Sleep problems linked to psychiatric disorders in young people
A new study found that young people with a genetic condition known as deletion syndrome (22q11.2DS) had significant alterations in their sleep patterns that are linked to psychiatric disorders.
The study was published in the journal, eLife, and led by Nicholas Donnelly, PhD, clinical lecturer at the Centre for Academic Mental Health at the University of Bristol in the United Kingdom. Previous research had shown that most young people with 22q11.2DS have sleep problems linked to psychiatric disorders. These studies, however, didn’t analyze brain activity during sleep, they were based off parents’ reporting their child’s sleep habits. For this study, Donnelly and his team of researchers sought to discover whether there are differences in brain activity during sleep in those with 22q11.2DS compared to those without the condition.
For their investigation, researchers recorded the brain activity during one night of sleep in 28 young people aged six to 20 years old with 22q11.2DS, along with 17 of their unaffected siblings. Researchers measured brain activity through an electroencephalogram (EEG), which records the brain’s electrical activity and sleep patterns know as spindles and slow-wave (SW) oscillations.
The study’s results showed that those with 22q11.2DS had a greater proportion of slow-wave sleep (N3 NREM), lower proportions of the lightest sleep stage at the beginning of sleep (N1), as well as reduced rapid eye movement (REM) sleep compared with their siblings. In addition, participants with 22q11.2DS demonstrated increased EEG power for SW oscillations and spindles. Spindle patterns were also increased in frequency and density and there was a stronger coupling between spindle and SW EEG features in those with 22q11.2DS. According to the researchers, these abnormal patterns suggest connections between the cortex and the thalamus, the regions of the brain where these oscillations are generated.
In addition, the team tested both groups’ morning recall through a 2D object location test before sleep and in the morning. For the test, participants had to remember where matching cards were on a screen. The researchers found that for those with 22q11.2DS, higher spindle and SW amplitudes were associated with lower accuracy. Conversely, for those without 22q11.2DS, higher amplitudes were associated with higher accuracy.
Finally, using a statistical method known as mediation, researchers estimated the impact of these altered sleep patterns on psychiatric symptoms in both groups. Their results suggested that effects on anxiety, attention deficit/hyperactivity disorder (ADHD), and autism disorder (ASD) associated with 22q11.2DS, were partially mediated by EEG differences.
“Our EEG findings together suggest a complex picture of sleep neurophysiology in 22q11.2DS and highlight differences that could serve as potential biomarkers for 22q11.2DS-associated neurodevelopmental syndromes,” said co-senior author Matt Jones, PhD, professorial research fellow in Neuroscience, University of Bristol, UK. “Further study will now need to clarify the relationship between psychiatric symptoms, sleep EEG measures and neurodevelopment, with a view to pinpointing markers of brain circuit dysfunction that could inform doctors which patients are most at risk, and support treatment decisions.”