ABSTRACT
Research on the social dynamics of social media use in preteen girls is scarce, yet crucial: suicidal thoughts and
depression have significantly increased among preteen girls in recent years, and this deterioration of mental
health coincides with changes in social media use. Our conceptual model highlights two potential factors that
may make preteen girls more susceptible to the negative effects of specific social media experiences: rejection
sensitivity and pubertal timing. Online rejection experiences, overt and perceived, are a key component of
preteen girls’ social media use that impacts mental health; however, these have not been directly quantified,
particularly among those high in rejection sensitivity. Early puberty may be a window of vulnerability to the
negative effects of social media use in girls, given the link between early puberty, depression, bullying, and social
struggles. To address this, we propose a longitudinal study to examine the bidirectional relations between
preteen girls' mental health and social media experiences, exploring psychological and developmental risk
factors that strengthen – as well as mitigate – these relationships. This study will recruit a community sample of
250 girls, ages 10-11 years at baseline, to assess their mental health, social media use, rejection sensitivity, and
hormone levels over three annual assessments (final age 12-13 years). The study will be the first to include
microEMA (8x per day for 14 days, collected via smartwatch) and daily diaries (14 days) to assess preteen girls’
social media use. This approach offers an unparalleled examination of social media engagement, encompassing
not only frequency and duration, but also how social media is used in daily life: the temporal unfolding of activities,
mood, and social connection and rejection experiences that occur during social media use on a day-to-day basis.
Weekly saliva samples will be collected across this period to assess global levels of puberty-related hormones
as well as whether weekly hormonal fluctuations are linked to social media use and/or rejection sensitivity. In
laboratory clinical interviews, questionnaires, and neural indices of rejection and acceptance sensitivity (EEG)
will complement the social media measures. The overarching aim of this study is to examine the relationships
between preteen girls' mental health and social media experiences, assessing whether high rejection sensitivity,
and puberty impact these relationships; the protective effects of social connection on SM and neural response
to acceptance will also be examined. Tests of the hypotheses within each of the aims will be performed through
a series multi-level (also known as mixed effects) regression models, including growth models which incorporate
time in the study as a variable. Through a detailed and focused assessment of how social media engagement
unfolds over time, we will be able to highlight key turning points where elements of problematic social media use
commence and persist, leading to the onset or maintenance of psychopathology. These elements of problematic
social media use could inform media use guidelines and be future targets for intervention and prevention,
particularly in those who may be sensitive to rejection and/or more advanced in pubertal development.
