Dr Andrew Coogan, a neuroscientist based at the Department of Psychology, has published the results of a study linking Attention Deficit Hyperactivity Disorder (ADHD) in adults to the circadian rhythm, commonly referred to as the body clock. The study shows a direct link between the 24 hour body clock and the symptoms of ADHD. It opens the door for a possible therapy for the condition, currently usually managed by an expensive medication regime.
The research paper, compiled with Professor Johannes Thome of the University of Rostock in Germany and Dr. Alison Baird and other colleagues at Swansea University, is published in the prestigious journal Molecular Psychiatry, the world’s leading psychiatry journal, part of the Nature Group.
The study indicates that people with ADHD have ‘out of sync’ body clocks. The more disrupted their body clock is, the more severe the symptoms of their ADHD become. Dr Coogan and Professor Thome plan to continue their work in this field with a view towards designing intervention strategies based on their novel findings.
ADHD is a condition characterised by poor attention span, impulsiveness and hyperactivity. It affects approximately 5% of children in Western countries. About half of those with childhood ADHD will go on to express a form of the condition in adulthood. At present, there is likely to be in the order of 100, 000 adults in Ireland with ADHD. Like many other psychiatric conditions, the disorder is associated with particularly upset sleeping patterns and these sleep issues may in turn contribute to and worsen the symptoms of ADHD. Dr. Coogan and Professor Thome wanted to examine the circadian rhythm of people with ADHD. In order to do this, they extracted body clock genes, the drivers of this 24 hour sleep cycle based on biochemical, physiological and behavioural processes.
While the most important part of the body clock is located in the brain, the team needed readily accessible tissue from which to extract the biological material and so targeted the body clock genes which are found in the mouth. Having recruited 13 ADHD patients and a control group of 23 people in Swansea, the team formulated a technique for extracting the body clock genes by taking cheek swabs. Extracting samples in this way increased the accuracy of the test results as participants were in the comfort of their own homes and therefore suffered less sleep disturbance than they might have otherwise if giving blood samples in a hospital setting.
Once the samples were collected, the team was able to locate the body clock genes because of their unique codes, much like fingerprints. On identifying the gene, the team then determined whether it was switched on or off. When a gene is switched on, it undergoes a process called transcription, where DNA is converted into RNA. That RNA is then translated into protein. Because it is possible to detect RNA in saliva, they could ascertain which genes were switched on or off.
“Each participant wore an Actiwatch for a week, which is a device like a pedometer, to monitor their activity. They also took the mouth swabs every four hours during one 24 hour period. The data from the Actiwatch, combined with the gene samples, meant we could ascertain which body clocks were working properly. We noted that healthy patients showed body clock genes that were switched on at appropriate times of the day whereas the ADHD patients exhibited body clock genes that were flat with little, or no, activity,” said Dr. Coogan, adding that the disruption of circadian rhythms in adults with ADHD seemed to get more pronounced with the worsening of ADHD symptoms.
Dr Coogan said he was inspired by the results of the study to continue his work in the field with Professor Thome.
“We found the body clock in ADHD patients to be delayed and out of synchronicity with what is going on around them. We would like to reset the clock. We think it would improve the symptoms of the Attention Deficit Hyperactivity Disorder. This might be done with a combination of light therapy and melatonin hormone therapy and we hope to begin that study as soon as possible”.
This resetting technique has been used experimentally in psychiatric conditions in clinical trials and is not yet a mainstream method for treating ADHD. Dr. Coogan believes there is good reason to believe that changing the body clock will improve ADHD symptoms.
“It would be another tool in the box. At the moment, the only treatment options available are a limited number of drugs and psychotherapies. Any further approach we can offer patients and clinicians are exciting avenues to explore”, he said.
The work was funded by the U.S. National Alliance for Research on Schizophrenia and Depression (NARSAD, now known as the Brain and Behavior Research Foundation), the world's largest mental health charity and by the Welsh Assembly Government.