Evaluation of a Guided Nature and Forest Therapy Walk for Internal Medical Residents - A Brief Report.

Background: Medical residents commonly face compassion fatigue, burnout, anxiety, and depression. Studies of nature-based interventions show improved mental and physical health; few focus on healthcare providers. Objective: To explore potential benefits of forest bathing for medical residents' wellbeing. Methods: Using the Association of Nature and Forest Therapy's framework, we piloted a forest bathing intervention among medical residents with pre/post-participation surveys assessing perceptions of mindfulness and psychological wellbeing. Responses were analyzed using a Fisher's exact test and Student's t-test for independent samples. Results: Fourteen of fifteen participants completed both surveys. We observed significantly improved mindfulness scores and expressions of feeling calm, vital, or creative, as well as a decreased sense of anxiety and depression. Nonsignificant trends towards decreased burnout and irritability were seen. Conclusion: This quality improvement pilot demonstrates trends that forest bathing can improve medical residents' psychological wellbeing and mindfulness. Further exploration of this intervention for healthcare providers is warranted.

Forest Therapy as a Nature-Based Intervention: An Option for Neurological Rehabilitation?

BACKGROUND: Forest therapy demonstrates positive effects on mood, immune system, stress levels, and general well-being. Studies on depression, stress-related illnesses, sleep disorders, and arterial hypertension have provided evidence-based proof of this. SUMMARY: The aim of this review was to examine the possible effects of forest therapy with regard to its evidence in the treatment of chronic neurological diseases such as stroke in the rehabilitation phase, Parkinson's disease, dementia, and multiple sclerosis. Therefore, the electronic databases Medline, Scopus, and Cochrane were searched for such clinical trials for the years 1970 to mid-2023 without language restriction. The literature search revealed only few studies with positive indications but too few cases to be able to make generalizable evidence-based statements. In terms of improvement in the Hamilton Depression Scale analysis of two studies in stroke patients showed slight benefits in the forest therapy group (standard mean difference -0.43; 95% CI: -0.76 to -0.10; p < 0.01). One observational study revealed a higher rate of stroke survival in patients living in marked greenness. Few nature-based interventions in dementia patients showed certain benefits in particular details. KEY MESSAGES: There are no evidence-based results on the benefit of forest therapy for chronic neurological diseases. However, there are hints that forest therapy could have a positive benefit. Therefore, a proposal for forest therapy as a component of multimodal neurological rehabilitation is presented.Die Waldtherapie zeigt positive Auswirkungen auf die Stimmung, das Immunsystem, das Stressniveau und das allgemeine Wohlbefinden. Studien zu Depressionen, stressbedingten Erkrankungen, Schlafstörungen und arteriellem Bluthochdruck haben dies evidenzbasiert belegt.Ziel dieser Übersichtsarbeit war es, die möglichen Wirkungen der Waldtherapie im Hinblick auf ihre Evidenz bei der Behandlung chronischer neurologischer Erkrankungen wie Schlaganfall in der Rehabilitationsphase, Morbus Parkinson, Demenz und Multiple Sklerose zu untersuchen. Dazu wurden die elektronischen Datenbanken Medline, Scopus und Cochrane für die Jahre 1970 bis Mitte 2023 ohne sprachliche Einschränkung nach solchen klinischen Studien durchsucht. Die Literaturrecherche ergab nur wenige Studien mit positiven Indikationen, aber zu wenigen Fällen, um verallgemeinerbare evidenzbasierte Aussagen machen zu können. Im Hinblick auf Verbesserung in der Hamilton Depressionsskala zeigte die Analyse von 2 Studien bei Schlaganfallpatienten leichte Vorteile der Waldtherapiegruppen (Standard Mean Difference −0.43; 95% CI: -0.76- -0,10; p < 0.01). Eine Beobachtungsstudie ergab eine höhere Schlaganfall-Überlebensrate bei Patienten, die in ausgeprägtem Grün leben. Einige naturbasierte Interventionen bei Demenzpatienten zeigten in einzelnen Parametern gewisse Vorteile.Es gibt bis dato keine verallgemeinerbaren evidenzbasierten Ergebnisse zum Nutzen der Waldtherapie bei chronischen neurologischen Erkrankungen. Es gibt jedoch Hinweise, dass die Waldtherapie einen positiven Nutzen haben könnte. Es wird daher ein Vorschlag für eine Waldtherapie als Bestandteil einer multimodalen neurologischen Rehabilitation vorgestellt.

