Individuals diagnosed with obsessive-compulsive disorder (OCD) experience obsessive thoughts and compulsive behaviors — hence the name of this condition. These symptoms can be distressing and highly disruptive, affecting a person's overall quality of life.
According to the Anxiety and Depression Association of America, OCD affects about 2.2 million adults in the United States, and the average age at onset is 19.
Researchers from Binghamton University, State University of New York, NY, have now found that where a person lives can influence how prominent their OCD symptoms are.
"The results of this project are exciting because they provide additional evidence for a new way of thinking about OCD," says Prof. Meredith Coles, first author of a new study that analyzes data on OCD prevalence rates according to geographic location.
"Specifically," she explains, "[the results] show that living in areas with more sunlight is related to lower rates of OCD."
The researchers' findings are published in the Journal of Obsessive-Compulsive and Related Disorders.
A 'misalignment' of the body clock?
Prof. Coles and colleagues collected and analyzed data from previous studies related to OCD, specifically looking for relationships between prevalence rates and geographical locations.
They found that individuals who live at higher latitudes — usually regions with few sunny spells — are exposed to more prevalent OCD symptoms. Why would this be?
Individuals living with OCD often complain that they are unable to fall asleep easily at night. Thus, they may end up waking late each morning, to make up for lost sleep the night before.
But this approach leads to a potentially harmful sleep-wake pattern that may worsen symptoms. For people who live in areas with shorter days, and less exposure to natural sunlight, this can mean that beneficial access to daylight is limited even further.
As Prof. Coles explains, "This delayed sleep-wake pattern may reduce exposure to morning light, thereby potentially contributing to a misalignment between our internal biology and the external light-dark cycle."
"People who live in areas with less sunlight may have less opportunities to synchronize their circadian clock [internal body clock that regulates our basic sleeping and eating patterns], leading to increased OCD symptoms," she adds.
Future studies, the researchers say, will look at potential treatment methods for OCD that take into account body clock disruptions, such as the ones that may occur in part due to environmental conditions.
"First, we are looking at relations between sleep timing and OCD symptoms repeatedly over time in order to begin to think about causal relationships. Second, we are measuring circadian rhythms directly by measuring levels of melatonin and having people wear watches that track their activity and rest periods."
Prof. Meredith Coles
"Finally," Prof. Cole says, "we are conducting research to better understand how sleep timing and OCD are related."
The team is also interested in learning whether heightened exposure to morning light would be beneficial to people with OCD; if so, this might also lead to better treatments addressing OCD symptoms.