Young adulthood is characterized by a period of entering adulthood within a broader social context (Benson and Elder, 2011). This stage involves major transitions such as taking on increased financial and personal responsibilities and managing changes in relationships (Bultmann et al., 2020). These changes can be more difficult for this group to manage and may increase the risk of poor mental health and suicidality (Kosidou et al., 2012; MacKinnon and Colman, 2016). Importantly, young adults show relatively higher suicide deaths and years of life lost due to self-harm compared to other age groups (IHME, 2024; World Health Organization, 2021).

Suicidal ideation is an antecedent for suicide attempt and suicide death (Gunnell et al., 2004; Turecki et al., 2019), and its course can vary over time through incidence, persistence, and remission (Wilcox et al., 2010). These changes, especially incidence and persistence, correlate with an increased risk of more severe suicidal behavior (e.g., suicide attempt) (Brezo et al., 2007; Deisenhammer et al., 2009; Miranda et al., 2014). Several studies examined the new-onset and persistence or remission of suicidal ideation through longitudinal designs across diverse age groups, with follow-up intervals varying from 12 months to 10 years (Antonelli-Salgado et al., 2021; Blasco et al., 2019; Borges et al., 2008; Gunnell et al., 2004; Hintikka et al., 2001; Husky et al., 2024; Mulholland et al., 2023; Shimin et al., 2021; Wilcox et al., 2010; Zhang et al., 2011, 2015). Although varying interval lengths offer different implications for suicide prevention, shorter intervals (e.g., <12 months) may be particularly useful for informing timely and targeted strategies to prevent the progression of more severe forms of suicidal behavior (Antonelli-Salgado et al., 2021; Blasco et al., 2019; Hintikka et al., 2001; Shimin et al., 2021; Wilcox et al., 2010; Zhang et al., 2011, 2015). Moreover, previous longitudinal studies on the course of suicidal ideation among young adults were limited (Blasco et al., 2019; Shimin et al., 2021; Wilcox et al., 2010), indicating the need for further evidence on the course of suicidal ideation in this population.

Previous studies showed that persistent or changing adverse socioeconomic and psychological factors increased the risk of suicide attempt and death (Bailey et al., 2025; Ernst et al., 2020; Narita et al., 2024; Park et al., 2025). A better understanding of the socioeconomic and psychological factors associated with incident and persistent suicidal ideation could also inform suicide prevention strategies (Gunnell et al., 2004). Previous studies investigated these factors (e.g., marital status, low income, depression) associated with the incidence and persistence (or remission) of suicidal ideation (Antonelli-Salgado et al., 2021; Blasco et al., 2019; Borges et al., 2008; Gunnell et al., 2004; Husky et al., 2024; Mulholland et al., 2023; Shimin et al., 2021; Wilcox et al., 2010; Zhang et al., 2011, 2015). However, many studies relied solely on either baseline or follow-up measurements, potentially overlooking how changes in personal or socioeconomic conditions may be associated with the course of suicidal ideation (Antonelli-Salgado et al., 2021; Hintikka et al., 2001; Husky et al., 2024; Mulholland et al., 2023; Shimin et al., 2021; Wilcox et al., 2010; Zhang et al., 2011). Given that these risk factors can also change over time, it would be more valuable to examine whether changes in these factors are associated with incident or persistent suicidal ideation. Only a few studies examined associations between changes in risk factors and the courses of suicidal ideation, including onset and recovery (Gunnell et al., 2004; Zhang et al., 2015). Changes in employment status, decreased social support, and increased life distress were associated with incident suicidal ideation (Gunnell et al., 2004; Zhang et al., 2015). Improvement in depression, anxiety, and hopelessness was associated with its remission (Zhang et al., 2015). Moreover, recent studies on incident and persistent suicidal ideation among young adults have relied either on a single-time exposure variable or solely on a mental health–related change variable (Blasco et al., 2019; Shimin et al., 2021). Further research is needed to broadly explore how changes in other socioeconomic and psychological factors, including financial hardship and happiness, are linked to incident and persistent suicidal ideation in this population.

South Korea, an East Asian country with a population of about 52 million, had higher young adult suicide rates than many other countries, with 27.9 and 18.9 per 100,000 among males and females, respectively, aged 20–39 years in 2020 (Choi et al., 2025). This population experiences many economic and psychosocial difficulties in a highly competitive society (Kim, 2015), providing a unique context for examining changes in suicidal ideation and associated factors among Korean young adults. Moreover, this highlights the need for a deeper understanding of suicidality, including the course of suicidal ideation, to develop effective prevention strategies for this population. We aimed to investigate the rates of incident and persistent suicidal ideation and explored a range of socioeconomic and psychological factors associated with incident and persistent suicidal ideation among young adults in South Korea. Specifically, we analyzed whether changes in socioeconomic and psychological factors are associated with incident and persistent suicidal ideation (Fig. 1).