How common is OCD? 740,000 people in the UK at any one time. UK ocduk.org affecting roughly 1 in 100 people 12 out of every 1,000 people ODC UK OCD-UK According to OCD-UK According to http://www.ocduk.org/how-common-ocd How common is OCD? half of those cases are severe 740,000 people in the UK at any one time.