| dc.description.abstract | Conduct problems refer to a group of behaviors that violate socially appropriate norms or pose risk of harm for self or others. Adolescence is a developmental phase where youth undergo psychological and biological changes at the same time that parental supervision decreases and influence by peers on behavior and identity evolvement increases. Many adolescents try out norm-breaking behavior during this phase. For some adolescents, such behaviors can be a part of normative development, while for others, the behaviors are more persistent, long-lasting, and may lead to detrimental consequences for themselves, victims, their families, and society at large. Various approaches to the classification of conduct problems have been suggested, but there is still no consensus in the field. In this Ph.D. project, we have chosen to zoom in on two distinct features of conduct problems, physical aggression and irritability, and we aim to contribute to an increased understanding of how these distinct features develop in adolescence. While irritability often is a precursor for physical aggression, physical aggression also has other incentives. Physical aggression in adolescence is seen as a severity indicator of present and long-lasting conduct problems. Recent studies have identified irritability as a distinct feature that can be separated from conduct problems in terms of comorbid conditions and long-term consequences.
There is a tendency in previous studies to focus on selected groups (boys, clinical populations, the juvenile justice system, and child protective services) and to have a narrow age range in the study sample. In this thesis, we are using data from the Young-HUNT study, an epidemiological representative study of adolescents in the age range 13 to 19 years old where boys and girls are equally represented. Increased knowledge of risk factors in early adolescence that predict physical aggression in late adolescence may lead to earlier identification of adolescents at risk. Boys have a higher prevalence of conduct problems and physically aggressive behavior, and due to an increased focus on boys in previous studies, we have more knowledge of the developmental courses and risk factors for boys’ behaviors than for girls’. Increased knowledge of sex similarities and sex differences in risk factors of physical aggression and irritability can inform whether interventions should be sex equal or sex specific.
The likelihood that an adolescent will develop conduct problems depends on a complex interplay of risk factors. In Paper I, we examined risk factors of physical aggression during the transition from early to late adolescence using a two-wave longitudinal population sample from Young-HUNT (Young-HUNT1 and Young-HUNT2). We aimed to examine if risk factors in early adolescence could predict physically aggressive behavior emerging in late adolescence and further why some adolescents desist physically aggressive behavior while others do not. The study sample consisted of 2289 Norwegian adolescents (1235 girls) who participated in the Young-HUNT1 study (mean age 14.5 years) and the follow-up study four years later, Young-HUNT2 study (mean age 18.4 years). Multinomial logistic regression and logistic regression were used to examine the data. One in six young adolescents reported participating in physical fighting. Physical aggression in early adolescence was significantly associated with male sex, attention problems, academic problems, being bullied, alcohol intoxication, and smoking. Male sex, alcohol intoxication, and smoking during early adolescence increased the risk for emerging aggressive behavior in late adolescence, while alcohol intoxication during early adolescence predicted persistent versus desisting aggressive behavior during adolescence.
In Paper II, we examined sex differences in concurrent associations between various mental health problems, trauma exposure, and substance use, and physical aggression. The study sample consisted of 3686 boys (mean age 15.9 years) and 3881 girls (mean age 16.0 years) from Young-HUNT3. Twenty-one percent of boys and three percent of girls reported participating in physical fighting. Attention problems, trauma exposure, and alcohol intoxication showed unique associations with physical aggression for both sexes, and post-traumatic stress symptoms showed a unique association for boys only. Interaction effects with sex were identified for attention problems, anxiety and depression, loneliness, traumatic exposure, alcohol intoxication, and drug use, with larger odds ratios for girls than for boys. In sum, boys’ and girls’ engagement in physical aggression was associated mainly with the same risk factors, but several of the factors increased the relative risk for girls more than for boys. In Paper III, we examined sex differences in the concurrent effects of trauma exposure on irritability and antisocial behavior. The sample consisted of 3611 boys (mean age 16.1 years) and 3811 girls (mean age 16.1 years). Boys reported more lying, stealing, disobedience, and fighting, while girls reported more irritability. Trauma exposure, both specific traumatic events and summed traumatic events, were associated with irritability and antisocial behavior for both boys and girls. Interaction effects for sex were identified for the association between summed traumatic events and irritability. The odds ratio was significantly higher for girls, indicating that the impact of experiencing one additional type of traumatic event increased the risk of irritability more for girls than for boys.
The findings from this Ph.D. project provide insights that can inform the development of preventative measures and interventions targeting physical aggression and irritability in adolescence. With the knowledge that the more risks present, the worse the child outcome, and the opposite implication “that every risk factor we can reduce matters” (p. 235) (Appleyard et al., 2005), increasing the knowledge on important risk factors, and identifying adolescents at risk as early as possible, provides hope for our future generations. | en_US |
