Trajectories of Mental Health Difficulties from Childhood To Adolescence: Evidence from Growing Up in Ireland

Abstract Many mental health difficulties first emerge in adolescence and can have lasting impacts on later-life outcomes. In this paper, we focus on young people’s mental health difficulties, as measured by the internalising and externalising difficulties subscales of the Strengths and Difficulties Questionnaire (SDQ). Using data from two cohorts of Growing Up in Ireland (GUI), we use group-based modelling techniques to examine how internalising and externalising difficulties evolve between the ages of 3 and 13 for the ’08 Cohort, and between the ages of 9 and 17 for the ’98 Cohort. We also focus on the key transition point of age 9 to 13, contrasting the experiences of young people from the two cohorts, born 10 years apart. The results indicate that most young people in Ireland display low levels of mental health difficulties, but that there is considerable change over time, and some young people experience persistently high levels of mental health difficulties. Consistent with prior research, girls display higher rates of internalising difficulties, while boys display higher rates of externalising difficulties. When comparing these difficulties across both cohorts between the ages of 9 and 13, we find an increase in internalising difficulties (most pronounced among girls) for the ’08 Cohort, in contrast to a decline between these ages for the ’98 Cohort. As further waves of the ’08 Cohort become available, it will be important to determine whether this reflects an earlier increase in young people’s internalising difficulties which continues beyond the age of 13, or whether this stabilises or possibly declines. The findings add to the emerging literature on how young people’s mental health difficulties vary by age and gender, and how internalising difficulties in particular have increased in recent times.