Which of the following is NOT classified as an obsessive-compulsive or related disorder?

Depression is not classified as an obsessive-compulsive or related disorder. Instead, it falls under mood disorders in the DSM-5. Obsessive-compulsive and related disorders, as defined in the DSM-5, include conditions characterized by the presence of obsessions (intrusive thoughts that cause anxiety) and/or compulsions (repetitive behaviors performed to reduce anxiety).

Hoarding Disorder, Trichotillomania (hair-pulling disorder), and Excoriation Disorder (skin-picking disorder) are all categorized within the obsessive-compulsive spectrum, as they involve compulsive behaviors intended to alleviate distress related to obsessions.

In contrast, depression is a mood disorder marked by persistent feelings of sadness, hopelessness, and a lack of interest or pleasure in previously enjoyed activities, without the distinctive compulsive behaviors associated with obsessive-compulsive or related disorders. This distinction in classification is crucial for understanding each condition's specific treatment approaches and therapeutic strategies.