Effects of Forest Therapy on Psychological Improvement in Middle-aged Women in Korea.

OBJECTIVES: Women experience more stress in middle age than in other periods of their lives. Therefore, health management programs that enable middle-aged women to cope with and manage stress are needed. This study investigated the psychological effects of a meditation-focused forest therapy program among 53 middle-aged women living in urban areas in Korea. METHODS: Participants were divided into 2 groups: one group underwent the program for 3 days in a forest, followed by 3 days in an urban environment, and the other group underwent the program for 3 days in the urban environment, followed by 3 days in the forest. The psychological effects of the forest therapy program were evaluated using the Profile of Mood States-Brief (POMS-B). Differences in mood state before and after the program conducted in the forest (experimental group) and in the urban environment (control group) were evaluated using the paired-samples t-test. RESULTS: The program in the forest significantly reduced tension, depression, anger, fatigue, and confusion among the domains of the POMS-B. The program in the urban area significantly reduced tension, but not depression, anger, fatigue, or confusion. CONCLUSIONS: Meditation-focused forest therapy programs are expected to contribute to promoting psychological health and enhancing the quality of life of middle-aged women.

Seasonal Differences in Physiological Responses to Walking in Urban Parks.

The aim of the current study was to assess seasonal differences in physiological responses to walking in urban parks. In total, 51 Japanese male university students participated in this research. During each season, the participants walked for 15 min in an urban park and a city area, which was used as the control site. Heart-rate variability and heart rate were used as physiological indicators. The mean values of each indicator in a comparison between walking in an urban park and a city area were compared according to each season. In addition, to show the physiological effect of walking in an urban park, differences (between walking in an urban park and walking in a city area) were calculated. Then, differences according to each season were compared. The results showed that the participants had increased parasympathetic nervous system activity in all seasons except summer. Moreover, they had decreased sympathetic nervous system activity in spring and fall and decreased heart rate in all seasons. Compared with walking in urban parks in summer, walking in urban parks in spring, fall, and winter had a greater relaxation effect on parasympathetic and sympathetic nervous system activities; hence, the physiological effects of walking in urban parks vary based on season.

Physiological and Psychological Relaxation Effects of Fir Essential Oil on University Students.

Numerous studies have reported a significant increase in stress experienced by students owing to the COVID-19 pandemic. Recently, interest in stress management using nature-derived substances has increased. However, studies examining the effects of olfactory stimulation by fir are lacking. The aim of this study was to investigate the physiological and psychological effects of inhaling fir essential oil. Additionally, differences between male and female participants were compared. Twenty-six university students (16 female and 10 male students; mean age, 21.5 ± 1.9 years) participated in this study. Fir essential oil was used for olfactory stimulation, with normal room air as the control. The odor was administered for 3 min. Heart rate variability and heart rate were used as indicators of autonomic nervous system activity. The Profile of Mood States and State-Trait Anxiety Inventory were used as psychological indicators. The ln(Low Frequency/High Frequency) ratio, which is an indicator of sympathetic nervous activity reflecting a stressful or aroused state during stimulation with fir essential oil, was significantly lower than during the control condition. Assessment of psychological indicators showed that the positive mood of "vigor" improved significantly and negative moods of "tension-anxiety", "depression", "anger-hostility", "fatigue" and anxiety levels reduced significantly after inhaling fir essential oil compared to the control condition. This study showed that inhalation of fir essential oil has physiologically and psychologically relaxing effects, with differences in results depending on the sex of the participants.

