The question of whether or not we perceive our lives as meaningful has profound implications for how we relate to ourselves and our environment . The evaluation of life as meaningful determines whether we see life as worth living at all and are thus motivated to invest in constructive interaction with the environment - even if this should be challenging . Apart from this activating and motivating function which has been replicated by several studies [e.g., 40, 41], meaningfulness also has a buffering function: It impacts how people cope with existing stress or pain [42, 43]. The present study offers another example of this buffer effect by focusing on stress caused by the COVID-19 pandemic. Over three months, meaningfulness predicted general mental distress directly. It also served as a moderator of the longitudinal relationship between COVID-19 stress and general mental distress: People who had reported high meaningfulness at T1 suffered substantially less from general mental distress at T2. Indeed, the total score of general mental distress (PHQ-4) was never elevated (exceeding a score of 3; [see 37]) when meaningfulness had been high at T1 (see Fig. 2). With a higher level of personal meaningfulness, severely stressed people were better able to cope with pandemic-related challenges and maintain their mental stability. Our study is thus in line with recent research that showed a risk-protective effect of meaning in life [27–29]. Additionally, it reveals how meaningfulness exerts a buffering effect under particularly stressful conditions.
Furthermore, we investigated the role of self-control. It is associated with numerous indicators of well-being, such as happiness , self-esteem , satisfaction with life , and mental health . According to longitudinal studies, self-control can predict well-being and health up to 30 years later . Also, in the present longitudinal study, people with high self-control at T1 reported less general mental distress three months later. However, a moderation effect of self-control was not confirmed. Thus, self-control did not buffer elevated stress over time, as observed in the cross-sectional study . This might be attributable to contextual influences. At T1, the appearance of the pandemic and accompanying measures demanded much self-control from all of us. But higher-order goals were salient, which may have motivated self-control, especially under high stress . As the pandemic situation at T2 was less critical, mental health might have been less dependent on self-control at this point.
A second focus of the current study was on the consequences of crises of meaning reported at the beginning of the pandemic. Here, a mediation effect was confirmed: High acute stress due to the pandemic was associated with elevated levels of crisis of meaning. These, in turn, predicted increased general mental distress three months later. Symptoms of anxiety and depression can thus partly be attributed to people's sense of having lost meaning in their lives. This can manifest in feelings of disorientation, alienation, arbitrariness, or incoherence . The direct effect between COVID-19 stress and general mental distress remained significant when controlling for crisis of meaning, which indicates that pandemic stress does not necessarily and for everyone translates into an existential crisis but contributes to feelings of anxiety and depression for other reasons as well. This was to be expected, of course, since crises are perceived very differently by different people.
The outcomes of the present study are in line with the general scientific evidence. Considering the overall responses to the pandemic, the majority seems to be resilient, whereas some experience it as a critical interruption of the continuity of their life . A significant minority questions previous social or personal priorities  and enters into a crisis of meaning . Although such crises are typically accompanied by psychological suffering [51–53] and even suicidality , they also have a considerable constructive potential: A more authentic approach to life, based on a more realistic - and thus more stable – worldview, seems to come into effect when crises are genuinely confronted [54, 55].
Strengths and limitations
This study's strengths include a longitudinal design with a substantial sample size and the employment of validated measures to assess general mental distress, meaning in life, and self-control. Its major limitation is the fact that the sample is not representative. We did not use random sampling, and women and more educated participants were over-represented. This was considered in the analyses by including education as a covariate, but not gender, as it was not related to the outcome variable, general mental distress. (When gender was included as a covariate nonetheless, results did not change substantially; findings not reported here.) Second, there was a slightly greater risk of dropout amongst individuals with lower education. However, this effect was small, and since the study focused on intrapersonal changes, we assume that attrition did not lead to any relevant bias.