Background: Horticultural therapy is defined as the process of utilising fruits, vegetables, flowers and plants facilitated by a trained therapist or healthcare provider, to achieve specific treatment goals or to simply improve a person's well-being. It can be used for therapy or rehabilitation programs for cognitive, physical, social, emotional, and recreational benefits, thus improving the person's body, mind and spirit. Between 5% to 15% of people with schizophrenia continue to experience symptoms in spite of medication, and may also develop undesirable adverse effects, horticultural therapy may be of value for these people.
Objectives: To evaluate the effects of horticultural therapy for people with schizophrenia or schizophrenia-like illnesses compared with standard care or other additional psychosocial interventions.
Search methods: We searched the Cochrane Schizophrenia Group Trials Register (Janurary 2013) and supplemented this by contacting relevant study authors, and manually searching reference lists.
Selection criteria: We included one randomised controlled trial (RCT) comparing horticultural therapy plus standard care with standard care alone for people with schizophrenia.
Data collection and analysis: We reliably selected, quality assessed and extracted data. For continuous outcomes, we calculated a mean difference (MD) and for binary outcomes we calculated risk ratio (RR), both with 95% confidence intervals (CI). We assessed risk of bias and created a 'Summary of findings' table using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach.
Main results: We included one single blind study (total n = 24). The overall risk of bias in the study was considered to be unclear although the randomisation was adequate. It compared a package of horticultural therapy which consisted of one hour per day of horticultural activity plus standard care with standard care alone over two weeks (10 consecutive days) with no long-term follow-up. Only two people were lost to follow-up in the study, both in the horticultural therapy group (1 RCT n = 24,RR 5.00 95% CI 0.27 to 94.34, very low quality evidence). There was no clear evidence of a difference in Personal Wellbeing Index (PWI-C) change scores between groups, however confidence intervals were wide (1 RCT n = 22, MD -0.90 95% CI -10.35 to 8.55, very low quality evidence). At the end of treatment, the Depression Anxiety Stress Scale (DASS21) change scores in horticultural therapy group were greater than that in the control group (1 RCT n = 22, MD -23.70 CI -35.37 to - 12.03, very low quality evidence). The only included study did not report on adverse effects of interventions.
Authors' conclusions: Based on the current very low quality data, there is insufficient evidence to draw any conclusions on benefits or harms of horticultural therapy for people with schizophrenia. This therapy remains unproven and more and larger randomised trials are needed to increase high quality evidence in this area.