Short-Term Effects of Forest Therapy on Mood States: A Pilot Study.

Immersion in forest environments was shown to produce beneficial effects to human health, in particular psychophysical relaxation, leading to its growing recognition as a form of integrative medicine. However, limited evidence exists about the statistical significance of the effects and their association with external and environmental variables and personal characteristics. This experimental study aimed to substantiate the very concept of forest therapy by means of the analysis of the significance of its effects on the mood states of anxiety, depression, anger and confusion. Seven forest therapy sessions were performed in remote areas and a control one in an urban park, with participants allowed to attend only one session, resulting in 162 psychological self-assessment questionnaires administered before and after each session. Meteorological comfort, the concentration of volatile organic compounds in the forest atmosphere and environmental coherence were identified as likely important external and environmental variables. Under certain conditions, forest therapy sessions performed in remote sites were shown to outperform the control session, at least for anxiety, anger and confusion. A quantitative analysis of the association of the outcomes with personal sociodemographic characteristics revealed that only sporting habits and age were significantly associated with the outcomes for certain psychological domains.

Effects of Nature-Based Group Art Therapy Programs on Stress, Self-Esteem and Changes in Electroencephalogram (EEG) in Non-Disabled Siblings of Children with Disabilities.

The purpose of the present study was to examine changes in brain waves, stress, and self-esteem after a continuous eight-week nature-based art therapy program in the forest in non-disabled siblings of children with disabilities. A total of 29 participants participated in this study (art therapy program group, n = 18; control group, n = 11). The art therapy program group received eight weekly sessions of art therapy lasting 60 min each. Pre- and post-test results showed positive changes in the brain function index and stress levels of the participants in the art therapy program group. On the self-esteem scale, overall and social self-esteem increased significantly. In conclusion, creative activities in the forest can increase resistance to diseases through mechanisms that relieve stress and increase self-esteem. If art therapy that emphasizes somatosensory experience, creative expression, and self-motivation is accompanied by forest activities, this combined intervention can elicit positive physical and psychological changes.

Psycho-Electrophysiological Benefits of Forest Therapies Focused on Qigong and Walking with Elderly Individuals.

We developed two distinct forest therapy programs (FTPs) and compared their effects on dementia prevention and related health problems for older adults. One was focused on Qigong practice in the forest (QP) and the other involved active walking in the forest (WP). Both FTPs consisted of twelve 2-h sessions over six weeks and were conducted in an urban forest. We obtained data from 25, 18, and 26 participants aged 65 years or above for the QP, WP, and control groups, respectively. Neuropsychological scores via cognition (MoCA), geriatric depression (GDS) and quality of life (EQ-5D), and electrophysiological variables (electroencephalography, bioimpedance, and heart rate variability) were measured. We analyzed the intervention effects with a generalized linear model. Compared to the control group, the WP group showed benefits in terms of neurocognition (increases in the MoCA score, and alpha and beta band power values in the electroencephalogram), sympathetic nervous activity, and bioimpedance in the lower body. On the other hand, the QP group showed alleviated depression and an increased bioimpedance phase angle in the upper body. In conclusion, both active walking and Qigong in the forest were shown to have distinctive neuropsychological and electrophysiological benefits, and both had beneficial effects in terms of preventing dementia and relieving related health problems for elderly individuals.

Benefits of Indirect Contact With Nature on the Physiopsychological Well-Being of Elderly People.

