Obsessive-compulsive disorder, also known as OCD, is a chronic mental health condition in which a person experiences unwanted or intrusive thoughts (obsessions) and repetitive behaviors (compulsions). Not everyone with OCD will have both obsessions and compulsions, but many do. According to WebMD, obsessive thoughts may include “good” or “bad” numbers or a fear of getting dirty. These intrusive thoughts can lead to compulsions or repetitive behaviors. For example, those who have thoughts about germs may feel the need to wash their hands a specific number of times to get clean.
There are many different symptoms of OCD, and symptoms vary by obsessions or compulsions, or both. Mayo Clinic reports obsessions tend to have a theme behind them, such as unwanted or horrific thoughts, fear of dirt, or needing particular items to be symmetrical or orderly. Obsessive thoughts can range from doubting you turned the stove off before bed to having troublesome sexual images.
Compulsive symptoms also tend to have a theme such as counting, cleaning, checking, and following a particular routine, notes Mayo Clinic. Repeatedly checking if doors are locked, counting in a pattern, or washing your hands until they’re raw are just a few of the compulsions that some people with OCD suffer from and then act upon.
Causes of OCD
The exact cause of OCD is still unknown, but there are many theories about what may be behind the mental health condition. OCD is partially genetic, meaning genetics play a role in your overall risk, but they aren’t the deciding factor in whether or not a person will develop the disorder, Director of the Yale OCD Research Clinic Dr. Christopher Pittenger told Insider.
To understand how genetics and OCD are linked, multiple studies have been conducted. According to a 2024 review published in Psychiatric Clinics of North America, the most robust study on the subject examined 5,409 pairs of twins, both fraternal and identical, and found the heritability of OCD to be 48%.
While more research needs to be done, other risk factors for OCD include trauma during childhood and differences in brain structure and functioning. In rare cases, a child may develop OCD after recovering from a streptococcal infection, or strep throat, according to MedlinePlus. These particular cases are also known as pediatric autoimmune neuropsychiatric disorders associated with streptococcal, or PANDAS.
