Background <p>Self-referential processing has been shown to increase spontaneous thoughts and impair memory performance relative to processing non-self-related information. However, it remains unclear whether increased vulnerability to depression interacts with self-referential processing to exacerbate maladaptive spontaneous thinking and further impair cognitive performance.</p> Methods <p>In the present study, 46 participants (<i>M</i>_age = 23.65 years, 67.4% female) were selected from an initial sample (<i>N</i> = 111) based on their scores on self-report questionnaires assessing vulnerability to depression. The final sample included 23 individuals with higher depression vulnerability and 23 with lower vulnerability. Participants completed a complex working memory task under both self-referential and control conditions, with embedded thought probes to capture spontaneous thinking.</p> Results <p>Individuals with higher depression vulnerability exhibited stickier spontaneous thoughts. Self-referential processing elicited more off-task, self-focused, and sticky thought patterns compared to the control condition. However, no interaction between depression vulnerability and self-referential processing on spontaneous thought patterns was observed. Moreover, increased off-task thinking, as well as stickier and more negatively valenced thoughts, were associated with poorer memory task performance.</p> Conclusions <p>The present findings suggest that while both depression vulnerability and self-referential processing influence spontaneous thinking, their effects appear to operate independently. The interplay between depression vulnerability, self-referential processing, and spontaneous thoughts is more complex than previously assumed.</p>