A new longitudinal study has found that individuals who were more irritable in childhood tended to show more problematic behaviors in adolescence, including behaviors such as physical aggression, rule-breaking, impulsivity, cheating or stealing. The link remained even after controlling for demographic factors and psychopathological disorders. The study was published in Research on Child and Adolescent Psychopathology.
Irritability — the proneness to quickly become annoyed, impatient and angry — is one of the central components of many different psychiatric disorders. In adolescents, more pronounced irritability is associated with both depression and anxiety. It is also linked to worse social functioning, school problems, financial strains, and suicides.
Theorists see irritability as a product of aberrant processing of emotions and low tolerance to frustration. “This produces exaggerated responses to blocked goal attainment, heightened anger, and temper outbursts,” the authors of the new study explain. Irritability is particularly common in very young children and infants. It has two aspects – emotional reactivity and reactive aggression.
Study author Margot E. Barclay and her colleagues wanted to explore whether irritability in childhood is associated with psychological problems in adolescence when controlling for attention-deficit/hyperactivity disorder (ADHD) and other psychopathological conditions. These factors are known to be associated with adverse psychological outcomes at later age.
They divided psychological problems into externalizing and internalizing problems. Externalizing problems include those where the problematic behavior of a person is directed towards its environment. Such externalizing problematic behaviors include physical aggression, cheating, stealing, rule-breaking, impulsive reactions, and others. Internalizing problems include those directed towards oneself such as feelings of sadness, depression, anxiety, low self-esteem, inhibited behaviors, and fears.
The researchers followed a group of 231 children (51.5% white, 32% female) with and without ADHD (121 with, 110 without ADHD) and their families from childhood (of the child) to early adolescence, a period of 6-7 years. Across this period, they completed 3 assessments.
Families went through a phone screening to check eligibility for a study. Eligible families attended laboratory assessments conducted by trained graduate students or staff. Parents had structured interviews and filled out rating scales for youth psychopathology, while youth took standardized tests and self-reported. Most rating scales were completed by parents at home and returned by mail.
The researchers noted that approximately 85-90% of the data was reported by mothers. In later years, assessment procedures were repeated with additions of assessments of alcohol and substance use as children matured. Assessments used included those of ADHD, oppositional defiant disorder and conduct disorder, parenting characteristics, peer status, social skills, and internalizing and externalizing problems.
Results showed that higher irritability in childhood (at the time the study started) was associated with higher levels of externalizing problems in adolescence (at the 3rd assessment) as reported by teachers, but not with these problems as reported by the child/adolescent him/herself. Irritability in childhood was not related to internalizing problems in adolescence. This link persisted even when controlling for sex, age, race, family income, parental education, ADHD diagnosis, and internalizing problems in childhood.
Higher irritability at the time of the first assessment (childhood) was also associated with more negative peer status several years later, at the time of the second assessment, as well as with lower social skills. Irritability in childhood was not related to parenting characteristics or the stress of parents. Low social skills at the time of the second assessment were linked with internalizing problems in adolescence.
“Given that individual differences in childhood irritability predicted key adolescent outcomes, interventions remediating irritability may improve trajectories of emotional functioning,” the researchers conclude and emphasize the importance of the link between poor social skills and the emergence of internalizing problems later in life.
The study contributes to the body of knowledge on links between psychological characteristics in childhood and later developments. However, it also has limitations that need to be taken into account. Notably, parents in the study had a much higher average education level compared to the general population (65% college graduates) and most of them were mothers. Results might not have been the same if assessments were given by fathers.
The paper, “Childhood Irritability: Predictive Validity and Mediators of Adolescent Psychopathology”, was authored by Margot E. Barclay, Jennifer A. Silvers, and Steve S. Lee.
