Being away and fascination appear to work as active components in a therapeutic horticulture intervention for clinical depression.

To further improve the use of the existing or planned gardens, an educational programme for staff that also includes skill training is recommended.

This study aimed to assess changes in psychological distress and social participation in adults diagnosed with clinical depression during and after participating in a therapeutic horticulture programme, and to investigate if the changes covaried with levels of group cohesiveness during the intervention. An intervention with a single-group design was repeated with different samples in successive years (pooled n = 46). In each year, five groups of 3-7 participants went through the intervention. Data were collected before, twice during, and immediately after a 12-week therapeutic horticulture programme, as well as at 3-months' follow up. Mental health assessments included the Beck Depression Inventory, the State Subscale of Spielberger State-Trait Anxiety Inventory, the Positive Affect Scale from the Positive and Negative Affect Scale, the Perceived Stress Scale, and the Therapeutic Factors Inventory-Cohesiveness Scale. The analysis of the pooled data confirmed significant beneficial change in all mental health variables during the intervention. Change from baseline in depression severity persisted at 3-months' follow up. Increased social activity after the intervention was reported for 38% of the participants. The groups quickly established strong cohesiveness, and this continued to increase during the intervention. The average level of group cohesiveness correlated positively, but not significantly, with change in all mental health outcome variables.

Clinically depressed persons suffer from impaired mood and distortion of cognition. This study assessed changes in depression severity and perceived attentional capacity of clinically depressed adults (N=18) during a 12-week therapeutic horticulture program. The Beck Depression Inventory (BDI) and Attentional Function Index (AFI) were administered at baseline, twice during (4 and 8 weeks), and immediately after the intervention (12 weeks), and at a 3-month follow-up. Experiences of being away and fascination related to the intervention were measured at 4, 8, and 12 weeks. The mean BDI score declined 9.7 points from pretest (27.3) to posttest (p < .001) and were clinically relevant (deltaBDI > or =6) for 72% of the cases. The mean AFI score increased 10.2 points from pretest (68.8) to posttest (p = .06). The greatest change in BDI and AFI scores occurred in the initial weeks of the intervention. The reduction in BDI scores remained significant and clinically relevant at the 3-month follow-up (N=16). The decline in depression severity during the intervention correlated strongly with the degree to which the participants found that it captured their attention. Therapeutic horticulture may decrease depression severity and improve perceived attentional capacity by engaging effortless attention and interrupting rumination.

Two studies with single-group design (Study 1 N = 18, Study 2 N = 28) addressed whether horticultural activities ameliorate depression severity and existential issues. Measures were obtained before and after a 12-week therapeutic horticulture program and at 3-month follow-up. In both studies, depression severity declined significantly during the intervention and remained low at the follow-up. In both studies the existential outcomes did not change significantly; however, the change that did occur during the intervention correlated (rho > .43) with change in depression severity. Participants' open-ended accounts described the therapeutic horticulture experience as meaningful and influential for their view of life.