The growing of plants are said to improve individuals’ physical and mental states. The growing of plants is a process through which the people are stimulated to positively change. Actually, the growing of plants has been used as a method of the psychological care of the person of the PTSD. For this reason, the growing of plants could be assumed to reflect plastic change in the brain. However, the neural basis of the growing of plants for PTSD is uncertain. This study sought to verify PTSD reaction reduction and changes in brain morphology and stress hormones by growing of plants in women with earthquake stress. Fiftyfour right-handed women with mild PTSD in a disaster area participated in this randomized, permuted block method, controlled, crossover trial. Participants were randomly assigned to a horticultural therapy (HT) intervention or stress education (SE) intervention group. Within the 8-week study period, magnetic resonance imaging, psychological index for intervention evaluations, and saliva tests were performed before and after interventions. The HT group showed significantly increased regional gray matter volume (rGMV) of the left subgenual anterior cingulate cortex and left superior frontal gyrus compared with the SE group. The HT group also showed significant improvement in PTSD reactions, posttraumatic growth, and positive affect compared with the SE group. The HT group showed greatly improved salivary cortisol and alpha amylase levels compared with the SE group. These results demonstrate that the growing of plants restore people with PTSD reactions to good condition. Additionally, the growing of plants reduced stress levels in people with PTSD reactions for an earthquake disaster. The growing of plants increased the rGMV of brain areas known to be reduced in PTSD patients. Neural plasticity may underlie the psychological and physiological effects of the growing of plants.
