Although DSM-5 doesn’t list subtypes of OCD, some researchers group obsessions and compulsions into “symptom dimensions.” These clusters of symptoms share similar anxieties and behavior patterns.
Here’s a brief look at the symptom dimensions as currently described in scientific literature:
Contamination and cleaning
Some people have an extreme fear of becoming contaminated by germs, bodily fluids, or other substances — including abstract contaminants like evil or bad luck. People may even fear that they’re contaminating others.
An obsession with contamination can lead to a cleaning compulsion. People may believe that by cleaning objects or spaces in a specific order or with a particular frequency, they can avoid or recover from contamination or infection.
Symmetry and ordering
Some people become preoccupied with arranging objects in a certain order, often because of a kind of magical thinking or magical ideation. For example, individuals with OCD may think, “If I don’t line up my toiletries exactly this far apart, someone is going to harm me today, or if I clean my sink five times this morning, my brother won’t get sick today.”
Researchers have found that people with symmetry obsession and an ordering compulsion often have trouble expressing anger in healthy ways and may have a personal history of trauma.
Doubt about harm and checking
Some people have intrusive thoughts and fears about harming others or being harmed themselves. An excessive dread of being responsible for harm can lead to compulsive checking behaviors — for example, repeatedly making sure you’ve turned off the stove or an iron.
People affected by checking compulsions describe a feeling of incompleteness unless they perform certain rituals or behaviors. Other common compulsions include repeating mantras, prayers, or safety words to ward off danger or reduce anxiety.
Similar to symmetry and order compulsions, checking compulsions have been associated with anger and trauma.
Unacceptable thoughts and mental rituals
Some people experience frequent intrusive thoughts about things that violate their own sense of morality and goodness. Often, these unwanted thoughts involve sex, violence, or religious images.
Although people with this symptom cluster generally have no history of violence, they spend a lot of time and energy trying to suppress or erase these thoughts. Trying to squelch the thoughts can lead to even more anxiety, which tends to produce more unwanted thoughts — resulting in an unhealthy cycle.
Two of these symptom dimensions have a clear link to cleaning tasks: contamination and cleaning as well as symmetry and ordering.