How Common Are Co-occurring Externalizing Disorders in Adolescents?

What you need to know

• This protocol outlines a planned systematic review and meta-analysis to examine how common co-occurring externalizing disorders are in adolescents aged 13-18.
• The review will focus on attention deficit/hyperactivity disorder (ADHD), conduct disorder, oppositional defiant disorder, and substance use disorders.
• Understanding patterns of co-occurrence can inform diagnosis, treatment, and models of how mental health problems develop and relate to each other.

Background on externalizing disorders

Externalizing disorders refer to a group of behavioral disorders that typically emerge in childhood and involve problematic behaviors directed outward toward others or the environment. Common externalizing disorders include:

• Attention deficit/hyperactivity disorder (ADHD): Characterized by inattention, hyperactivity, and impulsivity
• Conduct disorder: Involves persistent aggressive, destructive, or deceitful behaviors that violate social norms
• Oppositional defiant disorder: Involves a pattern of angry, irritable mood and defiant, argumentative behaviors
• Substance use disorders: Problematic use of alcohol or drugs that leads to significant impairment

These disorders are some of the most common reasons children and adolescents are referred for mental health treatment. They can cause significant difficulties for the individual, their family, and society if left untreated. Epidemiological studies suggest that 5-10% of school-aged children have serious, ongoing behavioral and emotional problems.

An important feature of externalizing disorders is that they frequently co-occur with each other and with other mental health conditions. Understanding these patterns of co-occurrence is crucial for several reasons:

1. It can inform more accurate diagnosis and treatment planning
2. It provides clues about shared risk factors and underlying causes
3. It helps refine theoretical models of how mental health problems develop and relate to each other

The need for a systematic review

While many studies have looked at co-occurring disorders in children and adults, less research has focused specifically on adolescents. The adolescent period (ages 13-18) is particularly important to study because:

1. Many mental health problems first emerge or intensify during this developmental stage
2. Patterns established in adolescence often persist into adulthood
3. It may be an optimal time for prevention and early intervention efforts

The researchers identified a gap in the literature - there have not been any comprehensive systematic reviews examining the prevalence of co-occurring externalizing disorders specifically in adolescents. This review aims to fill that gap.

Goals of the review

The primary objective is to determine how common co-occurring externalizing disorders are among adolescents aged 13-18. Specifically, the review will examine the prevalence of having both:

1. An externalizing disorder (ADHD, conduct disorder, oppositional defiant disorder, or substance use disorder) AND
2. Any other psychiatric disorder

Secondary objectives include:

• Examining co-occurrence patterns between different externalizing disorders
• Looking at gender differences in co-occurrence rates
• Investigating co-occurrence between externalizing disorders and other disorder categories (internalizing and thought disorders)
• Exploring reasons for differences in findings between studies

Methodology

The researchers have outlined a comprehensive methodology to ensure a rigorous and transparent review process:

Literature search

• Searching multiple electronic databases (e.g. PsycINFO, MEDLINE, Embase)
• Reviewing reference lists of included studies
• Searching grey literature sources
• Hand-searching key journals
• No language restrictions

Study selection

• Two independent reviewers will screen titles/abstracts and full texts
• Studies must:
  • Include adolescents aged 13-18
  • Examine prevalence of co-occurring externalizing disorders
  • Use DSM criteria for diagnoses
  • Have at least 25 participants
• Disagreements resolved through discussion or third reviewer

Data extraction and quality assessment

• Two independent reviewers will extract data and assess study quality
• Will use standardized forms and the JBI critical appraisal tool for prevalence studies

Data synthesis

• Meta-analysis to calculate pooled prevalence estimates where possible
• Subgroup analyses by gender, measurement method, study quality
• Assessment of heterogeneity and publication bias
• Sensitivity analyses

This rigorous methodology will help ensure the review produces reliable results that can inform clinical practice and future research.

Potential implications

The findings from this systematic review could have important implications for understanding and addressing mental health problems in adolescents:

For clinicians:

• Raise awareness of how frequently externalizing disorders co-occur with other problems
• Inform more comprehensive assessment practices
• Guide treatment planning and selection of interventions that can address multiple co-occurring issues

For researchers:

• Identify gaps in the current literature to guide future studies
• Provide data to refine theoretical models of psychopathology development
• Inform the design of prevention and early intervention programs

For policymakers:

• Highlight the need for integrated mental health services that can address multiple co-occurring problems
• Guide resource allocation for adolescent mental health services
• Inform school-based mental health screening and intervention programs

For patients and families:

• Normalize the experience of having multiple mental health challenges
• Encourage seeking comprehensive assessment and treatment
• Provide hope that addressing one problem area may have positive effects on others

Limitations and considerations

While this review protocol is well-designed, there are some potential limitations to consider:

1. Focus on DSM diagnoses: By only including studies using DSM criteria, the review may miss some relevant research using other diagnostic systems or dimensional approaches to measuring mental health problems.

2. Age range: The narrow focus on ages 13-18 is a strength in terms of developmental specificity, but may limit the number of eligible studies.

3. Exclusion of clinical samples: While focusing on community and school-based samples improves generalizability, it may miss important data from treatment-seeking populations.

4. Potential for high heterogeneity: Given the range of disorders, measurement methods, and populations included, there may be substantial variability between studies that makes it difficult to draw firm conclusions.

Conclusions

• This systematic review will provide valuable data on how frequently externalizing disorders co-occur with other mental health problems in adolescents.
• The findings can inform clinical practice, research, and policy related to adolescent mental health.
• Understanding co-occurrence patterns is crucial for developing more effective prevention and treatment approaches.
• Results should be interpreted cautiously given potential limitations, but will fill an important gap in the current literature.

By shedding light on the complex patterns of mental health challenges faced by adolescents, this review has the potential to improve our ability to support young people during this critical developmental period. The results will be eagerly anticipated by researchers and clinicians working in the field of adolescent mental health.