Which of the following is a common type of anxiety disorder?

Obsessive-compulsive disorder is a recognized type of anxiety disorder characterized by persistent, unwanted thoughts (obsessions) and repetitive behaviors or mental acts (compulsions) that the individual feels driven to perform in response to the obsessions. This disorder can significantly impact daily functioning and quality of life, as individuals engage in compulsive rituals to alleviate the distress caused by their obsessions.

In contrast, seasonal affective disorder pertains to mood changes related to seasonal patterns and is classified as a type of depression. Dissociative identity disorder involves a disruption of identity and is classified under dissociative disorders. Bipolar disorder is known for its mood swings between manic and depressive states, categorizing it as a mood disorder rather than an anxiety disorder. Thus, obsessive-compulsive disorder stands out as the common type of anxiety disorder among the options provided.