Background Advance Care Planning (ACP) discussions can be beneficial to people living with advanced illness. While research has focussed on ACP barriers, outcomes and completion, little is known about how ACP discussions influence thoughts, feelings and behaviours.

Aim To explore psychological responses to ACP discussions, and their potential influences on the thoughts, feelings and behaviours of people living with advanced illness.

Design Semi-structured, qualitative interviews with purposively sampled adults receiving hospice care. Data were analysed using framework analysis. Reflexive journalling and discussion of coding framework and emerging themes supported rigour.

Results 20 adults aged 30–93 with cancer (15) and non-cancer (5) diagnoses were interviewed. Participants described a range of responses to ACP discussions, including relief and satisfaction in expressing wishes, confidence in decision making, and appreciation of the support, acceptance, expertise and honesty of clinicians and relatives. A smaller number of negative emotions such as worry, anger, and doubt about achieving wishes were expressed. Existential responses included acceptance of their illness, hopes and fears for the future, and difficulty of facing mortality. Responses were tied to factors such as attitudes towards having a terminal illness, previous thoughts about ACP, personality, and previous experiences of death and dying.

ACP empowered participants, confirming previous end of life wishes, allowing them to address existential concerns, promoting openness with relatives, and encouraging them to make the most of time left.

Conclusion Participants described positive, negative and existential responses to ACP discussions. When considering both how to approach and support people after ACP discussions, clinicians must sensitively navigate their potential impact, being aware that they encourage people to consider their future, and their own mortality.

Funding Samuel Sebba Charitable Trust.