Discussion
depressive, depression, ’s psychological distress, anxiety
This study examined the effects of nature-based therapy on the psychological distress and well-being of individuals with depressive and anxiety symptoms during the COVID-19 pandemic. Overall, NBT showed significant treatment effects on psychological distress and well-being compared with the control group. As hypothesized, all psychological distress and well-being variables of participants in the therapeutic gardening program significantly improved compared with the control group. This result is consistent with many previous studies reporting the positive effects of NBT on psychological distress and well-beingRegarding psychological distress, the same result was derived from previous studies reporting that NBT showed a larger effect size for anxiety than for depressionPositive mental health and well-being aspects such as daily activity, life satisfaction, and mindfulness improved significantly, as did negative affect. In line with previous studies, NBT had a positive impact on life satisfaction. Interestingly, despite the absence of mindfulness-focused practices within the therapeutic gardening program, participants' levels of mindfulness improved. This could be explained by the possibility that similar mental process to mindfulness occur during nature-based activities, or it may be because the attention to the nature stimuli reduces mind wanderingWe also investigated the association between changes (post-score minus pre-score) in seven psychological distress and well-being variables: depression, anxiety, daily activity, life satisfaction, mindfulness, stress, and loneliness. As hypothesized, significant correlations were found between all the variables. This implies that people experience changes in psychological distress and well-being through comprehensive interactions and not independently. Psychological distress variables (depression, anxiety, and stress) showed large correlations with each other, while positive mental health and well-being variables (daily activity, life satisfaction, and mindfulness) correlated with large effect sizes. This is probably because people suffering from psychological distress experience a combination of negative emotions and improvements occur simultaneously through the intervention. Similarly, there were significant associations among depression, anxiety, and stress in studies on the psychological impact of COVID-19Finally, in line with our hypothesis, therapeutic alliances positively affected psychological distress and well-being. Specifically, therapeutic alliance scores at T2 (post-test) were higher than at T1 (mid-test) and had a greater impact on the intervention. This finding is inconsistent with the literature suggesting that early alliance scores are predictive of treatment outcomesThis study had several limitations. First, regarding the experimental design, we did not adopt a randomized controlled trial, and the discrepancy in the number of participants between groups necessitates caution in interpreting the representativeness of the sample and the generalizability of the study results. Since the research was conducted during the pandemic period, it was difficult to recruit participants and randomize them. While COVID-19 had subsided, vulnerable populations, such as those with mental health problems or the older adults, still had a fear of face-to-face contact with people and hesitant to return to social lifeDespite these limitations, the results of this study contribute to the effectiveness of nature-based therapy, represented by a therapeutic gardening program, as a psychosocial intervention for community dwellers suffering from psychological distress during COVID-19. There are very few experimental studies in the field of NBT research with a sample size exceeding 200We concluded that nature-based therapy is an effective and feasible psychosocial intervention and applicable for improving community’s psychological distress and well-being. In addition to the applicability of NBT, the current study explored the significant interactive association between changes in psychological distress and well-being, which can provide implication for future mechanism studies. Moreover, a later therapeutic alliance was found to play an important role in the intervention outcomes of NBT, similar to other psychosocial treatments. Therefore, future studies on nature-based therapy should focus on the effect mechanism, research methodology of random assignment, therapist competency, and adherence to evidence-based treatments.