Sleep and Trauma in Adolescents

• Optimal sleep supports healthy development and protects against mood-related disorders, potentially buffering against adverse mental health outcomes in trauma-exposed adolescents.
• A study was conducted in 2023 with 752 adolescents (mean age 13.8 years, 37% girls, 60% boys) from independent schools in Australia.
• The study used mixed-effects linear regression to assess if sleep moderated the association between trauma and symptoms of anxiety, depression, and mental wellbeing.
• 82% of participants reported exposure to at least one traumatic event, with a mean of 1.8 traumatic events reported.
• Trauma was independently associated with higher depressive and anxiety symptoms and lower mental wellbeing scores.
• Exposure to one or more traumatic events correlated with difficulties falling asleep and not meeting nightly sleep duration guidelines.
• Meeting nightly sleep duration guidelines significantly interacted with trauma exposure, resulting in lower depression and anxiety symptoms among trauma-exposed adolescents who met sleep guidelines.
• Getting enough sleep may help mitigate anxiety and depressive symptoms in non-clinical trauma-exposed adolescents; longitudinal research is required.

Mental Health in Young Australians

• Over a third of young Australians aged 16–24 have experienced a mental health disorder in the last 12 months.
• Mental illness is the leading cause of years of healthy life lost due to disability worldwide.
• Adolescence is a critical period for addressing mental health risk factors and preventing poor mental health trajectories.
• Childhood trauma is a major factor in the development of mental ill-health, including depression and anxiety.
• 41% of Australian adults have reported exposure to a traumatic event before the age of 17.
• Childhood maltreatment accounts for up to 21% of depressive disorders and 24% of anxiety disorders in Australia.
• Trauma during childhood or adolescence can disrupt development, causing enduring effects across social, academic, and emotional domains.
• Exposure to trauma may lead to increased threat detection and hypervigilance, which can heighten susceptibility to anxiety and depressive disorders.

The Role of Sleep

• Sleep plays a critical role in the development of cognitive functions and mental health.
• Both insufficient and excessive sleep are associated with a higher risk of poor mental health outcomes in adolescents.
• Sleep and circadian rhythm disruption are pivotal factors preceding anxiety and depression.
• Persistent insomnia is identified as a causal mechanism in the occurrence of mental health problems in young adults.
• Experimental studies show sleep duration causally affects mood states in adolescents.
• Sleep difficulties are associated with more complex mental health presentations and linked to suicidality and self-injury in adolescents.
• Those with sleep disturbances are significantly more likely to have mood and psychotic disorders onset during adolescence or early adulthood.
• Sleep disturbances may underlie the development of mental health disorders across biological, psychological, and social domains.
• Only 20% of adolescents in an Australian study were obtaining optimal amounts of sleep.
• Australian sleep duration guidelines were developed in 2018, incorporating physical activity, sedentary behavior, and sleep.
• Trauma is associated with sleep disturbances in adolescents, persisting into adulthood, potentially caused by physiological hyperarousal and cognitive hyperactivation.
• Disrupted sleep-wake cycles exacerbate physiological sensitivity to stress, leading to chronic psychological stress and maladaptation.
• Sleep has been posited as a core component in the pathophysiology of trauma-related disorders and a prognostic factor in the development of depression and anxiety.

Study Aims and Hypotheses

• The study aimed to investigate associations between sleep, trauma, and mental health and whether sleep moderates the relationship between trauma and mental health outcomes in Australian adolescents.
• It was hypothesized that adolescents reporting one or more exposures to traumatic events would score higher in depressive and anxiety symptoms and lower in mental wellbeing.
• The study also hypothesized that those with exposure to trauma would be more likely to report difficulties falling asleep and less likely to meet Australian sleep duration guidelines.
• It was additionally hypothesized that sleep would have a significant interaction with trauma, such that participants exposed to trauma with adequate sleep duration would show better mental health outcomes compared to their trauma-exposed peers with sub-optimal sleep duration.

Methods

• The study used baseline data from the OurFutures Mental Health study, a cluster randomized trial evaluating an online mental health intervention for Year 8 and 9 students.
• Independent schools Australia-wide were contacted and invited to participate in the study from 2022 to 2023.
• Schools were block randomized to intervention or control groups, and students who were not opted-out completed an online, self-report survey during class time.
• The study included 752 Year 8 and 9 students from nine participating schools across NSW, VIC, SA, and QLD.
• Trauma exposure was measured using the Child Trauma Screen (CTS), specifically four items assessing exposure to traumatic events.
• Sleep duration was assessed by asking participants to select their average nightly sleep duration, categorized into whether they met Australian sleep duration guidelines.
• Difficulties falling asleep was assessed by asking whether the participant has difficulty falling asleep (yes/no).
• Depressive symptoms were measured using the Patient Health Questionnaire adapted for Adolescents (PHQ-A).
• Anxiety symptoms were measured using the Generalised Anxiety Disorder Screen Tool (GAD-7).

Statistical Analysis

• Descriptive statistical analyses were conducted to obtain participant characteristics across variables.
• Mixed effects linear regression analyses with a random intercept were performed to account for the nested structure of the data.
• Linear mixed-effects models accounted for missing data through Restricted Maximum Likelihood (REML) estimation.

Key Findings

• 82.2% of participants reported exposure to at least one traumatic event.
• 49.9% of adolescents met Australian sleep duration guidelines.
• 43.3% of adolescents reported difficulties falling asleep.
• 25.5% met the GAD-7 threshold for probable anxiety, and 31.5% met the PHQ-A threshold for probable depression.
• Participants identifying as boys were more likely to meet nightly sleep duration guidelines, while girls reported more difficulties falling asleep.
• Trauma exposure was significantly associated with depressive symptoms, anxiety symptoms, and mental wellbeing.
• Not meeting nightly sleep duration guidelines was significantly associated with depressive and anxiety symptoms and mental wellbeing.
• Difficulties falling asleep was associated with significantly higher depressive symptoms and anxiety symptoms, and significantly lower mental wellbeing.
• Adolescents exposed to trauma were more likely to report difficulties falling asleep and obtain suboptimal amounts of sleep.
• Meeting sleep duration guidelines moderated the effect of trauma on depressive and anxiety symptoms.
• Sensitivity analyses confirmed the robustness of the results.

Sensitivity Analyses

• Sleep-related item removal from PHQ-A showed consistent results, with a modest effect size reduction for difficulties falling asleep.
• Excluding witnessing violence from the trauma measure yielded similar interaction model findings.

Interpretation of Results

• The study found that trauma was independently associated with higher levels of depressive and anxiety symptoms and lower mental wellbeing.
• Adolescents who reported exposure to one or more traumatic events were significantly more likely to report difficulties falling asleep and obtain sub-optimal amounts of sleep.

Strengths and Limitations

• Strengths include utilizing data obtained during adolescence.
• The study is one of few to examine the relationships in a non-clinical sample. This helps to minimize potential confounds.
• Limitations include the study's cross-sectional design which limits the ability to draw inferences about causality. Also, the sample was exclusively independent schools, which may not accurately represent the population of Australian adolescents.