Human Health & Plants Research: Horticultural Therapy for Veterans May Improve Overall Wellness and Lower Suicide Ideation

Dr. Charles Guy

Suicide in the US is a serious public health issue, particularly so among veterans, where in 2018 the rate of suicide was 27.5 per 100,000 compared to 18 per 100,000 for nonveterans.  Given the ever-increasing collection of empirical studies demonstrating a host of therapeutic benefits of people-plant interactions and activities, Meore1 and colleagues hypothesized whether horticultural therapy (HT) could diminish contributing risk factors and lower suicide risk in a small population of veterans participating in a month-long Resilience and Wellness Center Program in a Veterans Administration Medical Center.

In the Wellness program, high-risk veteran participants (n=20; 10 male, 10 female) were clinician-referred to the 4-week HT treatment.  Participants’ average age was 51 and had been diagnosed with depression or PTSD, other mental health illnesses, or experienced substance abuse.  A registered horticultural therapist led the 3.5-hour weekly HT sessions at the New York Botanical Garden in a vegetable garden, greenhouse, and indoor classroom.  All participants completed at least two HT sessions, and 13 completed all four sessions.  The HT activities included sowing seeds, seedling thinning and transplanting, staking, and trellising, harvesting, and general garden and plant maintenance.

Outcome measures from the HT treatment focused on stress, mood, pain, and social isolation (loneliness).  The researchers developed and administered a novel self-report thermometer scale (1-10) to indicate how the participants were feeling for each of the four outcome measure domains.  The self-report thermometer scales were compared and found to be moderate to highly correlated with validated and widely used self-report clinical instruments that the participants had completed at the study’s baseline.  Participants filled out the self-report thermometer graphic assessment immediately before and after each HT session.

Immediate improvements were observed across all four outcome domains beginning with the first HT session.  Furthermore, the researchers found a sustained reduction for all four risk domains over the course of the HT intervention. Reductions in stress, pain, mood, and loneliness corresponded to medium to large treatment effect sizes.  Additionally, a moderate to large correlation was found between the reduction in depressed mood and suicidal ideation from pre- to post-intervention assessments.  The researchers concluded: “These findings underscore the potential for therapeutic effect of nature-based therapy in improving overall wellness in at-risk veterans with history of suicidal ideation…”.

In summary, the researchers recorded significant improvements in the high-risk veteran population for stress, mood, pain, and loneliness following HT.  This proof-of-concept pilot study is yet another in a long list of non-randomly controlled studies that appear to demonstrate compelling treatment-prompted therapeutic benefits to a small population of participants.  This study further illustrates that it is well past time when major funding initiatives should be undertaken to fully support large-scale randomized controlled clinical trials of the therapeutic potentials of horticultural therapy towards improving the health and wellbeing of veterans and nonveterans alike.

1Meore, A., Sun, S., Bema, L., Alter, S., Vitale, A., Podolsk, E., Gilbard, B., Adams, T., Boyer, J., Gallfly, H., Yehuda, R., Feder, A., Highlight, F.  Pilot Evaluation of Horticultural Therapy in Improving Overall Wellness in Veterans with History of Suicidality.  Complementary Therapies in Medicine.  59, 102728.  (2021).

Charles Guy, Emeritus and Courtesy Professor
Department of Environmental Horticulture, University of Florida