Obsessive-compulsive disorder is where an individual is afflicted with uncontrollable persistent thoughts and behaviors. Obsessions are the unwelcome thoughts and ideas that preoccupy a person's mind, whereas compulsions are repeated behaviors, which is the main difference between obsession and compulsion. Obsessions are recurring thoughts and irrational ideas or images, whereas compulsions involve the acting out of the obsessive thinking, or repeating the idea.
Obsessions can cause fear, worry, and profound anxiety. Compulsions can cause harm to the body because of the extreme stress it puts on the mind to fight the urge to act out the obsession. Some common examples of compulsions that result from obsessions include brushing teeth repeatedly, excessive cleaning, checking whether doors are locked, and checking whether appliances are turned off.