OBJECTIVES: Exposure to nature or to green space has positive mental health benefits. Closing of parks and green spaces during the COVID-19 pandemic has reduced options for mental health and well-being benefits and could have a greater impact on vulnerable populations, especially the elderly. The present study, therefore, explores the physiopsychological impacts of indirect contact with nature, using forest imagery, on the brain activity and autonomic nervous systems of elderly people. STUDY DESIGN: A within-subject design experiment was used. METHODS: Thirty-four participants aged 82.9 ± 0.78 years were asked to look at bamboo and urban images for 2 min. During the visual stimulation, α relative waves were measured using electroencephalography as an indicator of brain activity. Heart rate variability and skin conductance (SC) responses were utilized as indicators of arousal. Afterward, psychological responses were evaluated using the semantic differential and the Profile of Mood States questionnaires. RESULTS: Visual stimulation with bamboo image induced a significant increase in α relative waves and parasympathetic nervous activity and a significant decrease in SC. In addition, a significant increase in perceptions of "comfortable," "relaxed," "cheerful," and "vigorous" feelings was observed. CONCLUSIONS: Indirect contact with nature enhances the physiological and psychological conditions of the elderly. Findings can be used to guide the new design, renewal, and modification of the living environments of the elderly and those who are unable to get outside.

Effect of Forest Therapy for Menopausal Women with Insomnia.

Female hormone changes during menopause can affect the autonomic nervous system, circadian rhythm, and secretion of cortisol/melatonin, resulting in a vulnerability to insomnia. In this light, therapy has been gaining attention as a way to reduce stress hormones by stabilizing the autonomic nervous system. Thus, this study aims to objectively and scientifically analyze the impact of forest therapy in postmenopausal insomnia patients. The forest therapy program lasted 6 days, wherein 35 postmenopausal women performed activities such as trekking, leg massages, stretches, and bathing in warm and cold water. They also underwent serologic tests, participated in polysomnography (PSG), and answered sleep questionnaires before and after the program. Further, a statistical analysis compared the results. Serologic tests showed a significant reduction of cortisol from 10.2 ± 3.79 to 7.75 ± 2.81, while PSGs showed how sleep efficiency increased to 89.3 ± 4.3% (p < 0.01), and how waking after sleep onset reduced to 47.4 ± 22.3 min (p < 0.01). The total sleep time also increased to 428.5 min and sleep latency was 11.1 ± 11.0 min. Despite its limitations, forest therapy could be a good alternative to nonpharmacological treatment for mitigating insomnia in postmenopausal women.

Association between the Psychological Effects of Viewing Forest Landscapes and Trait Anxiety Level.

The aim of this study was to validate the psychological advantages of viewing forest landscapes. Moreover, the associations between trait anxiety levels and psychological responses were evaluated. A total of 650 university male students (age, 21.7 ± 1.6 years) viewed a scenery in a forested area and an urban area for 15 min. Furthermore, the Profile of Mood States questionnaire and State-Trait Anxiety Inventory were employed for the assessment of the psychological responses and the level of trait anxiety, respectively, of the participants. Results showed that compared with viewing a city area, viewing forest areas increased positive mood state, such as vigor, and decreased negative mood states. Furthermore, trait anxiety level and changes in the psychological responses such as depression-dejection, fatigue, and confusion after viewing forest landscapes were significantly correlated. The participants with high anxiety levels had greater reduction in negative mood state, including confusion, than those with low anxiety levels. In conclusion, viewing forest landscapes induced psychological relaxation, which was more evident in individuals with high anxiety levels.

Health Benefits Derived from Forest: A Review.

In this paper the scientific literature on the association between forests, stress relief and relaxation is reviewed with the purpose to understand common patterns of research, the main techniques used for analysis, findings relevant to forest-therapy-oriented management, and knowledge gaps. The database of studies was collected with a keyword search on the Web, which returned a set of 32 studies that were included in the analysis. The main findings and patterns were identified with a text mining analysis of the abstract to search for keyword patterns across studies. The analysis indicates that most studies compared rest and relaxation performances across urban and forest environments and used a combination of self-reported measure of stress or rest collected with validate scales, e.g., the Profile of Mood of States (POMS) and the Restoration Outcome Scale (ROS), and a minority-only set of these two groups of indicators. Results of this review indicate that primary studies identified a positive association between forest exposure and mental well-being, in particular when compared to urban environments, thus suggesting that forest are effective in lowering stress levels. This study found that, to date, the characteristics of forests and characteristics of the visit are little investigated in the literature. For this reason, more research with a focus on forest variables such as tree species composition, tree density and other variables affecting forest landscape should be further investigated to inform forest management. Similarly, the characteristics of the visits (e.g., length of visit and frequency) should be further explored to provide robust forest therapy guidelines.

