Obsessive-compulsive disorder (OCD) is a mental illness that causes repeated unwanted thoughts or urges (obsessions). It also can cause you to do certain actions over and over again (compulsions). You may have both obsessions and compulsions.

OCD isn’t about habits such as biting your nails or thinking negative thoughts. An obsessive thought might be that certain numbers or colors are “good” or “bad.” For example, a compulsive habit might be to wash your hands seven times after touching something that could be dirty. Although you don’t want to think or do these things, you feel like you can’t stop.

OCD can be very upsetting and disruptive to your life. But treatments and coping strategies can help.