Obsessive-compulsive disorder (OCD) is typically thought of as a single mental health disorder. More recently, internally-focused (autogenous) and externally-focused (reactive) subtypes have been proposed. This study examined the language used in describing these subtypes using anonymous posts from Reddit. The study used natural language processing software to look at differences in the use of the linguistic variables of first-person singular, first-person plural, third-person singular, and third-person plural as well as use of the psychological variables negative emotion, anger, anxiety, insight, causation, certainty, risk, religion, swear words, body, health, sexual, discrepancy, future, and death. A log likelihood ratio (G2) was calculated to determine the differences of usage rates in the two corpuses. The results showed a large effect size of the use of first-person singular pronouns in both the autogenous and reactive corpuses. The psychological variables of “insight” and “sexual” had the largest effect sizes in the autogenous corpus, while “health” and “body” had the largest effect sizes in the reactive corpus. The differences in the usage rates of the linguistic and psychological variables in the corpuses show the heterogeneity of OCD and the importance of understanding lesser known forms of obsessions such as those with repugnant themes. Clinical implications and future research recommendations are discussed.Keywords: reactive OCD, autogenous OCD, obsessive-compulsive disorder, LIWC, corpus linguistics