The Adverse Childhood Experiences Study examined the physical health and psychosocial consequences of ACE across the lifespan. This study demonstrated adverse childhood experiences (ACE) prevalence to be high and a direct correlation between ACE scores (a tally of different types of abuse, neglect, and household dysfunction experienced under the age of 18) and prevalence of physical health and psychosocial problems in adulthood. Adults with \>3 ACE are more likely to experience social underachievement (e.g. lower educational achievement and economic productivity), physical and mental health problems (e.g. depression, heart disease, suicide attempts, substance abuse) and unhealthy lifestyle behaviours (e.g. smoking, physical inactivity). Worldwide, ACE have been shown to be prevalent, independent of social and economic factors, and highly interrelated. 12.5% of subjects reported \>4 ACE. Among post-secondary students, studies determined high ACE scores to be associated with higher prevalence of risk behaviours and physical health and psychosocial problems. Failure to support the physical and mental health of students can lead to increased attrition, deterioration of well-being, and intentional self-harm.

Recognition of ACE prevalence and its consequences has been paralleled by the development of interventions for mitigating the lifetime health and social consequences of ACE. A 2016 study examining interventions believed to improve the mental health of adults with significant ACE (\>3) identified mindfulness-based therapies (MBT) as being effective. Mindfulness is a form of cognitive training that cultivates self-regulative ability and enhances resilience.

As no Canadian post-secondary institution has comprehensively investigated the prevalence of student ACE, the objective of this study is to understand the prevalence of ACE in students and to determine whether MBT is effective for promoting mental health in students with high ACE scores (\>3).

A double-blind randomized control study will examine the efficacy of MBT, specifically Mindfulness-based Stress Resilience Training (MBSR), in promoting positive change in measures of hope, rumination, forgiveness and distress. Interventions that positively effect these measures are known to enhance quality of life. First year students enrolled at Dalhousie University will be recruited. Subjects will complete an ACE questionnaire and those with \>3 ACE prior to age 18 will be invited to participate in this study. Students with prior MBT training will be excluded. Subjects will be randomized to one of two groups: MBSR or an established active control (Health Enhancement Program (HEP)). We selected MBSR because it is secular, codified, and the most scientifically studied mindfulness-based intervention to date. Power analyses determined 25 subjects per group is sufficient to detect a significant difference in outcomes across the groups. Interventionists and subjects will be blinded. Students will be led in group based MBSR or HEP for 4 weeks. Prior to and after the 4-week intervention subjects' outcomes will be determined using the: Perceived Stress Scale; Rumination and Reflection Questionnaire; Heartland Forgiveness Scale and; Adult Dispositional Hope Scale.

Development of evidence-based programs that support the identification of ACE in students and identification of interventions that mitigate negative lifetime consequences of ACE outcomes is needed. This pilot study will increase understanding of Canadian student ACE and assess the effectiveness of MBSR as a tool for supporting the mental health of students who have experienced significant ACE.