Obsessive-compulsive disorder (OCD) is a mental health condition that involves compulsive recurring thoughts and/or behaviors. The Diagnostic and Statistical Manual of Mental Disorders doesn’t classify OCD into subtypes, so there aren’t formally agreed upon categories of OCD. However, many psychologists can agree that there are two broad types of OCD from the perspective of what drives the disorder.
“In the broadest sense, I think about OCD in terms of types that involve fear versus types that involve nervous system discomfort,” Kristin Bianchi, PhD, a licensed clinical psychologist who specializes in treating obsessive-compulsive spectrum disorders like OCD, tells Health.
Here’s what to know about those two major types of OCD—and how they might manifest.
OCD driven by fear
With fear-driven OCD, obsessive or compulsive behaviors, called rituals, are performed because the person strongly believes that if they don’t do them, the things they fear will actually happen. For example, someone whose OCD manifests as obsessions with harm may constantly fear that harm will come to them or their loved ones, and may therefore check things repeatedly.
“It could be the fear that if they don’t check all of their appliances and light switches, the house will catch fire while they’re at work,” Bianchi says. “And before they leave the house, they will do things like turn the stove and light switches on and off repeatedly until they’re certain they are off.”
Other people with OCD may have obsessions with health from a fear of sickness. These folks are frightened that they or people around them will fall ill if they don’t take certain actions. Obsessive fears of contagion like this are often accompanied by compulsive cleaning of surfaces because of the belief that the germs on it could make people sick.
Still other people with fear-driven OCD battle intrusive thoughts that constantly occupy the mind. “Intrusive thoughts that involve harming others or oneself or breaking rules are common,” Bianchi says, as are “upsetting thoughts and doubts revolving around romantic relationships.” A person with OCD may have intrusive thoughts involving “deviant sexual themes like incest, bestiality, pedophilia, and sexual aggression,” she adds.
Anyone can have these thoughts fleetingly, but with OCD, there is a strong fear that these thoughts represent who a person truly is.
To gain relief from their distress, people with intrusive thoughts will sometimes engage in certain actions repeatedly like people with harm obsessions. Other times, they’ll take up mental rituals, like counting or repeating certain words in their heads. Cases like these, when there are no overt behavioral rituals, may be referred to as “primarily obsessional” OCD or “pure” OCD, Bianchi says.
OCD driven by nervous system discomfort
In 2005, researchers from the Behavior Therapy Center of Greater Washington observed that there are people with OCD who have some symptoms related to those of Tourette syndrome. With Tourette syndrome, problems with the nervous system make the people who have it experience involuntary tics—sudden, short, and often repetitive movements or sounds.
So they hypothesized that Tourettic OCD, as the researchers called it, could also be driven by the nervous system. People with this type of OCD may feel the need to do some rituals over and over without there being any particular reason why—other than it’s really, really uncomfortable not to do them.
“People with this kind of OCD usually don’t know why something bothers them, and they’ll often describe it as just feeling not quite right,” Bianchi says. “It’s not so much that they’re afraid that something bad will happen.”
How these OCD types show up
No matter what drives a person’s OCD, there are some common ways in which OCD obsessions and compulsions are expressed.
- Checking compulsions: The need to constantly and repeatedly check things.
- Orderliness and symmetry compulsions: The need to constantly arrange and rearrange objects until they are perfectly in order or symmetrical.
- Cleaning compulsions: The need to clean or wash things or surfaces over and over.
- Counting compulsions: The need to count to certain numbers or to count items or steps.
The rituals involved in these compulsions are done to relieve feelings of distress, whether that distress is from a fear that something bad will happen otherwise or because it feels really uncomfortable not doing it.
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