Obsessive-compulsive disorder is associated with less of a distinction between specific acts of omission and commission.

Individuals with obsessive-compulsive disorder (OCD) seem to judge harm caused actively and passively as morally equivalent. In contrast, people generally choose harm by omission over harm by commission, a propensity known as omission bias. Two studies examined the hypothesis that OCD is associated with less omission bias. In Study 1, with a student population, symptoms of OCD and related cognitions were negatively associated with omission bias about washing and checking scenarios targeting common OCD fears. In contrast, neither symptoms nor cognitions related to OCD were associated with general omission bias. In Study 2, individuals with self-reported OCD evinced less omission bias about washing and checking scenarios than did individuals without OCD. Again, general omission bias was not related to OCD. These results support the idea that individuals with elevated OCD symptoms distinguish less than others between acts of omission and commission for harm relevant to general OCD concerns.