Rachel and Rhonda are identical twins, and they have each just broken off relationships with their boyfriends. Rachel feels guilty and sad about ending her relationship; Rhonda feels ending her relationship is probably a good decision. According to the research, Rachel and Rhonda are equally likely to develop depression following this same, negative life event.

Identical twins, like Rachel and Rhonda, share the same genetics but can have different responses to the same life events due to differences in their individual experiences, personalities, coping mechanisms, and perceptions of the event. Rhonda's positive outlook on the breakup could serve as a protective factor against depression, while Rachel's guilt and sadness might increase her risk.