Effects of Forest Therapy on Health Promotion among Middle-Aged Women: Focusing on Physiological Indicators.

Women experience more stress in middle age than in other life stages, and health in middle age is vital, because it influences the quality of life in old age. In this study, the effects of a forest therapy program on physiological changes in 53 middle-aged women (divided into two groups) who lived in the city were examined. One group participated in a three-day program in the forest, followed by three days in the city; the other group participated in a three-day program in the city, followed by three days in the forest. Forest experiments were conducted in a "healing forest," and urban experiments were conducted near a university campus. Blood tests were performed to evaluate the physiological effects of forest therapy. Differences in serotonin levels and vitamin D levels were verified before and after the forest (experimental group) and urban (control group) programs through paired t-tests. Statistically significant increases in serotonin levels were noted for participants in the forest program; vitamin D levels also increased, but not by statistically significant values. The findings of this study verify that forest therapy programs promote health among middle-aged women, and may prevent disease and improve quality of life.

Effects of forest bathing on pre-hypertensive and hypertensive adults: a review of the literature.

The aim in this literature review was (1) to explore the physiologically and psychologically therapeutic benefits of forest bathing on adults suffering from pre-hypertension or hypertension, and (2) to identify the type, duration, and frequency of an effective forest bathing intervention in the management of pre-hypertension and hypertension, so as to provide directions for future interventions or research. The electronic databases PubMed, Cochrane Library, CINAHL, PsyINFO, and the China Academic Journals (CAJ) offered through the Full-text Database (CNKI) were searched for relevant studies published from the inception of the databases to April 2019. Of the 364 articles that were identified, 14 met the criteria for inclusion in this review. The synthesis of the findings in the included studies revealed that forest bathing interventions were effective at reducing blood pressure, lowering pulse rate, increasing the power of heart rate variability (HRV), improving cardiac-pulmonary parameters, and metabolic function, inducing a positive mood, reducing anxiety levels, and improving the quality of life of pre-hypertensive or hypertensive participants. Forest walking and forest therapy programs were the two most effective forest bathing interventions. Studies reported that practicing a single forest walking or forest therapy program can produce short-term physiological and psychological benefits. It is concluded that forest bathing, particularly forest walking and therapy, has physiologically and psychologically relaxing effects on middle-aged and elderly people with pre-hypertension and hypertension.

Benefits of a Three-Day Bamboo Forest Therapy Session on the Physiological Responses of University Students.

