Background <p>Basic and clinical research on rumination assumes that the rumination that was studied in one year sufficiently resembles that which is present today. As the way psychological constructs are defined and manifest often change over time, we examined the extent to which the content of rumination changes over time.</p> Methods <p>We clustered idiosyncratic rumination statements, from people who reported being ruminators, on computationally derived features.</p> Results <p>Data suggested that indeed the linguistic content of rumination appeared to change over time, as cluster memberships for rumination statements varied by year, whether or not other clinical features were accounted for.</p> Conclusions <p>Thus, we suggest that work on rumination may reflect the time in which assessed ruminations or ruminators were examined.</p>