Impact of dynamic greenspace exposure on symptomatology in individuals with schizophrenia

Abstract

There are currently many tools available for capturing and defining the context of one's environment. Digital phenotyping, the use of technology and sensors to capture moment-to-moment behavior, has shown potential in quantifying the lived experience of mental illness and in the identification of individualized targets related to recovery. Environmental data suggests that greenspace may have a restorative capacity on mental health. In this paper, we explore the relationship of greenspace derived from geolocation with self-reported symptomatology from individuals with schizophrenia as well as healthy controls. Individuals with schizophrenia had less exposure to greenspace than controls, but their exposure demonstrated a dosage effect: high greenspace environments were associated with lower symptoms for anxiety (Cohen's d = -0.70), depression (d = -0.97), and psychosis (d = -0.94), whereas effect sizes for healthy controls were all negligible or small (d < 0.38). The notion that greenspace may have a more pronounced effect on individuals with mental illness presents both potential areas for recovery as well as implications for health care policy, especially in cities with a broad range of greenspace environments.

Fig 1. NDVI map of Boston, MA.

NDVI values in Boston range from -0.7 to 0.89. Map data is available under the Open Data Commons Open Database License: https://www.openstreetmap.org/copyright.

Fig 2. NDVI group differences.

Box and whisker plots of symptom survey response (ranging from 0 to 3) separated by NDVI group. The box limits represent the 25th and 75th percentiles and a median line is drawn within. The whiskers extend to at most 1.5 times the inter-quartile range in each direction and outliers are plotted individually.