An exaggerated obsessive worry about one's health, endless internet researching  symptoms, repeat visits to doctors, odd diets, or reassurance seeking.  Ordinary physiological sensations can be misinterpreted as cancer, heart disease, HIV, etc. (Read more...)

Collecting, buying, and not discarding possessions, or not using new items to avoid damaging them.  Hoarders don't allow people into their home out of embarrassment, or prevent others moving their belongings for fear they won't find them.  (Read more...)

Unwanted gay or lesbian thoughts or abrupt doubts about gender identity.  HOCD sufferers check whether they get aroused by a variety of same-sex situations to test their sexual orientation.  (Read more...)

Sexual OCD sufferers experience upsetting obsessions about inappropriate sexual relationships, such as family members, children, married people, animals, or rape.  They have intrusive thoughts they'll become a pedophile, rapist, molester, adulterer, or pornographer.  Sexual OCD sufferers test their arousal to these targets hoping to reassure themselves that they're normal.  (Read more...)

Exaggerated sense of guilt, over-responsibility, dread of punishment, ostracism, or retaliation.  Sufferers fear they did something offensive, illegal, immoral, or sinful.  They compulsively apologize, confess minor infractions, seek reassurance, over-justify themselves, review past events, or engage in excessive religious rituals.  (Read more...)

Distorted body image, checking, concealing, or over-grooming  part of their body (hair, fat, stomach, chest, skin, teeth, birth marks, face shape, eyebrows, nose, etc.). BDD can also be an imaginary body odor.  BDD is often misdiagnosed as an eating disorder like anorexia, but its cause and treatment is very different.  (Read more...)

"Pure O" (purely obsessional) OCD is really a misnomer and an often used but obsolete term. The sufferer thinks they have only obsessions and not compulsions.  In reality, they have internal mental compulsions, usually self-reassurance, rather than behavioral compulsions. Pure O sufferers try to talk themselves out of their worry, answer an unanswerable question, or ask others to reassure them.

Fear that something or someone is contaminated (by germs, dirt, asbestos, chemicals, a spirit, a bad thought).  Contamination OCD can also entail feeling disgusted by contact, without fear of danger.  People feel compelled to avoid, clean, launder, throw out, or isolate contaminated objects.