Studies have indicated that natural environments have the potential to improve the relationship between a stressful life and psychological well-being and physical health. Forest therapy has recently received widespread attention as a novel solution for stress recovery and health promotion. Bamboo is an important forest type in many countries, especially in East and Southeast Asia and in African countries. Bamboo is widespread throughout southwestern China. Empirical field research on the physiological effects of bamboo forest therapy is currently lacking. To explore the benefits of bamboo forest therapy on the physiological responses of university students, 120 university volunteers between the ages of 19 and 24 participated in this study (60 males and 60 females) and were randomly divided into four groups of equal size (15 males and 15 females in each). Four sites were selected for the experiment, including two natural bamboo forests (YA and YB), a bamboo forest park (DJY), and an urban environment (CS). During the testing period, all participants were asked to view the landscape for 15 min in the morning and then walk in the testing area for 15 min in the afternoon. Blood pressure (BP), heart rate (HR), and peripheral oxygen saturation (SpO2) were measured as the physiological indexes, and the semantic differential method (SDM) questionnaire was completed for the environmental satisfaction evaluation. The SDM for the subjective environmental evaluation differed significantly among the university students; they obtained a better environmental experience, in terms of sensory perception, atmosphere, climate, place, and space, in the bamboo forest sites. The three-day bamboo forest therapy session improved the physiological well-being of university students. First, the blood pressure and heart rate of the university students decreased, and the SpO2 increased, after the three-day viewing and walking activities of the three-day bamboo forest therapy session. The viewing activities had a more pronounced effect on decreased heart rate in university students. Additionally, three-day bamboo forest therapy had a positive impact on decreased systolic blood pressure and heart rate in the university students, and it was significantly decreased in females, while peripheral oxygen saturation (SpO2) remained relatively low. Finally, compared with the urban site (CS), the bamboo forest sites effectively improved the university students' physiological state of health, decreased their physical pressure, and stabilized their physiological indicators. These findings provide scientific evidence that a three-day bamboo forest therapy session can increase positive physiological responses. The potential for a longer-term effect on human physiological health requires further investigation.

Six-Step Model of Nature-Based Therapy Process.

Several studies have confirmed that the natural environment has psychophysiological healing effects. However, few studies have investigated the healing process involved in the effect of the natural environment. To date, no theoretical model on the nature-based therapy process has been clearly established. Thus, the aim of this study was to develop a theoretical model of the nature-based therapy process by analyzing individual empirical data. Research materials were 180 self-reported essays on "Forest Therapy Experiences" submitted to the Korea Forest Service. This study was conducted based on grounded theory. Data were analyzed through open coding. A total of 82 concepts, 21 subcategories, and six categories were derived. Results revealed that the nature-based therapy process contained six categories: Stimulation, acceptance, purification, insight, recharging, and change. When in the natural environment, participants first experienced positive emotional change, followed by cognitive and behavioral changes. Based on these results, a nature-based therapy process model was derived. This study revealed that the nature-based therapy process did not consist of just a single element or step, but involved an integrated way of healing with emotional and cognitive changes. This study is significant in that it derives a theoretical model of the nature-based therapy process with comprehensive mechanisms. Further research is needed to establish more systematic theoretical model.

Nature-based rehabilitation for adults with acquired brain injury: a scoping review.

The objective of this review was to provide an overview of the existing knowledge of the benefits of nature-based rehabilitation for patients with impairments after acquired brain injury. Systematic searches were conducted across PubMed, CINAHL, PsycINFO and Scopus, and seven studies were found to be included for review. Results suggest that nature-based rehabilitation may benefit individuals with acquired brain injury, as both motor - and sensory-motor functions, as well as cognitive functions were significantly improved. Furthermore, two studies found an improvement in quality of life. The benefits on anxiety and depression were not clear. The studies used different approaches, outcome measures and study designs that made comparisons difficult. Recommendations for future studies are offered.

Effects of forest bathing on pre-hypertensive and hypertensive adults: a review of the literature

The aim in this literature review was (1) to explore the physiologically and psychologically therapeutic benefits of forest bathing on adults suffering from pre-hypertension or hypertension, and (2) to identify the type, duration, and frequency of an effective forest bathing intervention in the management of pre-hypertension and hypertension, so as to provide directions for future interventions or research. The electronic databases PubMed, Cochrane Library, CINAHL, PsyINFO, and the China Academic Journals (CAJ) offered through the Full-text Database (CNKI) were searched for relevant studies published from the inception of the databases to April 2019. Of the 364 articles that were identified, 14 met the criteria for inclusion in this review. The synthesis of the findings in the included studies revealed that forest bathing interventions were effective at reducing blood pressure, lowering pulse rate, increasing the power of heart rate variability (HRV), improving cardiac-pulmonary parameters, and metabolic function, inducing a positive mood, reducing anxiety levels, and improving the quality of life of pre-hypertensive or hypertensive participants. Forest walking and forest therapy programs were the two most effective forest bathing interventions. Studies reported that practicing a single forest walking or forest therapy program can produce short-term physiological and psychological benefits. It is concluded that forest bathing, particularly forest walking and therapy, has physiologically and psychologically relaxing effects on middle-aged and elderly people with pre-hypertension and hypertension.

