Child maltreatment among young adolescents: Effects on mental health, academic functioning and substance use

Sammanfattning: The main aim of this doctoral thesis was to investigate how experiences of childhood maltreatment affected three developmentally salient areas of functioning in adolescent development. Participants were recruited through the Swedish multidisciplinary program Longitudinal Research on Development in Adolescence (LoRDIA). Study I explored the relationship between self-reported emotional maltreatment (i.e., emotional neglect and emotional abuse), mental health, and mental well-being among 1134 girls and boys (mean age 12.7 years, SD 0.6). Emotional maltreatment had significant negative effects on mental health and mental well-being in both girls and boys. There were also significant effects of the interaction between gender and level of emotional maltreatment on mental health: girls reported decreased mental health and mental well-being at lower levels of emotional maltreatment than did boys; furthermore, girls reported more mental health problems in response to emotional maltreatment than did boys. The aim of Study II was to examine the relationship between child maltreatment and school absenteeism among adolescents (n = 1316; mean age 14.3 years, SD 0.6), focusing on the prevalence of self-reported child maltreatment among non-absentees and absentees. Furthermore, differences between maltreated and non-maltreated absentees in mental health, perceived school environment, and peer victimization in school were analyzed. About 25% of absentees reported one subtype of maltreatment (16% of the total sample) and a mean of 22% of absentees reported two or more subtypes of maltreatment (11% of the total sample). Maltreated absentees reported more mental health problems, personal harassment, and negative relationships with their teachers than did non-maltreated absentees. Study III investigated the longitudinal relationship (at three time points) between being subjected to no maltreatment, one type of maltreatment, and multiple types of maltreatment, and experiencing substance-use–related negative consequences (SURNCs) in adolescence (n = 406; mean ages at the three time points were 13.5, 14.4, and 14.9 years). SURNCs are the proximal consequences of substance use consumption, consequences such as getting into fights with friends or family, stealing, neglecting responsibilities, and being unable to cut down on substance use. Estimates from zero-inflated Poisson growth curve models revealed that experiencing multiple types of maltreatment before the age of 12 years was associated with increased frequency of SURNCs during the transition from early to mid-adolescence. This association was partly mediated by alcohol and illicit substance use frequency. Results of the three studies included in this thesis indicate that child maltreatment is associated with negative outcomes concerning three developmentally salient domains of functioning in adolescence: mental health, academic functioning (i.e., school absenteeism), and substance use. Further research should address gender differences in the consequences of maltreatment and factors that mediate and moderate the relationship between child maltreatment and mental health, school absenteeism, and substance use. In addition, it is important to evaluate trauma-informed preventive interventions that can be implemented within regular mental healthcare, schools, and substance use treatment centers.