The dyadic effects of personality traits on depression in advanced lung cancer patients and caregivers: The mediating role of acceptance of illness

This study aimed to explore the intrapersonal and interpersonal effects of three personality traits-neuroticism, extraversion and conscientiousness-on depression and examine whether acceptance of illness mediates the actor and partner effects in advanced lung cancer patients and caregivers using the Actor-Partner Interdependence Mediation Model (APIMeM).A total of 304 dyads of advanced lung cancer patients and caregivers were studied. Personality traits, acceptance of illness and depression were measured using 44-item Big Five Inventory, the Acceptance of Illness (AIS) scale and the Patient Health Questionnaire (PHQ-9).The APIMeMs suggested that there were significant actor-actor effects of the three personality traits on depression through their own acceptance of illness. Additionally, significant actor-partner effects of neuroticism and extraversion on depression were also found. Specifically, patients' neuroticism was negatively related to their own acceptance of illness, which increased caregivers' depression, and caregivers' higher extraversion was related to their own higher acceptance of illness, which reduced patients' depression. Furthermore, a significant partner-actor effect was only found in the neuroticism model. Patients' neuroticism was negatively related to caregivers' acceptance of illness, which increased caregivers' depression.The three personality traits had both interpersonal and intrapersonal effects on depression in advanced lung cancer patient-caregiver dyads, and acceptance of illness played an important mediating role in these relationships.