Obsessive-compulsive disorder (OCD) is characterized by repeated, intrusive, and unwanted thoughts (called obsessions) and/or rituals that seem impossible to control (called compulsions). To be characterized as a disorder, actions and thoughts related to obsessions and compulsions must occupy a significant amount of an individual’s time and interfere with their ability to carry out day-to-day activities and function in their roles (e.g. work, school, family).
Obsessions are persistent thoughts, ideas, impulses, or images that are intrusive and inappropriate and that cause marked anxiety or distress. These thoughts are often distasteful, violent, and/or frightening to the person and are not related to everyday issues or problems. There are several types of obsessions, including sexual obsessions, obsessions of violence, obsessions regarding symmetry, somatic obsessions, pathologic doubt, and contamination. Individuals with obsessions usually attempt to ignore, suppress, or counteract such thoughts or impulses by engaging in compulsions. Individuals with obsessions recognize that their intrusive thoughts are formed within their own mind, and do not believe that they are caused by someone or something else.
Compulsions are repetitive actions or movements that individuals use in an effort to reduce their feelings of anxiety. In some cases, these compulsions occur as a response to obsessions; they are used to alleviate the anxiety caused by intrusive thoughts or impulses. They are often used to prevent something negative from happening, even though they are not directly related to what the person is trying to prevent (ie. obsessions about a family member being harmed may lead to a compulsion to rearrange items in a cupboard to prevent this from happening). In other cases, compulsions are not directly related to specific obsessions, but performing them does alleviate or stave off anxiety.
Most people find it very psychologically difficult to stop performing their compulsions, even if those compulsions interfere with their ability to live their regular life. Examples of compulsions include repetitive behaviors (such as hand washing, ordering, or checking), mental acts (such as praying, counting, or repeating words), hoarding behaviours, actions related to symmetry and precision, and a need to ask/confess. They are often performed in a ritualistic way.
References: Stein, D. (Ed.) (2004). Clinical manual of anxiety disorders. Washington: American Psychiatric Publishing, Inc.