Previous studies have produced mixed results when examining whether experiencing an adverse event can lead to changes in Neuroticism. We sought to examine this effect when (a) the event was relatively recent, (b) the event occurred during a relatively early development stage (i.e., emerging adulthood), and (c) the event was severely adverse. A sample of 1,108 undergraduates completed three measures of Neuroticism twice, separated by approximately 3 months, and indicated the most traumatic or adverse event they experienced during the intervening 3 months. We examined two operationalizations of adverse events: one that is more objectively defined (indicated experiencing a trauma listed on a trauma history measure) and another more subjectively defined (participant ratings of event centrality). The results revealed that high Neuroticism at Time 1 predicted future exposure to both types of adverse events. Critically, participants who experienced either type of adverse event during the semester reported significant increases in Neuroticism. Experiencing a high event centrality event was also associated with small increases in the personality traits Openness to Experience and Conscientiousness. The results are discussed in terms of the conditions necessary for adverse events to affect personality traits.