Obsessive thinking is extremely common and mostly harmless, a new study shows.

Those nagging concerns that interrupt our day-to-day lives aren’t always a sign of serious mental distress. As it turns out, an overwhelming majority of us are pestered by some unwelcome thoughts.

Obsessive-compulsive thinking is completely normal, with about 94 percent of the population experiencing some kind of unwanted or intrusive thought at some point, according to an international study co-authored by Adam Radomsky, a professor of psychology at Concordia University in Montréal, Canada.

This research, published in the Journal of Obsessive-Compulsive and Related Disorders, would suggest that there is always someone else in the world who is also wondering whether or not they’ve left the oven on.

Researchers surveyed 777 participants in 13 countries across six continents. The participants were asked whether they had experienced at least one unwanted, intrusive thought (UIT) in the past three months. (These unwanted, intrusive thoughts were distinguished from lingering worries or rumination.) Nearly everyone in the sample reported at least one unwanted thought during the previous three-month period, and more than 90 percent of participants at most sites reported at least one kind of UIT.

Doubting intrusions were the most commonly reported types of intrusive thoughts. Repugnant intrusions, such as sexual or blasphemous thoughts, were the least commonly reported.

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Our brains are remarkable mechanisms, but sometimes, they provide us with more information than we want or need.

“The human brain is quite a creative little engine that drives us,” said Dr. Simon Rego, Director of Psychology Training and the CBT Training Program at Montefiore Medical Center/Albert Einstein College of Medicine “What it does is frequently generate thoughts of all types. Some are quite creative and wonderful, but some unfortunately are nonsensical and useless, and some are even extremely unpleasant or distasteful.”

Radomsky shares similar views.

“We are a thinking species,” he said. “If you pause for a moment, you’ll probably notice that you’re experiencing all kinds of different thoughts. We have many thoughts we barely notice, but these particular (unwanted, intrusive) thoughts, images and impulses are often noticeable in part because they intrude, or ‘pop’ into our awareness.”

These unwanted thoughts have deep roots, going all the way back to our primitive ancestors and their will to survive.

“In the evolutionary history of our society, our current generation is the byproduct of generation after generation after generation that…played it conservatively,” Rego explained. “Each subsequent generation survived because the brain was saying, ‘watch out, listen.’”

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Unwanted, intrusive thoughts may be a nuisance, but even the strangest thoughts that cross our minds are really quite common.

“The biggest thing to take home is obsessions are normal,” Rego said. “There’s nothing pathological in and of itself in experiencing an obsessive thought.”

UITs are a common occurrence, as the study shows, and are usually harmless. It’s how people react to these thoughts that’s of the greatest concern. Most people are able to brush off irritating yet benign thoughts, but for those with obsessive-compulsive disorder (OCD), tuning out these intrusions can be much more difficult.

“People in lay terms use ‘I’m obsessive’ in a way that’s not a clinical way,” Rego said.

He used a humorous mnemonic device distinguish between obsessive thinking and full blown OCD: “’I’m obsessed over Justin Bieber’ isn’t the same as having an obsessive thought about Justin Bieber,” he explained.

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Strange or unpleasant thoughts generally come and go for most people, but for those whose thoughts repeatedly plague them, therapy can provide much-needed relief. Rego highly recommends cognitive behavioral therapy (CBT), which focuses heavily on talking through issues, to combat obsessive thinking.

“In the cognitive model of obsessive compulsive disorder, we don’t pay a lot of attention to the content of the thoughts because we know content is quite common,” Rego said. “We pay attention to the appraisal of the content that one makes.”

Virtually everyone has experienced some outrageous or upsetting thought, but understanding how to react to these intrusions can help people to get on with their lives and learn to not sweat the “what ifs.”