Annually, tens of thousands of lives are affected by suicide, including those who die by suicide, attempt non-fatal suicidal behaviors, and suffer from suicidal thoughts and ideation as well as friends and family affected by the loss of loved ones. Although a number of predictors of suicidal thoughts and behaviors have been examined in the literature, the current study investigated the presence of anti-mattering and suicidal ideation in online peer support communities through the r/SuicideWatch subreddit community. A historical archive of posts made in the subreddit was collected using the Python Reddit API Wrapper (PRAW), resulting in a final anonymized corpus of 500,548 posts. A sample of 1,700 posts were hand-labeled for the presence of anti-mattering and other constructs in order to train and evaluate a classification model for automated labeling. Using the resulting model and keyword dictionaries, the entire corpus was labeled, informing a nomological network of anti-mattering in online peer-support communities.