Hi ! Intriguing article.
1. What epi study design is used to make this measure? The 1/5 figure was based on findings from a cross-sectional study (survey based on face-to-face interviews with participants.)
"For instance, exposure to nature has been shown to lower cortisol levels, a measure of stress."
Based on the wording above, ("shown", rather than associated"), it's likely to be an intervention study that showed this, although a case-control study could "suggest that exposure to nature lowers cortisol".
2. What study design is used to make this conclusion? How would you measure the exposure?
"If patients are less stressed, they may make faster and more lasting progress during treatment, experts say."
I'm not sure what study design was used, but the following studies could be appropriate
(1) intervention trials that reduce stress & look at progress of therapy and/or aggression. While this is the most powerful design, it's more likely that case-control studies were used to ascertain this.
(2) case-control study to compare "cases" that had less (or short-lived ) "progress" with "controls" that showed large improvements; perhaps "cases" showed higher stress (exposure) hence why they progressed less?
Depending on the definition of stress, different methods can be used to measure it:
(1) cortisol levels via blood samples to measure "physiological stress"
(2) perceived levels of stress through surveys & self-reports like the Perceived Stress Scale
(3) environmental stressors - like overcrowding in rooms or even noise levels - are for some researchers considered as types of stress. This has been "measured" by the number of patients per room (social crowding) and the presence/absence of noise-reducing architectural features (noise stress) - these methods were used in this study.
On a side note, about the the link provided in that same paragraph - researchers used a retrospective analytical design that compared two hospitals that differed in terms of design features and levels of aggression seen in patients. Could this be considered a quasi-experimental (retrospective) design, or not really?
3. How do experts know this? Can someone fact-check this??
"Paths will be lined with cedars and pines, rosemary and lavender — plants whose scents activate “natural killer” cells that can strengthen immunity, said Richard Dallam, a managing partner at NBBJ and a leader of the firm’s health care practice."A
review suggests that essential oils can have beneficial effects on immune function. In one experiment cited with a l
imited sample size (N=12), researchers exposed subjects to vaporized essential oils that seemed to affect immune function - including natural killer cells - based on analysis of blood samples.
HOWEVER - If paths in a centre are lined with such trees, it's unlikely the concentration of essential oils in the air would be significant enough to bolster immunity of patients (e.g. wind, how close patients are to the plants). In a forest or an isolated room, this is more likely.
PS: I am a little surprised that the author mentions the immune-related effects of essential oils rather than their relaxing properties, especially in a mental health clinic.
5. How would you design a study to test whether building design affects recovery from severe mental illness?
I'm not sure. Happy to hear thoughts....
One option is to carry out an RCT version of the study design that was mentioned in Q2 (link), but with a higher sample size of buildings (instead of one with "good design" and one with "bad design"). However, this may be unethical if there's sufficient evidence that building design affects mental health (in which case retrospective designs would seem more appropriate), and it seems like there is some good evidence to suggest this.
For logistical/geographical reasons, an RCT may also be inappropriate in this case.
It's also quite complicated to study mental health outcomes because recovery from a mental health illness depends on a host of contextual "non-specific factors", like a therapist's personality (hard to control for!) or a person's context, which can be highly dynamic and thus influence their mental health. The latter argument is especially relevant for marginalized groups like internationally displaced migrants or asylum seekers, for instance. Other factors apart from demographics, like the type of therapy administered, would also need to be similar across groups...
PS: it seems intuitive that good building design is beneficial for well-being. However, if there's no formal evidence that good building design reduces severe mental health illness, what would you do if you had the resources?
