How Common Are Intrusive Thoughts? What the Research Actually Counted
Published August 17, 2026. Last updated August 17, 2026.
How common are intrusive thoughts? The best single answer comes from a study that interviewed 777 university students at 15 sites in 13 countries across six continents and found 93.6% of them had experienced at least one unwanted intrusive thought in the previous three months. That paper prints a second rate of 94.3% on the 683 participants left after exclusions, and its site rates run from 81.2% to 100%. Research on this question goes back to 1978 and has landed in the 80s and 90s in every sample since. Each number below carries its data collection year, its population, and the document reporting it.
Key statistics
- 93.6% of 777 university students interviewed at 15 sites in 13 countries across six continents reported an unwanted intrusive thought in the previous three months, in data collected before the paper’s June 2013 submission; the paper reports no fieldwork dates (Radomsky et al., 2014).
- The international intrusions study submitted for publication in June 2013 prints a second rate of 94.3% in its results section, on the 683 university-student participants left after 94 exclusions, with no fieldwork dates reported (Radomsky et al., 2014).
- Site rates in the international intrusions study submitted for publication in June 2013 ran from 81.2% in Thessaloniki to 100% in Fredericton, Montreal and Tehran, with no fieldwork dates reported (Radomsky et al., 2014).
- 28.2% of 2,073 U.S. adults reported lifetime obsessions or compulsions, in face-to-face household interviews conducted February 2001 to December 2003 for the National Comorbidity Survey Replication (Ruscio, Stein, Chiu, & Kessler, 2010).
- 2.3% of those same 2,073 U.S. adults met full DSM-IV criteria for obsessive-compulsive disorder across their lifetime, and 1.2% within the previous 12 months (Ruscio, Stein, Chiu, & Kessler, 2010).
Cite this page
APA: Eduard, S. (2026, August 17). How common are intrusive thoughts? What the research actually counted. StumbleTowardTheLight. https://stumbletowardthelight.com/how-common-are-intrusive-thoughts/
MLA: Eduard, Sebastian. “How Common Are Intrusive Thoughts? What the Research Actually Counted.” StumbleTowardTheLight, 17 Aug. 2026, stumbletowardthelight.com/how-common-are-intrusive-thoughts/.
The source table
| # | Statistic | Data collected | Source type | Source |
|---|---|---|---|---|
| 1 | 93.6% of 777 university students at 15 sites in 13 countries reported an intrusion in the previous three months | 2007-2013 (collection dates unstated; interview schedule dated 2007, manuscript received June 12, 2013) | primary study (structured interview) | Radomsky et al., 2014 |
| 2 | 94.3%, the same paper’s results-section rate, on the 683 participants left after 94 exclusions | same fieldwork as row 1 (collection dates unstated; before the June 2013 submission) | primary study (structured interview) | Radomsky et al., 2014 |
| 3 | Site rates ran from 81.2% (Thessaloniki) to 100% (Fredericton, Montreal, Tehran) | same fieldwork as row 1 (collection dates unstated; before the June 2013 submission) | primary study (structured interview) | Radomsky et al., 2014 |
| 4 | 28.2% of 2,073 U.S. adults reported lifetime obsessions or compulsions; checking (15.4%), hoarding (14.4%), ordering (9.1%) led | February 2001 to December 2003 (published 2010) | federal survey | Ruscio, Stein, Chiu, & Kessler, 2010 |
| 5 | 2.3% lifetime and 1.2% twelve-month DSM-IV OCD prevalence among those same 2,073 adults | February 2001 to December 2003 (published 2010) | federal survey | Ruscio, Stein, Chiu, & Kessler, 2010 |
| 6 | 104 of 124 non-clinical participants (84%) reported unacceptable intrusive thoughts or impulses | before 1978 publication (dates unreported) | primary study (via Radomsky et al., 2014; original paywalled) | Rachman and de Silva, 1978 |
| 7 | 88.2% of participants in the first replication reported unwanted intrusions | before 1984 publication (dates unreported) | primary study (via Radomsky et al., 2014; original paywalled) | Salkovskis and Harrison, 1984 |
| 8 | 99% of 293 students reported at least one intrusive thought from a checklist of about 50 items | before 1993 publication (dates unreported) | primary study (via University of Rochester Medical Center, 2023; original paywalled) | Purdon and Clark, 1993 |
| 9 | “More than 6 million people in the United States” have distressing intrusive thoughts (traced below) | no fieldwork; undated arithmetic estimate | derived (arithmetic shown in the myth section below) | Seif, undated |
How common are intrusive thoughts in the general population?
