Bereaved parents are at increased risk of developing mental and physical health problems and bereavement is even associated with an increased risk of mortality, especially in mothers. Prolonged grief disorder (PGD) are persistent and intensive grief reactions which can persist for years. It is characterized by an intense and lasting yearning for the deceased, intense emotional pain, such as difficulty accepting the loss and an inability to experience positive mood. Parents are among the most vulnerable to develop PGD.

The goal is to increase the accessibility to evidence-based and cost-effective interventions for parents of children who have died of cancer, and thus facilitate the grieving process and decrease the risk for parents to develop long-term distress.

Specific aims are:

• To evaluate the acceptability and feasibility of a mobile app, "My Grief ", a self-help app for prolonged grief, in parents who lost a child to cancer.
• To evaluate possible beneficial effects of the mobile app on parents' mental health.

There is a lack of studies evaluating the effect of interventions for bereaved parents. Thus, there is a need for accessible interventions with documented efficacy for preventing or reducing negative mental health consequences after the loss of a child. Today, many individuals carry smartphones and these devices can be used to access self-help interventions aiming to improve both physical and mental health. Currently, there are an excess of apps available for smartphone users that assert that they help people with their physical or mental health. However, for most of these apps, there is a lack of empirical support, i.e., their efficacy is unknown. It is therefore important to evaluate mobile apps in scientific studies with rigorous designs. In addition, before conducting rigorous studies of novel psychosocial interventions, such as a mobile app, it is important to conduct more basic work evaluating development and feasibility of the intervention. One such self-help app, the PTSD Coach, has been evaluated in a randomized controlled trial conducted with traumatized participants recruited from the community, which found that access to the PTSD Coach app was associated with improvements in posttraumatic stress (PTS) symptoms, depression, and psychosocial functioning. The PTSD Coach app is based on cognitive behavioural therapy (CBT) principles and there is a growing body of evidence that elements of CBT are effective interventions for prolonged grief. Thus, an app targeting prolonged grief using elements of CBT could potentially be effective in improving the mental health in bereaved parents. To our knowledge no such app has been developed and evaluated. The Grief Coach app will be based on the smartphone app PTSD Coach. A Swedish version of the PTSD Coach has been developed and a pilot study has been conducted as well as an ongoing RCT. Consultant programmers at Uppsala University will develop the mobile app. The content of the app will be developed together with experts in the field of grief, inspired by other grief apps and CBT therapy manuals, to modify parts of the PTSD Coach app to grief.

The main aim of this study is to examine the effectiveness of the app My Grief as compared to a waiting list comparison in reducing symptoms of prolonged grief in bereaved parents. The primary hypothesis is that the parents in the intervention group will report decreased levels of prolonged grief symptoms after having used the app. A second aim is to examine the effect of the app on related mental health problems (posttraumatic stress symptoms, depression symptoms, quality of life) and cognitive behavioral variables putatively explaining the effect of CBT techniques (i.e., grief avoidance, grief rumination and negative grief cognitions). The secondary hypotheses are that the parents in the intervention group will report improved mental health (i.e., lower symptom levels of depression and posttraumatic stress, higher quality of life), and lower grief avoidance, grief rumination, negative grief-related cognitions. A third aim is to evaluate the feasibility of the app, including participant satisfaction, evaluation of the app's strengths and weaknesses, and adverse events.

Potential participants are identified using the Swedish Childhood Cancer Registry, the Cause of Death Registry, and the Swedish Population Register at the Swedish Tax Agency. By linking the Cause of Death Registry with the Swedish Childhood Cancer Registry, children diagnosed with a malignancy and who died due to the malignancy 1 to 10 years previously will be identified. Next, the children's parents/caregivers are identified through the Swedish Population Register and will be sent a letter with an invitation to participate in the study. Participants will complete a web based pre-assessment and then given access to the app for three months followed by a web based post-assessment and an interview via telephone regarding their experiences of using the app, with follow-ups att 6 and 12 months.

Inclusion Criteria:

• Parents/caregivers of children who have died of cancer, at the earliest 12 month ago
• Have symptoms of prolonged grief (PGD)
• Understand Swedish language
• Have access to a smartphone

Exclusion Criteria:

• Ongoing severe psychiatric problems (e.g. suicidal thoughts, psychosis)

All collected IPD