A 12-month longitudinal study of adolescents found that those experiencing a higher number of negative life events tended to have more severe depressive symptoms. This association was especially notable regarding negative self-evaluation. Girls who experienced more negative life events reported larger increases in negative self-evaluation symptoms than boys. The paper was published in Scientific Reports.
Depression is a mental health disorder characterized by persistent sadness, emptiness, or loss of interest in activities. It affects how a person feels, thinks, behaves, and functions in daily life. Common symptoms include low mood, fatigue, difficulty concentrating, sleep problems, changes in appetite, and feelings of worthlessness or guilt. Some people also experience irritability, physical discomfort, slowed movement, or restlessness.
Depression is more severe and long-lasting than ordinary sadness caused by everyday disappointments. Difficult life events may contribute to depression, but it can also develop without an obvious external cause. A diagnosis generally requires that symptoms persist for at least two weeks and cause meaningful distress or impairment.
Study author Kate Ryan Kuhlman and her colleagues explored how stress contributes to the onset of depression in adolescents by exploring the association between negative life events and depressive symptoms. They noted that the risk for psychiatric disorders rapidly increases during adolescence. A previous study found that only four percent of 12-year-olds suffer from depression but that this increases to almost 14 percent by age 15.
Negative life events are stressful or harmful experiences that may negatively affect a person’s emotional or psychological well-being. In adolescence, these include events such as parental divorce, bullying, bereavement, family conflict, academic failure, illness, abuse, or friendship and relationship problems.
Study participants were 97 adolescents enrolled in the Teen Resilience Project, a prospective and longitudinal study of behavioral factors that link early life adversities with the onset of depression. The participants’ average age was 14 years old. Approximately 46 percent of them were girls.
Study authors recruited these participants by mass mailing households with adolescents. These mass mailings included a letter inviting parents to contact the researchers to learn more. Adolescents were eligible to participate if they were between 11 and 17 years of age.
Participants completed questionnaires at the start of the study, and then at four, eight, and 12 months after enrollment. They received $60 at the end of the first visit and an additional $15 at each follow-up. During the study, participants completed assessments of negative life events using an 18-item checklist asking about stressful occurrences involving family, friends, and school.
At the start of the study, participants also completed an assessment of early life adversity. Their parents completed a similar assessment regarding adverse childhood experiences. The researchers used these tools to specifically over-sample participants who had experienced early life adversity, a known risk factor for depression.
The study authors report that negative life events were common in their sample. Participants reported experiencing at least one negative life event in 71 percent of assessments. At each time point, between 20 and 30 percent of participants reported clinically elevated depressive symptoms, while 13 percent were identified as experiencing a full depressive episode at some point during the study period.
Over the study period, participants’ depressive symptoms tended to increase. This increase was specific to dysphoric mood and somatic complaints. Anhedonia and negative self-evaluations did not change significantly over time for the group as a whole. Dysphoric mood is a persistent state of sadness, irritability, unease, or emotional distress. Somatic complaints are physical symptoms such as headaches, fatigue, pain, sleep problems, or stomach discomfort.
Participants who experienced more negative events overall tended to have more severe depressive symptoms. This association was largely driven by an increase in negative self-evaluation. Girls who experienced a higher number of negative events tended to report much larger increases in negative self-evaluations than boys.
“The present data supported the well-established association between negative events and depressive symptoms, particularly negative self-evaluation symptoms and among females. Data support efforts to prevent depression among ELA-exposed [early life adversity-exposed] adolescents regardless of ongoing stress exposure as well as sex-specific symptom targets that may mitigate risk,” the study authors concluded.
The study contributes to the scientific understanding of the links between depressive symptoms and negative life events. However, it should be noted that the study was conducted on a small group of adolescents from southern California. Results on other cultural groups might not be identical. Additionally, the observational design of the study does not allow any direct cause-and-effect conclusions to be derived from the results.
The paper, “Sex, early life adversity, and negative self-evaluation shape the association between negative life events and depressive symptoms in adolescence,” was authored by Kate Ryan Kuhlman, Elizabeth E. Antici, Haley Dveirin, Mai-Lan M. Tran, Natalie A. Hall, Paul Delacruz, and Julienne E. Bower.