Benefits of A Three-Day Bamboo Forest Therapy Session on the Psychophysiology and Immune System Responses of Male College Students.

Forest therapy is a fast-growing treatment approach, as it has the potential to alleviate stressful life events and to improve psychological well-being and physical health. Bamboo forests are widespread in southwestern China. Nevertheless, a knowledge gap on the specific health benefits of bamboo forest (BF) therapy still exists. To explore the psycho-physiologic responses of participants to the effects of BF therapy, 60 male adults aged between 19 and 24, with similar healthy conditions, were selected to participate in this study. A one-group pretest-posttest design was used for the BF sites and the city site (CS) to compare the difference in the psycho-physiologic responses of participants before and after the test. Participants at the BF sites participated in a three-day bamboo forest therapy session, and those at the CS participated in a three-day urban program. Blood pressure, heart rate, and peripheral oxygen saturation were measured as the physical signs, and the profile of mood state (POMS) questionnaire was completed by the participants for the psychological evaluation. Blood was sampled, and natural killer (NK) activity, the number of NK cells, and the levels of corticosterone, granulysin, perforin, and granzyme A/B in peripheral blood lymphocytes (PBLs) were measured. All the measurements mentioned above were performed at 08:00 on the first and fourth days within the test. Results indicated that the three-day BF therapy was capable of enhancing positive mood states and also reducing negative mood states in the male participants. The blood pressure and heart rates of the male participants decreased, while the peripheral oxygen saturation increased after the three-day BF therapy session. Furthermore, BF therapy significantly increased NK activity and the number of NK cells and perforin-, granulysin-, and granzyme A/B-expressing cells and significantly decreased the corticosterone level in PBLs in the male participants. The three-day BF therapy session improved the psychological and physiological well-being and enhanced the immune functions of the male college students.

The Effects of a Forest Therapy Programme on Mental Hospital Patients with Affective and Psychotic Disorders.

The positive effect of forest bathing on the mental health and wellbeing of those suffering from post-traumatic stress disorder or experiencing stress has been proven. It is not known, however, how 'forest therapy' affects the mental health of people who are treated in a psychiatric hospital for affective or psychotic disorders. Potentially, forest therapy could bring many benefits to these people. To test the potential effectiveness of this therapy, a quasi-experiment was carried out in a psychiatric hospital in Olsztyn (north Poland). In the summer and autumn of 2018, the patients of the psychiatric hospital in Olsztyn participated in forest therapy interventions. The proposed forest therapy consisted of participating in one hour and forty-five minutes walks under the supervision of a therapist. Subjects filled out the Profile of Mood States Questionnaire (POMS) and the State Trait Anxiety Inventory (STAI-S) before and after the study. In the case of a group of patients with affective disorders, forest therapy had a positive effect on nearly all POMS scale subscales, with the exception of the 'anger-hostility' subscale, which did not change its values significantly after the intervention. In these patients, the greatest impacts were noted in the subscales 'confusion' and 'depression-dejection'; the level of anxiety measured with the STAI-S scale also significantly decreased. In the case of patients with psychotic disorders, the values of the 'confusion' and 'vigour' subscales and the STAI-S scale exhibited the greatest changes. These changes were positive for the health of patients. Regarding the 'fatigue' subscale, no significant changes were observed in patients with psychotic disorders. The observed changes in psychological indicators in psychiatric hospital patients with both kinds of disorders indicate that the intervention of forest therapy can positively affect their mental health. The changes observed in psychological indicators were related to the characteristics of the given disorder.