Can Childhood Behaviors Predict Future Delinquency in People with ADHD?

What you need to know

• Early conduct problems, not ADHD symptoms, best predicted later delinquent behavior in young adults diagnosed with ADHD as children.
• Low nonverbal intelligence was an additional risk factor for future delinquency.
• Behavioral interventions focused on reducing conduct problems may help prevent later delinquency in children with ADHD and behavior issues.

Understanding ADHD and delinquency risk

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common reasons children are referred for mental health treatment. About 4% of children have ADHD, with boys being diagnosed about twice as often as girls. Children with ADHD often struggle with staying focused, controlling impulses, and regulating their activity level. They are also at higher risk for developing other behavioral problems as they get older.

Several studies have found that children diagnosed with ADHD are more likely to engage in delinquent or criminal behavior as teenagers and adults compared to those without ADHD. For example, one study found that adults who had ADHD as children were over 3 times more likely to be arrested and over 2 times more likely to be convicted of a crime.

However, it’s not clear if ADHD itself leads directly to delinquent behavior, or if other factors are involved. Some researchers have argued that ADHD alone increases risk for later delinquency. Others suggest that ADHD only predicts future delinquency when it occurs along with early behavior problems like aggression or rule-breaking.

Understanding what factors best predict delinquency risk in people with ADHD is important. It could help identify which children may need additional support and guide the development of more effective early interventions.

The Cologne Adaptive Multimodal Treatment (CAMT) Study

To examine this issue, researchers conducted a long-term study called the Cologne Adaptive Multimodal Treatment (CAMT) Study. They followed a group of 75 children diagnosed with ADHD into young adulthood. All of the children received individualized ADHD treatment between ages 6-10, including medication, behavioral therapy, or a combination of both.

The researchers assessed the participants again 13-24 years later when they were young adults (average age 26). At this follow-up, they asked about any police contacts, offenses, or convictions the participants had experienced. Based on this information, they divided participants into two groups:

1. Non-delinquent group (n=34): No reported police contacts or convictions
2. Delinquent group (n=25): At least one reported police contact or conviction

They then looked back at various child and family factors measured after the initial ADHD treatment to see which ones best predicted whether someone ended up in the delinquent or non-delinquent group as an adult.

Key findings on delinquency predictors

The study found several important differences between the delinquent and non-delinquent groups:

Intelligence scores

The non-delinquent group had significantly higher scores on two measures of intelligence:

• Achievement scale (measures knowledge of facts and academic skills)
• Nonverbal scale (measures cognitive abilities using visual/hands-on tasks)

This suggests that stronger cognitive and academic abilities may help protect against future delinquency risk.

Behavior problems

The delinquent group had significantly higher scores on parent and teacher ratings of:

• Delinquent behaviors
• Externalizing problems (acting out, aggression, rule-breaking)

They were also more likely to meet diagnostic criteria for conduct disorder based on parent and teacher reports.

This indicates that early behavior problems, beyond just ADHD symptoms, are a key risk factor for later delinquency.

Family factors

Based on clinician ratings, the delinquent group was more likely to experience:

• Mental health issues in family members (other than parents)
• Lack of warmth in the parent-child relationship
• Poor parental supervision/inconsistent discipline
• Insufficient learning opportunities at home

These findings highlight how family dynamics and home environment can influence delinquency risk.

ADHD symptoms

Importantly, ratings of ADHD symptom severity in childhood were not significantly associated with later delinquency. This suggests that ADHD symptoms alone do not drive increased delinquency risk.

Best predictors of future delinquency

To determine which factors were the strongest predictors of delinquency, the researchers used a statistical technique called Chi-squared automatic interaction detector (CHAID) analysis. This method identifies the variables that best differentiate between groups.

The CHAID analysis found that delinquent behavior in young adulthood was best predicted by:

1. Meeting diagnostic criteria for conduct disorder based on parent ratings AND having a nonverbal intelligence score of 106 or lower

2. High teacher ratings of delinquent behavior problems

Using just these two factors, the researchers were able to correctly classify 81% of participants as delinquent or non-delinquent.

Implications for treatment and prevention

These findings have important implications for identifying children with ADHD who may be at higher risk for future delinquency, as well as for developing more targeted interventions. Some key takeaways include:

Focus on conduct problems, not just ADHD symptoms

Early conduct problems like aggression and rule-breaking were the strongest predictors of later delinquency - more so than ADHD symptoms. This suggests that behavioral interventions focused specifically on reducing conduct problems may help prevent later delinquency in children with ADHD.

Consider cognitive abilities

Lower nonverbal intelligence scores were an additional risk factor when combined with conduct problems. Providing extra academic support and building cognitive skills may help reduce risk in some children.

Address family factors

Issues like lack of parental warmth, poor supervision, and limited learning opportunities at home were associated with delinquency risk. Parent training and family-based interventions may be beneficial.

Identify at-risk children early

Using parent and teacher ratings of conduct problems, along with cognitive testing, could help identify which children with ADHD may need more intensive or tailored interventions to prevent future delinquency.

Provide ongoing support

While all participants received ADHD treatment as children, many still engaged in later delinquent behavior. This highlights the need for continued monitoring and support as children with ADHD enter adolescence and young adulthood.

Limitations and future directions

It’s important to note some limitations of this study:

• The sample size was relatively small (59 participants), which may have limited the ability to detect smaller effects.

• All participants were referred for and received ADHD treatment as children, so results may not generalize to untreated ADHD.

• The study did not compare different types of childhood interventions, so it can’t determine if certain treatments were more effective for preventing later delinquency.

Future research with larger samples could help clarify the relationships between ADHD, conduct problems, cognitive abilities, and delinquency risk. Studies comparing different treatment approaches would also be valuable for developing more effective early interventions.

Additionally, this study grouped all types of delinquent behavior together. Future work examining predictors of specific types of offenses could provide more nuanced insights.

Conclusions

• Early conduct problems, not ADHD symptoms, best predicted future delinquent behavior in young adults diagnosed with ADHD as children.
• Lower nonverbal intelligence was an additional risk factor when combined with conduct problems.
• Using parent/teacher ratings of conduct problems and cognitive testing may help identify children with ADHD at higher risk for later delinquency.
• Behavioral interventions focused on reducing conduct problems, building cognitive skills, and addressing family factors may help prevent later delinquency in at-risk children with ADHD.