Between 80% and 100% of non-clinical participants report them, depending on the site and the method. The tightest figure comes from the international interview study, where 93.6% of 777 university students on six continents reported an unwanted intrusive thought in the previous three months (Radomsky et al., 2014). Interviewers read each participant a careful definition of what counts as an unwanted intrusive thought, then asked about seven content areas one at a time.
Two caveats travel with that number. Participants were university students, a group the authors write “can normally be considered to have a high level of functioning,” and the interview supplied examples of each thought type, which the authors flag as a possible pull toward endorsement. Rates also spread widely inside the average: 100% in Fredericton, Montreal and Tehran, 88% in Firenze and Padova, 84% in Buenos Aires, 81.2% in Thessaloniki. The authors write that they cannot tell from this study whether that spread reflects culture or method, such as how the interview was translated or administered at each site.
What percentage of people have intrusive thoughts?
93.6% in the six-continent interview sample, and the studies feeding into it landed in the same territory. The line begins with a paper published in 1978, in which 99 of 124 non-clinical participants, a mix of students and hospital employees, reported having unacceptable thoughts or impulses; five more were counted after volunteering descriptions of their own, taking the total to 104 of 124, or 84% (Rachman and de Silva, described in Radomsky et al., 2014). Salkovskis and Harrison’s replication, published in 1984, reported 88.2%. A checklist study of 293 students by Purdon and Clark, published in 1993, reported 99% (University of Rochester Medical Center, 2023).
Checklist studies sit at the top of that range, which follows from the method: a list of 50 candidate thoughts gives a person 50 chances to recognise one.
Which intrusive thoughts are most common?
Doubting intrusions, which the international study reports as the most commonly endorsed category “at nearly every site” (Radomsky et al., 2014). These are thoughts about whether the door was locked, whether the message was sent, whether that thing you said landed wrong. The authors list the sheer prevalence of doubt among the findings they call unexpected, write that it “was discussed at length by the study authors,” and report checking whether doubts about cleanliness had been miscoded as doubting intrusions, which “did not appear to be the case.” Sexual, religious and immoral intrusions were reported least often, and the authors count them among the most difficult to control.
U.S. household data lines up on content. Among 2,073 adults interviewed between February 2001 and December 2003, the most commonly reported lifetime obsessions and compulsions were checking (15.4%), hoarding (14.4%) and ordering (9.1%), with sexual or religious content at 2.3% and harming content at 1.7% (Ruscio, Stein, Chiu, & Kessler, 2010). Doubt-shaped thoughts turn up everywhere. The frightening, taboo ones are rarer and heavier, which is a large part of why they feel diagnostic to the person having them. Anyone tracking their own patterns can work from the signs of overthinking.
Intrusive thoughts statistics and what they measure
Every prevalence figure here counts one event: a person reporting at least one unwanted thought, image or impulse arriving unbidden inside a stated window. Frequency, distress or interference, the importance of removing the thought and the difficulty of removing it each ride on their own 0-to-5 scale, and in the international study the means for each participant’s most distressing intrusion ran from 1.78 (difficulty removing a contamination intrusion) to 3.62 (importance of removing a sexual intrusion) (Radomsky et al., 2014).
How many people with intrusive thoughts have OCD?
A small fraction. In the National Comorbidity Survey Replication, 28.2% of 2,073 U.S. adults reported obsessions or compulsions at some point in their lives, 2.3% met full DSM-IV criteria for obsessive-compulsive disorder across their lifetime, and 1.2% met them in the previous 12 months (Ruscio, Stein, Chiu, & Kessler, 2010). Those interviews ran face to face with a nationally representative sample from February 2001 to December 2003, at a 70.9% response rate. The probability of meeting OCD criteria climbed with the number of types reported, from 7.4% at three to 36.4% at four types.
The cognitive model built on this research treats the arrival of an intrusion as ordinary human cognition and the interpretation of it as the part that varies. Someone whose intrusions have become frequent, distressing or hard to put down deserves a proper assessment from a clinician who works with OCD and anxiety, and getting that early tends to make the work shorter. Readers may meanwhile recognise themselves in the pathological overthinker profile, or in the question of whether overthinking is anxiety wearing another name.
Where does the “6 million Americans have intrusive thoughts” figure come from?
It comes from an arithmetic estimate published by psychologist Martin N. Seif, a cofounder of the Anxiety and Depression Association of America. His page shows the working: “there are no formal studies that ask people, ‘Do you have unwanted intrusive thoughts that cause you a great deal of distress?'” He starts from about one in ten people having an anxiety disorder in their lifetime, applies a figure of about 20% of those people having unwanted intrusive thoughts, and reaches 2% of a 350 million U.S. population, about 7 million (Seif, undated). The page carries both the 6 million headline and the roughly 7 million his own math produces, with no year given for the inputs.
