How Are Sleep Problems and ADHD Connected Genetically?

What you need to know

• Children with ADHD often experience sleep problems, but the reasons for this are not fully understood
• This study found limited evidence that sleep problems in children with ADHD are caused by genetic factors related to sleep or ADHD
• The genetic factors influencing sleep in adults may be different from those affecting children with ADHD

Background on ADHD and sleep problems

Attention-deficit/hyperactivity disorder (ADHD) is a common condition that affects children’s ability to focus, control impulses, and regulate activity levels. Many children with ADHD also have trouble sleeping. These sleep issues can make ADHD symptoms worse and negatively impact quality of life for both children and their families.

Some of the sleep problems that children with ADHD often experience include:

• Difficulty falling asleep at night
• Waking up frequently during the night
• Not feeling rested after sleeping
• Excessive daytime sleepiness
• Nightmares

Researchers have been trying to understand why sleep problems and ADHD so often occur together. One theory is that ADHD and sleep issues may have some of the same genetic causes. This study aimed to investigate potential genetic links between ADHD and sleep problems.

How genes influence complex traits

To understand this study, it’s helpful to know a bit about how genes can influence traits like ADHD or sleep patterns. Most human characteristics are influenced by many genes, not just one or two. Researchers can look at large groups of genes, called polygenic scores, to measure someone’s genetic tendency toward certain traits.

Polygenic scores take into account small effects from many different genes. A higher polygenic score for a trait means a person’s genes give them a greater chance of having that trait. However, genes are not destiny - environmental factors also play an important role in how traits develop.

What this study investigated

This study looked at polygenic scores related to sleep traits and ADHD in children diagnosed with ADHD and their parents. The researchers wanted to know:

1. Do children with ADHD inherit more genetic risk factors for sleep problems from their parents than would be expected by chance?

2. Are genetic risk factors for adult sleep traits associated with actual sleep problems in children with ADHD?

3. Does a higher genetic risk for ADHD increase the chances of having sleep problems in children already diagnosed with ADHD?

Key findings

Inheritance of sleep-related genetic factors

The study found limited evidence that children with ADHD inherit more sleep-related genetic risk factors than expected. There was some weak evidence that children with ADHD may inherit slightly more genetic factors associated with longer sleep duration. However, they did not seem to inherit more genetic risk for insomnia or differences in sleep timing preferences.

Genetic risk for adult sleep traits and childhood sleep problems

Interestingly, genetic risk scores for adult sleep traits were not associated with reported sleep problems in children with ADHD. This suggests that the genetic factors influencing sleep in adults may be different from those affecting sleep in children with ADHD.

ADHD genetic risk and sleep problems

The study did not find evidence that higher genetic risk for ADHD increases the chances of having sleep problems among children already diagnosed with ADHD. This indicates that sleep issues in ADHD may not simply be a sign of more severe ADHD.

Why these findings matter

These results suggest that the common occurrence of sleep problems in children with ADHD may not be primarily due to shared genetic factors. This is important because it points researchers toward investigating other potential causes.

Some other factors that could contribute to sleep issues in children with ADHD include:

• Environmental factors like family routines or stress
• Side effects of ADHD medications
• Behavioral factors related to ADHD symptoms (e.g. difficulty winding down at night)

Understanding the causes of sleep problems in ADHD is crucial for developing effective treatments. If sleep issues were mainly genetic, treatments focusing on environmental or behavioral factors might be less effective. However, this study suggests that such non-genetic approaches to improving sleep may indeed be worthwhile for children with ADHD.

Limitations and future directions

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

• The sample size was relatively small, which can make it harder to detect subtle genetic effects
• Sleep problems were assessed using interviews rather than objective measures like sleep studies
• The genetic risk scores were based on studies of adults, which may not capture all the relevant genetic factors for children

Future research could address these limitations by:

• Using larger sample sizes
• Including objective measures of sleep alongside questionnaires
• Developing genetic risk scores based on studies of children’s sleep patterns

Additionally, more research is needed to understand how environmental factors interact with genetic risks to influence sleep in children with ADHD.

Conclusions

• There is limited evidence that sleep problems in children with ADHD are caused by the same genetic factors that influence sleep in adults
• Sleep issues in children with ADHD do not appear to be simply a sign of more severe ADHD from a genetic perspective
• Other factors, such as environment and behavior, likely play important roles in sleep problems among children with ADHD
• Treatments targeting these non-genetic factors may be helpful for improving sleep in children with ADHD