For those unfamiliar with the concept of our multidimensional anatomy, the koshas, refer to Structural Yoga Therapy, chapter 6.
Stress has not changed. The ways in which we respond to it have changed. There are many studies on the changing of epidemics, heart disease, cancer, and more recently environmental toxicity. When one looks at ancient medical texts death came much earlier and often due to traumas from wars and the malnutrition brought on by loss of crops during wartime.
The two sutlest koshas vijnana and ananda are indicators of spiritual stress, not being connected to wisdom and higher power. Much of our wisdom has needed to survive the test of time thus we seek wisdom from those texts that are highly revered for thousands of years. That which is available as contemporary insights would rarely survive such a test. We need the help of a thorough investigation into this human condition and what has been of help in the past. By seeking historical ways of dealing with stress we can see how wise people of our era have adapted these teachings for this modern life.
In looking at Classical Yoga of the Yoga Sutras II, 4 we see that Patanjali viewed all stress as originating from avidya, ignorance which is the fourth kosha. When we disidentify ourself to be merely our physicla body we tend to not listen to messages that come from a subtler level. Then there are others who are more "in their heads" who do not listen to messages comign from a grosser kosha. So it depends on where you conceive yourself to live that is the source of your perspective of stress. namaste