Trouble focusing may be both a cause and result of teen depression

Depression affects about 8% of adolescents worldwide. During the middle and high school years, it can influence friendships, physical health, and academic performance. In adults, depression is often tied to problems with thinking, remembering, and concentrating. Scientists have long wondered whether the same pattern appears in younger people.

Earlier studies offered mixed answers because most examined adolescents at only one moment in time. That type of research cannot show whether depression causes thinking difficulties or whether existing cognitive struggles increase the risk of depression.

To better understand the relationship, researchers analyzed data from the Adolescent Brain Cognitive Development Study, a large long-term project tracking youth health and brain development across the United States. The study included 10,552 participants with an average starting age of 9.9 years. About 48% were girls.

Researchers assessed the participants 3 times: at the beginning of the study, after 2 years, and again after 4 years. Caregivers completed questionnaires about depressive symptoms, and professionals conducted interviews with both children and caregivers to determine whether participants met the criteria for a clinical diagnosis of depression. In total, 1,122 participants were diagnosed with depression.

The study also measured several aspects of thinking ability through standardized digital tests. These examined attention, working memory, long-term memory, language ability, and executive function, which includes skills such as planning and controlling impulses.

At the start of the study, depression was linked to lower scores across several areas. Children with stronger depressive symptoms performed worse in attention, memory, and executive function tests.

But the longer-term results showed a different pattern. Over 4 years, most of the early cognitive differences disappeared. By the two-year and four-year follow ups, depression was no longer strongly connected to difficulties with memory or planning.

Researchers say this change may reflect how depression evolves as children enter adolescence. Younger children with depression often experience fatigue and mental exhaustion, which can affect test performance. As teenagers grow older, depression tends to appear more through emotional and social struggles, such as difficulties with identity or peer relationships.

Attention problems, however, showed a lasting connection to depression. Higher depressive symptoms at the start predicted poorer attention 2 years later. In turn, weaker attention predicted stronger depressive symptoms at the 4 year-mark.

This pattern suggests a feedback loop. A teenager who is depressed may struggle to focus in class, leading to poor grades or frustration. Academic setbacks can then worsen feelings of sadness or failure, deepening the depression.

Researchers also observed an unexpected link between depressive symptoms and stronger language skills over time. One possible explanation is rumination, the habit of repeatedly thinking about negative feelings. Teens who dwell on their emotions may develop a richer vocabulary to describe them. Another possibility is that adolescents with strong language skills communicate their distress more clearly, making caregivers more likely to report symptoms.

The researchers note some limitations. Much of the information about depressive symptoms came from caregivers, who may not fully know what their children are experiencing. Future studies may include more reports directly from adolescents.

Earlier, Qazinform News Agency reported that a noninvasive brain treatment shows promise for depression.