How Do Mental Health Issues Co-Occur and Change Over Time in Children and Adolescents?

What you need to know

• The study identified six distinct developmental trajectories of co-occurring ADHD, internalizing, and externalizing symptoms in youth from ages 7 to 15.
• Most youth with elevated symptoms showed issues in multiple areas rather than just one domain.
• Different risk factors were associated with different trajectory groups, providing insights into the development of co-occurring mental health issues.
• Understanding these developmental patterns can help improve early identification and treatment of mental health problems in youth.

Background and Purpose

Mental health issues often co-occur and change over time as children develop. However, most research has looked at different types of symptoms separately rather than examining how they develop together. This study aimed to identify distinct developmental trajectories of commonly co-occurring mental health issues in youth - specifically ADHD, internalizing problems (like anxiety and depression), and externalizing problems (like aggression and rule-breaking). The researchers also wanted to determine what early risk factors might predict which trajectory a child follows.

Methods

The study analyzed data from 1,620 youth in Zurich, Switzerland who were assessed at ages 7, 8, 9, 10, 11, 12, 13 and 15. Teachers reported on the children’s ADHD, internalizing, and externalizing symptoms at each time point. The researchers used a statistical technique called group-based multi-trajectory modeling to identify distinct developmental patterns across all three symptom domains simultaneously. They then examined how factors like gender, prenatal smoking exposure, maternal depression, child personality, bullying victimization, and academic achievement were associated with following different trajectory paths.

Key Findings

Six Distinct Developmental Trajectories

The analysis revealed six distinct trajectory groups that youth tended to follow from childhood into adolescence:

1. Unaffected (32.5% of youth): Consistently low levels of all symptoms
2. Normative Maturing (27.9%): Slightly elevated early symptoms that declined over time
3. Internalizing (10.6%): Elevated internalizing problems but low ADHD/externalizing
4. Multimorbid Late Onset (13.5%): Increasing levels of all symptoms over time
5. Multimorbid Remitting (12%): Initially high symptoms in all areas that improved somewhat
6. Multimorbid with Remitting Externalizing (3.4%): Stable high ADHD and internalizing symptoms, but improving externalizing problems

This shows that most youth with mental health issues experienced elevations in multiple symptom domains rather than just one area. It also highlights different patterns of how symptoms can emerge or improve over development.

Risk Factors Associated with Trajectories

Several early risk factors were linked to following particular developmental trajectories:

• Males were more likely to be in the multimorbid groups with both emotional and behavioral issues.
• Smoking during pregnancy was associated with all elevated symptom trajectories.
• Maternal postnatal depression predicted early-onset symptom trajectories but not late-onset patterns.
• Bullying victimization was linked to multimorbid symptom patterns but not internalizing-only.
• Lower academic achievement was associated with all elevated symptom trajectories.

These findings provide clues about which children may be at risk for particular patterns of co-occurring mental health issues over time.

Implications

Understanding these common developmental trajectories of co-occurring mental health issues can help clinicians better identify at-risk youth and provide appropriate early intervention. The findings highlight the importance of assessing multiple symptom domains, even when a child is referred for one particular issue. They also suggest that risk factors like prenatal smoking exposure and early maternal depression may have lasting impacts on child mental health development.

The identification of distinct trajectory groups raises the possibility that different developmental patterns may have different causes, outcomes, or treatment needs. More research is needed to determine whether these trajectory-based subtypes are clinically meaningful and could inform diagnosis or treatment planning.

Limitations

The study relied only on teacher reports of symptoms, which may differ from parent or youth perspectives. The researchers could not examine why symptoms improved in some youth. The trajectory groups are useful summaries but should not be seen as literally existing subtypes. Replication in other samples is needed to confirm the patterns found.

Conclusions

This study provides new insights into how commonly co-occurring mental health issues tend to develop together from childhood into adolescence. The findings highlight the complexity of symptom trajectories, with most affected youth experiencing issues in multiple areas that change over time. Understanding these developmental patterns and their associated risk factors may help improve early identification and treatment of mental health problems in youth.