The natural context of mental health: An exploration of the health-promoting effects of nature and daylight employing ecological momentary assessment

Both natural environments and daylight have been found to exhibit beneficial
effects on many facets of well-being. Both have been found to improve cognitive
performance, mood, and mental and physical health. Furthermore, stress
reduction and an increase in vitality have also been reported.

Such effects have been reported for the general population, but effects may be
even more pronounced for those in poor mental health, in particular pertaining
to depressive symptoms, burnout, and declined self-regulation capacity. The
literature also indicates that most studies have been performed in laboratories
with relatively low ecological validity and exposures limited in duration. In
contrast, field studies with high ecological validity typically confounded
nature and daylight exposure, often without acknowledging this. Lastly we
should note that many of the field studies * particularly those centred on
daylight * have been retrospective in nature or even based on archival data.

In the current study, we propose to employ the experience sampling methodology
to explore the dynamics of mood, vitality and self-control in relation to the
availability of natural elements and daylight exposure. ESM has been
successfully employed in previous research to explore the phenomenology,
symptom patterns, and environmental risks for various psychiatric disorders. An
ambulatory assessment protocol will explore correlational patterns of mood and
context, reported in the moment and in daily life. Moreover, the structured
recording of daylight and natural elements in the direct environments may help
untangle the separate effects of these stimuli. We expect to find a positive
influence of daylight and nature on mood, self-control, stress reduction, and
vitality. We will first of all investigate whether indeed natural elements and
daylight can produce measurable beneficial effects on mental health. Secondly,
we will investigate whether severity of mental complaints will affect the
beneficial effects of nature and daylight.

The main objective of the study is to investigate whether natural elements
and/or daylight can produce measurable beneficial effects on mental health * in
particular mood, vitality, stress relief and self control strength * during the
course of the day, based on assessments in the moment (no recall bias) and in
the real world (ecological validity). Secondly, we will investigate whether
mental health status moderates the restorative effects of nature and daylight.

Observational and longitudinal: The Experience Sampling Method (ESM) is a
structured diary method in which subjects are asked in daily life to report
their thoughts and feelings, context (e.g. location, company, activity), and
their appraisal of the context.

The study consists of an introduction session, an Experience Sampling Protocol,
and the debriefing. Participants visit the GGzE or TU/e campus twice, once for
the introduction session and once for the debriefing. During the experience
sampling period, each participant receives a smart phone on which the
experience sampling questionnaires run as an application. For 6 consecutive
days, they will receive eight requests to fill out the questionnaire on
(stratified) random moments between 8:00 a.m. and 10:00 p.m. Filling out the
experience sampling questionnaire will take 4-5 minutes, but they can decide to
stop halfway the questionnaire.

The main burden for participation in the study will be time consumption. No
adverse or serious adverse events are expected beyond the time expenditure.
Participants will receive a compensation for their effort (¤ 30,00) as well as
travel expenses. Furthermore, approximately a week after their participation
they will receive an overview of their own experience sampling data and at the
end of the study a newsletter will be sent to all participants explaining the
results of the study.