This three-paper dissertation aims to enhance our understanding of the role of positive psychology constructs, hope, and positive emotions during bereavement among older adults. The study will be mainly guided by the Broaden-and-Build Theory of Positive Emotion, the Hope Theory, and the Revised Stress and Coping Theory. This dissertation is based on secondary data analysis using two different data - the Health and Retirement Study (HRS) for Paper 1 and the Complicated Grief Treatment in Older Adults Study (CGTOA) for Paper 2 and Paper 3. Paper 1 examines the level of positive and negative emotions before and after bereavement, and the impact of positive emotions on bereavement adjustment outcomes such as depression and purpose in life among a nationally representative sample of widowed older adults. Paper 1 finds that recently widowed older adults experience a significant decrease in positive emotions and an increase in negative emotions (compared to the married comparison group) after the loss of their spouse, but they still experience a considerable level of positive emotions during bereavement.

The level of post-loss positive emotions was significantly associated with better adjustment outcomes, lower odds of having depression, and a higher level of purpose in life. A significantly greater impact of positive emotions on purpose in life was found among the widowed group compared to the married counterparts. However, the beneficial impact of positive emotions on depression did not differ between the widowed and married groups. Paper 2 and Paper 3 explore hope among the bereaved older adults with complicated grief using data from the CGTOA Study, a randomized clinical trial, which compared the treatment efficacy of complicated grief treatment (CGT) with interpersonal psychotherapy (IPT). Paper 2 focuses on evaluation of the psychometric properties of the Trait Hope Scale (THS) among older adults with complicated grief before proceeding to address the role of hope in CGT in Paper 3. Paper 2 suggests that overall the THS is a valid and reliable tool to measure hope among older adults with complicated grief.

The THS demonstrated its sensitivity to change with treatment, showing a significantly greater increase in hope score among treatment responders (in both CGT and IPT) compared to non-responders. However, unlike the theoretically supported two-factor structure of the THS (Pathways and Agency), a different two-factor structure was identified in the study, which suggests that further validation of the factor structure of the THS in older adults with complicated grief is necessary in future studies. Paper 3 investigates the role of hope in CGT, particularly examining hope as a potential moderator and/or mediator of treatment effects. Paper 3 found that both CGT and IPT groups increased their hope scores significantly during the treatment. However, there was no significant difference in increases in hope between CGT and IPT groups. Mediation analysis showed that hope is not a mediator of treatment effects of CGT over IPT. However, significant treatment effects of CGT (over IPT) were found for reduction in the level of grief-related avoidance among those with lower baseline hope, but not for those with higher baseline hope, which confirmed hope is a moderator of treatment effects for only the grief-related avoidance outcome.

The findings of this dissertation suggest that 1) positive emotions during bereavement may play a beneficial role in adaption to bereavement, 2) the Trait Hope Scale is a valid and reliable tool to measure hope among older adults with complicated grief, and 3) hope can be improved in complicated grief interventions (both CGT and IPT), and regaining hope may be an important factor associated with the resolution of complicated grief symptoms.