The figure circulates on its own. A March 8, 2023 Fortune article by Alexa Mikhail relays it as “intrusive thoughts are estimated to affect six million Americans, according to the Anxiety and Depression Association of America,” and states in the same piece that over 90% of people experience intrusive thoughts, naming no study for either (Mikhail, 2023).
The two numbers count two different groups. Seif’s estimate covers people whose intrusive thoughts cause them great distress. The 93.6% covers people who experience one at all. Side by side they describe a very common experience that turns serious for a small share of those who have it.
Methodology
Statistics here were selected from the primary intrusions literature, then the widely relayed 6 million figure was traced back to the page where its author sets out his derivation. The Radomsky et al. (2014) paper was read in full: its abstract rate (93.6%), results-section rate (94.3%), exclusion count, site range and stated limitations all come from the published text. That paper reports no data-collection dates; its interview schedule is dated 2007 and its manuscript was received June 12, 2013, so the page states that bound as a bound. The Ruscio et al. (2010) figures and the February 2001 to December 2003 fieldwork dates were confirmed against that paper’s methods and results sections. Where an original sits behind a paywall, the source table names the document reporting the figure, and the number appears only where independent published descriptions agree; the 1978, 1984 and 1993 rows are handled this way. A 99.4% rate from a 2004 Spanish sample was left off because the originating paper could not be read directly. Sources last verified August 17, 2026.
Cite this page
APA: Eduard, S. (2026, August 17). How common are intrusive thoughts? What the research actually counted. StumbleTowardTheLight. https://stumbletowardthelight.com/how-common-are-intrusive-thoughts/
MLA: Eduard, Sebastian. “How Common Are Intrusive Thoughts? What the Research Actually Counted.” StumbleTowardTheLight, 17 Aug. 2026, stumbletowardthelight.com/how-common-are-intrusive-thoughts/.
Frequently asked questions
Does everyone get intrusive thoughts? Close to it, within the samples studied. Every participant at three of the 15 sites in the international interview study reported an intrusion, and the lowest site rate was 81.2% (Radomsky et al., 2014). Those samples were all university students, so a community-wide figure stays an open question the authors themselves raise.
Is the “6 million Americans have intrusive thoughts” statistic real? It is a published expert estimate, derived by applying a 20% share to an anxiety-disorder lifetime rate, and its author states plainly on his own page that no formal study asks the question (traced above).
How many people with intrusive thoughts develop OCD? Among 2,073 U.S. adults interviewed between February 2001 and December 2003, 28.2% reported lifetime obsessions or compulsions and 2.3% met full lifetime criteria for OCD (Ruscio, Stein, Chiu, & Kessler, 2010). A persistent pattern often responds to overthinking therapy, and to understanding what makes someone an overthinker.
References
Kelly, J. M. (2023, November 1). Intrusive thoughts: Are they problematic? University of Rochester Medical Center Behavioral Health Partners.
Mikhail, A. (2023, March 8). 6 million Americans have intrusive thoughts. Here are 4 ways to get rid of them. Fortune.
Purdon, C., & Clark, D. A. (1993). Obsessive intrusive thoughts in nonclinical subjects. Part I. Content and relation with depressive, anxious and obsessional symptoms. Behaviour Research and Therapy, 31(8), 713-720.
Rachman, S., & de Silva, P. (1978). Abnormal and normal obsessions. Behaviour Research and Therapy, 16(4), 233-248.
Radomsky, A. S., Alcolado, G. M., Abramowitz, J. S., Alonso, P., Belloch, A., Bouvard, M., Clark, D. A., Coles, M. E., Doron, G., Fernandez-Alvarez, H., Garcia-Soriano, G., Ghisi, M., Gomez, B., Inozu, M., Moulding, R., Shams, G., Sica, C., Simos, G., & Wong, W. (2014). Part 1: You can run but you can’t hide: Intrusive thoughts on six continents. Journal of Obsessive-Compulsive and Related Disorders, 3(3), 269-279.
Ruscio, A. M., Stein, D. J., Chiu, W. T., & Kessler, R. C. (2010). The epidemiology of obsessive-compulsive disorder in the National Comorbidity Survey Replication. Molecular Psychiatry, 15(1), 53-63.
Salkovskis, P. M., & Harrison, J. (1984). Abnormal and normal obsessions: A replication. Behaviour Research and Therapy, 22(5), 549-552.
Seif, M. N. (n.d.). How many people have unwanted intrusive thoughts? Martin N. Seif, PhD.