When green enters a room: A scoping review of epidemiological studies on indoor plants and mental health

Tianyu Zhao; Iana Markevych; Dorota Buczyłowska; Marcel Romanos; Joachim Heinrich

doi:10.1016/j.envres.2022.114715

When green enters a room: A scoping review of epidemiological studies on indoor plants and mental health

Environ Res. 2023 Jan 1;216(Pt 3):114715. doi: 10.1016/j.envres.2022.114715. Epub 2022 Nov 3.

Authors

Tianyu Zhao¹, Iana Markevych², Dorota Buczyłowska², Marcel Romanos³, Joachim Heinrich⁴

Affiliations

¹ Institute and Clinic for Occupational, Social and Environmental Medicine, University Hospital, LMU Munich, Munich, Germany; Comprehensive Pneumology Center Munich (CPC-M), German Center for Lung Research (DZL), Munich, Germany. Electronic address: tianyu.zhao@med.uni-muenchen.de.
² Institute of Psychology, Jagiellonian University, Krakow, Poland.
³ Centre of Mental Health, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany.
⁴ Institute and Clinic for Occupational, Social and Environmental Medicine, University Hospital, LMU Munich, Munich, Germany; Comprehensive Pneumology Center Munich (CPC-M), German Center for Lung Research (DZL), Munich, Germany; Allergy and Lung Health Unit, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia.

PMID: 36334835
DOI: 10.1016/j.envres.2022.114715

Abstract

Background: Increasing numbers of epidemiological studies are investigating the association between outdoor greenery and various health outcomes. However, in the case of indoor plants, although experimental studies seem relatively abundant, epidemiological studies remain scarce, and research considering the mental health effects is even more limited. Thus, we aim to identify and summarise the relevant epidemiological studies on indoor plant exposure and mental health via this scoping review, thereby presenting the current state of knowledge and research niches.

Methods: PubMed and PsycINFO were systematically searched for epidemiological studies on indoor plant exposure and mental health, including mental and behavioural disorders, quality of life, and cognitive function. The publication period was from the inception of these two databases to 22nd June 2022. We extracted information on exposure to indoor plants and mental health-related outcomes from the relevant studies.

Results: The systematic search yielded 1186 unique results. Six studies met the inclusion criteria and were finally included in this scoping review. All included studies were Europe-based cross-sectional studies on mental and behavioural disorders. One study was conducted in 2015 and investigated the office environment, whereas the other five were conducted during the COVID-19 pandemic and focused on the home environment. Despite considerable heterogeneity in outcome assessments and indoor plant exposure metrics, all six studies generally reported beneficial associations between having indoor plants and mental health, such as reducing stress, depressive symptoms, and negative emotions.

Conclusions: Epidemiological evidence on exposure to indoor plants and mental health is currently limited. In general, favourable effects of indoor plants are supported, although most relevant studies were conducted in the context of COVID-19. Before conducting more studies to explore the associations, data collection methods must be refined with more elaborate designs that allow for the measurement of more comprehensive metrics of indoor plants.

Registration: Open Science Framework, osf.io/5xr6b.

Keywords: COVID-19; Cognition; Epidemiology; Greenspace; Psychology; Quality of life.

Publication types

Systematic Review
Review
Research Support, Non-U.S. Gov't

MeSH terms

COVID-19* / epidemiology
Cross-Sectional Studies
Epidemiologic Studies
Humans
Mental Health*
Pandemics
Quality of Life