Evolutionary lifestyle and mental health

From the book : Evolutionary Psychology 6 issue 1 : 67-76.
Some have suggested that psychological distress may be lower if individuals adopt a lifestyle more similar to our evolutionary past.
In this study, we assessed relationships between distress and six lifestyle elements (sleep, omega-3 consumption, exercise, rumination, sunlight exposure, and socialization).
A large sample (N 495) of college undergraduates reported levels of each lifestyle element and their distress on the Beck Depression Inventory and Hopkins Symptom Checklist.
Analysis revealed a positive relationship for rumination and a curvilinear relationship for sleep.
In contrast, none of the other elements correlated reliably with distress.
The findings raise the possibility that relationships between these lifestyle elements and distress may not be critical for the range of exposure typically experienced in a normal, nonclinical population.