These terms refer to different types of obsessive thoughts that individuals with OCD might struggle with. Examples include:

• Contamination OCD — fear of germs, illness, or causing harm through contact

• Harm OCD — intrusive thoughts about hurting oneself or others, despite having no desire to do so

• Relationship OCD (ROCD) — relentless doubt about the rightness of a relationship, one's feelings for a partner, or other relationship-related issues

• Scrupulosity — moral or religious obsessions; fear of sinning, offending God, or being a bad person

• "Pure O" — obsessions that appear to be purely mental, without obvious physical rituals (though mental compulsions are almost always present)

• Checking and reassurance-seeking — repeated checking of locks, appliances, or seeking confirmation from others to neutralize doubt

• Mental Health OCD - obsessive concerns about having a serious psychiatric illness, along with compulsions often involving checking symptoms, seeking medical help, and Googling/researching

• Meta OCD/OCD about OCD - persistent obsessive worries about whether or not one has OCD, whether they are treating their OCD correctly, or whether their OCD might get worse/precipitate a nervous breakdown.

• Sensorimotor OCD - anxiety and distress associated with a fixation on or unwanted awareness of autonomic or partially automatic bodily functions and processes (blinking, swalloing, heartbeat)

What these presentations share is a core feature: doubt that can't be resolved through logic or reassurance alone, and responses that provide short-term relief while maintaining the cycle long-term.