The Marmot studies into stress and health levels within the UK Civil Service came up with some unexpected findings. They thought senior executives would be the most stressed because of their high pressure work and major decision responsibilities. In fact lower level staff were found to be the more stressed, largely because they have much less control and discretion in their job.
There seems little doubt there's a strong link between the increasing levels of stress and the many changes over which we have so little control. It also strengthens the link between mental health and enjoying your favourite leisure/recreation interest - a life-enriching experience over which you have total control.