The National Comorbidity Survey Replication (NCS-R) investigated the epidemiology of obsessive-compulsive disorder (OCD) in the U.S. adult population. The study found that 2.3% of respondents met full DSM-IV criteria for lifetime OCD, and 1.2% for 12-month OCD. Over 28% of respondents reported experiencing obsessions or compulsions at some point in their lives. OCD is associated with significant comorbidity, including anxiety, mood, impulse-control, and substance use disorders. Severity of OCD, measured by the adapted Yale-Brown Obsessive Compulsive Scale (Y-BOCS), is linked to poor insight, high comorbidity, and high role impairment. The high prevalence of subthreshold OCD symptoms may explain inconsistencies in prevalence estimates across surveys, suggesting a larger public health burden than indicated by low prevalence. The study also found that OCD is more common in males, with early-onset cases being more prevalent. OCD is associated with a wide range of disorders and has a significant impact on daily functioning. The study highlights the need for more detailed information on OCD's impact and severity, as well as the implications for its classification in the DSM-V. The findings suggest that OCD is a serious disorder with significant public health implications, and that current diagnostic criteria may not fully capture its complexity. The study also found that severe OCD cases are more likely to be treated, but many moderate cases remain untreated. The results emphasize the importance of further research to improve the understanding and treatment of OCD.The National Comorbidity Survey Replication (NCS-R) investigated the epidemiology of obsessive-compulsive disorder (OCD) in the U.S. adult population. The study found that 2.3% of respondents met full DSM-IV criteria for lifetime OCD, and 1.2% for 12-month OCD. Over 28% of respondents reported experiencing obsessions or compulsions at some point in their lives. OCD is associated with significant comorbidity, including anxiety, mood, impulse-control, and substance use disorders. Severity of OCD, measured by the adapted Yale-Brown Obsessive Compulsive Scale (Y-BOCS), is linked to poor insight, high comorbidity, and high role impairment. The high prevalence of subthreshold OCD symptoms may explain inconsistencies in prevalence estimates across surveys, suggesting a larger public health burden than indicated by low prevalence. The study also found that OCD is more common in males, with early-onset cases being more prevalent. OCD is associated with a wide range of disorders and has a significant impact on daily functioning. The study highlights the need for more detailed information on OCD's impact and severity, as well as the implications for its classification in the DSM-V. The findings suggest that OCD is a serious disorder with significant public health implications, and that current diagnostic criteria may not fully capture its complexity. The study also found that severe OCD cases are more likely to be treated, but many moderate cases remain untreated. The results emphasize the importance of further research to improve the understanding and treatment of OCD.