Subjective well-being will be assessed using the Warwick-Edinburgh Mental Wellbeing Scale.

Uses a 5-point Likert scale: 1= none of the time, 2= rarely, 3 = some of the time, 4 = often, and 5 = all of the time. Possible scores range from 14 to 70, with higher scores indicating greater mental-wellbeing

Modified International Physical Activity Questionnaire includes open-ended questions surrounding individuals':

• Physical activity. Frequency score ranging from 0-7 days per week. Average time spent on one of those days ranging from 0-24 total hours. Separate questions for vigorous intensity, moderate intensity, mild intensity and walking.
• Sitting reported in average hours per day ranging from 0-24 total hours.
• Occupational and recreational screentime. Reported using a separate daily average for weekdays and weekends ranging from 0-24 total hours.
• Sleep reported using average number of hours per night ranging from 0-24 total hours.