Date of Award


Degree Type


Degree Name

Doctor of Psychology (PsyD)

Committee Chair

Michael Christopher, PhD

Second Advisor

Paul Michael, PhD

Third Advisor

Christiane Brems, PhD


The effectiveness of integrating nature-based interventions into acceptance and commitment therapy (ACT) for individuals with anxiety and comorbid medical diagnosis was examined. Participants experienced a 5-minute nature-based exercise before every session and were asked to spend at least 15 minutes in nature every day between sessions. These nature-based interventions were integrated with an adapted eight-week protocol for ACT. Relying on a quasi-experimental single subject design involving two participants from the Pacific Northwest, this study found clinically significant changes in anxiety, mindfulness, and experiential avoidance for participant one but clinically non-significant change in these areas for participant two. Although change in general health was found to not be clinically significant at post-treatment for both participants, it was at 3-month follow-up for participant one. Common journal themes for the two participants included an increased sense of calmness and increased present moment awareness with insight. Limitations included absence of a control group, an untested protocol, restricted generalizability, and the use of self-report measures. This was the first study to use a combination of nature-based intervention and ACT to treat this population. The potential effectiveness of using nature-based interventions was supported. Future research is needed to test whether a true difference exists between treatment using ACT with a nature-based component and ACT alone through randomly-controlled study. Also, future research should compare the effects of this treatment with PTSD versus GAD, as well as its impact on individuals with and without a comorbid medical diagnosis. Other research could explore ways to maximize the effectiveness of nature-based interventions and help individuals overcome barriers to spending time in nature. Further research could investigate more extensive long-term effects.


Library Use: LIH