The Effect of Increasing Physical Activity or Reducing Mobile Phone Use on Mental Health in Young People in Austria

Introduction: Data show adolescent mental health has declined in recent years, possibly due to increased uncertainty and loss of opportunities. The SPARKY study aims to test an at-home intervention which aims to promote autonomous healthy levels of physical activity and smartphone use, in turn reducing clinical mental illness symptoms and increasing wellbeing.

Methods and analysis: Adolescents (14-19 years) in Austria and Germany will be recruited and randomised into one of three groups (physical activity, smartphone, control). The physical activity (PA) and smartphone time (ST) groups will be guided over 12-weeks to increase PA or decrease ST respectively. All groups will objectively measure PA using wrist-worn trackers and ST using an app and will regularly self-report on standardised mental health scales. Analyses will be run to assess the pre-post changes in mental health in the intervention groups compared to the control.

Ethics and dissemination: The conduct of the trial was approved by the institutional research ethics board and written informed consent will be obtained from participants and the parents of those under 18. Data will be stored open access. Findings will be disseminated through conferences, media interviews and publications to peer-reviewed journals.

Overall, mental health interventions are sorely needed in adolescents to counteract the effects of the pandemic and other uncertainties. The at-home nature of the intervention will promote autonomous healthy habit formation in youth.

Design: A three-arm randomised controlled trial with a physical activity group, a smartphone-use group and a control group. Outcome assessments are to be conducted at baseline, biweekly during the intervention, at three months (post-intervention), and at one month, six months and one year post-intervention (follow-ups). The study is not blinded.

Hypotheses:

The predictions can be divided into two categories: 1. improvements in mental health and 2. assessing behaviour change. All hypotheses are directional.

1. Mental health:

   * The primary hypothesis is that the intervention groups will show a greater improvement in their mental health than the control group from pre- to post-intervention.
   * Secondly, it is predicted that these improvements in mental health will be sustained at the follow-up stage.
   * Thirdly, those individuals who meet the goals will have better mental health than those who do not.
2. Behaviour change:

   * As a measure of the success of the intervention, it is predicted that those in the intervention groups will be more likely to meet the physical activity and screen time goals at post-intervention and follow-up than the control group.
   * Finally, it can be predicted that merely tracking daily activity and screen time is enough to promote some behaviour change and therefore it is predicted that the control group will be more likely to meet the goals at post-intervention than pre-intervention.

Eligibility Criteria:
Inclusion Criteria:

* aged 14-19
* own a smartphone
* use their phones more than 4 hours per days
* do less than 60 minutes of vigorous sport on 3 days per week and/or less than 60 minutes of moderate activity on 5 days per week.
* conduct work/school in German
* hair at least 1cm long

Exclusion Criteria:

* should not be in current medical care or have physical constraints which affect movement.
* should not have a diagnosis of schizophrenia/psychotic disorder, substance use disorder, symptoms of an eating disorder (≥2 positive answers on SCOFF questionnaire).
* should not have dyed hair. Participants will complete an online screening questionnaire to assess eligibility for inclusion.