Obsessive-compulsive and related disorders is a category of psychiatric conditions that include:

• Obsessive-compulsive disorder (OCD)
• Body-dysmorphic disorder
• Hoarding disorder
• Trichotillomania (hair-pulling disorder)
• Excoriation disorder (skin picking)
• Substance/medication-induced obsessive-compulsive and related disorder
• Obsessive-compulsive and related disorder due to another medical condition

Each condition in this classification has its own set of diagnostic criteria.

Obsessive-Compulsive Disorder

The diagnostic criteria in the DSM-5 specify that in order to be diagnosed with obsessive-compulsive disorder, a person must experience obsessions, compulsions, or both.

• Obsessions are defined as recurrent, persistent thoughts, impulses, and urges that lead to distress or anxiety.
• Compulsions are repetitive and excessive behaviors that the individual feels that they must perform. These actions are performed to reduce anxiety or to prevent some dreaded outcome from occurring.

The obsessions and compulsions must also be time-consuming (taking up an hour or more per day) or cause significant distress or functional impairment, must not be attributable to another medical condition or substance use, and must not be better explained by another psychiatric condition (such as generalized anxiety disorder). 

Treatments for OCD usually focus on a combination of therapy and medications. Cognitive-behavioral therapy (CBT) or a form of CBT known as exposure and response prevention (ERP) if commonly used. Antidepressants such as clomipramine or fluoxetine may also be prescribed to manage symptoms.