Religious and spiritual interventions in mental health care: a systematic review and meta-analysis of randomized controlled clinical trials

Despite the extensive literature assessing associations between religiosity/spirituality and health, few studies have investigated the clinical applicability of this evidence. The purpose of this paper was to assess the impact of religious/spiritual interventions (RSI) through randomized clinical trials (RCTs). A systematic review was performed in the following databases: PubMed, Scopus, Web of Science, PsycINFO, Cochrane Collaboration, Embase and SciELO. Through the use of a Boolean expression, articles were included if they: (i) investigated mental health outcomes; (ii) had a design consistent with RCTs. We excluded protocols involving intercessory prayer or distance healing. The study was conducted in two phases by reading: (1) title and abstracts; (2) full papers and assessing their methodological quality. Then, a meta-analysis was carried out. Through this method, 4751 papers were obtained, of which 23 remained included. The meta-analysis showed significant effects of RSI on anxiety general symptoms (p < 0.001) and in subgroups: meditation (p < 0.001); psychotherapy (p = 0.02); 1 month of follow-up (p < 0.001); and comparison groups with interventions (p < 0.001). Two significant differences were found in depressive symptoms: between 1 and 6 months and comparison groups with interventions (p = 0.05). In general, studies have shown that RSI decreased stress, alcoholism and depression. RCTs on RSI showed additional benefits including reduction of clinical symptoms (mainly anxiety). The diversity of protocols and outcomes associated with a lack of standardization of interventions point to the need for further studies evaluating the use of religiosity/spirituality as a complementary treatment in health care.