Stress and the singleton

After a couple of days of limited internet connectivity left me in a state of deep panic and mortal gloom, I found myself wondering if there are any reliable contemporary statistics that compare the extent to which conditions such as stress and depression -- which are endemic in modern society in most developed economies -- affect the sole practitioner to a greater or to a lesser extent than they might trouble his more team-oriented colleagues. Presumably there are no available figures concerning sick-leave for the self-employed.

I have secretly envied the facility with which some people, who already get paid for not working over several weeks in the course of the year [ie they have holidays ...], can unilaterally "throw a sickie" and take the day off, secure in the knowledge that the system enables them to do so without the pricking of conscience I experience if I occasionally stray out of clicking distance of my mouse.