Depression in early adolescence is linked to attention problems that worsen over time

A new study published in the Journal of Affective Disorders provides evidence that while depression in early adolescence is linked to various cognitive difficulties at first, most of these issues do not persist as teens grow older. The exception is inattention, which tends to fuel a two-way relationship where poor attention worsens depression and vice versa. These findings suggest that addressing attention problems in school could be an effective way to help adolescents struggling with their mental health.

Depression is a major mental health concern that affects roughly eight percent of adolescents worldwide. As young people move through middle and high school, depression can negatively impact their relationships, physical health, and academic performance. Scientists recognize that depression in adults often comes with cognitive impairment, meaning difficulties with thinking, remembering, and concentrating.

When looking at adolescents, previous studies have provided mixed results regarding whether depression causes similar cognitive problems. Most prior research on young people has been cross-sectional. A cross-sectional study looks at a single moment in time. Because of this design, past research could not determine if depression leads to cognitive problems or if pre-existing cognitive struggles make a young person more likely to become depressed.

“Although research in adults has shown a strong association between depression and cognitive dysfunction, studies of adolescents have primarily looked at only one point in time and findings have been mixed. We wanted to examine the relationship between depression and cognition over time, to better understand whether one precedes the other. This information would be helpful in directing targeted intervention to improve mental health and educational outcomes for school aged children,” said study author Daphne J. Korczak, the SickKids’ Chair in Child and Youth Medical Psychiatry, director of the Children’s Integrated Mood and Body Depression Program, and an associate professor at the University of Toronto

The scientists used data from the Adolescent Brain Cognitive Development Study. This is a massive, long-term project tracking youth health and brain development across the United States. The current study included an exact sample size of 10,552 participants. At the beginning of the study, the children had an average age of 9.9 years. About 48 percent of the group was female.

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The researchers examined the participants at three different points in time. These included a baseline assessment, a two-year follow-up, and a four-year follow-up. Caregivers completed questionnaires about their children to measure the severity of depressive symptoms.

In addition, professionals conducted clinical interviews with both the children and their caregivers. This helped determine if a participant met the criteria for a formal depression diagnosis. Out of the total sample, 1,122 participants had a clinical diagnosis of depression.

To ensure accuracy, the scientists controlled for several outside factors. They accounted for participant age, sex at birth, ethnicity, caregiver education, annual household income, and the presence of other mental health conditions. Controlling for these variables ensures that the final results are actually due to depression and not a separate demographic factor.

To measure cognitive function, the participants completed a series of standardized tests using digital tablets. These assessments tested five specific areas of brain function. The scientists measured long-term memory, working memory, attention, language, and executive function.

Working memory refers to the ability to hold and manipulate information in the mind over short periods. Executive function involves higher-level skills like planning, controlling impulses, and following complex instructions. Long-term memory involves storing information over longer durations, while language assessments measure vocabulary skills.

During the baseline assessment, the scientists found that depression was broadly linked to poorer mental performance. Higher depressive symptoms and a formal depression diagnosis were associated with lower scores in attention, long-term memory, working memory, and executive function. These initial results aligned with previous research showing that depressed children often experience cognitive difficulties.

However, the longitudinal findings painted a different picture. Over the four-year tracking period, most of the initial cognitive deficits disappeared. By the two-year and four-year marks, issues with working memory, long-term memory, and executive function were no longer significantly linked to depression in the same way.

“Our study suggests that there are developmental shifts in the way that depression symptoms present in later childhood and early adolescence; cognitive symptoms may be more prominent in younger children,” Korczak told PsyPost.

The scientists suggest that this shift might happen because the nature of depression changes as children become teenagers. In early adolescence, depression often shows up as physical and mental fatigue, which directly impacts test performance.

As teenagers grow older, their depression tends to shift toward emotional and social issues. They might struggle more with identity development or face difficulties with peer relationships. This shift toward emotional concerns might explain why the direct effects on memory and planning fade away over time.

Despite most cognitive deficits fading, the researchers discovered a persistent and reciprocal relationship between depression and attention. Higher depressive symptoms at baseline predicted poorer attention two years later. In turn, lower attention scores at the two-year mark predicted higher depressive symptoms at the four-year mark.

“The findings suggest that depression and attention deficits may exacerbate one another over time, and contribute to an overall pattern that can impair academic performance and daily functioning,” Korczak said.

A depressed teenager might struggle to focus in class, which can lead to poor grades. The resulting academic failure can then make the teenager feel worse about themselves, ultimately increasing their depressive symptoms.

In an unexpected twist, the researchers also found that higher depressive symptoms predicted better language skills over time. The scientists suspect this might be related to rumination, which is the habit of repeatedly thinking about negative feelings. Teenagers who ruminate might develop a larger vocabulary to describe their emotional pain.

Alternatively, their advanced language skills might simply make their parents more aware of their struggles. Adolescents who can clearly articulate their sadness might prompt their caregivers to report higher levels of depression on questionnaires. Future studies are needed to fully explain this specific link between vocabulary and mood.

“Our findings have both educational and clinical implications,” Korczak explained. “In educational settings, these results highlight the importance of considering the etiological role of depression when inattention is identified, as teachers may be more likely to notice attentional difficulties than depression symptoms. In clinical settings, our study results suggest that children and adolescents referred for either depression or attention difficulties should be evaluated for both problems in order to receive the most appropriate academic accommodations and psychiatric treatment.”

While this research provides a detailed look at adolescent mental health, it has some limitations. The study relied heavily on caregiver reports to measure depressive symptoms. Parents might not always know exactly what their children are feeling internally. Future studies should include self-reported data directly from the adolescents. This would help capture a more complete picture of their emotional state.

The participants also came from the general community and generally had mild levels of depression. “More research is needed to see whether these patterns are similar in young people with more severe depression,” Korczak said.

The study, “Depression and cognition in adolescents: A comparison of cross-sectional and longitudinal effects,” was authored by Sarah Kuburi, Anett Schumacher, Eric Tu, and Daphne J. Korczak.